Question

8. Are missense or nonsense mutations more likely to be the underlying cancer causing mutations in a) oncogenes, b) tumor suppressor genes? Explain your reasoning?

Answer 1

8. complexity of each cancer genome is far greater than expected and that extensive variations exist between different cancer types as well as between different tumor samples of the same cancer type.mostly MISSENSE mutations are more likely to be underlying cancer causing mutations in tumor supprssor gene than oncogene.The effects of mutations on protein function, with respect to their cancer transforming ability, can drastically differ in tumor suppressor genes (TSG) and oncogenes,In general, mutations in TSG can cause cancer through the inactivation of their products, whereas mutations in oncogenes may result in protein activation.

structural effects of mutations have found that disease mutations primarily occur in the protein core. This trend was confirmed only for the set of tumor suppressors. In contrast, core residues in oncogenes are significantly less often mutated than expected by chance.specific mutations of functional sites that can either disable enzymatic activity and regulatory mechanisms or increase protein activity are often responsible for oncogene activation.

most frequently mutated types of functional sites in oncogenes are ATP and GTP binding sites and that the frequency of mutation is significantly higher than expected. This suggests that mutations of ATP and GTP binding sites are specific and common mechanisms of oncogene activation.

silent mutations have significantly higher average mutability values than nonsense or missense mutations .