Epidemiology of Polyps in the Rectum and Sigmoid Colon: Size, Enzyme Levels, DNA Distributions, and Nuclear Diameter in Polyps of the Large Intestine

Abstract

Enzyme activity and cell cycle variables were measured in 38 adenomas and 9 hyperplastic large-intestinal polyps equal to or larger than 5 mm in diameter. The polyps were resected endoscopically from patients 50–59 years old. A significantly higher activity of lactate dehydrogenase (LD) was found in polyps from women than in those from men. A higher LD activity was also observed in adenomas with moderate to severe dysplasia than in those with mild dysplasia. A significantly higher activity was found for LD and glucose-6-phosphate dehydrogenase (G₆PD) in adenomas <10 mm than in adenomas < 10mm in diameter. DNA flow cytometry showed that all hyperplastic polyps were diploid and that two of the adenomas had an aneuploid DNA stemline in addition to the diploid one. The S-phase fraction varied from 3.5% to 26.5% and the G₂ fraction from 0.4% to 6.7%. Two overlapping populations were found, based on nuclear size measurements. Hyperplastic polyps had almost only small nuclei, whereas adenomas had both small and large nuclei in various ratios. No statistical correlations were found between the S-phase or G₂-phase fractions and polyp size or the presence of dysplasia. The number of adenomas with aneuploidy was too small to disclose a relationship to polyp size or enzyme activity. The increased enzyme activity in larger polyps and in polyps from women may point to certain risk factors in these special groups. The results indicate a further need for studies of combination of markers for prognostic evaluation of large-intestinal adenomas.

Key Words:

• Bioluminescence
• DNA
• enzyme activity
• flow cytometry
• glucose-6-phosphate dehydrogenase
• lactate dehydrogenase
• polyps of the large intestine