KLK3 and prostate small cell carcinoma: Particularly, LNCaP cells express androgen receptors (AR) and prostate-specific antigen (PSA), are androgen-dependent and similar to most of the prostate cancer encountered clinically; on the other hand, PC3 cells do not express AR and PSA, are androgen-independent, show highly aggressive behavior, possess higher migratory capability than LNCaP cells, and show features that are characteristic of prostatic small cell neuroendocrine carcinoma (Seim et al. 2017; Tai et al. 2011).