Cellular oncogenes, mutations and cancer.

The multistep nature of cancer suggested from chemical carcinogenesis studies, epidemiological data and cell culture experiments could be explained by the occurrence of somatic mutations resulting in inappropriate expression of normal cellular sequences which have an intrinsic potential of becoming cancer genes. The discovery that cancer genes could be transferred from one cell to another lends further support that cancer could be due to somatic mutations. Moreover, DNA transfer of cancer genes indicates that at least some of these mutations act dominantly in the transformed cells. The isolation and characterization of human cancer genes has now become a reality.