Life / Biology & Genetics

Tumor Suppressor Genes

Genes that brake cell division cause cancer when both copies fail; the retinoblastoma gene, cloned in 1986, was the first, followed by p53 and BRCA1.

In 1971 Alfred Knudson studied 48 cases of the childhood eye cancer retinoblastoma and proposed that two separate hits, one per copy of a gene, are needed to start a tumor. In 1986 Friend, Weinberg, Dryja and colleagues isolated that gene, RB1, the first tumor suppressor gene cloned. p53, found in 1979 and shown to be a suppressor in 1989, is altered in a large share of human cancers, and BRCA1, mapped in 1990 and cloned in 1994, lets families with breast and ovarian cancer learn their risk.