Human
tissue kallikrein-related
peptidases are a family of 15 secreted
serine proteases, located at chromosome 19q13.4. Most of them have been reported to be potential
biomarkers for several
carcinomas and other diseases. Human
tissue kallikrein-related
peptidase 7 (KLK7) has been purified from human stratum corneum and resembles a chymotryptic
endopeptidase originally called stratum corneum chymotryptic
enzyme (SCCE). In this study, we examined for the first time, the prognostic value of KLK7
mRNA expression, using a semi-quantitative RT-PCR method, in 105
colorectal cancer tissues for 54 of which, paired normal colonic mucosa were available. Furthermore, we analysed the expression of KLK7 in 10
adenomas, in 18 biopsies of inflamed colon mucosa, as well as in 22 human
cancer cell lines of various origin, four of them being of colon. A defined number of
colon cancer samples were also examined by immunohistochemistry. KLK7 expression was higher in cancerous than in normal tissues. Less differentiated
tumors of more advanced stage showed higher KLK7 expression. Follow-up analysis revealed that KLK7 was significantly associated with shorter overall survival (OS) and disease-free survival (DFS). In addition, selected
colon cancer samples highly expressing KLK7 gene, showed intense immunohistochemical staining for KLK7, enhancing RT-PCR results. Present data suggest that KLK7 gene is up-regulated in
colon cancer and its expression predicts poor prognosis for
colon cancer patients.