Abstract
Background
B7-h6, a member of the B7 family molecules, participates in the clearance of tumor cells by binding to NKp30 on NK cells. The expression of B7-H6 in esophageal squamous cell carcinoma and the clinical significance is unknown. The goal of this study was to determine the expression of B7-H6 in esophageal squamous cell carcinoma and the clinical significance of B7-H6 expression.
Patients and methods
We retrospectively collected clinical data from 145 patients diagnosed with esophageal squamous cell carcinoma between January 2007 and December 2008. These patients had all previously undergone surgical treatment for esophageal cancer, were clearly diagnosed, and had not received chemotherapy or radiotherapy. In addition, pathological tissue samples from the 145 patients were collected to detect the expression of B7-H6 by immunohistochemistry. The chi-square (χ2) test was used to analyse the relationships between B7-H6 and clinicopathological characteristics. The prognosis of the patients were analysed by Cox proportional hazards regression analysis and Kaplan-Meier analysis.
Results
B7-H6 was present in 133/145 (91.72%) of the esophageal squamous cell carcinoma samples and all localized in the cytoplasm. The expression level of B7-H6 was correlated with T stage (P=0.036) and lymphatic metastasis status (P=0.044). According to the results of the ROC curve analysis, H-score =90 was selected as the cut-off value. The 145 patients were divided into two groups, the high B7-H6 expression (H-score>90) group and the low B7-H6 expression (H-score≤90) group. Cox proportional hazards regression analysis indicated that tumour size (P=0.021), B7-H6 expression (P=0.025) and lymphatic metastasis status (P=0.049) were independent prognostic factors for esophageal squamous cell carcinoma. Kaplan-Meier analysis with the log-rank test demonstrated that the patients with high B7-H6 expression (P = 0.003), lymphatic metastasis (P <0.001) or a tumour size ≥ 3.0 cm (P = 0.001) had significantly worse survival than those with low B7-H6 expression, no lymphatic metastasis or a tumour size < 3.0 cm respectively.
Conclusion
B7-H6 is widely expressed in esophageal squamous cell carcinoma and high expression of B7-H6 can be used as a predictor of poor prognosis.
The functional SNP in the matrix metalloproteinase-3 promoter modifies susceptibility and lymphatic metastasis in esophageal squamous cell carcinoma but not in gastric cardiac adenocarcinoma