Overview of CB1R expression in prostate tissue. Prostate tissue sections were obtained after RP of four patients (original magnification ×100). In non-tumoural prostatic epithelium in general, no expression was seen (A), although some randomly distributed areas of weak positivity were noted (B). In PCa, the overall expression pattern was a mixture of negative (C) and weak positive (D) areas. Some foci of moderate positivity were randomly dispersed (E). CB1R expression in the seminal vesicles was used as an internal positive control (F).