Of the two classes of genes associated with cancer, tumor-suppressor genes and oncogenes, mutations in which group can be considered gain-of-function mutations? In which group are the loss-of-function mutations? Explain.

Key Concepts

Oncogenes

Oncogenes are mutated forms of normal genes (proto-oncogenes) that promote cell growth and division. Gain-of-function mutations in oncogenes lead to increased activity, resulting in uncontrolled cell proliferation, which can contribute to cancer development. Examples include mutations in the RAS gene, which can drive tumorigenesis by continuously signaling for cell division.

Tumor-Suppressor Genes

Tumor-suppressor genes are responsible for regulating cell growth and preventing tumor formation. Loss-of-function mutations in these genes result in a decrease or complete loss of their protective effects, allowing cells to grow uncontrollably. A well-known example is the TP53 gene, which encodes a protein that helps prevent the proliferation of cells with damaged DNA.

Mutations in Cancer Genetics

Mutations in cancer genetics can be classified into gain-of-function and loss-of-function categories. Gain-of-function mutations enhance the activity of oncogenes, promoting cancer, while loss-of-function mutations in tumor-suppressor genes diminish their ability to control cell growth. Understanding these mutations is crucial for developing targeted cancer therapies and interventions.