The changes in purine metabolism in gastric cancer

Abstract

Background. Gastric cancer (GC) is considered an urgent problem of oncology, due to its high incidence and morta­lity, diagnosis at a later stage of the disease progression, anatomical and topographical features of the organ affected by the tumor and the low effectiveness of the existing methods of treatment. The role of purine dysmetabolism in carcinogenesis remains insufficiently studied, and its clinical significance requires clarification. An increased level of uric acid in the blood is a risk factor for the deve­lopment and further severe course of gastric cancer. Purine bases are considered to belong to the tumor biomarkers; however, their diagnostic and prognostic significance in GC remains uninvestigated. The purpose was to assess the state of purine metabolism in patients with gastric cancer, to establish the clinical and pathogenetic significance of the identified changes. Materials and me­thods. A total of 88 patients with cancer (all men) aged from 29 to 79 years (mean age 60 years) were analyzed. Localization of the tumor process occurred in the stomach pylorus in 76 % cases, in the body — in 16 %, in the antrum — in 3 %, and in 2 % of all cases examined the entire stomach was affected. Adenocarcinoma was diagnosed in 72 % of cases, undifferentiated adenogenic stomach cancer — in 18 %, squamous cancer — in 8 %, colloid GC — in 2 %. The ratio of IA, IB, IIA, IIB, IIIA, IIIB and IV stages of the GC was 1 : 3 : 9 : 12 : 6 : 5 : 6. The tumor spread to the spleen was found in 15 % of cases, the pancreas — in 7 %, the liver — 6 %, the esophagus — 3 %, the diaphragm — 2 %, the gallbladder — 1 %. Lymph node metastases were found in 60 % of the GC observations, distant metastases — in 14 %. The blood serum levels of products of purine metabolism — uric acid, hydroxypurinol, adenine, guanine, xanthine, hypoxanthine, xanthine oxidase, xanthine deaminase, adenosine deaminase, and 5'-nucleotidase activities were stu­died. Results. The changes in purine metabolism were found in all patients with gastric cancer, including compared with the control group of healthy people, the level of uric acid was 2.0 times higher, oxypurinol 4.5 times higher, adenine — by 16 %, xanthine oxidase activity by 2.1 times, xanthine deaminase — by 33 % and adenosine deaminase — by 7.1 times, the elevated rates of which were found in 99, 84, 39, 90, 53 and 100 % of cases, respectively, depending on the severity of the tumor process, total lesion of the stomach, spread of the tumor to the liver, pancreas, and esophagus, the presence of metastases in para-aortic lymph nodes, liver, lung, bones and brain. The altered purine metabolism worsens three-year survival of patients against the background of surgical, medical, and radiation treatment. Conclusion. Changes in purine metabolism are involved in the pathogenetic constructions of the GC, reflect the peculiarities of the course of the tumor process; and the parameters of uric acid and adenine have prognostic significance.