PROGNOSTIC VALUE OF THE ATROPHIA MARKERS IN GASTRIC CANCER RISK AT THE WEST SIBERIA POPULATION
Background: atrophic gastritis (AG) associated with Helicobacter pylori (H. pylori-infection) is one of the precancerous lesions and associated with low level of serum pepsinogen I (PGI) and PGI/PGII ratio, which are also recognized like predictive markers for gastric cancer (GC) development. The aim of the study: to analyze the predictive value of biomarkers in the GC development in a prospective “case-control” study conducted in Caucasian population of Western Siberia (8 years follow-up). Material and Methods: GC cases and control were selected from population cohort of residents of Novosibirsk within the international HAPIEE project during 2003-2005 with inclusion of subjects (n=9360) of both sexes at the age of 45-69 years. Serum samples were stored at -70<sup>0</sup>С. GC cases received from Population Cancer Registry until 2012 were compared with the database of HAPIEE with selection of appropriate on sex and age control in the ratio 1:2. Finally, 156 serum samples (52 - the main group and 104 - control) were available for analysis, and biomarkers were measured. The following criteria for biomarkers of atrophic gastritis were used: PGI < 30 µg/l, PGII < 3 µg/l, PGI/PGII < 3, G-17 < 1 pmol/l. Results: The mean levels of PGI and PgI/PgII ratio in the GC group was lower in comparison with the control (p < 0.005 and p< 0.0001, respectively); no difference was shown in respect to the other biomarkers. The cut-off values of atrophy have appeared above the recommended parameters: for PGI-55 µg/l (р=0.0001; OR=4.1; 95 % CI 2.0-8.4) and PGI/PGII ratio-5 (р=0.0001; OR =5.8; 95 % CI 2.7-12.4). Conditional (fixed effects) logistic regression analysis with inclusion into the model sex, age of the patients, and all biomarkers of test system showed PGI/PGII ratio as the most powerful indicator in the model (OR=2.9; 95 % CI: 1.0-8.0). Conclusions: for the first time the predictive value of low indicators of PGI and PGI/PGII ratio in GC risk development in Caucasian population for 8 years follow-up was demonstrated.