Overexpression of 5 alpha-reductase type 1 increases sensitivity of prostate cancer cells to low concentrations of testosterone.

Introduction: Conversion of testosterone to dihydrotestosterone (DHT) by the enzymes 5 alpha-reductase types 1 (5 alpha R1) and 2 (5 alpha R2) is important for normal and pathological growth of the prostate. The predominant isoenzyme in normal prostate is 5 alpha R2. However, prostate cancer (PCa) development is accompanied by a decrease in 5 alpha R2 and an increase in 5 alpha R1.

Type 1 and type 2 5alpha-reductase expression in the development and progression of prostate cancer.

Objectives: Both normal and pathological growth of the prostate is dependent on dihydrotestosterone (DHT) synthesis, which is catalysed by two 5alpha-reductase (5alphaR) isoenzymes, 5alphaR1 and 5alphaR2, of which only 5alphaR2 has traditionally been viewed as important in the prostate. The objective of this study was to evaluate the role of both isoenzymes during development/progression of prostate cancer.

Methods: A thorough literature search was performed with the MEDLINE database to identify studies that have assessed expression of 5alphaR1/2 in prostate tissue.

Levels of 5alpha-reductase type 1 and type 2 are increased in localized high grade compared to low grade prostate cancer.

Purpose: In the prostate testosterone is converted to dihydrotestosterone by 5alpha-reductase type 1 and/or 2. Although 5alpha-reductase type 2 is predominant in normal prostates, type 1 is increased in cancer vs benign tissue. It is unclear whether 5alpha-reductase type 1/2 levels correlate with cancer grade.