[Nucleotide composition and the methylated cytosine level in the DNA from a cancerous stomach tumor].

Under study was the nucleotide content and the level of methylated cytosine (5-MC) in the DNA, isolated from adenocarcinoma of the stomach, gastric mucosa in patients with duodenal ulcer as well as from the mucosa of intact human stomach. The difference (reliable statistically) was found in the amount of 5-MC between the tissues concerned. So, in adenocarcinoma the amount of 5-MC was 4.64 +/- 0.3 mol.%, in gastric mucosa in case of duodenal ulcer--2.63 +/- 0.3 mol.%, while in mucosa of intact stomach--1.52 +/- 0.3 mol.%. The increased level of DNA methylation should influence its structure and activity.