Among the novel fusions, none of the NONO-TFE3 rearranged renal cell carcinomas have been shown to express cathepsin K, whereas RBM10-TFE3 rearranged renal cell carcinoma [33] and some MED15-TFE3 [34] rearranged renal cell carcinoma are reactive for this marker. Here, MED15 is linked to hereditary clear cell renal cell carcinoma.