AFP and neoplasm: Hormones released locally by the tumor, such as beta-human chorionic gonadotropin (b-HCG), alpha-fetoprotein (AFP), and lactate dehydrogenase (LDH), are hypothesized to increase estradiol levels in the testis, thus affecting spermatogenesis, as estrogens may inhibit the high intratesticular testosterone concentrations required for spermatogenesis [27,28].