The Neurofibromin 1 gene is a negative regulator of the Ras oncogene signal transduction pathway. Eventually this normal gene mutated into an abnormally functioning oncogene within the Rous sarcoma virus. Gene amplification is among the most common mechanisms of oncogene activation. Cancers usually result from disruption of a tumor repressor or dysregulation of an oncogene. Upregulation of BRAFP1 led to an overexpression of the BRAF oncogene. One example is the Myc oncogene, which has important roles in cell growth and apoptosis. The viral oncogene was derived from cellular genome. This allows the retrovirus to implant nearby a cellular oncogene. SRC was first discovered as an oncogene in a chicken retrovirus. The gene that codes for FAS has been investigated as a possible oncogene. This protein is the ligand for MLP/C MPL, the product of myeloproliferative leukemia virus oncogene. The resultant protein encoded by an oncogene is termed oncoprotein. The gene for Sox2 lies within this region, which effectively characterizes Sox2 as an oncogene. It was the first retroviral oncogene to be discovered. She wrote her thesis on neu, a non-Ras oncogene.