Reproduction and the APUD system.

Substantial evidence for involvement of the APUD system in the normal reproductive tract is limited to the prostate gland and uterine cervix. Most supportive data simply documents the presence of neuro-endocrine cells in these tissues. A biological product(s) or role(s) remains to be discovered, but appears likely in the prostate. Tumors possessing cells with APUD characteristics have been described in many reproductive tissues including the prostate, cervix, endometrium, ovary, and testes. These tumors are generally aggressive in behavior, and optimum therapy needs to be determined.