Enzyme activities in human gastric cancer and polyps

Enzyme activities and the protein to DNA ratio in gastric biopsy specimens from patients with gastric cancer and polyps have been measured and compared with values from controls. In uninvolved mucosa in antral gastric cancer increased activities were found for several membrane and lysosomal enzymes, whereas the monoamine oxidase (MAO) activity was decreased (p less than 0.0005). In cancer tissue the MAO was also decreased (p less than 0.0003). In uninvolved mucosa in gastric cancer of the body, most membrane and lysosomal enzyme activities were increased. In the cancer tissue itself an increase in membrane enzyme activities was found for several enzymes, whereas the MAO activity was decreased (p less than 0.0001). Differences between activities in specimens from the gastric mucosa in patients with gastric polyps and those in controls were less pronounced than between gastric cancer and controls. A discriminant analysis, using the enzymes most sensitive to establish correct diagnosis, could identify normal gastric mucosa in 85-95%, atrophic gastritis in 56-63%, and uninvolved mucosa in gastric cancer in 66-78%.