Localization of cellular retinoid-binding proteins in human cervical intraepithelial neoplasia and invasive carcinoma

Cellular retinoic acid-binding protein (CRABP) and cellular retinol-binding protein (CRBP) were localized in biopsies of normal squamous epithelium, cervical intraepithelial neoplasia (CIN), and invasive squamous cell cancer of the cervix uteri by immunohistochemistry. In both the normal stratified squamous epithelium of the exocervix and low-grade CIN, CRABP I was present predominantly in the basal layer of the epithelium. The more superficial, differentiated cell layers lacked immunoreactive protein. In high-grade CIN (CIN2-3), the distribution of CRABP I was altered. Immunoreactive CRABP I was detected in all layers of high-grade CIN. In squamous cell carcinoma of the cervix, CRABP I was detected in cells throughout the tumor but was minimal in cells demonstrating squamous differentiation. In contrast to CRABP I, CRBP was diffusely present throughout the cervical epithelium irrespective of the state of differentiation or the presence of disease.