Decreased MAP kinase activity in human gastric adenocarcinoma.

We investigated the cellular signaling events involved in gastric cancer by examining the role of mitogen activated protein kinase (MAPK) in normal and transformed human gastric tissue. A significant loss in both MAPK abundance and activity was found in the membrane fractions of the adenocarcinomas when compared to the histologically normal gastric tissue, while no significant alteration in MAPK was seen in the cytosolic fractions from these two tissue types. These findings suggest that reduction in MAPK abundance and activity are associated with loss of normal growth control in human gastric adenocarcinoma.