Immunohistochemical detection of fibroblast growth factor receptor 3 in human breast cancer: correlation with clinicopathological/molecular parameters and prognosis.

OBJECTIVE Reportedly, fibroblast growth factor receptor 3 (FGFR3) that regulates embryonic growth and development may function as an oncoprotein in certain malignancies. We aimed to investigate the biological significance of FGFR3 expression in invasive breast cancer. METHODS FGFR3 expression was investigated in 50 invasive breast cancer specimens by immunohistochemistry. The association between FGFR3 expression and clinicopathological/molecular parameters or prognosis was evaluated. RESULTS Weak FGFR3 expression was observed in myoepithelial cells, but not in duct epithelial cells, of the normal mammary ducts and lobules. FGFR3 expression in breast cancer cells was observed in 19 of 50 (38.0%) cases (9 weak positive and 10 strong positive). Besides the cytoplasm and cell membrane, nuclear staining was observed in 3 of 10 strong-positive cases. FGFR3 was further detected in non-neoplastic duct epithelial cells or duct papillomatosis in 5 strong-positive cases. No significant correlation was observed between FGFR3 expression and specific clinicopathological/molecular parameters. In contrast, FGFR3 expression was found to be significantly associated with overall survival in our cohort. CONCLUSIONS FGFR3 expression in invasive breast cancer was not found to be significantly associated with specific clinicopathological/molecular parameters, but might be used as a candidate marker for a poor prognosis.