Cancer is a genetic disease that arises due mutations in growthpromoting genes (oncogenes) and in growth suppressing genes (tumorsuppressor genes). Mutations in oncogenes that can lead to cancerare gain-of-function mutations that result in the constitutiveactivation of the proteins encoded by these genes. An example ofsuch a gene is Ras, a gene mutated in over 90% of pancreaticcancers. When mutated, the Ras signaling is constitutively active,leading to uncontrolled cell growth. Tumor suppressor genes encodeproteins whose normal function is to prevent excessive cellsproliferation. Mutations in tumor suppressor genes are loss offunction mutations. When mutated, they are no longer able tosuppress excessive cell proliferation, leading to uncontrolled cellgrowth. Drugs that inhibit DNA methylation or histone acetylationare often used to treat cancer. Which drug is best to use dependson the nature of the mutated gene driving cancer cell growth.
A. Explain the effect DNA methylation inhibitor of would have ongene expression levels
B. Explain the effect a histone acetylation inhibitor of wouldhave on gene expression levels.
C. For pancreatic cancers driven by mutant Ras, which type oftreatment would be a more effective drug to use for treatment, onethat inhibits DNA methylation or one that inhibits histoneacetylation. Justify your answer.
D. For cancers that are driven by mutations in tumor suppressorgenes, would you recommend using the same drug as foroncogene-driven cancers? Why or why not?
