Relative expression of fibroblast growth factor receptors in feline sarcomas

Fibroblast growth factor receptors (FGFRs) are involved in many physiological processes as well as cancer development and progression. At least two splice variants (IIIb and IIIc) have been described for FGFR1-3. Expression switching of FGFR2IIIb to the IIIc isoform relates to epithelial to mesenchymal transition in human prostate and bladder cancer and leads to a more invasive and metastatic tumor phenotype. While extensive research investigated the role of FGFRs in epithelial tumors, very little is known about their role and expression in sarcomas. The hypothesis of this study was that feline injection site sarcomas(ISSa) and non-injection site sarcomas (non-ISSa) would have differential expression of the FGFRs and their splice variants. Expression levels of mRNA for these genes were evaluated by RT-PCR using cDNA from six cell lines (4 ISSa and 2 non-ISSa), eight tumor samples (5 ISSa and 3 non-ISSa) stored in RNA later at - 80°C and forty-nine FFPE samples (39 ISSa and 10 non-ISSa). The relative quantification was performed by normalization against expression of RPL17, YWHAZ and PPIA genes. No statistically significant difference was found for FGFR1, FGFR2IIIb, FGFR3 and FGFR4. FGFR2IIIc was up-regulated in ISSa if compared to non-ISSa (P=0.028). The present study demonstrated that FGFR2IIIc is differentially expressed in feline ISSa compared to non-ISSa. More research is needed to evaluate if different expression levels are related to the more malignant behavior of ISSa.