CD18 inhibits progression of kidney cancer by down-regulating Treg cell levels.

Gene mutation is closely related to the occurrence of tumor. Renal cell carcinoma is a malignant tumor, seriously threatening patients' life quality. Regulatory T cells (Treg) play important roles in the development of several cancers. This study aimed to investigate whether CD18 affects renal carcinoma cell proliferation.Thirty mice with renal cell carcinoma were constructed using gene-engineering mouse with CD18 deficiency, and another 30 normal C57 mice were used as control. Ki67 and micro-vessel density were detected by using immunohistochemistry (IHC) and immunofluorescence, respectively. The expression of CD3, CD4 and CD8 were detected in blood and spleen by quantitative PCR (q-PCR). Flow cytometry was used to detect the changes of Treg cells.The expression of Ki67 in C57 was significantly higher than that in CD18-/- mice (p<0.05). IHC results showed that CD31 was also significantly downregulated in CD18-/- group compared to control group (p<0.05). It was found that only high expression of CD4 in mesenteric lymph nodes of CD18-/- was considered as non-tumor-bearing. Flow cytometry results showed that Treg cells were significantly decreased in CD18-/- compared to C57 group (p<0.05).CD18-/- down-regulates Treg cells and inhibits the pathogenesis of renal cell carcinoma.