Type I and III of SRD5A coexist in prostate cancer cells to boost the AR pathway and support prostate cancer initiation and progression, thus downregulating either SRD5A1 or SRD5A3 may restrict the AR pathway and further inhibit the growth of prostate cancer cells (Uemura et al., 2008; Godoy et al., 2011). The gene discussed is SRD5A1; the disease is prostate cancer.