Understanding of the molecular mechanisms of tumor development has improved considerably over the past 25 years, dramatically altering strategies for the treatment of cancer as well as spurring development of new cancer therapies. The discovery of molecular targets that are crucial for the initiation and progression of malignant diseases has contributed to development of a number of molecularly targeted cancer therapies, with some offering considerable benefit for cancer patients in terms of efficacy and tolerability compared with traditional systemic chemotherapy. Enhanced understanding of molecular mechanisms has also allowed health care providers to tailor treatments with these new molecularly targeted therapies and existing cancer therapies, based on their patient?s germline, tumor predictive genomic biomarkers, and/or prognostic biomarkers. Predictive biomarkers are markers that are predictive of treatment response, whereas prognostic biomarkers are those that indicate patient survival independent of therapy received.
