The document summarizes Hanahan and Weinberg's hallmarks of cancer. It describes the six original hallmarks proposed in 2000 of self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, evading apoptosis, limitless replicative potential, sustained angiogenesis, and tissue invasion and metastasis. In 2011, they added two emerging hallmarks of deregulating cellular energetics and avoiding immune detection, as well as two enabling characteristics of genome instability and tumor-promoting inflammation.
These hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis.
Cellular Signaling Pathways have direct implications on our understanding of tumor cell behavior. A general overview is presented here followed by a brief discussion of some of the major pathways currently implicated in cancer progression : Ras/RAF/MAP kinase pathway and PI3K/AKT/mTOR pathway s
Clinical oncology basic fundamental For undergraduate studies part I .pdfMona Quenawy
Cancer is a disease of uncontrolled growth and proliferation whereby cells have escaped the body’s normal growth control mechanisms and have gained the ability to divide indefinitely. It is a multi-step process that requires the accumulation of many genetic changes over time (Figure 1). These genetic alterations involve activation of proto-oncogenes to oncogenes, deregulation of tumour suppressor genes and DNA repair genes and ‘immortalisation
Cancer ranks as a leading cause of death and an important barrier to increasing life expectancy in every country of the world.1 According to estimates from the World Health Organization (WHO) in 2019, cancer is the first or second leading cause of death before the age of 70 years in 112 of 183 countries and ranks third or fourth in a further 23 countries . Cancer's rising prominence as a leading cause of death partly reflects marked declines in mortality rates of stroke and coronary heart disease, relative to cancer, in many countries.
Between 30–50% of all cancer cases are preventable. Prevention offers the most cost-effective long-term strategy for the control of cancer. WHO works with Member States to strengthen national policies and programmes to raise awareness and, reduce exposure to cancer risk factors, and also ensure that people are provided with the information and support they need to adopt healthy lifestyles.
To strengthen national efforts to address the burden of cancer and other noncommunicable diseases (NCDs), the WHO Global Action Plan for the Prevention and Control of NCDs 2013–2020 provides a road map to reduce premature mortality from NCDs by 2025 through targeting many of the risk factors below:
Tobacco
Worldwide, tobacco use is the single greatest avoidable risk factor for cancer mortality and kills more than 8 million people each year, from cancer and other diseases. Nearly 80% of the 1.1 billion smokers in the world live in low- and middle-income countries.
Alcohol
Alcohol, as classified by the International Agency for Research on Cancer, is a toxic, psychoactive, and dependence-producing substance and a Group 1 carcinogen that is causally linked to 7 types of cancer, including oesophagus, liver, colorectal, and breast cancers. Alcohol consumption is associated with 740 000 new cancer cases each year. Globally, 1 in 20 breast cancers is attributed to alcohol consumption.
Physical inactivity,infection with HPV,Environmental pollution,Industrial carcinogen and radiation exposure are also global preventable causes.
this basic discussion highlight the topics of the main types of cancer and cancer theory.prevention cancer staging with TNM and other methods .management of emergency situation in clinical oncology .basics of surgical oncology and chemotherapy handling.
These hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis.
Cellular Signaling Pathways have direct implications on our understanding of tumor cell behavior. A general overview is presented here followed by a brief discussion of some of the major pathways currently implicated in cancer progression : Ras/RAF/MAP kinase pathway and PI3K/AKT/mTOR pathway s
Clinical oncology basic fundamental For undergraduate studies part I .pdfMona Quenawy
Cancer is a disease of uncontrolled growth and proliferation whereby cells have escaped the body’s normal growth control mechanisms and have gained the ability to divide indefinitely. It is a multi-step process that requires the accumulation of many genetic changes over time (Figure 1). These genetic alterations involve activation of proto-oncogenes to oncogenes, deregulation of tumour suppressor genes and DNA repair genes and ‘immortalisation
Cancer ranks as a leading cause of death and an important barrier to increasing life expectancy in every country of the world.1 According to estimates from the World Health Organization (WHO) in 2019, cancer is the first or second leading cause of death before the age of 70 years in 112 of 183 countries and ranks third or fourth in a further 23 countries . Cancer's rising prominence as a leading cause of death partly reflects marked declines in mortality rates of stroke and coronary heart disease, relative to cancer, in many countries.
