ABCF2 expression in endometrial cancer and breast cancer

Abstract

5035 Background: ABCF2 is a new member of the ATP-binding cassette transporter superfamily gene. We previously reported that ABCF2 protein is new biomarker in clear cell adenocarcinoma (CC) of the ovary and its expression may predict the response to chemotherapy and survival of CC patients (Proc ASCO 2005, Clin Cancer Res 2005). Both breast cancer (BC) and endometorial cancer (EC) are estrogen-dependent tumors, however, their biological behavior differ. In this study, we examined ABCF2 expression in EMCA and BC and evaluated the relationship between ABCF2 expression and clinical factor. Methods: Formalin-fixed surgical samples from 100 EMCA and 191 BC patients were included in this study. ABCF2 expression was investigated by immunohistochemistry. Positive expression of ABCF2 was > 10% based on the cytoplasmic staining. Results: Histologic types and stage were as followed: EMCA: (Endometrioid (EM): 92; Adenosquamous (AS): 8), (I: 63; II: 5; III: 30; IV: 2). BC: (Papillo tu (PP): 60; Solid tub (SL): 38; Scirrhous (SC): 77; Other (OT): 15). Breast cancer was sub-classified into 3 types according to the criteria of the Japanese Breast Cancer Society. The relationship between ABCF2 expression and histologic type was shown in table. In EMCA and BC, there were no significant relationship between ABCF2 expression and clinical factor like stage, histologic type, grade and estrogen receptor (ER). In EMCA, ABCF2 expression was not related with disease free survival (DFS). However, in BC, ABCF2-positive tumors had longer DFS than ABCF2-negative tumors (p = 0.03). The ABCF2 expression were correlated with further biological variables such as tumor stage, lympho node metastasis, nuclear grade and ER status for DFS by univariate and multivariate Cox regression analysis. Multivariate analysis revealed that ABCF2 was an independent prognostic factor (HR 0.46; p = 0.018). Conclusion: The role of ABCF2 protein may differ between EMCA and BC. [Table: see text] No significant financial relationships to disclose.