The role of oncogenes in cancer

Researchers have accumulated evidence suggesting that most human cancers are the result of multiple events involving many genes functioning at various levels of expression over a long period of time. Recently, an important segment of cancer research has focused on oncogenes, a group of altered normal genes. The normal genes, known as proto-oncogenes, encode proteins necessary for the cell's structure, growth, and mitotic activity. Oncogenes have been found to be the activated forms of proto-oncogenes, which become activated as a result of point mutations, nucleotide deletions/insertions, or chromosomal translocations. Approximately 50 types of oncogenes have been discovered to date, and research had led us to believe that oncogenes are derived from normal genes that regulate growth and development. A general discussion of oncogenes will be presented in this review.