Between 30–50% of all cancer cases are preventable. Prevention offers the most cost-effective long-term strategy for the control of cancer. WHO works with Member States to strengthen national policies and programmes to raise awareness and, reduce exposure to cancer risk factors, and also ensure that people are provided with the information and support they need to adopt healthy lifestyles.
To strengthen national efforts to address the burden of cancer and other noncommunicable diseases (NCDs), the WHO Global Action Plan for the Prevention and Control of NCDs 2013–2020 provides a road map to reduce premature mortality from NCDs by 2025 through targeting many of the risk factors below:
Tobacco
Worldwide, tobacco use is the single greatest avoidable risk factor for cancer mortality and kills more than 8 million people each year, from cancer and other diseases. Nearly 80% of the 1.1 billion smokers in the world live in low- and middle-income countries.
Alcohol
Alcohol, as classified by the International Agency for Research on Cancer, is a toxic, psychoactive, and dependence-producing substance and a Group 1 carcinogen that is causally linked to 7 types of cancer, including oesophagus, liver, colorectal, and breast cancers. Alcohol consumption is associated with 740 000 new cancer cases each year. Globally, 1 in 20 breast cancers is attributed to alcohol consumption.
Physical inactivity,infection with HPV,Environmental pollution,Industrial carcinogen and radiation exposure are also global preventable causes.
this basic discussion highlight the topics of the main types of cancer and cancer theory.prevention cancer staging with TNM and other methods .management of emergency situation in clinical oncology .basics of surgical oncology and chemotherapy handling.
Cell, Vol. 100, 57–70, January 7, 2000, Copyright 2000 by Cel.docxzebadiahsummers
Cell, Vol. 100, 57–70, January 7, 2000, Copyright 2000 by Cell Press
The Hallmarks of Cancer Review
evolve progressively from normalcy via a series of pre-Douglas Hanahan* and Robert A. Weinberg†
*Department of Biochemistry and Biophysics and malignant states into invasive cancers (Foulds, 1954).
These observations have been rendered more con-Hormone Research Institute
University of California at San Francisco crete by a large body of work indicating that the ge-
nomes of tumor cells are invariably altered at multipleSan Francisco, California 94143
†Whitehead Institute for Biomedical Research and sites, having suffered disruption through lesions as sub-
tle as point mutations and as obvious as changes inDepartment of Biology
Massachusetts Institute of Technology chromosome complement (e.g., Kinzler and Vogelstein,
1996). Transformation of cultured cells is itself aCambridge, Massachusetts 02142
multistep process: rodent cells require at least two intro-
duced genetic changes before they acquire tumorigenic
competence, while their human counterparts are moreAfter a quarter century of rapid advances, cancer re-
difficult to transform (Hahn et al., 1999). Transgenicsearch has generated a rich and complex body of knowl-
models of tumorigenesis have repeatedly supported theedge, revealing cancer to be a disease involving dy-
conclusion that tumorigenesis in mice involves multiplenamic changes in the genome. The foundation has been
rate-limiting steps (Bergers et al., 1998; see Oncogene,set in the discovery of mutations that produce onco-
1999, R. DePinho and T. E. Jacks, volume 18[38], pp.genes with dominant gain of function and tumor sup-
5248–5362). Taken together, observations of humanpressor genes with recessive loss of function; both
cancers and animal models argue that tumor develop-classes of cancer genes have been identified through
ment proceeds via a process formally analogous to Dar-their alteration in human and animal cancer cells and
winian evolution, in which a succession of geneticby their elicitation of cancer phenotypes in experimental
changes, each conferring one or another type of growthmodels (Bishop and Weinberg, 1996).
