Furthermore, the expression of PNPO protein was higher in EOC cell lines OVCAR-3 and SK-OV-3, but not in other two adenocarcinoma cell lines CAOV-3 and A2780 and a clear cell line ES-2, compared with non-tumorous human ovarian surface epithelial cell line HOSEpiC (P < 0.05; Supplementary Figure S3a and S3b). This evidence concerns the gene PNPO and adenocarcinoma.