AKR1C2, -C3, and -B1 proteins were knocked down using two siRNAs (Figure 4D), and AKR1C2 and -B1 knockdown significantly attenuated the viability of cancer cells after exposure to etoposide, doxorubicin, and daunorubicin compared with that of the negative control (Figure 4E and Figure S2B). This evidence concerns the gene AKR1C2 and cancer.