AUTOMATED AND QUANTITATIVE IMMUNOCYTOCHEMICAL ASSAYS OF CD44V6 IN BREAST CARCINOMAS

CD44 variants carrying sequences encoded by exon v6 are preferentially expressed in metastatic animal cancer cell lines. CD44v6 overexpressi on correlates tumor dedifferentiation and progression in some human ca rcinomas, but the relationship of CD44v6 overexpression with metastati c behavior of tumor observed in animal models is controversial, partic ularly in breast carcinomas. The discrepancies probably result from an alytical bias. We investigated CD44v6 and CD44s expression in 218 froz en samples of primary breast carcinomas. Immunocytochemical procedure was performed under optimal technical conditions using commercially av ailable 2F-10 monoclonal antibody (MAb), a microprocessor-controlled a utomated device (Ventana Medical Systems, Tucson, AZ), and quantitativ e evaluation of results by processing digitized-colored microscopic im ages (SAMBA, Grenoble, France). CD44v6 expression in tissue sections w as shown to be independent of the patient age, tumor size, histologica l types and grades, and the lymph node status. CD44v6 expression was a lso independent of the expression of molecules endowed with poor progn ostic significance detected by MAbs (anti-p53, anti-c-erb B-2 protein, MIB1) on consecutive sections. No significant relationship could be e videnced either between CD44v6 expression, and CD31 involved stromal a ngiogenesis and cathepsin D. Finally, CD44v6 was independent of marker s of hormone dependence (estrogen and progesterone receptors, pS2) and of multidrug resistance (P-glycoprotein). Similar results were observ ed with anti-CD44s. We conclude that the true prognostic significance of CD44v6 overexpression still remains to be shown under rigorous tech nical conditions (frozen samples, well-documented MAbs, and optimal st andardization of procedure using automation and quantitative analysis) providing data appropriate for further correlation with long-term pat ient follow-up. Copyright (C) 1997 by W.B. Saunders Company.