IMMUNOHISTOCHEMICAL LOCALIZATION OF FILAGGRIN IN BENIGN, PREMALIGNANTAND MALIGNANT CERVICAL TISSUE

Epithelial distribution of filaggrin, a histidine-rich protein related to squamous terminal differentiation, was investigated in 87 cervical biopsies using an avidin-biotin-peroxidase technique with a monoclona l anti-human filaggrin antibody (AKH1). Normal squamous cervical epith elium exhibited a positive homogeneous immunoperoxidase stain in the u pper parabasal, intermediate and superficial cell layers. Similar find ings were obtained in cervical condylomas, although full-thickness sta ining was observed in 35.7% of the cases (P < 0.001). Filaggrin expres sion in CIN was inversely related to the severity of the lesion (P < 0 .001). An irregular staining pattern was present in most high-grade CI N. Filaggrin expression was closely connected to the degree of tumour differentiation (P < 0.05) in squamous cell carcinomas of the cervix. Abnormal filaggrin stainings identified a premalignant/malignant cervi cal squamous lesion with a positive predictive value of 92.3%. Non-squ amous epithelia showed lack of filaggrin expression. Filaggrin may the refore be considered a marker of squamous differentiation in both the normal and pathological human uterine cervix.