Different Phenotypes in Human Prostate Cancer: 6 or 3 Integrin in Cell–extracellular Adhesion Sites

The distribution of 6/ 3 integrin in adhesion complexes at the basal membrane in human normal and cancer prostate glands was analyzed in 135 biopsies from 61 patients. The levels of the polarized 6/ 3 integrin expression at the basal membrane of prostate tumor glands were determined by quantitative immunohistochemistry. The 6/ 3 integrin expression was compared with Gleason sum score, pathological stage, and preoperative serum prostate specific antigen (PSA). The associations were assessed by statistical methods. Eighty percent of the tumors expressed the 6 or 3 integrin and 20% was integrin-negative. Gleason sum score, but not serum PSA, was associated with the integrin expression. Low Gleason sum score correlated with increased integrin expression, high Gleason sum score with low and negative integrin expression. Three prostate tumor phenotypes were distinguished based on differential integrin expression. Type I coexpressed both 6 and 3 subunits, type II exclusively expressed 6 integrin, and type III expressed 3 integrin only. Fifteen cases were further examined for the codistribution of vinculin, paxillin, and CD 151 on frozen serial sections using confocal laser scanning microscopy. The 6/ 3 integrins, CD151, paxillin, and vinculin were present within normal glands. In prostate carcinoma, 6 integrin was colocalized with CD 151, but not with vinculin or paxillin. In tumor phenotype I, the 6 subunit did not colocalize with the 3 subunit indicating the existence of two different adhesion complexes. Human prostate tumors display on their cell surface the 6 1 and/or 3 1 integrins. Three tumor phenotypes associated with two different adhesion complexes were identified, suggesting a reorganization of cell adhesion structures in prostate cancer. Neoplasia (2002) 4, 243 – 254 DOI: 10.1038/sj/neo/7900223