Immunohistochemical analysis of alpha 1-integrins in cervical cancer.

Abstract

The purpose of this study was to determine and compare the expression of the alpha 2-, alpha 3-, alpha 4- and alpha 5-subunits of the beta 1-family of integrins in both the normal and the carcinomatous cervix. A total of 22 solid tissue specimens (18 cancer and 4 normal) were analyzed immunohistochemically. The double-stain technique used an avidin-biotin complex kit to identify the various integrins and alkaline phosphatase-anti-alkaline phosphatase kit to identify the epithelial cells. Staining intensity, the main outcome measured, was graded as absent, weak, moderate, or strong. Statistical analysis was performed with the Wilcoxon rank sum test for nonparametric data. The alpha 2- and alpha 3-integrins stained the normal cervix epithelium more intensely than the stroma (p = 0.03). The alpha 4- and alpha 5-integrins stained both the stroma and the normal epithelium similarly. The alpha 2-integrin was absent in the stroma of all 18 cancer specimens despite being present in the epithelial regions of 14 to 18 cancers. The alpha 3-integrin had a greater staining intensity in the stroma of the cancers than in the epithelial regions (p = 0.002). Both alpha 4- and alpha 5-integrins were absent in the epithelial regions of the cancers but present in the stroma. The distribution and intensity of integrin expression in cervical cancer differ from their expression in the normal cervix. In particular, the fibronectin receptors, alpha 4 and alpha 5, were absent in the epithelial regions of the cervical cancers, and alpha 3 also had diminished expression in the malignant epithelium. These changes correlate well with the changes expected in malignant transformation.