Biomarker testing or genetic testing is a group of tests that looks for the molecular signs of health so that doctors can treat with best care. Biomarkers, foundation of precision oncology, are very important in management of gastro-esophageal cancer, breast cancer and lung cancer. Testing practices are intensely deliberated, influencing diagnostic quality and affecting pathologists, oncologists and patients. The advances in biomarker testing are mainly in the fields of cancers in which divided in to Chromosomes tests, Gene tests & Biochemical tests. MicroRNA biomarkers, Insilco biomarkers and several other clinical biomarkers evolved in the recent research have opened to the path for biomarker testing broader.