The first cancer-causing genes to be discovered were Oncogenes. The early insights into how neoplastic growth in cells occurred initially derived from studies of viruses that cause cancer in animals. The results produced from these experiments led to the identification of oncogenes. (Rous , 1910)(8) isolated a tumour from a barred Plymouth Roth hen and demonstrated that through a cell free filtrate , sarcomas can be induced into healthy chickens. The Rous Sarcoma Virus (RSV) was identified as the causative agent. (molecular biology of cancer). Further studies of RSV mutants by Peter Vogt (1971)(9) revealed that the RSV contained a single extra gene in its genome that did not function in viral replication. But were necessary to induce both transformation of fibroblast in tissue culture and sarcomas in chickens (oncogenes …show more content…
(molecular biology of cancer). The v-src gene encodes a 60kDa intracellular phosphoprotein called pp60src. (11) This protein possess kinase activity by catalysing the transfer of a terminal phosphoryl group of ATP to tyrosine residues. (11). (Bishop and Varmus 1976)(12) discovered that the gene sequence in v-src shared close similarities to the sequence found in normal DNA of a variety of bird species. Further studies (Spector 1978)(13) indicated that this gene could also be found in organisms such as fish and other mammals. Varmus and Bishop concluded that Src proto-oncogene (c-src) was the cellular homologue of the v-src gene. They hypothesised that retroviral oncogenes (v-src) are simply transformed versions of their cellular homologue- proto-oncogenes (c-src) that have been incorporated into the genome of the viral gene by recombination with host DNA, a process known as viral transduction (14). The RNA genetic codes from the retrovirus is used to generate complimentary pro virus DNA that is subsequently inserted into the DNA of a host cell(15). The retroviral DNA generated