The formation mechanisms of tumor-associated tissue eosinophilia in gastric cancer and colon cancer
Tumor-associated tissue eosinophilia is defined as eosinophilic stromal infiltration of a tumor. Tumor-associated tissue eosinophilia is believed to play a significant role in carcinogenesis. It is believed that eosinophils have antitumor activity due to the release of cytotoxic proteins. The aim of this study was to investigate the molecular-genetic mechanisms of formation of tumor-associated tissue eosinophilia in patients with gastric cancer and colon cancer. Methods. Tumor tissue samples from patients with gastric cancer and colon cancer were reviewed. We counted the number of infiltrating eosinophils in neoplastic lesion tissue and we evaluated the expression of eotaxin-1 (a key factor of chemotaxis of eosinophils) and its receptor CCR3 in tumor tissue by immunohistochemical staining. The distribution of polymorphic variants of genes CCL11 (А384G), CCR3 (Т51С), IL5 (С703Т) and of the IL5R (G80А) was studied. DNA was isolated from tumor tissue samples. Genotyping of polymorphisms was carried out by polymerase chain reaction (PCR), followed by digestion with the appropriate restriction enzyme (PCR-RFLP) and agarose-gel electrophoresis. Results. It is shown that higher expression eotaxin-1 and CCR3 is determined in the tumor tissue of gastric cancer and colon cancer associated with eosinophilia. It is established that eosinophilic infiltration of the tumor tissue is associated with the carriers of CC genotype and C allele of the gene CCR3 (Т51С) and CC genotype and C allele of gene IL5 (С703Т). Conclusion. The formation of tumor-associated tissue eosinophilia in gastric cancer and colon cancer is mediated through the action eotaxin-1 and its receptor. The results of molecular-genetic studies indicate a genetically determined character of eosinophilia in gastric cancer and colon cancer.