b) Since proto-oncogenes represent distinct liabilities for an organism, in that they can incite cancer, why have these genes not been eliminated from the genomes of mammals? c) Overexpression of the Myc protein is a common feature of many types of cancer cells, contributing to their excessive cell growth and proliferation. By contrast, when Myc is overexpressed in most normal cells, the result is not excessive proliferation, but cell-cycle arrest or apoptosis. How do you suppose that overexpression of Myc can have such diļ¬€erent outcomes in normal cells and in cancer cells? b) the proto-oncogenes have not been eliminated because they are neccessary for the cell to live/ reproduce. c) due to a translocation - every time it wants to downregulate myc it actually upregulates it