PADI4 and neoplasm: To confirm the role of PADI4 in GC in vivo conditions, we made a xenograft tumor model by subcutaneously injecting MGC80-3 cells stably over-expressing PADI4, the results showed that the average tumour weight in mice injected with PADI4-overexpressing virus transfected MGC80-3 cells was 534.7 mg, while the tumour weight of the control group was 320.7 mg (P = 0.012; Fig. 4A–D).