The high expression of HtrA2 in HCC was further confirmed by the GSE121248 (P < 0.001), GSE101685 (P=0.012), GSE76427 (P < 0.001), and GSE76297 (P < 0.001) data set from GEO (Figures 1(i)–1(l)). Here, HTRA2 is linked to hepatocellular carcinoma.