Editorial

Hung T KhongUniversity of South Alabama, Mitchell Cancer institute, Mobile, AL, USAWith the completion of the human genome project and the explosion of knowledge derived from genomics, proteomics, metabolomics, and other-omics, there are a vast and ever increasing number of potential druggable targets and therapeutic candidates. Each of these targets can be considered a potential biomarker that serves as a risk assessment tool and/or a biological predictor of prognosis and treatment outcome. For example, the risk of developing breast cancer in a woman who has inherited a deleterious breast cancer antigen (BRCA)1 mutation is five times that of a woman in the general population.1 When cells are damaged by chemotherapy, DNA damages are often repaired by the BRCA pathway. In cells that are deficient in BRCA functionality, an alternative pathway such as the base excision repair pathway is utilized. This pathway is dependent on poly (ADP-ribose) polymerase (PARP) being fully functional.2 Therefore, BRCA1-deficient cancer cells are exquisitely sensitive to the combination of PARP inhibitor and chemotherapy.3,4 In this case, BRCA1 serves as a biomarker for both risk of developing breast cancer and favorable outcome to certain treatments.