Tumor suppressor gene (TSG)

A **tumor suppressor gene** (TSG), also known as an anti-oncogene, is a gene that regulates and restrains cell division and replication to prevent uncontrolled cell growth. Typical functions include slowing down cell division, repairing DNA damage, and inducing programmed cell death (*apoptosis*) in cells where DNA is damaged beyond repair. When these genes become mutated or silenced, their loss of function can allow cells to grow uncontrollably, contributing to cancer development. Tumor suppressor genes include categories such as "gatekeepers" (directly regulate cell cycle and apoptosis), "caretakers" (maintain genome stability via DNA repair), and "landscapers" (influence the environment that surrounds cells)[1][2][3]. Mutations can be inherited (as in certain familial cancer syndromes like Li-Fraumeni or those involving BRCA1/2), or acquired during life. Drugs like azacitidine and decitabine act by reversing epigenetic silencing of these genes in tumors[1]. **Note:** "Growth suppressor gene" is an informal, non-standard synonym; the canonical and scientifically accepted term is "tumor suppressor gene" (TSG), representing a broad class of genes, not a specific molecule or receptor. Therefore, this group is not considered a therapeutic target in the same way as a protein receptor or enzyme; rather, specific tumor suppressor gene products such as p53 (encoded by TP53), BRCA1, BRCA2, or PTEN may be considered targets. For structured or database applications, refer to a specific gene or protein, not the general class.

Other names

anti-oncogene

Epigenetic reactivation of silenced genes (e.g., via DNA hypomethylation), Induction of apoptosis