In this study, the potential diagnostic value of cytokeratin 17 (CK17) and SRY-box2 (SOX2) immunohistochemistry was assessed in a series of 150 vulvar lesions, originally diagnosed as high-grade VIN and re-assessed by six pathologists (including H&E, p16INK4a, p53, Ki-67, CK17, and SOX2 immunohistochemistry). The gene discussed is SOX2; the disease is vulvar intraepithelial neoplasia.