[medhahegde]

In humans the genes BRCA1 and BRCA2 are involved in tumor suppressor protein production. These proteins play a key role in the up keeping of the genetic material stability by repairing the damaged DNA. An alteration or mutation in either of the genes results in non functional protein product which is incapable of repairing the damaged DNA accurately. As a consequence the cells are more liable to accumulate additional genetic mutations that can direct the cell to become cancerous.

The inherited mutations in the genes BRCA1 and BRCA2 elevate the risk of breast and ovarian cancers in the females and also the genes have been linked with increased risks of developing various other cancer types. The mutations in BRCA1 and BRCA2 genes collectively account for around 20 to 25% of the breast cancers that are hereditary and around 5 to 10% of all breast cancers. Additionally the mutations in the two genes also account for about 15% of overall ovarian cancers. In comparison to the sporadic breast cancers the breast cancers associated with hereditary mutations in genes BRCA1 and BRCA2 develop at young age.

The p53 (TP53) gene encodes proteins that control the cell cycle and hence plays a key role in tumor suppression. The gene is described by the scientists as the guardian of genome as it is vital for the cells of multi-cellular creatures in cancer suppression. The name is derived from its molecular weight (53 kilodalton fraction of the cell proteins).The individual who inherits only one functioning copy of the gene p53 is prone to cancer and generally acquires various independent tumors in the adulthood. This rare condition is termed as Li-Fraumeni syndrome. Nevertheless, p53 gene mutations are found in many tumor varieties and therefore contribute to the complicated molecular events resulting in tumor formation. The gene p53 is present on chromosome number 17 of human beings.