tumor suppressor gene
Gene that normally prevents cancer development; loss of function contributes to malignant transformation.
Full Definition
Tumor suppressor genes are normal genes that protect cells from becoming cancerous by regulating cell division, promoting DNA repair, or triggering programmed cell death when damage is irreparable. Loss of tumor suppressor gene function through mutation, deletion, or epigenetic silencing removes these protective mechanisms and contributes to cancer development. Classic examples include p53 (the 'guardian of the genome'), RB (retinoblastoma gene), APC (associated with colorectal cancer), and BRCA1/BRCA2 (breast cancer susceptibility genes). Unlike oncogenes, tumor suppressor genes follow Knudson's two-hit hypothesis, requiring loss of both alleles for cancer development.
Usage
Usage note: Contrast with oncogenes, which promote cancer when activated rather than when lost.
In Context
- "Genetic testing revealed a pathogenic mutation in the p53 tumor suppressor gene." — Genetic counseling report
- "Loss of function in tumor suppressor genes was identified through sequencing analysis." — Molecular pathology report