Studies have often demonstrated that these tumour-specific alterations are associated with activation of cellular proto-oncogenes or the inactivation of tumour suppressor genes.
Understanding cancer -- patient-genetic_backgroundBoadicea123
While a cancer genome profile provides information, it does not tell the full story on its own. A patient's genetic background, which varies between individuals due to inherited and environmental factors, also influences cancer risk and treatment outcomes. This background includes single nucleotide variations across the genome as well as variations in genes related to drug metabolism and cancer susceptibility. Additional epigenetic and non-coding factors can also indirectly affect gene expression and cancer predisposition within a person. Understanding all of these intrinsic patient-specific influences is important for a complete diagnosis and personalized cancer care.
Mutations are changes in genetic material that can be caused by errors in DNA replication or by exposure to mutagens. There are several types of mutations including substitutions, insertions, deletions, and chromosomal mutations. Mutations can have varying effects, from being harmless to causing genetic disorders or cancer. Carcinogenesis is the process by which normal cells are transformed into cancer cells through a series of mutations that disrupt the balance between cell proliferation and cell death.
Answer:
Cellular oncogene formation: Carcinogenesis, tumorogenesis or oncogenesis are developed from
normal cells into a lethal cancer due to the following mechanisms inside the cell.
1. Point mutation: This mutation induces alteration in cellular DNA sequence through
synonymous nucleotide substitution result in normal gene becomes protooncogene finally
become oncogene due to chromosomal DNA replication. For example normal Ras protein
synthesizing gene become mutant Ras oncogene due to point mutation.
2. Gene amplification: This is the process of abnormal amplification of DNA in chromosomes
and generates protooncogenes into oncogenes due to numerous replications of chromosomal
DNA in succession. Example is presence of MYC gene family in lung and breast cancer cells
due to amplied DNA homogeneously.
3. Chromosomal translocation: BCR-ABL leukemia is the due to chromosomal translocation and
meticulous translocation of chromosmomal regions leading to coding of a fusion protein from an
oncogene. Ex. Philadelphia chromosome
4. DNA rearrangement: Insertions, deletions, transposition & inversion of nitrogen bases of
nucleotide sequences in DNA rearrangement generates cellular oncogenes. These rearrangements
are due to exposure of cells to carcinogenic agent
5. Insertional mutagenesis: This type of oncogene development is mainly due to retrovirus as
explained
below
For example:
The genetic changes are expected to alter the activity of the gene product --> loss of
heterozygosity ---> abnormal phenotype
Mutations result in genetic drift, which in turn results in the loss of heterozygosity. This loss of
one parental copy of nucleotide gene bases may lead to the lethal and dangerous consequences of
the living being in the following of life. This loss or drift may result in the occurrence of cancer
(breast cancer) hereditary retinoblastoma, because there may be nonexistence of the functional
tumor suppressor gene in the lost region. One parental copy only can be noticed at that lost
region there by hemizygosity.
But however there is one more functional gene copy inside the genome copy thereby offspring
can get resistance proteins synthesis against the mutation induced cancer.
If both copies are bad or one copy is become badly due to mutation the remaining gene copy
responsible for the tumor growth (the tumor suppressor gene example p53) can be denaturated by
another point mutation, result in complete suppression of gene to protect the body.
A lot of catastrophic events and consequences may occur with loss of heterozygosity (LOH).
Genetic drift results in loss of heterozygosity which may reduce and limit longevity of asexual
organisms in a population there by low population size.
During intermittent cancer development, usually inactivation of the TSG induced due to the two
somatic mutations acting on respective 2 alleles. In contrast, during the familial cancer
development merely one somatic mutation is considerably enough to generate inactivation of
TSG (p.
This document discusses the genetic and epigenetic changes that cause cancer. It explains that cancer arises due to alterations that disrupt normal cell proliferation, senescence, and death. Key changes include mutations in oncogenes that increase cell growth and tumor suppressor genes that normally inhibit growth. Cancer development involves multiple genetic hits over time that transform cells and allow unchecked growth. Epigenetic alterations like DNA methylation and histone modifications also contribute to carcinogenesis. The complex interplay between a person's genetic factors and environmental exposures ultimately leads to the development of cancer.
The document discusses epigenetics, which refers to changes in gene expression that do not involve changes to DNA sequence. It describes several epigenetic mechanisms including DNA methylation and histone modifications. Epigenetic changes play a role in diseases like cancer, where aberrant patterns of DNA methylation and histone acetylation are common. Emerging therapies target epigenetic processes by inhibiting DNA methylation or histone-modifying enzymes. These therapies aim to reverse epigenetic changes and reactivate genes silenced in cancer.
