Furthermore, we found that the plasma concentrations of ENO1 in 10 of 15 PC patients with normal CA19-9 level were beyond the proposed reference value of ≤12.88 ng/ml, For PDAC patients of Lewis-negative phenotype with normal CA19-9 level, it necessitates caution when high level of ENO1 is detected. This evidence concerns the gene ENO1 and pachyonychia congenita.