oncogene /ong″kōjēn/ [Gk, onkos + genein, to produce] , a potentially cancer-inducing gene. Under normal conditions such genes play a role in the growth and proliferation of cells, but, when altered in some way by a cancer-causing agent such as radiation, a carcinogenic chemical, or an oncogenic virus, they may cause the cell to be transformed to a malignant state.
