Elevation of glycoprotein galactosyltransferase activity in human lung cancer related to histological types

Uridine diphosphogalactose:glycoprotein galactosyltransferases were examined in human lung adenocarcinoma and squamous cell carcinoma. The galactosyltransferase activities in tissue homogenates from both carcinomas were higher than in adjacent normal control with asialoagalactofetuin as a substrate. This activity in adenocarcinoma (27 cases) was two times higher than that in squamous cell carcinoma (19 cases) with statistical significance (p less than 0.001). Using Triton-solubilized enzymes from a particulate fraction, similar differences in the activity were observed with ovalbumin, asialoagalactofetuin, and its beta-eliminated derivative as acceptors but not with bovine submaxillary mucin. These observations mean that the higher activity of galactosyltransferase(s) in lung carcinomas (especially in adenocarcinoma) is mainly responsible for galactosylation of carbohydrate chains in N-glycoside-type but not O-glycoside-type glycoproteins.