QUESTION 3
1. Describe the normal cellular functions of tumor suppressorgenes and explain their roles in cancer. List all possiblemechanisms by which tumor suppressor genes are inactivated andexplain. Explain why loss-of-heterozygosity of a particularchromosome/chromosomal region in tumor DNA suggests the existenceof a tumor suppressor gene in that region.
2. Why is pRB function compromised in human tumors throughmutations of its encoding gene while the genes encoding its twocousins, p170 and p130, have virtually never been found to suffermutations in the genomes of cancer cells?