advantage, leads to the progressive conversion of nor-Some would argue that the search for the origin and
mal human cells into cancer cells (Foulds, 1954; Nowell,treatment of this disease will continue over the next
1976).quarter century in much the same manner as it has in
the recent past, by adding further layers of complexity
to a scientific literature that is already complex almost An Enumeration of the Traits
beyond measure. But we anticipate otherwise: those The barriers to development of cancer are embodied
researching the cancer problem will be practicing a dra- in a teleology: cancer cells have defects in regulatory
matically different type of science than we have experi- circuits that govern normal cell proliferation and homeo-
enced over the past 25 years. Surely much of this change stasis. T.
Cell, Vol. 100, 57–70, January 7, 2000, Copyright 2000 by Cel.docxketurahhazelhurst
Cell, Vol. 100, 57–70, January 7, 2000, Copyright 2000 by Cell Press
The Hallmarks of Cancer Review
evolve progressively from normalcy via a series of pre-Douglas Hanahan* and Robert A. Weinberg†
*Department of Biochemistry and Biophysics and malignant states into invasive cancers (Foulds, 1954).
These observations have been rendered more con-Hormone Research Institute
University of California at San Francisco crete by a large body of work indicating that the ge-
nomes of tumor cells are invariably altered at multipleSan Francisco, California 94143
†Whitehead Institute for Biomedical Research and sites, having suffered disruption through lesions as sub-
tle as point mutations and as obvious as changes inDepartment of Biology
Massachusetts Institute of Technology chromosome complement (e.g., Kinzler and Vogelstein,
1996). Transformation of cultured cells is itself aCambridge, Massachusetts 02142
multistep process: rodent cells require at least two intro-
duced genetic changes before they acquire tumorigenic
competence, while their human counterparts are moreAfter a quarter century of rapid advances, cancer re-
difficult to transform (Hahn et al., 1999). Transgenicsearch has generated a rich and complex body of knowl-
models of tumorigenesis have repeatedly supported theedge, revealing cancer to be a disease involving dy-
conclusion that tumorigenesis in mice involves multiplenamic changes in the genome. The foundation has been
rate-limiting steps (Bergers et al., 1998; see Oncogene,set in the discovery of mutations that produce onco-
1999, R. DePinho and T. E. Jacks, volume 18[38], pp.genes with dominant gain of function and tumor sup-
5248–5362). Taken together, observations of humanpressor genes with recessive loss of function; both
cancers and animal models argue that tumor develop-classes of cancer genes have been identified through
ment proceeds via a process formally analogous to Dar-their alteration in human and animal cancer cells and
winian evolution, in which a succession of geneticby their elicitation of cancer phenotypes in experimental
changes, each conferring one or another type of growthmodels (Bishop and Weinberg, 1996).
advantage, leads to the progressive conversion of nor-Some would argue that the search for the origin and
mal human cells into cancer cells (Foulds, 1954; Nowell,treatment of this disease will continue over the next
1976).quarter century in much the same manner as it has in
the recent past, by adding further layers of complexity
to a scientific literature that is already complex almost An Enumeration of the Traits
beyond measure. But we anticipate otherwise: those The barriers to development of cancer are embodied
researching the cancer problem will be practicing a dra- in a teleology: cancer cells have defects in regulatory
matically different type of science than we have experi- circuits that govern normal cell proliferation and homeo-
enced over the past 25 years. Surely much of this change stasis. T ...
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 results from a series of molecular events that fundamentally alter the normal properties of cells. In cancer cells the normal control systems that prevent cell overgrowth and the invasion of other tissues are disabled.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
2. Summary
In 2000, Hanahan & Weinberg (1) proposed most cancer cell genotypes are manifestation of six essential
alterations in cell physiology that collectively dictate malignant growth that become known as Hallmarks of
Cancer:
Self-sufficiency in growth signals, insensitivity to growth-inhibitory (antigrowth) signals, evasion of programmed cell
death (apoptosis), limitless replicative potential, sustained angiogenesis, and tissue invasion and metastasis.
