Tumor-suppressor genes versus Proto-oncogenes. This is a library-research topic in which you are required to provide your sources. Mutations in tumor suppressor genes can contribute to or cause cancer, just as mutations in proto-oncogenes can also contribute to or cause cancer. However, tumor suppressor genes are very different from proto-oncogenes.
· (a) What is the basic difference between a tumor suppressor gene and a proto-oncogene?
· (b) Explain why a gain-of-function mutation to a proto-oncogene (or its promoter) may be associated with increased risk of cancer.
· (c) Explain why a loss-of-function mutation to a tumor suppressor gene may be associated with increased risk of cancer.