Therefore, the aims of this study were to evaluate the expression of MCT1, MCT2, MCT4 and CD147 in normal tissues and TGCTs, using tissue microarrays (TMAs), to validate the TMA method for the study of these proteins in a heterogeneous type of tumor, to compare the expression in tumors with normal tissue, to correlate the expression with clinicopathological data, and to further explore the contribution of MCTs for tumor aggressiveness using GCT in vitro models. This evidence concerns the gene BSG and granular cell tumor.