Kojima et al. (2015) used gene chip technology to develop a diagnostic index to distinguish PC from other clinical conditions, including eight miRNAs. This study showed that the sensitivity, specificity and accuracy of these miRNA were 80.3, 97.6, and 91.6%, respectively, which were higher than those of CA19-9 (65.6, 92.9, and 82.1%) and CEA (40.0, 88.6, and 71.8%). Five out of the eight miRNAs (miR-125a-3p, miR-6075, miR-6836-3p, miR-4294, and miR-4476) (Kojima et al., 2015) were also identified by us. Here, CEACAM5 is linked to pachyonychia congenita.