CD10 is positive in ccRCC [35] and in RCC-FMS, but negative or focally positive in ccpRCC [36], an irregularity in staining that has been brought to light in the literature as well as in our results, where CD10 evidenced a diffuse and, at the same time, patchy positivity in a ccRCC background. The gene discussed is MME; the disease is renal cell carcinoma.