Pathological studies have reported PAD4 overexpression in a variety of malignancies, including breast carcinomas, lung carcinomas, hepatocellular carcinomas (HCCs), colorectal carcinomas, ovarian adenocarcinoma, uterine adenocarcinoma, bladder carcinomas, chondromas, and other metastatic carcinomas [28,29], suggesting PAD4 involvement in the tumorigenesis of multiple tissues. Here, PADI4 is linked to hepatocellular carcinoma.