Prognostic significance of human tissue kallikrein-related peptidases 6 and 10 in gastric cancer.

The prognosis of patients following surgery for gastric cancer is often poor and is estimated using traditional clinicopathological parameters, which can be inaccurate predictors of future survival. Kallikreins are a group of serine proteases, which are differentially expressed in many human tumors and are being investigated as potential cancer biomarkers. This study assessed the prognostic utility of human tissue kallikrein-like peptidases 6 and 10 (KLK6 and KLK10) and correlated their expression with histopathological and clinical parameters in gastric cancer. We constructed a gastric tumor tissue microarray from 113 gastrectomy specimens and quantified KLK6 and KLK10 expression using immunohistochemistry. To overcome the problem of inter-observer variability and subjectivity in immunohistochemistry interpretation, a whole-slide scanned image of the tissue microarray was analyzed using an automated algorithm to quantify staining intensity. KLK6 expression was positively correlated with nodal involvement (p=0.002) and was predictive of advanced-stage disease (p<0.05). Kaplan-Meier survival curves revealed that tumors expressing high levels of KLK6 were significantly associated with significantly lower overall survival (p=0.04). KLK10 overexpression was also a predictor of advanced-stage disease (p<0.01), but was not significantly correlated with lymph node involvement or survival period. Our results show the potential ability of KLK6 as a prognostic marker for gastric cancer.