TP53 encodes the p53 protein, a critical tumor suppressor that acts as a transcription factor to protect cells from damage. When activated by cellular stress such as DNA damage, p53 triggers responses including DNA repair, cell cycle arrest, and programmed cell death (apoptosis) to prevent the propagation of damaged cells. TP53 is the most frequently mutated gene in human cancers, and loss of its function contributes to tumor development, invasion, drug resistance, and genomic instability. Inherited mutations in TP53 cause Li-Fraumeni syndrome, a rare hereditary condition that greatly increases the risk of developing multiple types of cancer at a young age.

TP53 encodes the p53 tumor suppressor, whose loss of function drives cancer development and whose inherited mutations cause Li-Fraumeni syndrome. This p.Gly266Val variant is classified as a Variant of Uncertain Significance: it is absent from population databases and predicted damaging by Align-GVGD and BayesDel, but without variant-specific functional or familial evidence its impact on p53 tumor-suppressor function cannot yet be determined.