This document discusses genetic instability. It defines genetic instability as an increased rate of genomic alterations ranging from point mutations to chromosome rearrangements. It describes three main types: nucleotide instability, microsatellite instability, and chromosomal instability. Causes of genetic instability include replication errors, defects in DNA repair pathways, and issues during cell division. Methods for detecting instability include karyotyping, FISH, and array technologies. Genetic instability is a hallmark of cancer and helps accelerate tumor genesis by increasing mutations. Cells use mechanisms like DNA proofreading and cell cycle checkpoints to maintain stability.
Understanding cancer -- patient-genetic_backgroundBoadicea123
While a cancer genome profile provides information, it does not tell the full story on its own. A patient's genetic background, which varies between individuals due to inherited and environmental factors, also influences cancer risk and treatment outcomes. This background includes single nucleotide variations across the genome as well as variations in genes related to drug metabolism and cancer susceptibility. Additional epigenetic and non-coding factors can also indirectly affect gene expression and cancer predisposition within a person. Understanding all of these intrinsic patient-specific influences is important for a complete diagnosis and personalized cancer care.
Mutations are changes in genetic material that can be caused by errors in DNA replication or by exposure to mutagens. There are several types of mutations including substitutions, insertions, deletions, and chromosomal mutations. Mutations can have varying effects, from being harmless to causing genetic disorders or cancer. Carcinogenesis is the process by which normal cells are transformed into cancer cells through a series of mutations that disrupt the balance between cell proliferation and cell death.
Answer:
Cellular oncogene formation: Carcinogenesis, tumorogenesis or oncogenesis are developed from
normal cells into a lethal cancer due to the following mechanisms inside the cell.
1. Point mutation: This mutation induces alteration in cellular DNA sequence through
synonymous nucleotide substitution result in normal gene becomes protooncogene finally
become oncogene due to chromosomal DNA replication. For example normal Ras protein
synthesizing gene become mutant Ras oncogene due to point mutation.
2. Gene amplification: This is the process of abnormal amplification of DNA in chromosomes
and generates protooncogenes into oncogenes due to numerous replications of chromosomal
DNA in succession. Example is presence of MYC gene family in lung and breast cancer cells
due to amplied DNA homogeneously.
3. Chromosomal translocation: BCR-ABL leukemia is the due to chromosomal translocation and
meticulous translocation of chromosmomal regions leading to coding of a fusion protein from an
oncogene. Ex. Philadelphia chromosome
4. DNA rearrangement: Insertions, deletions, transposition & inversion of nitrogen bases of
nucleotide sequences in DNA rearrangement generates cellular oncogenes. These rearrangements
are due to exposure of cells to carcinogenic agent
5. Insertional mutagenesis: This type of oncogene development is mainly due to retrovirus as
explained
below
For example:
The genetic changes are expected to alter the activity of the gene product --> loss of
heterozygosity ---> abnormal phenotype
Mutations result in genetic drift, which in turn results in the loss of heterozygosity. This loss of
one parental copy of nucleotide gene bases may lead to the lethal and dangerous consequences of
the living being in the following of life. This loss or drift may result in the occurrence of cancer
(breast cancer) hereditary retinoblastoma, because there may be nonexistence of the functional
tumor suppressor gene in the lost region. One parental copy only can be noticed at that lost
region there by hemizygosity.
But however there is one more functional gene copy inside the genome copy thereby offspring
can get resistance proteins synthesis against the mutation induced cancer.
If both copies are bad or one copy is become badly due to mutation the remaining gene copy
responsible for the tumor growth (the tumor suppressor gene example p53) can be denaturated by
another point mutation, result in complete suppression of gene to protect the body.
A lot of catastrophic events and consequences may occur with loss of heterozygosity (LOH).
Genetic drift results in loss of heterozygosity which may reduce and limit longevity of asexual
organisms in a population there by low population size.
During intermittent cancer development, usually inactivation of the TSG induced due to the two
somatic mutations acting on respective 2 alleles. In contrast, during the familial cancer
development merely one somatic mutation is considerably enough to generate inactivation of
TSG (p.
This document discusses the genetic and epigenetic changes that cause cancer. It explains that cancer arises due to alterations that disrupt normal cell proliferation, senescence, and death. Key changes include mutations in oncogenes that increase cell growth and tumor suppressor genes that normally inhibit growth. Cancer development involves multiple genetic hits over time that transform cells and allow unchecked growth. Epigenetic alterations like DNA methylation and histone modifications also contribute to carcinogenesis. The complex interplay between a person's genetic factors and environmental exposures ultimately leads to the development of cancer.
