PLK1 and liver cancer: We tested two predicted OCN pairs in each cancer type, including NCSTN and DNM1, and NCSTN and OGT in liver cancer; CCNA2 and PTP4A1, and HIF1A and PARP1 in lung cancer; and CCNA2 and PTP4A1, and PLK1 and PTP4A1 in breast cancer.