5th March 2024

Tumour suppressor gene

Tumour suppressor genes typically produce the necessary enzymes and signalling proteins that control cell proliferation. This includes DNA repair mechanisms, inhibiting cell replication and inducing cell death via apoptosis. Most conditions involving tumour suppressor genes are inherited in an autosomal dominant fashion, while on a cellular level, the cells display a homozygous recessive pattern before displaying a malignant phenotype. This stems from the “2-hit theory”, whereby the initial genetic mutation provides the first hit against the tumour suppressor genes, making it more likely for a second mutation to occur in the other functioning copy of the gene, resulting in tumorigenesis.

Examples of such genes include the BRCA1/BRCA2 gene, RB1 gene in retinoblastomas, APC in familial adenomatous polyposis, TP53 in Li-Fraumeni syndrome, ATM gene in ataxic telangiectasia and NF1/NF2 genes in neurofibromatosis types 1 and 2 respectively.