The document discusses epigenetics, which refers to changes in gene expression that do not involve changes to DNA sequence. It describes several epigenetic mechanisms including DNA methylation and histone modifications. Epigenetic changes play a role in diseases like cancer, where aberrant patterns of DNA methylation and histone acetylation are common. Emerging therapies target epigenetic processes by inhibiting DNA methylation or histone-modifying enzymes. These therapies aim to reverse epigenetic changes and reactivate genes silenced in cancer.
This document discusses genetic instability. It defines genetic instability as an increased rate of genomic alterations ranging from point mutations to chromosome rearrangements. It describes three main types: nucleotide instability, microsatellite instability, and chromosomal instability. Causes of genetic instability include replication errors, defects in DNA repair pathways, and issues during cell division. Methods for detecting instability include karyotyping, FISH, and array technologies. Genetic instability is a hallmark of cancer and helps accelerate tumor genesis by increasing mutations. Cells use mechanisms like DNA proofreading and cell cycle checkpoints to maintain stability.
Introduction to Cancer
Stem cells and cancer cells
major pathways that lead to formation of tumors.
Tumor Supressors
Colon cancer to prove Knudson hypothesis.
The modern treatments available to treat cancer.
cancer pharmaco therapeutics - 3.3 1.pptxmathihadassa
Cancer develops through a multistage process of genetic mutations that alter the normal control of cellular growth and proliferation. The initial step is initiation by carcinogens, which cause DNA damage and mutations in proto-oncogenes and tumor suppressor genes. This gives cells a selective growth advantage. Promotion makes the environment favor growth of these mutated cells. Finally, progression leads to increased proliferation and metastasis. Oncogenes stimulate growth while tumor suppressors inhibit it. Loss of control over these genes, through acquired or inherited mutations, drives carcinogenesis.
The Amerithrax investigation followed the 2001 anthrax attacks that killed 5 people. Letters containing anthrax spores were sent to media outlets and two senators. The FBI investigation into the source of the anthrax took 7 years.
Mutations are changes in DNA sequences that are present in less than 1% of a population. Mutations can range from single DNA base changes to missing or extra chromosomes. They can affect protein function and transcription. Most mutations are recessive and cause loss of function, while gain-of-function mutations tend to be dominant.
Sickle cell disease was the first genetic illness understood at the molecular level. It results from a single amino acid substitution in the beta globin protein that causes
Kenyatta university. hmb201 dna repairdocxLando Elvis
Gene mutations can be hereditary or acquired. DNA has multiple repair mechanisms to correct damage from environmental factors and replication errors. These include mismatch repair, nucleotide excision repair, photoreactivation repair, base excision repair, and double-strand break repair through nonhomologous end joining or homologous recombination. Errors in DNA repair can lead to mutations and genetic disorders if damage is not corrected. The cell cycle is also regulated to check for DNA damage and delay progression until repairs are complete.
DNA Methylation and Epigenetic Events Underlying Renal Cell Carcinomaskomalicarol
Renal cell carcinoma (RCC) refers to a group of tumors that develop from the epithelium of the kidney tubes, including clear cell
RCC, papillary RCC, and chromophobe RCC. Most clear cell renal
carcinomas have a large histologic subtype, genetic or epigenetic
genetic von Hippel-Lindau (VHL). A comprehensive analysis of
the genetic modification genome suggested that chromosome 3p
loss and chromosome gains 5q and 7 may be a significant copy
defect in the development of clear kidney cell cancer. A more potent renal cell carcinoma may develop if chromosome 1p, 4, 9,
13q, or 14q is also lost. Renal carcinogenesis is not associated with
chronic inflammation or histological changes. However, regional hypermethylation of DNA in CpG C-type islands has already
accumulated in cancer-free kidney tissue, implying that the presence of malignant kidney lesions may also be detected by modified
DNA methylation. Modification of DNA methylation in cancerous
kidney tissue may advance kidney tissue to epigenetic mutations
and genes, leading to more serious cancers and even determining
a patient’s outcome
Sperm DNA fragmentation can negatively impact fertility and pregnancy outcomes. DNA becomes vulnerable during spermatogenesis when protamine replaces histones in chromatin compaction. Tests can evaluate sperm DNA fragmentation levels, which are correlated with lower fertilization and implantation rates. Factors like oxidative stress, temperature, and infections can intrinsically or extrinsically damage sperm DNA. Repair mechanisms attempt to resolve DNA double-strand breaks, but extensive unrepaired damage may be incompatible with embryo development. Treatments aim to address underlying causes of DNA fragmentation or use testicular sperm or ICSI to bypass ejaculated sperm issues.
