KK-LC-1 may be an effective prognostic biomarker for gastric cancer

BACKGROUND: The objective of the study was to detect the expression of Kita-Kyushu lung cancer antigen-1 (KK-LC-1) in gastric cancer (GC) specimens and analyse the associations between KK-LC-1 expression and clinicopathological parameters and clinical prognosis. METHODS: All of the 94 patients in this study were GC patients who underwent surgical resection. KK-LC-1 protein expression in GC tissue was detected by immunohistochemistry. This report applies the histological score (H-score) to evaluate KK-LC-1 expression. To calculate this indicator, the number of positive cells in each section and their staining intensity were converted to corresponding values. The expression of KK-LC-1 in the cytoplasm of cancer and normal tissues was scored to obtain their respective H values. The chi-square test, Kaplan-Meier method and Cox regression were used to analyse the linear association between KK-LC-1 expression and clinicopathological data and prognosis. RESULTS: In the cytoplasm, KK-LC-1 expression in tumour tissues was significantly higher than that in normal tissues (P < 0.001). Using the median H-score as the cut-off value, we discovered that GC patients with high levels of KK-LC-1 expression in the cytoplasm had favourable overall survival (OS) (P = 0.016), and this result was statistically significant in the Cox regression analysis. Additionally, a negative correlation was found between KK-LC-1 protein expression and the pathological grade of the tumour (P = 0.036), with significantly more KK-LC-1 protein expression observed in the intestinal type of GC than in the diffuse type (P = 0.008). CONCLUSIONS: Our research data showed that KK-LC-1 expression was greater in GC tissues than in normal tissues, and higher KK-LC-1 expression was associated with longer OS of GC patients. KK-LC-1 can be used as a biomarker for a good prognosis in GC patients.