A proto-oncogene is a normal cellular gene whose product regulates cell growth, differentiation, and the transduction of mitogenic signals; an oncogene is the mutated or dysregulated form of that gene, whose activity drives unregulated proliferation. Conversion from proto-oncogene to oncogene is a gain-of-function event that occurs through three mechanistic classes — mutation or deletion in coding or regulatory sequence, gene amplification or increased mRNA stability, and chromosomal rearrangement (translocation to a new regulatory context or fusion with an actively transcribed gene) — all of which reduce to one of two outcomes: a normal protein produced in excess, or a normal amount of a hyperactive protein. This concept belongs to cancer biology and molecular genetics, and it supplies the mechanistic basis for tumorigenesis as a dominant, gain-of-function disorder of growth signaling, complementary to the loss-of-function logic of tumor suppressors.
A proto-oncogene is a normal cellular gene whose product regulates cell growth, differentiation, and the transduction of mitogenic signals; an oncogene is the mutated or dysregulated form of that gen…