Retinoblastoma Gene Mutations in Human Cancer

The retinoblastoma gene (RB) was identified because of germ-line mutations that strongly predisposed infants with the mutant gene to a rare cancer of the retina. However, the RB protein turned out to be a regulator of transcription in all cells of adults. The active form of the protein represses the expression of genes required for cells to proceed through the cycle of cell division. Phosphorylation, mediated by a complex of several proteins regulated by the cell cycle (a cyclin and a cyclin-dependent kinase), inactivates the RB protein, allowing cell division to begin. It is easy to understand that mutations resulting . . .