In another study of EUS–FNA, up‐regulation of MUC1 (77.5%), MUC2 (10.0%) and MUC5AC (80.0%) was reported in patients with PC, and positive ratios of MUC1 (25.0%), MUC2 (31.3%) and MUC5AC (43.8%) were detected in benign pancreatic diseases, respectively.103. The gene discussed is MUC5AC; the disease is pachyonychia congenita.