Molecular characteristics and infection rates in patients with gastric cancer in Western Poland: a comparative analysis of gastrectomy specimens across two decades.

[INTRODUCTION] Gastric cancer incidence and characteristics vary due to environmental factors, and technical advances facilitate early detection of the disease. This study aimed to assess whether significant socio-economic changes and technological advancements in Poland - one of the most rapidly developing countries worldwide - affected the molecular characteristics and detection rates of early gastric cancer sub-types in Western Poland.

[METHODS] Ninety-two patients undergoing gastrectomy for gastric cancer in 1998-2002 and 2016-2020 were studied. Surgical specimens were re-analyzed for histopathological features, including tumor type, grade, and stage (up-dated World Health Organization [WHO] classification). Immunohistochemical markers (Ki-67, p53, E-cadherin, CD10, CD31, bcl-2) and antigens for Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV) were evaluated. Microsatellite instability (MSI) was assessed via PMS2/MSH2 protein expression.

[RESULTS] The groups were comparable in age and gender, with male predominance. Histological features, H. pylori and EBV colonization, and most molecular markers showed no significant differences. However, Ki-67 proliferation index significantly increased in cancers diagnosed in 2016-2020, correlating with intestinal-type tumors and p53 expression. In this group, higher Ki-67 levels were also linked to H. pylori infection, microsatellite stability, and increased angiogenesis.

[CONCLUSIONS] Despite advancements in H. pylori research and technology over 20 years, no improvement was observed in H. pylori-positive tumor rates or early gastric cancer detection in Western Poland. Although molecular characteristics remained largely unchanged, the increased proliferation index in recently diagnosed cancers merits further study.