Cancer-Critical Genes II: Tumor Suppressor Genes

Cancer-critical genes are a group of genes that, upon mutation or alteration, contribute to the development of cancer. 

These genes can be categorized into two major classes based on how the mutation affects gene activity - proto-oncogenes and tumor-suppressor genes.

Tumor-suppressor genes generally encode proteins that inhibit cell proliferation and trigger cell apoptosis – either directly or indirectly.

A loss-of-function mutation occurring in a single allele of the tumor-suppressor gene does not necessarily affect the gene’s overall function as the loss-of-function mutations act in a recessive manner.

Hence, both the alleles must lose their function to cause the uncontrolled proliferation of cells.

For example, the inactivation of the tumor suppressor gene, p53 has been identified in various human cancers, including leukemia and lymphoma.