P Z 0.0016). Within the 100 genes, enriched biological functions relate to clusters of genes governing protein degradation, RNA processing, apoptosis, the cell cycle, ATP synthesis, and a large cluster of genes relating to protein localization. Conclusion: We have identified three novel intrinsic subtypes of prostate cancer in the largest study of its kind, and validated our findings across sequencing platforms, storage methods, and within both retrospective and prospective cohorts. In defining unique biological clusters of disease, the PC100 represents a step towards personalization of prostate cancer care. Future work will focus on validating the predictive capacity of these subtypes to therapy such as radiation therapy.