Reversed-phase liquid chromatographic investigation of nucleosides and bases in mucosa and modified nucleosides in urines from patients with gastrointestinal cancer.

Reversed-phase high-performance liquid chromatography (HPLC) has been used to determine the level of nucleic acid metabolites in perchloric acid extracts of gastrointestinal mucosa. By comparing the levels of these compounds in the normal portion with the levels in the neoplastic portion of mucosa resected from patients with malignant cancer, it was found that uracil was significantly elevated in the neoplastic colorectal mucosa (adenocarcinoma) of eight patients with colorectal cancer (P less than 0.01, statistically significant with the paired t test). The mean level of uracil in neoplastic colorectal mucosa was 2.7-fold higher than that in normal mucosa. However, in neoplastic gastric mucosa, only one out of four patients with gastric cancer showed elevated uracil. In neoplastic mucosa, the levels of hypoxanthine and uridine for colorectal cancer, and inosine for gastric cancer, were also significantly higher than those in normal mucosa (P less than 0.05, with the paired t test). The urinary modified nucleosides were prefractionated with a boronate affinity gel column, and their levels determined by the same HPLC method. No significant differences in the concentrations of pseudouridine, 1-methylguanosine, N2-methylguanosine or N2,N2-dimethylguanosine were observed in pre- and post-operative urines from patients with colorectal cancer and normal urines.