This document discusses single gene disorders and their patterns of inheritance. It begins by defining some key genetic terms like genes, alleles, loci, genotypes, phenotypes, mutations, and codons. It then describes the main patterns of inheritance for single gene disorders: autosomal dominant, autosomal recessive, X-linked recessive, and X-linked dominant. For each pattern, it explains how the disorder is transmitted from parents to children based on whether the gene is located on an autosome or sex chromosome, and if the trait is dominant or recessive. The document provides examples like sickle cell anemia, cystic fibrosis, and Tay-Sachs disease to illustrate different types of mutations and their effects. It concludes by
Genetic and environmental factors are the two keys that make human phenotype variations. When the genomic DNA sequences on equivalent chromosomes of any two individuals are compared, there is substantial variation in the sequence at many points throughout the genome. The term polymorphism was originally used to describe variations in shape and form that distinguish normal individuals within a species from each other. These days, geneticists use the term genetic polymorphisms to describe the inter-individual, functionally silent differences in DNA sequence that make each human genome unique. In order to better understand the phenomenon of genetic polymorphism, an emphasis has been laid on the structures and functions of nucleotides, genes and nucleic acids, including their relationship with polymorphism.
Polymorphism can be caused by factors such as mutation, which is defined as a permanent transmissible change in DNA sequence. Mutations are classified based on where they occur somatic and germ line mutations) and the length of the nucleotide sequences they affect (gene-level and chromosomal mutations). The various types of polymorphisms include; single nucleotide polymorphisms (SNPs), small-scale insertions/deletions, polymorphic repetitive elements, microsatellite variation and haplotypes.
Variations in DNA sequences may have a major impact on how human beings respond to disease, bacteria, viruses, toxins, chemicals, drugs, and other therapies. Many clinical phenotypes observed in diseases seem to have considerable genetic components.
Determining genetic polymorphism can be based on morphological, biochemical, and molecular types of information. However, molecular markers have advantages over other kinds, where they show genetic differences on a more detailed level without interferences from environmental factors, and where they involve techniques that provide fast results detailing genetic diversity. Some of the techniques used in studying polymorphisms include; PCR based techniques and techniques involving DNA based markers.
Key words: Genetic polymorphism, effects in a population,
This document discusses gene mutations. It defines gene mutations as permanent alterations in DNA sequence that differ from what is typically found. Mutations can range in size from a single DNA base pair to a large chromosome segment. The document outlines several types of mutations including point mutations, insertion mutations, deletion mutations, and more. It explores how mutations can affect health and cause genetic disorders by altering protein function. Environmental factors and errors in DNA replication and transcription are presented as common causes of gene mutations.
ONCOGENE AND PROTOONCOGENE
P53 GENE AND ITS APPLICATION IN CANCER ETIOLOGY
TUMOUR SUPPRESSOR GENE AND BCA AND BAC GENE AND ITS APPLICATION ON THE APOPTOSIS AND DEATH RECEPTORS
Mutations are changes in the nucleotide sequence of DNA. They may occur spontaneously during DNA replication or be induced by mutagens like chemicals, radiation, or viruses. Mutations can be harmful, harmless, or beneficial depending on their location and effects. There are several types of mutations including substitutions, insertions, deletions, and frameshifts which can alter protein functions and cause diseases. Bacteria can develop resistance to antibiotics via mutations selected through antibiotic use.
DNA methylation, an epigenetic mechanism, plays a major role in gene expression and silencing. Changes in DNA methylation patterns, including global hypomethylation and hypermethylation of tumor suppressor genes, are consistently observed in cancer cells and contribute to tumor formation. Both hypomethylation of oncogenes and hypermethylation of tumor suppressor genes can provide a selective growth advantage for cancer cells.
Genotoxic stress occurs when chemical agents damage genetic information within cells, causing mutations directly or indirectly through DNA damage. Cells have defense mechanisms that form a complex signal transduction network in response to genotoxic stress. This network activates transcription factors that regulate genes for DNA repair, cell cycle arrest, and apoptosis. Exposure to certain chemicals has been linked to various human cancers by causing genotoxic mutations. To cope with DNA damage from genotoxic stresses such as chemicals, radiation, and normal cell metabolism, cells have developed DNA repair and cell cycle regulation responses that are important for preventing carcinogenesis when altered.
This document discusses the relationship between cell cycle mechanisms and cancer. It focuses on mammalian cell cycle checkpoints and their role in maintaining DNA stability when exposed to genotoxic stress. Key points covered include: 1) Heritable human cancer syndromes often have defects in DNA damage response pathways and cell cycle checkpoints. 2) Ataxia telangiectasia is caused by defects in the ATM gene and results in impaired DNA damage checkpoints. 3) Retinoblastoma involves defects in the Rb gene and disruption of cell cycle control. 4) Li-Fraumeni syndrome involves germline p53 mutations and loss of p53-mediated checkpoints and apoptosis.
