(Science: molecular biology, oncology) Mutated and/or overexpressed version of a normal gene of animal cells (the proto-oncogene) that in a dominant fashion can release the cell from normal restraints on growth and thus alone or in concert with other changes, convert a cell into a tumour cell. A gene that causes normal cells to change into cancerous tumor cells.A viral [[ Gene causing cancer induction.
An oncogene is a modified gene, or a set of nucleotides that codes for a protein, that increases the malignancy of a tumor cell. Some oncogenes, usually involved in early stages of cancer development, increase the chance that a normal cell develops into a tumor cell, possibly resulting in cancer. New research indicates that small rnas 21-25 nucleotides in length called miRNAs can control expression of these genes by downregulating them.
The first oncogene was discovered in 1970 and was termed src (pronounced SARK). Src was in fact first discovered as an oncogene in a chicken retrovirus. Experiments performed by dr g. Steve martin of the university of California, Berkeley demonstrated that the src was indeed the oncogene of the virus. In 1976 Drs. J. Michael bishop and Harold E. Varmus of the university of California, San Francisco demonstrated that oncogenes were defective proto-oncogenes, found in many organisms including humans. For this discovery bishop and Varmus were awarded the Nobel Prize in 1989.