GAL and pachyonychia congenita: To confirm our findings that Gal-ratio had potential to complement the drawback of high false negative diagnostic results using CA19-9, we further tested Gal-ratio in an independent validation cohort including 50 healthy controls, 19 patients with BPD, and 64 patients with PC when all the samples with negative CA19-9 levels (CA19-9 < 37 U/ml).