Each of these physiologic changes—novel capabilities acquired during tumor development—represent the
successful breaching of an anticancer defense mechanism hardwired into cells and tissues.
Authors proposed that these six capabilities are shared in common by most and perhaps all types of human
tumors and that this multiplicity of defenses may explain why cancer is relatively rare during an average human
lifetime.
In 2011, Hanahan & Weinberg (2) updated these Hallmarks with addition of two Emerging Hallmarks and two
Enabling Characteristics:
Emerging Hallmarks: Deregulating cellular energetics, avoiding immune detection
Enabling Characteristics: Genome instability and mutation, Tumor-promoting Inflammation
References:
1. Hanahan D. and Weinberg R.A. (2000) The Hallmarks of Cancer. Cell 100: 57-70.
2. Hanahan D. and Weinberg R.A. (2011) The Hallmarks of Cancer: The Next Generation. Cell 144: 646-674.
3. Hallmarks illustrated
Six original Hallmarks proposed in 2000(1).
References:
1. Hanahan D. and Weinberg R.A. (2000) The Hallmarks of Cancer. Cell 100: 57-70.
2. Hanahan D. and Weinberg R.A. (2011) The Hallmarks of Cancer: The Next Generation. Cell 144: 646-674.
Six original Hallmarks definitions updated in 2011(2).
4. Hallmarks illustrated
References:
1. Hanahan D. and Weinberg R.A. (2000) The Hallmarks of Cancer. Cell 100: 57-70.
2. Hanahan D. and Weinberg R.A. (2011) The Hallmarks of Cancer: The Next Generation. Cell 144: 646-674.
Two additional Emerging Hallmarks & Two Enabling Characteristics added in 2011(2).
5. Hallmarks Detailed
1. Acquired Capability: Self-Sufficiencyin growth signals /
Sustaining proliferative signaling
Acquired GS (growth signal) autonomy: Tumor cells generate many of their own growth signals, thereby reducing their
dependence on stimulation from their normal tissue microenvironment.
Three common molecular strategies for achieving GS autonomy include involving alteration of extracellular growth
signals, of transcellular transducers of those signals, or of intracellular circuits that translate those signals into action.
Cancer cells can also switch the types of extracellular matrix receptors (e.g. integrins) they express, favoring ones that
transmit progrowth signals.
The SOS-Ras-Raf-MAPK cascade plays a central role here. In about 25% of human tumors, Ras proteins are present in
structurally altered forms that enable them to release a flux of mitogenic signals into cells, without ongoing stimulation by
their normal upstream regulators.
6. Hallmarks Detailed
2. Acquired Capability :Insensitivity to anti-growth signals /
Evading growth suppressors.
STOP signals are disabled – in analogy to failed brakes. Normal cell division is controlled by tumor suppressor genes,
in cancer, these tumor suppressor proteins are altered so that they don't effectively prevent cell division, even when
the cell has severe abnormalities.
Normal cells response to antigrowth signals is associated with the cell cycle clock, specifically the components
governing the transit of the cell through the G1 phase of its growth cycle.
Antigrowth circuit converge onto tumor suppressors encode the RB (retinoblastoma-associated) and TP53 proteins
that operate as nodes in cellular regulatory circuits that govern the decisions of cells to proliferate or, alternatively,
activate senescence and apoptotic programs.
Cell proliferation depends on avoidance of cytostatic antigrowth signals. It is apparent that tumor cells use various
strategies to avoid this terminal differentiation. One strategy for avoiding differentiation directly involves the c-myc
oncogene, which encodes a transcription factor.
7. Hallmarks Detailed
3. Tissue invasion & metastasis / Activating invasion &
metastasis.
