KRT18 and pachyonychia congenita: By analysis of a panel of five biomarkers including EV-miR.409, EV-CK18 mRNA, EV-CD63 mRNA, ccfDNA concentration, and CA 19-9, the algorithm-based model enables identification of patients with PC versus those without PC, with an AUC of 0.95 and accuracy of 92%, as compared to CA 19-9 (89%).