The document discusses epigenetics and its role in environmental diseases. It defines epigenetics as mechanisms that regulate gene expression without changing DNA sequence. Environmental factors can cause epigenetic changes through pathways like DNA methylation and histone modification. Abnormal epigenetic changes have been implicated in diseases like cancer, aging, and neurodevelopmental disorders. Certain environmental exposures are also linked to epigenetic alterations, though causal relationships are difficult to establish.
This document provides information about cancer genetics and cell biology. It defines cancer as uncontrolled cell growth and classifies tumors as benign or malignant. The main cancer types - carcinomas, sarcomas, and leukemias/lymphomas - are described based on their cell of origin. Key concepts in cancer development are discussed, including the roles of oncogenes, tumor suppressor genes, DNA repair genes, and failures in cell cycle control. Cancer results from mutations that disable normal controls on cell growth and division.
This document discusses mutations, which are alterations in an organism's DNA sequence. There are several types of mutations, including base substitutions, deletions, and insertions. Mutations can occur due to errors during DNA replication or repair. While most mutations are harmful, some can be beneficial for evolution. The effects of mutations depend on factors like how many DNA bases are affected. Mutation rates vary within and between genomes.
This document discusses mutations, which are alterations in an organism's DNA sequence. There are several types of mutations, including base substitutions, deletions, and insertions. Mutations can occur due to errors during DNA replication or repair. While most mutations are harmful, some can be beneficial for evolution. Mutations may affect single bases or entire chromosomes. They can originate in somatic or germ cells. Certain DNA regions called hotspots are especially prone to mutations. The effects of mutations range from neutral to strongly beneficial or deleterious, depending on factors like how many base pairs are altered.
Introduction to Cancer
Stem cells and cancer cells
major pathways that lead to formation of tumors.
Tumor Supressors
Colon cancer to prove Knudson hypothesis.
The modern treatments available to treat cancer.
cancer pharmaco therapeutics - 3.3 1.pptxmathihadassa
Cancer develops through a multistage process of genetic mutations that alter the normal control of cellular growth and proliferation. The initial step is initiation by carcinogens, which cause DNA damage and mutations in proto-oncogenes and tumor suppressor genes. This gives cells a selective growth advantage. Promotion makes the environment favor growth of these mutated cells. Finally, progression leads to increased proliferation and metastasis. Oncogenes stimulate growth while tumor suppressors inhibit it. Loss of control over these genes, through acquired or inherited mutations, drives carcinogenesis.
The Amerithrax investigation followed the 2001 anthrax attacks that killed 5 people. Letters containing anthrax spores were sent to media outlets and two senators. The FBI investigation into the source of the anthrax took 7 years.
Mutations are changes in DNA sequences that are present in less than 1% of a population. Mutations can range from single DNA base changes to missing or extra chromosomes. They can affect protein function and transcription. Most mutations are recessive and cause loss of function, while gain-of-function mutations tend to be dominant.
Sickle cell disease was the first genetic illness understood at the molecular level. It results from a single amino acid substitution in the beta globin protein that causes
Kenyatta university. hmb201 dna repairdocxLando Elvis
Gene mutations can be hereditary or acquired. DNA has multiple repair mechanisms to correct damage from environmental factors and replication errors. These include mismatch repair, nucleotide excision repair, photoreactivation repair, base excision repair, and double-strand break repair through nonhomologous end joining or homologous recombination. Errors in DNA repair can lead to mutations and genetic disorders if damage is not corrected. The cell cycle is also regulated to check for DNA damage and delay progression until repairs are complete.
DNA Methylation and Epigenetic Events Underlying Renal Cell Carcinomaskomalicarol
Renal cell carcinoma (RCC) refers to a group of tumors that develop from the epithelium of the kidney tubes, including clear cell
RCC, papillary RCC, and chromophobe RCC. Most clear cell renal
carcinomas have a large histologic subtype, genetic or epigenetic
genetic von Hippel-Lindau (VHL). A comprehensive analysis of
the genetic modification genome suggested that chromosome 3p
loss and chromosome gains 5q and 7 may be a significant copy
defect in the development of clear kidney cell cancer. A more potent renal cell carcinoma may develop if chromosome 1p, 4, 9,
13q, or 14q is also lost. Renal carcinogenesis is not associated with
chronic inflammation or histological changes. However, regional hypermethylation of DNA in CpG C-type islands has already
accumulated in cancer-free kidney tissue, implying that the presence of malignant kidney lesions may also be detected by modified
DNA methylation. Modification of DNA methylation in cancerous
kidney tissue may advance kidney tissue to epigenetic mutations
and genes, leading to more serious cancers and even determining
a patient’s outcome
Sperm DNA fragmentation can negatively impact fertility and pregnancy outcomes. DNA becomes vulnerable during spermatogenesis when protamine replaces histones in chromatin compaction. Tests can evaluate sperm DNA fragmentation levels, which are correlated with lower fertilization and implantation rates. Factors like oxidative stress, temperature, and infections can intrinsically or extrinsically damage sperm DNA. Repair mechanisms attempt to resolve DNA double-strand breaks, but extensive unrepaired damage may be incompatible with embryo development. Treatments aim to address underlying causes of DNA fragmentation or use testicular sperm or ICSI to bypass ejaculated sperm issues.