In most human cancer, primary tumor masses spawn pioneer cells that move out, invade adjacent tissues,
and thence travel to distant sites where they may succeed in founding new colonies, this process of metastases—
are the cause of 90% of human cancer deaths. Invasion and metastasis are exceedingly complex processes, and their
genetic and biochemical determinants remain incompletely understood.
Several classes of proteins are alerted in cells possessing invasive or metastatic capabilities. These include
cell–cell adhesion molecules (CAMs)—notably members of the immunoglobulin and calcium-dependent cadherin families,
both of which mediate cell-to-cell interactions—and integrins.
The multistep process of invasion and metastasis has been schematized as a sequence of discrete steps, often termed the
invasion-metastasis cascade that includes: local invasion, then intravasation by cancer cells into nearby blood and lymphatic
vessels, transit of cancer cells through the lymphatic and hematogenous systems, followed by escape of cancer cells from the
lumina of such vessels into the parenchyma of distant tissues (extravasation), the formation of small nodules of
cancer cells (micrometastases), and finally the growth of micrometastatic lesions into macroscopic tumors, this last step
being termed “colonization.”
8. Hallmarks Detailed
4. Limitless replicative potential / Enabling replicative
immortality.
All mammalian cells carry an intrinsic, cell-autonomous program that limits their multiplication to 60–70 doublings,
also known as Hayflick limit, after which they reach senescence.
The senescence of cultured human fibroblasts can be circumvented by disabling their pRb and p53 tumor suppressor
proteins, enabling these cells to continue multiplying for additional generations until they enter into a second state termed
crisis that results in massive cell death and occasional immortalized cell able to multiply without limit.
The counting device for cell doublings is the telomere, which decreases in size (loses nucleotides at the ends of
chromosomes) during each cell cycle. About 85% of cancers upregulate telomerase to extend their telomeres and the
remaining 15% use a method called the Alternative Lengthening of Telomeres.
Telomerase, the specialized DNA polymerase that adds telomere repeat segments to the ends of telomeric DNA,
is almost absent in non-immortalized cells but expressed at functionally significant levels in the vast majority (∼90%) of
spontaneously immortalized cells, including human cancer cells. These cells acquire the unlimited replicative potential—
termed cellular immortality—that is required to spawn large tumor masses.
9. Hallmarks Detailed
5. Sustained angiogenesis / Inducing angiogenesis
Like normal tissues, tumors require sustenance in the form of nutrients and oxygen as well as an ability to evacuate
metabolic wastes and carbon dioxide. The tumor-associated neovasculature, generated by the process of angiogenesis,
addresses these needs.
The cells within aberrant proliferative lesions initially lack angiogenic ability, curtailing their capability for expansion.
In order to progress to a larger size, incipient neoplasias must develop angiogenic ability
The ability to induce and sustain angiogenesis seems to be acquired in a discrete step (or steps) during tumor development,
via an “angiogenic switch” from vascular quiescence. Tumors appear to activate the angiogenic switch by
changing the balance of angiogenesis inducers and countervailing inhibitors.
The angiogenesis-initiating signals are exemplified by vascular endothelial growth factor (VEGF) and acidic and basic
fibroblast growth factors (FGF1/2). Each binds to transmembrane tyrosine kinase receptors displayed by endothelial cells
10. Hallmarks Detailed
6. Evading apoptosis / Resisting cell death.
The ability of tumor cell populations to expand in number is determined not only by the rate of cell proliferation but
also by the rate of cell attrition. Programmed cell death—apoptosis—represents a major source of this attrition.
Evidence suggest that that acquired resistance toward apoptosis is a hallmark of most and perhaps all types of cancer.
The apoptosis machinery can be broadly divided into two classes of components—sensors and effectors. The sensors
are responsible for monitoring the extracellular and intracellular environment for conditions of normality or
abnormality that influence whether a cell should live or die. These signals regulate the second class of components,
which function as effectors of apoptotic death e.g. IGF-1/IGF-2 ligand pair via their receptor.
