KRT7 and cervical intraepithelial neoplasia: Furthermore, cytokeratin 7 (CK7), a known marker of the squamous columnar junction cells, and CK19 have been found to be expressed in cervical intraepithelial neoplasia (CIN1) at risk to progress to CIN3 compared with CK7 negative lesions, suggesting their importance as predictive marker of cervical neoplasia progression [7].