RESUMO
D-glucuronyl C5-epimerase (GLCE) is one of the key enzymes in proteoglycan biosynthesis. However, nothing is known about expression and activity of the protein in cancer. In this study, we investigated GLCE expression in human breast cancer using multipex RT-PCR, QRT-PCR and Western-blot assays. In total, 21 patients without malignancy and 74 patients with breast tumor were investigated. The obtained data showed that in 82-84% of human breast tumors there is either downregulation or loss of D-glucuronyl C5-epimerase mRNA expression and significant decrease of the protein content. In most cases (77%), GLCE expression was decreased also in the normal-appearing tissue surrounding the tumor node but the protein amount was comparable to normal breast tissue. These findings represent the first data about involvement of human D-glucuronyl C5-epimerase in malignant transformation.