This document discusses single gene disorders and their patterns of inheritance. It begins by defining some key genetic terms like genes, alleles, loci, genotypes, phenotypes, mutations, and codons. It then describes the main patterns of inheritance for single gene disorders: autosomal dominant, autosomal recessive, X-linked recessive, and X-linked dominant. For each pattern, it explains how the disorder is transmitted from parents to children based on whether the gene is located on an autosome or sex chromosome, and if the trait is dominant or recessive. The document provides examples like sickle cell anemia, cystic fibrosis, and Tay-Sachs disease to illustrate different types of mutations and their effects. It concludes by
Genetic and environmental factors are the two keys that make human phenotype variations. When the genomic DNA sequences on equivalent chromosomes of any two individuals are compared, there is substantial variation in the sequence at many points throughout the genome. The term polymorphism was originally used to describe variations in shape and form that distinguish normal individuals within a species from each other. These days, geneticists use the term genetic polymorphisms to describe the inter-individual, functionally silent differences in DNA sequence that make each human genome unique. In order to better understand the phenomenon of genetic polymorphism, an emphasis has been laid on the structures and functions of nucleotides, genes and nucleic acids, including their relationship with polymorphism.
Polymorphism can be caused by factors such as mutation, which is defined as a permanent transmissible change in DNA sequence. Mutations are classified based on where they occur somatic and germ line mutations) and the length of the nucleotide sequences they affect (gene-level and chromosomal mutations). The various types of polymorphisms include; single nucleotide polymorphisms (SNPs), small-scale insertions/deletions, polymorphic repetitive elements, microsatellite variation and haplotypes.
Variations in DNA sequences may have a major impact on how human beings respond to disease, bacteria, viruses, toxins, chemicals, drugs, and other therapies. Many clinical phenotypes observed in diseases seem to have considerable genetic components.
Determining genetic polymorphism can be based on morphological, biochemical, and molecular types of information. However, molecular markers have advantages over other kinds, where they show genetic differences on a more detailed level without interferences from environmental factors, and where they involve techniques that provide fast results detailing genetic diversity. Some of the techniques used in studying polymorphisms include; PCR based techniques and techniques involving DNA based markers.
Key words: Genetic polymorphism, effects in a population,
This document discusses gene mutations. It defines gene mutations as permanent alterations in DNA sequence that differ from what is typically found. Mutations can range in size from a single DNA base pair to a large chromosome segment. The document outlines several types of mutations including point mutations, insertion mutations, deletion mutations, and more. It explores how mutations can affect health and cause genetic disorders by altering protein function. Environmental factors and errors in DNA replication and transcription are presented as common causes of gene mutations.
ONCOGENE AND PROTOONCOGENE
P53 GENE AND ITS APPLICATION IN CANCER ETIOLOGY
TUMOUR SUPPRESSOR GENE AND BCA AND BAC GENE AND ITS APPLICATION ON THE APOPTOSIS AND DEATH RECEPTORS
Mutations are changes in the nucleotide sequence of DNA. They may occur spontaneously during DNA replication or be induced by mutagens like chemicals, radiation, or viruses. Mutations can be harmful, harmless, or beneficial depending on their location and effects. There are several types of mutations including substitutions, insertions, deletions, and frameshifts which can alter protein functions and cause diseases. Bacteria can develop resistance to antibiotics via mutations selected through antibiotic use.
DNA methylation, an epigenetic mechanism, plays a major role in gene expression and silencing. Changes in DNA methylation patterns, including global hypomethylation and hypermethylation of tumor suppressor genes, are consistently observed in cancer cells and contribute to tumor formation. Both hypomethylation of oncogenes and hypermethylation of tumor suppressor genes can provide a selective growth advantage for cancer cells.
