AKR1C4 and prostate cancer: AKR1C family includes AKR1C1, AKR1C2, AKR1C3 and AKR1C4. Studies have shown that compared with matched benign tissues, the expression of AKR1C2 and AKR1C1 genes in prostate cancer samples has 9 selective reductions, while the expression of AKR1C3 genes is not selectively reduced [36].