CANCERCANCERA. THE NATURE OF CANCER

def - sudden uncontrolled growth of cells

1. FEEDS ON THE BODY’S NUTRIENTS

RESULTS FROM ANGIOGENESIS - FORMATION OF NEW BLOOD VESSELS

2. DEPLETES BODY’S SUPPLY OF NUTRIENTS

AMINO ACIDS, GLUCOSE, FATTY ACIDS

3. BLOCKS PASSAGEWAY FOR MATERIAL FLOW

4. DISRUPTS, OR PREVENTS PROTEIN SYNTHESIS

5. SECRETE PROTEASES

LEADS TO METASTASIS

6. BLOCKS DIFFERENTIATION

CELLS PRODUCED LACK SPECIALIZATION, THEIR FUNCTION IS THEREFORE INHIBITED

7. NO CONTACT INHIBITION

LEADS TO METASTASIS CELLS MOVE OVER UNDER

AND THROUGH NEIGHBORING CELLS

8. LACK ANCHORAGE DEPENDENCY

CELLS FLOAT FREELY CELLS DO NOT REMAIN AT

ORIGINAL SITE LEADS TO METASTASIS

9. GENETIC INSTABILITY

HIGH MUTATION RATE LEADS TO DRUG RESISTANCE CONTAIN GENETIC

ABBERRATIONS

10. GROWTH FACTOR REQUIREMENTS ARE LOW

RECEPTORS TO REGULATE GROWTH MALFUNCTION

IT DOESN’T REQUIRE MUCH TO INITIATE GROWTH

B. POSSIBLE CONTRIBUTING FACTORS

1. GENETIC PREDISPOSITION 2. CARCINOGENS 3. DIET 4. RADIATION 5. VIRUSES

C. MOLECULAR LEVEL

1. ONCOGENES – GENES THAT TRIGGER RAPID CELL DIVISION

(GAS PEDAL) FORM WHEN PROTO-ONCOGENES

MUTATE TO FORM ONCOGENES

discovery discovered because of a viral link

to some cancers and also from the ability to transfer genes from cancer cells to normal cells resulting in cancerous growth in the previously normal cells. THIS IS KNOWN AS TRANSFORMATION

2. TUMOR SUPPRESSOR GENES

GENES THAT SUPPRESS CELL GROWTH, KEEP IT IN CHECK

discovery - from the fusion of a normal cell

with a cancer cell resulting in no cancer activity

ex. - retinoblastoma - arises from a deletion of a gene on chromosome #13

p53 gene

tumor suppressor gene found on chromosome #17 plays a role in lung, breast,

colon/rectal cancers some leukemias and lymphomas - about 1 out of 3 cancers

3. DNA REPAIR GENES

OVER 130 HAVE BEEN IDENTIFIED MAY BE INVOLVED IN MANY KINDS OF CANCERS XERODERMA PIGMENTOSUM

E. RESULTS 1. GROWTH SURROUNDED BY

A MEMBRANE 2. ANGIOGENESIS 3. ENZYMES RELEASED BY

CANCER CELLS DISSOLVE THE MEMBRANE

4. CANCER METASTASIZES

5. CANCEROUS GROWTHS SPRING UP ELSEWHERE

F. HOW CANCER ELUDES THE IMMUNE SYSTEM

1. CANCER CELLS ARE SELF CELLS, SOMETIMES THE CHANGE IN SURFACE PROTEINS IS SO SLIGHT THAT IT GOES UNNOTICED

2. THEY CAN EMIT DECOY ANTIGENS INTO THE BLOODSTREAM IN HIGH NUMBERS, AS ANTIBODY BINDS TO DECOYS, TUMOR GOES UNNOTICED

3. NON COMPLEMENT BINDING ANTIBODIES SURROUND BUT DO NOT HARM THE TUMOR

4. PIECE OF TUMOR BREAKS OFF - CLUMP IS DESTROYED, IMMUNE SYSTEM’s RESPONSE FOCUSED ON THE CLUMP, TUMOR REMAINS - A STATE OF SUPPRESSION OCCURS

5. ANTI-ANTIBODIES SHUT DOWN AN ATTACK, ALONG WITH T SUPPRESSOR CELLS

G. PREVENTION

1. HABITS smoking excessive alcohol consumption excessive exposure to the sun diet (low fat, high fiber, low in

pickled, smoked, cured foods

2. POSSIBLE POSITIVE ACTIONS

intake of vitamins A, C, D,E beta carotene calcium avoid exposure to carcinogens,

radiation, sunlight

H. WARNING SIGNS

CHANGE IN BOWEL/BLADDER HABITS

A SORE THAT DOES NOT HEAL

UNUSUAL BLEEDING OR DISCHARGE

Thickening or lump in breast or elsewhere

Indigestion or difficulty in swallowing

Obvious change in wart or mole Nagging cough or hoarseness

I. EARLY DETECTION/SCREENING

PAP SMEAR - cervical carcinoma Breast/testicular self exam Prostate/ colon-rectal exams Mammography Annual exams Ames Test – for carcinogenicity

SOME CANCERS CANNOT BE OR ARE NOW DIFFICULT TO DETECT AT EARLY STAGES – ESPECIALLY LUNG CANCERS

J. TREATMENTS 1. SURGERY 2. RADIATION 3. CHEMOTHERAPY 4. IMMUNOTHERAPY-active – ex

cancer vaccines and passive -ex monoclonal antibodies

5. PROTON THERAPIES – easier to aim, cancer cells poor at repair

6. ANGIOSTATIC DRUGS7. GENE THERAPY8. BONE MARROW

TRANSPLANTATION9. HORMONE THERAPY –

tamoxifen to block estrogen receptors in breast cancer

10. COMBINATION THERAPIES11. HIGH INTENSITY

THERAPIES

12. PHOTODYNAMIC

THERAPY – photosensitizing agent injected, remains in cancer cells longer, 2-3 d later exposed to light

13. TARGETED THERAPIES- Enzyme inhibitors- Apoptosis inducing drugs- gleevec

FUTURE? GENE THERAPY? PROBLEM OF

DELIVERY MORE TARGETED APPROACHES CLASSIFY CANCER

ACCORDING TO THE MUTATION, NOT THE LOCATION

Go to the following web site:

www.goorulearning.org Look up cancer – diagnosis and treatment