As an important component of solid tumors, mast cells show specific phenotypes in various tumor microenvironments. However, the precise mechanism of mast cell accumulation and the phenotypic features of thyroid cancer (TC) remain largely unknown. Here, we found that mast cells were obviously recruited to tumor tissue by TC-derived stem cell factor (SCF). With tumor progression, mast cell levels increased gradually. In addition, intratumoral mast cells expressed higher levels of the immunosuppressive molecule galectin-9, which effectively suppresses CD8+ T-cell antitumor immunity in vitro. Blocking galectin-9 on tumor-infiltrating mast cells reversed the immunosuppression of CD8+ T cells. In conclusion, our data elucidated novel protumorigenic and immunosuppressive roles of mast cells in TC. In addition, our results indicated that blocking mast cells may impede tumor progression and ameliorate the prognosis of TC patients.

We have developed a novel method for fast determination of chromium(VI) using egg albumin(EAB) as fluorescence probe. The influence factors, including pH, reaction time, concentration of EAB, were investigated on the performance of the method and the optimum experimental conditions were determined. Under the optimum conditions, the relative fluorescence intensity of albumin was linearly proportional to Cr(VI) over a concentration range from 1.0x10-7 to 6.0x10-5 mol L-1 with a correlation coefficient of 0.9936 and a detection limit of 5.2 nmol L-1. This is a fast, simple, high selective and environment-friendly method, which has been employed to detect trace Cr(VI) in drinking water samples with satisfactory. The infrared spectral information indicated that the possible mechanism of fluorescence quenched may be the change of the secondary structures of EAB in the presence of Cr(VI).