DIAGNOSTIC SIGNIFICANCE OF SERUM PROGASTRIN AND CLAUDIN-2 LEVELS IN PATIENTS WITH GASTRIC CANCER

Abstract

The present study investigated the serum levels of progastrin and claudin-2 in patients with gastric cancer and evaluated their relationship with mutations in the XRCC1 and ERCC1 DNA repair genes. The study included 50 patients with histologically confirmed gastric cancer and 50 age- and sex-matched practically healthy individuals as a control group. Mutations in all exons of the XRCC1 and ERCC1 genes were analyzed by polymerase chain reaction (PCR) and direct sequencing, while serum progastrin and claudin-2 concentrations were determined by enzyme-linked immunosorbent assay. The results demonstrated that median serum progastrin levels in patients with gastric cancer were 3.8 times higher (286.5 pg/ml vs. 74.6 pg/ml; p<0.001), and claudin-2 levels were 6.0 times higher (2.1 ng/ml vs. 0.5 ng/ml; p<0.001) than in the control group. In patients carrying mutations in DNA repair genes, both markers were further elevated compared with mutation-negative cases: progastrin by 1.4-fold (p=0.036) and claudin-2 by 1.5-fold (p=0.004). ROC analysis confirmed an acceptable diagnostic performance of progastrin in patients with mutations in exon 9 of the XRCC1 gene (AUC=0.722; p=0.022). The findings suggest that serum progastrin and claudin-2 may serve as clinically relevant biomarkers reflecting both the biochemical activity of the tumor and the molecular-genetic background of the disease. The combined assessment of these proteins together with the mutational status of DNA repair genes may contribute to the development of personalized diagnostic strategies in gastric cancer.