Growth Factors Receptors G factors protein kinases transcription factors 2. Explain why approximately six mutations are required to produce cancerous cells. Explain why larger abnormally growing precancerous masses of cells are more dangerous than smaller masses. Explain the natural protective systems available in humans to stop the development of cancer. Explain why a defect in proofreading newly synthesized DNA can lead to an increased rate of colon cancer.
Cancer results from mutation.
Explain why mutations to produce oncogenes should be much less common than mutations to inactivate suppressors. Explain away the apparent contradiction between the need for several mutations to produce cancer and the ability to transfer a single gene to a cell line to produce cancerous clones. Discuss the medical and social repercussions of cancer and subsequent treatments. Explain why some carcinogens are not mutagens and vice versa. Refer to the Ames test.