The promise of precision cancer medicine is that we will be able to pair clinical and genomic data to provide better and more efficient treatment for cancer care. Although the focus is on the optimal pairing of existing Food and Drug Administration-approved drugs with the patient׳s tumor, precision medicine should also help determine a patient׳s risk for disease progression. Precision medicine will hopefully also lead to improved molecular biomarkers. The specific needs for predictive biomarkers vary significantly based on cancer type. The chief aim for prostate cancer biomarker development is to help distinguish indolent from aggressive disease.