ROC curve analyses further showed that ULBP2 was more appropriate than CA 19-9 for discriminating healthy controls from patients with PC diagnosed as TNM-T1/T2 (AUC = 0.854 [95% CI, 0.778–0.930] versus AUC = 0.796 [95% CI, 0.690–0.901]), TNM-N0 (AUC = 0.866 [95% CI, 0.811–0.920] versus AUC = 0.841 [95% CI, 0.764–0.917]) or stage I/II (AUC = 0.846 [95% CI, 0.798–0.895] versus AUC = 0.839 [95% CI, 0.782–0.896]; Fig. 4C). Here, ULBP2 is linked to pachyonychia congenita.