Cancer Genetics – Oncogenes and Tumor Suppressors
Cancer is fundamentally a genetic disease. It arises from the accumulation of mutations that allow cells to divide uncontrollably and evade programmed cell death (apoptosis).
Drivers of Malignancy
Oncogenes: These are mutated versions of normal genes (proto-oncogenes) that promote cell growth. When stuck in the "on" position, they drive rapid cell division.
Tumor Suppressor Genes: These genes normally act as "brakes" on cell division or repair DNA damage. Mutations that inactivate these genes (like the BRCA1 or p53 mutations) remove these protections.
Somatic vs. Germline Mutations
Most cancers are caused by somatic mutations—acquired during a lifetime due to environmental factors. However, germline mutations are inherited from parents and predispose individuals to "hereditary cancer syndromes."