VLA2 integrin expression in breast carcinomas evaluated by automated and quantitative immunohistochemistry

VLA(2) is thought to be involved in the metastatic process in malignant tumours, in particular in carcinomatous cell adhesion to vessel basement membrane. VLA(2) expression was immunohistochemically investigated in 204 breast carcinomas. Frozen tissue sections were probed with monoclonal anti-VLA(2) using automated (Ventana ES 320 System) and quantitative (SAMBA 2005 image processor) immunoperoxidase. A positive anti-VLA(2) immunoreaction was observed in 48 rumours (23.5%), within epithelial carcinomatous cells. The VLA(2)-positive surface in rumours varied from 3% to 20% (mean 8.75, S.D. 7.17) and was correlated with histoprognostic indicators and tumour expression of various antigens detected using the same method as that for VLA(2). The results show that VLA(2) immunoexpression was independent of the tumour size, grade, type and aneuploidy, and of the nodal status. VLA(2) significantly correlated with ELAM, VCAM, VLA(2) and P-glycoprotein (P-gp) (P < 0.01) and inversely correlated with cathepsin D (P < 0.001), but was independent of Ki67/MIB1, p53, bcl-2, c-erbB-2, E cadherin, CD44v, CD31, cestrogen and progesterone receptors' (ER, PR) antigenic sites and pS2, The exact role, if any, of VLA(2) in tumour cell dissemination remains to be elucidated and the clinical relevance of VLA(2) immunodetection in breast carcinomas requires further investigation of the correlation between VLA(2) immunocytochemical expression and patients' outcome and response to chemotherapy.