3133

It is known that heparan sulfates are involved in the signaling regulation of several growth factors. A member of this family, the Glypican-3 (GPC3), is broadly expressed in the embryo but it disappears in most of the adult tissues, except the mammary gland, ovary and macrophages. Several studies have involved GPC3 with cancer and recent data indicate that its mRNA is diminished in breast tumors. Therefore, we analyzed the expression of GPC3 in paraffin embedded sections of cancer samples (n=56, SI=14, SIIA=22 and SIIB=20) and benign breast pathologies (n=23) by IHC. It is important to highlight that this is the first study that analyzes GPC3 expression in breast cancer at immunological level, because the antibody has been only recently develop. GPC3 expression was associated, by univariate analysis, with the parameters frequently used in the clinic, as age, status, stage, tumor size, histology, metastatic axillary nodules, histologic grade, nuclear grade, mitotic index, hormonal receptors, as well as with the disease free survival probability (DFS). GPC3 expression was also correlated with the expression at proteins level of other molecules altered in breast cancer, as Ki 67, cyclins D1, E, B1 and the CDKIs p16 and p21. We observed that only 20% of cancer samples and 10% of benign pathologies presented specific membrane staining. In no case the staining overcomes the 20% of the cells. We did not find any association between GPC3 expression and the main clinical-pathological parameters in breast cancer (Chi square test and Pearson correlation). The expression of the cell cycle regulator molecules did not associated with GPC3 expression either. Finally, the Kaplan-Meier curves and the log rank test indicated that GPC3 expression was not able to predict the DFS of breast cancer patients. In conclusion, we found a poor GPC3 expression in benign as well as in breast cancer pathologies. Besides, this expression seems not to be useful as a prognostic marker in low stage breast cancer.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]