Interleukin‐10 expression significantly correlates with minor CD8⁺ T‐cell infiltration and high microvessel density in patients with gastric cancer

We aimed to investigate the relationships between interleukin-10 (IL-10) expression and both the clinicopathological findings and prognoses in patients with gastric cancer and to compare IL-10 expression with microvessel (MV) density and CD8+ T lymphocyte infiltration to evaluate its effects on angiogenesis and immune responses in gastric cancer. IL-10 expression was determined in gastric cancer patients by reverse transcription-polymerase chain reaction (RT-PCR) or immunohistochemical procedures. Two of 7 normal gastric tissues showed IL-10 mRNA expression, while its expressions were confirmed in all advanced gastric carcinoma tissues examined (n=11) by RT-PCR. Immunohistochemical staining demonstrated that IL-10 expression was detected in 52 (47.7%) of 109 cases. There was a close correlation between IL-10 expression and MV density. IL-10 expression inversely correlated with CD8+ T-lymphocyte infiltration. The prognoses of patients whose tumors expressed IL-10 were significantly worse than those of patients whose tumors did not express IL-10. Multivariate analysis indicated IL-10 expression was an independent prognostic factor. IL-10 might be associated with tumor progression by stimulating angiogenesis and suppressing immune responses in gastric cancer.