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

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: CD18-/- down-regulates Treg cells and inhibits the pathogenesis of renal cell carcinoma.