In TCGA database, compared with normal tissues, KCNQ4 was significantly up-regulated in tumor tissues in three cancers, including LIHC, PCPG and CHOL, while it was significantly down-regulated in 13 cancers, including CESC, COAD, READ, BRCA, KIRP, KIPAN, PRAD, UCEC, HNSC, LUSC, THCA, READ and BLCA (Fig. 1A). The gene discussed is KCNQ4; the disease is cancer.