Quantitative RT-PCR analysis and immunohistochemical localization of the kallikrein-related peptidases 13 and 14 in lung.

Expression of the KLK13 and KLK14 genes was examined at the mRNA and protein levels in a cohort of 57 patients with non-small-cell lung cancer (NSCLC). The mRNA levels, assessed by real-time RT-PCR, were significantly different in malignant tissues compared to adjacent non-malignant tissues (KLK13, ps0.006; KLK14, ps0.022). KLK13 and KLK14 mRNA overexpression in tumors (1/3 of the patients) was associated with a positive nodal status in multivariate analysis (ps0.018 and ps0.069, respectively). KLK13 and KLK14 were localized in the cytoplasm of epithelial cells of normal bronchus and NSCLC, as determined by immunohistochemistry. Moreover, positive staining was significantly associated with adenocarcinoma histotype (KLK13, ps0.014) and tumor size (KLK14, ps0.048). Although the results are marginally significant, patients with high KLK13 expression at the mRNA or protein level had lower overall survival.