Genotoxic stress occurs when chemical agents damage genetic information within cells, causing mutations directly or indirectly through DNA damage. Cells have defense mechanisms that form a complex signal transduction network in response to genotoxic stress. This network activates transcription factors that regulate genes for DNA repair, cell cycle arrest, and apoptosis. Exposure to certain chemicals has been linked to various human cancers by causing genotoxic mutations. To cope with DNA damage from genotoxic stresses such as chemicals, radiation, and normal cell metabolism, cells have developed DNA repair and cell cycle regulation responses that are important for preventing carcinogenesis when altered.
This document discusses the relationship between cell cycle mechanisms and cancer. It focuses on mammalian cell cycle checkpoints and their role in maintaining DNA stability when exposed to genotoxic stress. Key points covered include: 1) Heritable human cancer syndromes often have defects in DNA damage response pathways and cell cycle checkpoints. 2) Ataxia telangiectasia is caused by defects in the ATM gene and results in impaired DNA damage checkpoints. 3) Retinoblastoma involves defects in the Rb gene and disruption of cell cycle control. 4) Li-Fraumeni syndrome involves germline p53 mutations and loss of p53-mediated checkpoints and apoptosis.
The document discusses epigenetics and its role in environmental diseases. It defines epigenetics as mechanisms that regulate gene expression without changing DNA sequence. Environmental factors can cause epigenetic changes through pathways like DNA methylation and histone modification. Abnormal epigenetic changes have been implicated in diseases like cancer, aging, and neurodevelopmental disorders. Certain environmental exposures are also linked to epigenetic alterations, though causal relationships are difficult to establish.
This document provides information about cancer genetics and cell biology. It defines cancer as uncontrolled cell growth and classifies tumors as benign or malignant. The main cancer types - carcinomas, sarcomas, and leukemias/lymphomas - are described based on their cell of origin. Key concepts in cancer development are discussed, including the roles of oncogenes, tumor suppressor genes, DNA repair genes, and failures in cell cycle control. Cancer results from mutations that disable normal controls on cell growth and division.
This document discusses mutations, which are alterations in an organism's DNA sequence. There are several types of mutations, including base substitutions, deletions, and insertions. Mutations can occur due to errors during DNA replication or repair. While most mutations are harmful, some can be beneficial for evolution. The effects of mutations depend on factors like how many DNA bases are affected. Mutation rates vary within and between genomes.
This document discusses mutations, which are alterations in an organism's DNA sequence. There are several types of mutations, including base substitutions, deletions, and insertions. Mutations can occur due to errors during DNA replication or repair. While most mutations are harmful, some can be beneficial for evolution. Mutations may affect single bases or entire chromosomes. They can originate in somatic or germ cells. Certain DNA regions called hotspots are especially prone to mutations. The effects of mutations range from neutral to strongly beneficial or deleterious, depending on factors like how many base pairs are altered.
Travel Clinic Cardiff: Health Advice for International TravelersNX Healthcare
Travel Clinic Cardiff offers comprehensive travel health services, including vaccinations, travel advice, and preventive care for international travelers. Our expert team ensures you are well-prepared and protected for your journey, providing personalized consultations tailored to your destination. Conveniently located in Cardiff, we help you travel with confidence and peace of mind. Visit us: www.nxhealthcare.co.uk
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Does Over-Masturbation Contribute to Chronic Prostatitis.pptxwalterHu5
In some case, your chronic prostatitis may be related to over-masturbation. Generally, natural medicine Diuretic and Anti-inflammatory Pill can help mee get a cure.
The skin is the largest organ and its health plays a vital role among the other sense organs. The skin concerns like acne breakout, psoriasis, or anything similar along the lines, finding a qualified and experienced dermatologist becomes paramount.
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Mercurius is named after the roman god mercurius, the god of trade and science. The planet mercurius is named after the same god. Mercurius is sometimes called hydrargyrum, means ‘watery silver’. Its shine and colour are very similar to silver, but mercury is a fluid at room temperatures. The name quick silver is a translation of hydrargyrum, where the word quick describes its tendency to scatter away in all directions.
The droplets have a tendency to conglomerate to one big mass, but on being shaken they fall apart into countless little droplets again. It is used to ignite explosives, like mercury fulminate, the explosive character is one of its general themes.
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DECLARATION OF HELSINKI - History and principlesanaghabharat01
This SlideShare presentation provides a comprehensive overview of the Declaration of Helsinki, a foundational document outlining ethical guidelines for conducting medical research involving human subjects.
2. Studies have often demonstrated that these tumour-
specific alterations are associated with activation of cellular
proto-oncogenes or the inactivation of tumour suppressor
genes.
