Androgens have been proposed to be actively produced in situ in human
prostate cancer. These locally produced
androgens have also been considered to play important roles in the pathogenesis and development of
prostate cancer. Therefore, it is important to examine the status of this in situ
androgen metabolism and/or synthesis in detail in order to improve the clinical response to hormonal
therapy in patients diagnosed with
prostate cancer. Several studies have previously demonstrated the expression of
androgen-producing
enzymes such as 5alpha-reductase types 1 and 2, and
17beta-hydroxysteroid dehydrogenase type 5 (17beta-HSD5), in human prostate
carcinoma cells. However, their
biological significance has remained largely unknown. In this study, we evaluated the immunoreactivities of these steroidogenic
enzymes in human
prostate cancer obtained from surgery (n = 70), and correlated the findings with clinicopathological features of the patients. 17Beta-HSD5 immunoreactivity was detected in 54 cases (77%), 5alpha-reductase type 1 in 51 cases (73%) and 5alpha-reductase type 2 in 39 cases (56%). 5Alpha-reductase type 2 immunoreactivity was significantly correlated with that of
androgen receptor (AR), and 17beta-HSD5 positive cases were significantly associated with clinical stage (TNM stage pT3 vs pT2). These data all suggest that
androgen-producing
enzymes, such as 5alpha-reductase type 1 and type 2, and 17beta-HSD5 are expressed in a majority of
prostate cancers, and are involved in the local production and actions of
androgens in
prostate cancers.