EPO and renal cell carcinoma: The prevalence of erythropoietin-producing tumors, which are mainly detected in renal cell carcinoma or hepatocellular carcinoma, is very low in secondary erythrocytosis; the prevalence of erythropoietin-producing uterine myoma is even lower, accounting for only 0.02–0.5% of all uterine myoma cases [8].