Tumor Infiltrating Mast Cells (TIMs) Confers a Marked Survival Advantage in Nonmetastatic Clear-Cell Renal Cell Carcinoma

Purpose The role played by the innate immune system in determining the clinical outcome of clear-cell renal cell carcinoma (ccRCC) was still blurred. This study was designed to investigate the prognostic significance of tumor infiltrating mast cells (TIMs) in ccRCC. Methods The study retrospectively enrolled a training set (474 patients) and a validation set (188 patients) with nonmetastasis (pT1-4N0M0) ccRCC from two institutional medical centers of China. TIMs was evaluated by immunohistochemical staining of tryptase and its association with clinicopathologic features and prognosis were evaluated. Results In ccRCC tissues, TIMs ranged from 0 to 103 cells/mm 2 and 0 to 113 cells/mm 2 in the training set and validation set, respectively. TIMs was negatively correlated with tumor size ( P