KLK3 and posterior cortical atrophy: Increasing evidence confirms that the less differentiated PSA (i.e. no and low expression of PSA [PSA−/low]) AR−/low cell subset in PCa exhibits CSC characteristics (e.g. gene expression profile and epigenetic modification, asymmetric cell division capacity, enhanced DNA damage repair capacity, and tumorigenic ability) similar to those of normal stem cells [41,76].