ELAM SELECTIN EXPRESSION IN BREAST CARCINOMAS DETECTED BY AUTOMATED AND QUANTITATIVE IMMUNOHISTOCHEMICAL ASSAYS

ELAM is an E-Selectin adhesion molecule involved in the inflammatory p rocess but it is also thought to potentially participate in the develo pment of blood borne metastases, by facilitating tumour cell adhesion to vessels wall. ELAM expression in rumours was immunohistochemically investigated in 203 breast carcinomas. Frozen tissue sections were pro bed with monoclonal anti ELAM (Clone 1.2B6) using automated and quanti tative immunoperoxidase systems. A positive anti-ELAM immunoreaction w as observed in 113 tumours (57%). The mean surface of positive tumours varied from 3% to 50% (mean = 11.75%, SD = 8.7) and was correlated wi th histoprognostic indicators and tumour expression of various antigen s detected according to the same method as ELAM. The results showed th at ELAM immunoexpression was independent of the tumour size, grade and type and of the nodal status but significantly increased parallel to patients' age (p<0.01). ELAM expression was independent of Ki-67/MIB1, anti-P53 and anti-Bcl2, anti-CD44v, anti-c-erbB-2, anti-CD31, anti-RE /RP, anti-PS2, and anti-VLA, immunoreactions. But ELAM expression corr elated with that of the VCAM vascular cell adhesion molecule (p=0.0004 ), VLA, (p<0.0001), P-glycoprotein (p=0.025), and of Cathepsin D to a lower degree (p=0.06) and inversely correlated with E-cadherin (p=0.03 ). The results suggest that endothelial cell activation is independent of tumour cell proliferative activity and of stromal angiogenesis and that the precise role and regulation of ELAM in rumours remains to be elucidated. Also the clinical relevance of ELAM immunohistochemical e xpression requires further investigation and correlation with patients ' follow-up.