Although VTCN1 mRNA expression level obtained from the frozen tissue specimens was not associated with that of VIM, VTCN1 mRNA expression level from the GEPIA online analysis tool was inversely related to that of VIM. These results indicate that B7-H4 is associated with mesenchymal-to-epithelial transition (MET) in ovarian serous carcinoma. This evidence concerns the gene VTCN1 and ovarian serous carcinoma.