The association of MCT1, MCT4 and CD147 expression with characteristics of worse prognosis, such as nonseminomatous histology, higher stages, higher metastasis occurrence, vascular invasion and higher risk stratification, reflect the function of these proteins in lactate efflux, in maintaining the extracellular acid pH, and, as a result, in glycolytic phenotype and tumor aggressiveness. This evidence concerns the gene BSG and neoplasm.