The ultimate effectors of apoptosis include an array of intracellular proteases
termed caspases.
11. Emerging Hallmarks Detailed
7. Deregulating cellular energetics.
Since early twentieth century Otto Warburg first observed an anomalous characteristic of cancer cell energy metabolism:
even in the presence of oxygen, cancer cells can reprogram their glucose metabolism, and thus their energy production,
by limiting their energy metabolism largely to glycolysis, leading to a state that has been termed “aerobic glycolysis.”
Cancer cells exhibiting the Warburg effect upregulate glycolysis and lactic acid fermentation in the cytosol and prevent
mitochondria from completing normal aerobic respiration (oxidation of pyruvate, the citric acid cycle, and the
electron transport chain).
A functional rationale for the glycolytic switch in cancer cells has been elusive, given the relatively poor efficiency of
generating ATP by glycolysis relative to mitochondrial oxidative phosphorylation.
Altered energy metabolism is proving to be as widespread in cancer cells as many of the other cancer-associated traits
that have been accepted as hallmarks of cancer.
12. Emerging Hallmarks Detailed
8. Avoiding immune destruction
Unresolved issue surround the role that the immune system plays in resisting or eradicating formation and progression of
incipient neoplasias, late-stage tumors, and micrometastases.
Immune surveillance is supposed to be responsible for recognizing and eliminating the vast majority of incipient cancer cells
and nascent tumors, in practice though solid tumors that do appear have somehow managed to avoid detection by the
various arms of the immune system or have been able to limit the extent of immunological killing, thereby evading
eradication.
The role of defective immunological monitoring of tumors would seem to be validated by the striking increases of certain
cancers in immunocompromised individuals.
However, it may be too simplistic to assume highly immunogenic cancer cells may well evade immune destruction by
disabling components of the immune system that have been dispatched to eliminate them.
Immunoevasion is presented as another emerging hallmark, whose generality as a core hallmark capability remains to be
firmly established.
13. Emerging Characteristics Detailed
9. Genome instability & mutation
A diverse array of defects affect various components of the DNA-maintenance machinery—often referred to
as the “caretakers” of the genome.
Caretaker genes are responsible for 1) detecting DNA damage and activating the repair machinery,
(2) directly repairing damaged DNA, and (3) inactivating or intercepting mutagenic molecules before they have damaged the
DNA.
Caretaker genes behave much like tumor suppressor genes, in that their functions can be lost during the course of tumor
progression, with such losses being achieved either through inactivating mutations or via epigenetic repression.
Telomerase is also now been added to the list of critical caretakers responsible for maintaining genome integrity
Advances in economical DNA-sequences reveal distinctive patterns of DNA mutations in different tumor types. In the not-
too-distant future, the sequencing of entire cancer cell genomes promises to clarify the prevalence of ostensibly random
mutations scattered across cancer cell genomes. Thus, recurring genetic alterations may point to a causal role of particular
mutations in tumor pathogenesis.
14. Emerging Characteristics Detailed
10. Tumor promoting inflammation
By 2000, there were already clues that the tumor-associated inflammatory response had the unanticipated,
paradoxical effect of enhancing tumorigenesis and progression, in effect helping incipient neoplasias to acquire
hallmark capabilities.
It is now believed that inflammation can contribute to multiple hallmark capabilities by supplying bioactive molecules to
the tumor microenvironment, including growth factors that sustain proliferative signaling, survival factors that limit cell
death, proangiogenic factors, extracellular matrix-modifying enzymes that facilitate angiogenesis, invasion, and metastasis,
and inductive signals that lead to activation of EMT and other hallmark-facilitating programs.
Importantly, inflammation is in some cases evident at the earliest stages of neoplastic progression and is demonstrably
capable of fostering the development of incipient neoplasias into full-blown cancers.
Additionally, inflammatory cells can release chemicals, notably reactive oxygen species, that are actively mutagenic for
nearby cancer cells, accelerating their genetic evolution toward states of heightened malignancy.