Molecular Mechanism of Carcinogenesis

Abstract

Most of the genetic changes in cancer consist of two categories: gain of function mutations in proto-oncogenes stimulating cell growth, division, and survival and loss of function mutations in tumor suppressor genes which normally check unrepressed cellular growth and promote DNA repair and commencement of cell cycle checkpoints (Lee and Muller 2010). The genes involved in cell cycle control, apoptosis, DNA repair, aging and immortalization, angiogenesis, and metastasis play a significant role in cancer. The most important genes affecting cell growth and mutation in cancers are oncogenes and tumor suppressor genes. The modifications are generally somatic events, while germ line mutations predispose a person to heritable or familial cancer passing on to future generations. A single genetic mutation may not be sufficient for the development of a malignancy but a multistep process of sequential alterations in a number of tumor suppressor genes, oncogenes, and DNA repair mechanisms (Croce 2008).