Expression of keratinocyte growth factor receptor (KGFR/FGFR2 IIIb) in human uterine cervical cancer

Keratinocyte growth factor receptor (KGFR), also known as FGFR2 IIIb, is a splice variant of FGFR-2. KGFR is expressed in many types of epithelial cell and is activated with four known ligands [FGF-1, FGF-3, FGF-7 (also known as KGF) and FGF-10] that are predominantly synthesized by mesenchymal cells. KGFR is highly expressed in the late-proliferative phase of a normal endometrium and in endometrial adenocarcinoma. In the present study, we attempted to determine the expression and localization of KGFR in human cervical cancer cell lines and cervical cancer tissues. The KGFR protein was detected in CaSki and HeLa cells, but not in ME-180 cells of cervical cancer cell lines. In non-cancer cervical tissues, KGFR immunoreactivity was weakly expressed in the surface of squamous epithelial cells and vascular smooth muscle cells. Immunohistochemically, the KGFR protein was detected in squamous cell carcinoma in 36 of 42 (86%) cervical cancer patients. In cervical cancer tissues, KGFR was detected in 17 of 18 (94%) of patients with the keratinizing type and 19 of 24 (79%) of patients with the non-keratinizing type of cervical cancer. Furthermore, KGFR was prominently localized in proliferating reserve cells and squamous metaplastic reserve cells adjacent to cancer cells. In contrast, KGFR was not detected in cervical ductal cells in cancer or non-cancer cervical tissues. These findings may indicate that KGFR mediates the growth and differentiation of reserve cells and squamous cell carcinoma in the cervix.