To this end, we analyzed LEDGF protein expression by immunohistochemistry in patient biopsies representing different degrees of premalignant cervical lesions (cervical intraepithelial neoplasia, CIN): CIN I (n = 16), CIN II (n = 7), CIN III (n = 13), and established squamous cell carcinomas (n = 7). This evidence concerns the gene PSIP1 and squamous cell carcinoma.