Likewise, a multicenter study of serum samples from different study groups (early-and late-stage PC, chronic pancreatitis, benign pancreatic disease, and healthy controls) by Kaur et al. [89] found that the diagnostic accuracy of CA19-9 was improved by its combination with MUC-5AC, which achieved 83% sensitivity and 75% specificity to discriminate early-stage PC and cancer-free groups and 83% sensitivity and 83% specificity to discriminate between PC and cancer-free groups. The gene discussed is MUC5AC; the disease is pachyonychia congenita.