Study of the soluble MICA in gastric cancer patients in different stages and relation with prognosis

Abstract

Objective To observe the features of soluble MHC class I chain-related gene A (sMICA)in patients with gastric cancer of different differentiation degrees, the relationship between sMICA and the stage of gastric cancer and the relationship between sMICA and the metastasis of gastric cancer. To provide a new and useful marker in the differential diagnosis and staging of gastric cancer. Methods The peripheral blood examples of 200 gastric cancer patients and 60 health donors were collected. The serum levels of soluble MICA of peripheral blood were determined by MICA-specific enzyme-linked immunosorbent assay.Results The serum levels of sMICA in the patients with gastric cancer and health donors were (359.45 ±114.15) pg/ml and (210.07 ±31.01) pg/ml respectively. sMICA levels in the patients were significantly higher than those of the health donors (t =16.58, P 0.05). The serum levels of sMICA in the patients with gastric cancer steped up gradually while increasing of the TNM stages.There were significant differences between stage Ⅱ and Ⅲ, stage Ⅱand Ⅳ, stage Ⅱ and Ⅳ (P <0.05). The serum levels of sMICA in the patients with gastric cancer steped up gradually while aggravating of metastasis extent.Conclusion sMICA-release of MICA from cancer cells may reduce the expression of NKG2D. This may impair NKG2D-mediated immune surveillance of gastric cancer and leads to the tumor escaping; In the patients with gastric cancer, the serum levels of sMICA correlate with cancer stage and metastasis but show no correlation with cell differentiation. Key words: Stomach neoplasms; Genes; MHC class Ⅰ; Prognosis