2. CANCER
Abnormal faster growth of some tissues
is called as cancer.
They use all food of body.
They first damage the organ and then
entire body.
The cancer cells do not have definite life
span.
They divide until the body dies.
They do not have proteins regulating
cell division due to gene mutation.
3. TYPES OF CANCER
Sarcoma – Cancer in muscles,
cartilage, bones, blood vessels,
connective tissues.
Carcinoma – Cancer in skin or linings
of internal organs.
Lymphoma – Cancer in lymph glands
or lymph nodes.
Leukaemia – Cancer in blood
forming organs specially bone
marrow.
4. TYPES OF TUMERS
Benign Tumour :- Enclosed in
connective tissue, localised to
particular part of body.
Malignant Tumours :- Spread to
different parts of body called
metastasis.
5. TYPES OF TUMOURS
Benign Tumour :- Enclosed in
connective tissue, localised to
particular part of body.
Malignant Tumours :- Spread to
different parts of body called
metastasis.
6. CAUSES OF CANCER
Point mutation / mutation
Telomerase and cancer
Oncogenes
Protooncogenes
Tumour suppressor genes
Carcinogens – Dyes, chemicals, heavy
metals.
Excessive smoking / alcoholism Chewing
tobacco, betel nuts.
Ionic radiations as X-ray, gamma ray etc.
Pollutants as dust, smoke, chemicals etc.
7. Point mutation / mutation
A mutation in gene encoding for
protein regulating cell division causes
cancer.
It may be alteration of single
nucleotide (point mutation) or more
nucleotides (mutation).
e. g. – in case of ras induced bladder
cancer – change of a single Guanine
base with Thymine base can form
valine in place of glycine in the protein.
8. Telomerase and cancer
Telomerases are short sequences of
nucleotides, repeated thousands of times on
ends of chromosomes.
As DNA polymerase is unable to copy entire
chromosome, telomerasses are lost on every
cell division.
This inhibition of telomerase replication is
very effective break on cell division.
Any mutation, releasing telomerase inhibitor,
release this break and cause cancer.
e. g. – in human, ovarian tumour cells
telomerase inhibitor is found.
9. Oncogenes
Oncogenes are cancer causing genes.
e. g. – ras and myc genes. Expression of myc
gene form Cyclins and Cyclin-dependent
protein kinases (Cdks) but oncogene
mutation stop myc activation.
Protooncogenes
Oncogenes of acute transforming
retroviruses have homologous counterparts
in animal genomes called proto-oncogenes.
They participate in normal cell function.
A mutation or abarrant activation of
protooncogene causes tumour formation.
10. Tumour suppressor genes
In normal cells, cell division is switched off
by proteins that prevent binding of cyclins to
Cdks.
The genes coding these proteins are called as
Tumour Suppressor genes.
Their mutant alleles are genetically recessive.
e. g. – Rb proteins, p16, p21, and p53
proteins.
Carcinogens – These are cancer causing
agents such as Dyes, chemicals, heavy
metals, pollutants, dust etc..
11. Excessive smoking / alcoholism Chewing
tobacco, betel nuts
About one third of world cancer is caused by
cigarette smoking.
Active smoking – smoker himself / herself.
Passive smoking – persons near smoker.
Tertiary smoker – when some parts of
cigarette or tobacco fall on ground and
accidentally inhaled or ingested by others.
Tobacco smoke contain about 3000 chemical
components, most are mutagens for cancer.
Example is in the next slide :-
12. E. g. – Benzopyrene (BP) is a potent mutagen
in tobacco smoke. Lungs cells absorb BP and
chemically alter it into a derivative
Benzopyrene-diolepoxide (BPDE). BPDE
binds to tumour suppressor gene p53 and
mutate and hence inactivate it. P53 coding
for a protein to control G1 phase of cell cycle,
which is not coded by mutant. This
inactivation of p53 cause about 70% of lung
cancer.
Ionic radiations as X-ray, gamma ray etc. –
They may induce mutation and cause cancer.
13. Persistently growing mole or wart.
A thickening or hard part or lump in any
body part.
Persistent cough or hoarseness.
Difficulty in swallowing.
Persistent changing bowel movement.
Unusual bleeding.
Weight loss without any specific cause.
POSSIBLE SYMPTOMS OF CANCER
14. Biopsy of suspected tissue – (Taking a small sample
from any part of body for microscopic examination).
Study of blood and bone marrow sample
Microscopic examination of body fluids
Radiography
CT scan – Computerised Tomography
Magnetic Resonance Imaging.
Antibodies against cancer specific antigens are used
for certain cancer detection.
Transfection is a technique to isolate nuclear DNA
from tumour cells and cleaving it into fragments.
Each fragment is than individually tested to induce
cancer into assimilated cells.
DIAGNOSIS OF CANCER
15. Cancer cells - Grow through the walls of
blood vessels.
Carried by blood to other parts of body.
Pass through lymph vessels and lymph
glands.
Spread from tissue to tissue.
TRANSMISSION OF CANCER
16. Preventing initiation of Cancer
Preventing spread of cancer
Therapies
Surgery
Radiotherapy
Chemotherapy
Immunotherapy
TREATMENT OF CANCER
17. To check Growth factor, it is a protein
carrying the dividing signal for cells.
Relay signal or entry of signal into cell
interior by a muted protein Ras protein.
Amplification of signal in cytoplasm by
anti-sense RNA.
Removal of break of cell division.
Integrity of cell DNA by tumour
suppressor protein p53.
PREVENTING INITIATIION OF CANCER
18. Formation of small blood vessels to
supply tumours is called angiogenesis.
Angiogenesis inhibitors as angiostatin or
endostatin inhibit this and regress
tumours to microscopic size.
Preventing metastasis by inhibiting RhoC,
a GTP hydrolysing enzyme ( it favours
migration of cells by providing needed
GTP ).
PREVENTING SPREAD OF CANCER
19. Surgery :- Removal of cancerous parts by
surgery.
Radiotherapy :- Cancerous cells are killed
by irradiation.
Chemotherapy :- Cancerous cells are
killed by some chemicals.
Immunotherapy :- Body’s immune system
is activated against cancer by use of
monoclonal antibodies.
THERAPIES FOR TREATING CANCER