SRD5A1 and prostate cancer: Additionally, it remains controversial how the 5α-reductase level changes with prostate cancer development and progression, as shown in a recent study by Wako et al. [42]: using semiquantitative immunohistochemical analysis, they found no significant change in SRD5A1 and SRD5A2 levels between localized prostate cancer samples and normal prostatic tissues.