Unique expression pattern of the alpha 6 beta 4 integrin and laminin-5 in human prostate carcinoma

BACKGROUND. The alpha6 beta4 integrin and its ligand, laminin-5, are essent ial gene products for the maintenance and remodeling of a stratified epithe lium. Apparent loss of polarized alpha6 beta4 integrin and laminin-5 protei n expression in invasive prostate cancer as compared to normal prostate gla nds is known to occur. It is unknown whether these alterations occur in pro static intraepithelial neoplasia (PIN) lesions and whether this combined de fect occurs in other epithelial cancers. METHODS. Human prostate tissues containing both normal, PIN, and cancerous regions and normal and cancer tissue from breast and colon were obtained at surgery and examined for beta4 integrin and laminin-5 using standard immun ofluorescence staining methods. RESULTS. Both normal prostate glands and PIN lesions contain beta4 integrin and laminin-5. Prostate carcinoma was unique in that both beta4 integrin a nd laminin-5 expression was uniformly absent. Tn contrast, the beta4 integr in and its ligand, laminin-5 were detected in all of the colon carcinoma ca ses and in 60% of the breast carcinomas. CONCLUSIONS. The beta4 integrin and its ligand, laminin-5 are altered durin g the transition of PIN lesions to invasive prostate carcinoma These data s uggest the loss of these proteins during cancer progression. In both prosta te and breast carcinoma, the normal expression pattern of the beta4 integri n and laminin-5 is interrupted, in contrast to the persistent beta4 integri n and laminin-5 expression detected in colon carcinoma. ((C) 2001 Wiley-Lis s, Inc.