Association between expression levels of CA 19-9 and N-acetylglucosamine-beta 1,3-galactosyltransferase 5 gene in human pancreatic cancer tissue

Objective: CA 19-9, equivalent to Sialyl Lewis(a) antigen, is a well-known tumor marker in pancreatic cancer. At the initial step of the biosynthesis of CA 19-9, N-acetylglucosamine-beta,3-galactosyltransferase (beta3Gal-T) transfers galactose to N-acetylglucosamine (GlcNAc). Recently, beta3Gal-T5 has been presumed to be related to the formation of the type 1 chain in an in vitro experiment in terms of kinetic enzyme characterization. The purpose of this study was to investigate which beta3Gal-T is related to the synthesis of CA 19-9 in human pancreatic cancer tissues. Methods: We examined beta3Gal-T1, T2, T3, T4, and beta3Gal-T5 mRNA expressions in 13 noncancerous and cancerous tissues of the human pancreas using real-time polymerase chain reaction, and compared those gene expression levels with the immunoreactivity of CA 19-9 and its precursor DUPAN-2 in cancerous tissues. Results: beta3Gal-T5 gene expression significantly augmented in cancerous tissues, when compared with the adjacent noncancerous tissues. Additionally, there was a good correlation between beta3Gal-T5 gene transcription levels and immunohistochemical grades of CA 19-9 or its precursor DUPAN-2 in cancerous tissues. However, no correlation was observed between beta3Gal-T1, T2, T3, and beta3Gal-T4 gene expression levels and CA 19-9 or DUPAN-2 immunoreactive grades in cancerous tissue. Conclusion: beta3Gal-T5 is presumed to be responsible for the synthesis of CA 19-9 in pancreatic cancer tissue. Copyright (C) 2004 S. Karger AG, Basel.