tumor suppressor gene

The cell cycle. Many tumor suppressors work to regulate the cycle at specific checkpoints in order to prevent damaged cells from replicating. A tumor suppressor gene (TSG), or anti-oncogene, is a gene that regulates a cell during cell division and replication. When a tumor suppressor gene is mutated, it results in a loss or reduction in its function. In combination with other genetic mutations, this could allow the cell to grow abnormally. The loss of function for these genes may be even more significant in the development of human cancers, compared to the activation of oncogenes.

TSGs can be grouped into the following categories: caretaker genes, gatekeeper genes, and more recently landscaper genes. Caretaker genes ensure stability of the genome via DNA repair and subsequently when mutated allow mutations to accumulate. Meanwhile, gatekeeper genes directly regulate cell growth by either inhibiting cell cycle progression or inducing apoptosis. Lastly, landscaper genes regulate growth by contributing to the surrounding environment, and when mutated, can cause an environment that promotes unregulated proliferation. The classification schemes are evolving as medical advances are being made from fields including molecular biology, genetics, and epigenetics.