Abstract 286: Expression and role of fibroblast growth factor receptor2 IIIc in human uterine cervical intraepithelial neoplasia (CIN) and invasive cervical cancer

Abstract

Abstract Fibroblast growth factor receptors (FGFR) FGFR1 through FGFR3 possess IIIb and IIIc isoforms as the result of alternative splicing of the immunoglobulin-like domain. The IIIb isoforms are mainly expressed in normal epithelial cells, and IIIc isoforms are expressed in mesenchymal cells. Single nucleotide polymorphisms (SNPs) of the FGFR2 gene are associated with endometrial cancer, and missense mutations or copy number gains of the FGFR2 gene occur in breast cancer. In uterine cervical cancer, FGFR2 IIIb, also known as keratinocyte growth factor receptor (KGFR), was reported to be highly expressed in squamous cell carcinoma (SCC), which accounts for 90% of all cervical cancer patients. However, there has been no report on the expression and roles of FGFR2 IIIc in cervical cancer. In the present study, we determined the expression and roles of FGFR2 IIIc in CIN and cervical SCC. In noncancerous cervical tissues, FGFR2 IIIc immunoreactivity was either not present or very faintly localized in squamous epithelial cells. In CINs 1 and 2, FGFR2 IIIc was localized at the basal to lower two-thirds of squamous epithelium, whereas FGFR2 IIIc was strongly expressed in most of the squamous epithelium, except for the superficial layer in CIN 3. FGFR2 IIIc protein was detected in keratinizing and non-keratinizing types of SCC in all cervical cancer patients examined (8 and 21 cases, respectively). In situ hybridization (ISH) analysis using an FGFR2 IIIc-specific antisense RNA probe showed that the expression patterns of FGFR2 IIIc mRNA are similar to those of FGFR2 IIIc protein in noncancerous and CIN tissues. In addition, FGFR2 IIIc mRNA was strongly expressed in the invasive fronts of cancer cell nests in cancer tissues. Moreover, full-length FGFR2 IIIc cDNA, subcloned to pIRES2-EGFP vector, was stably transfected into CaSki cells, which are derived from a well-differentiated type of SCC. The growth rates of the FGFR2 IIIc-transfected CaSki cells were higher than those of mock cells in vitro. Cell migration assays did not show any differences between FGFR2 IIIc-transfected CaSki cells and mock cells. To assess the effect of FGFR2 IIIc expression on tumorigenicity, the CaSki cells were injected into nude mice. The FGFR2 IIIc-transfected CaSki cells tended to form larger subcutaneous tumors than mock cells in nude mice. These findings suggest that FGFR2 IIIc plays important roles in the carcinogenesis and proliferation of cervical cancer cells. FGFR2 IIIc is considered to be a novel therapeutic target for inhibiting the growth of CIN and cervical cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 286.