Ionizing radiation induces a broad range of neoplasms in
both man and experimental animals. Point mutations and
chromosome translocations that activate proto-oncogenes
and deletions that lead to a loss of function of tumour
suppressor genes all probably play a role in the initiation
(and progression) of these diseases.
The DNA of a cell is damaged by ionizing radiation that
may principally, but not exclusively, initiate oncogenesis
through mechanisms involving deletion ,rearrangement of
segments of DNA or both.
3. The activation of proto-oncogenes seems to occur
through two mechanisms. For example, in proto-
oncogenes such as RAS, the DNA base pair (bp)
changes needed for activation are limited thus
providing a small molecular target of may be only a
few base pairs.
For the gene-specific translocations involving
juxtaposition of proto-oncogenes such as ABL or BSL-2
with other genes, the target would be larger (maybe up
to 10' bp) although it could, in principle, be necessary
to damage the DNA at two specific sites rather than
one.
4. However, with the loss-of-function mutations
characteristic of tumour suppressor genes, such as Rb, APC
or p53, the situation is different.
Inactivation may occur through point mutation, small
deletions within the gene or larger deletions involving
whole chromosome segments (about 107 bp), the principal
limit to the size of such DNA deletions being the extent to
which the cell can sustain viability following large losses of
genetic material.
Thus, on simple biophysical arguments it would seem that
radiation induced loss-of-function mutations, since they
appear to offer the larger target size by perhaps two or three
orders of magnitude, may dominate the spectrum of
initiating events for radiation-induced carcinogenesis
5. Support for this concept comes from molecular studies
with radiation-induced mutations where the main
mechanism has been shown to be through gross
genetic change - usually DNA deletions. Although
such studies in no way exclude radiation mutagenesis
through point mutation, they indicate ionizing
radiation to be a rather weak point mutagen
6. Many chemical agents also induce gross chromosomal
damage, but the mechanisms are fundamentally different
from those of radiation as the majority of chemicals
principally act to produce point mutations.
Thus, the major mechanistic difference at the cellular level
between radiation-induced and chemical-induced
oncogenesis is probably related to their relative efficiencies
at inducing point mutations or activation of proto-
oncogenes, and some variations in the spectrum of
neoplasms induced by radiation and chemical carcinogens
are, therefore, possible.
Moreover, it is feasible that specific point mutations in
tumour genes may serve as a signature of prior exposure to
chemical carcinogens
7. The commonest and most extensively characterized genetic
abnormalities that are associated with leukaemia are the
chromosomal translocations that give rise to fusion genes
encoding oncogenic proteins. The classical example, found
in CML, gives rise to the Philadelphia (Ph) chromosome
which involves a translocation between chromosomes 9
and 22 and results in the juxtaposition of the BCR gene and
the ABL proto-oncogene
several other types of chromosomal aberrations exist and
their fusion genes have been identified in acute leukaemia.
These include the DEK-CAN (chromosomes 6 and 9) and
AML1-ETO (chromosomes 8 and 21) genes in AML, and the
TEL AML1 (chromosomes 12 and 21) and MLL-AF1P genes
(chromosomes 1 and 11) in ALL. Also trisomy and polysomy
of chromosome 21 are frequent anomalies in ALL
8. High doses of ionizing radiation are capable of
generating such fusion genes in haemopoetic cell lines
in vitro. The genes are generally induced at different
frequencies - AML1-ETO having the highest frequency
and differ for the different cell lines
9. Typically in these secondary leukaemias, loss of part or all of
chromosomes 5 and/or 7 is observed with the frequency of
abnormalities of both chromosomes being more prevalent in
patients who receive both types of therapy.
In the case of secondary AML following treatment with
chemotherapeutic drugs, there are some significant genotypic
and phenotypic differences between, for example, AML
associated with alkylating agents and the epipodophyllotoxins.
While non-balanced abnormalities of chromosomes 5 and 7 are
again the most frequently observed in neoplastic processes
arising after alkylating agent therapy, leukaemias occurring after
treatment that includes epipodophyllotoxins often feature
balanced chromosomal translocations. These latter leukaemias
often have a latency period of about 2 years compared with
typically 6 years following treatment with alkylating agents.
10. Chromosome rearrangements and deletions are major
features of the oncogenic process and there is an ongoing
debate about the significance of specific sites of instability-
the so-called fragile sites.
Some fragile sites are believed to be preferential targets for
the clastogenic action of DNA-damaging agents such as
ionizing radiation, although no overall association between
common fragile sites and cancer-associated breakpoints
has yet been shown-except possibly with respect to certain
leukaemias.
The molecular structures of fragile sites are not known,
but it seems likely that they contain certain repeat DNA
sequences in particular telomere-like repeat (TLR)
sequences which may recombine at high frequency.