Published online Feb 14, 2015. doi: 10.3748/wjg.v21.i6.1838
Peer-review started: April 18, 2014
First decision: May 29, 2014
Revised: August 4, 2014
Accepted: September 5, 2014
Article in press: September 5, 2014
Published online: February 14, 2015
AIM: To investigate fibroblast growth factor receptor 4 (FGFR4) protein expression in Chinese patients with resectable gastric cancer (GC) and the association with clinicopathological characteristics and survival.
METHODS: One hundred and seventy-five GC patients who underwent curative surgical procedures were enrolled in this study. The protein expression of FGFR4 in formalin-fixed, paraffin-embedded (FFPE) GC tissues was determined by immunohistochemical (IHC) analysis. Patient clinicopathological data and survival information were also collected and χ2 statistical analysis was performed to analyze FGFR4 protein expression in the subgroups with differing clinicopathological characteristics including; gender, age, tumor location, differentiation, tumor-node-metastasis stage, macroscopic type, depth of invasion, lymph node metastases, distant metastasis, neural invasion and vascular invasion. Furthermore, some common molecular markers of GC in our cancer center, including p53, p27, topoisomerase IIα (Topo IIα) were also determined by IHC and their association with FGFR4 protein expression evaluated. The probability of survival for different subgroups with different clinicopathological characteristics was calculated using the Kaplan-Meier method and survival curves plotted using the log rank test.
RESULTS: Seventy seven cases (44%) were found to have high expression of FGFR4 protein. Significantly different FGFR4 expression was observed between gastric cancers with differing expression of Topo IIα (log rank χ2 = 9.4760, P = 0.0236). No significant differences were observed between subgroups defined by any of the other clinicopathological characteristics. The median survival time of the FGFR4 high expression (77 cases) and low expression groups (98 cases) was 27 mo and 39 mo, respectively. The five-year survival rates and median survival times of gastric cancers with high FGFR4 expression were worse than those with low expression (30.8% vs 39.2%, 27 mo vs 39 mo), respectively, however, no significant difference was observed in survival time (log rank χ2 = 1.0477, P = 0.3060). Survival analysis revealed that high expression of FGFR4 was a predictor of poor outcome in GC patients if the tumor was small (less than or equal to 3 cm in size) (log rank χ2 = 5.5033, P = 0.0190), well differentiated (log rank χ2 = 7.9757, P = 0.0047), and of T1 or T2 stage invasion depth (log rank χ2 = 4.8827, P = 0.0271).
CONCLUSION: Our results suggest that high tumor expression of FGFR4 protein is not an independent risk factor for GC cancer initiation, but is a useful prognostic marker for GC patients when the tumor is relatively small, well differentiated, or in the early stages of invasion.
Core tip: This study investigated the possible contributions of fibroblast growth factor receptor 4 (FGFR4) protein expression as a risk factor for gastric cancer (GC), and the associations between protein expression and clinicopathological parameters. The results suggested that FGFR4 protein expression may correlate with the expression of Topo IIα. Furthermore, we demonstrated that FGFR4 protein expression is not a risk factor for GC initiation, but may be a useful prognostic marker for GC patients with tumors which are relatively small, well differentiated, or in the early stages of invasion.