Alterations in the expression of proprotein convertase genes in human esophagus squamous cell carcinomas

Proprotein convertases (PCs) constitute an enzyme family that includes nine highly specific human subtilisin-like serine proteases. It is known that the PCs mRNA levels vary in tumors, and that these proteases are involved in carcinogenesis. Thus, PCs may be considered as potential markers for typing and predicting the course of the disease, as well as potential targets for therapy. We used quantitative real-time PCR to evaluate the expression levels of PC genes in the paired samples of tumor and adjacent normal tissues derived from 19 patients with esophageal squamous cell carcinomas. We observed a significant enrichment of <i>PCSK6</i>, <i>PCSK9</i>, <i>MBTPS1</i>, and <i>FURIN</i> mRNAs in the tumor tissue, which may be indication of the involvement of these PCs in the development and progression of esophageal cancers. Additionally, cluster analysis of PC expression alteration patterns in tumor compared to normal adjacent tissues (esophageal and previously analyzed lung tissue samples) revealed a limited set of scenarios for the changes in PC expression. These scenarios are implemented during malignant transformation of lung and esophagus cells, as well as, probably, the cells of other organs. These findings indicate that PC genes may be important markers of human cancers.