1. Carcinogens and Other Contributing Factors

2. Carcinogens (cancer “causing” agents) affect cells at the DNA level
They can change proto-oncogenes into oncogenes
They can affect the “good” defenses during neoplastic transformation

3. Carcinogen?

4. Contributing Factors to Cancer:
1. Genetics: Some people are more susceptible to specific carcinogens

5. Ex. About 10% of breast cancers are inherited
Mutation in either the BRCA 1 or BRCA 2 gene

6. 2. Electrolyte exposure:
Electrolytes: any substance containing free ions that behave as an electrically conducive medium
Act as free radicals
Exposure to high concentrations of specific metal ions

7. Nickel

9. 3. Carcinogenic chemical exposure
There are over 600 chemicals found in human tissue that are not part of our bodies
Many of these act as free radicals
Examples: cigarette smoke, pesticides---DDT, insulation (asbestos)

10. Build up of normal background radiation over many years of exposure
X-ray, uranium, plutonium exposure
Ex. Chernobyl

12. 5. Chronic Sub-lethal Tissue Damage:
Tissue is damaged enough to form a tumor, but not enough for cell death to occur
Ex. Polyps—constant irritation

14. 6. Viruses:
Viruses interact with the cell’s DNA and can lead to neoplastic transformation
Ex. HPV, Epstein Bar Virus, hepatitis

16. 7. Hormonal Imbalances:
Too much of a hormone can influence the production of neoplasms
20% of breast cancers are hormonally sensitive

17. In the 1940s, researchers found that mixing synthetic estrogen into the cattle feed resulted in the cows gaining weight faster
Ranchers found that the cows did not miscarry when given the hormone

18. Doctors began prescribing it for pregnant women (called DES)
Women gave birth to healthy children…however
When the female babies reached puberty, doctors began to see many cases of infertility and vaginal cancer