Overexpression of CrkL as a novel biomarker for poor prognosis in gastric cancer

BACKGROUND: The signaling adapter protein CrkL plays vital roles in multiple cancers. However, the expression pattern of CrkL protein and its clinical significance have not been well characterized in human gastric cancer (GC) so far. OBJECTIVE: To investigate the association of tissue-based CrkL protein expression level with the clinicopathological characteristics and prognosis of GC patients. METHODS: The expression level of CrkL protein in 380 GC patients was analyzed by immunohistochemistry. The associations of CrkL protein expression level with clinicopathologicalal characteristics and clinical outcome were evaluated. RESULTS: Compared with the matched adjacent non-tumor tissues, CrkL protein expression level was significantly up-regulated in tumor tissues. In addition, there was a positive correlation between CrkL and Ki67 expression levels in GC patients. An elevated CrkL level statistically correlated with aggressive clinicopathologicalal characteristics, such as larger tumor size, deeper local invasion, more lymph node metastasis, advanced TNM stage, and poorer prognosis. Notably, multivariate analysis identified tissue-based CrkL level as an independent predictor for the unfavorable prognosis of GC. CONCLUSIONS: These results indicate that CrkL protein may serve as a novel prognostic biomarker in GC.