Expression of erythropoietin and neuroendocrine markers in clear cell renal cell carcinoma

: The aim of the study was to investigate the expression of erythropoietin and neuroendocrine markers in clear cell renal cell carcinoma (CCRCC). We retrospectively reviewed the medical records and re-evaluated histopathological specimens of 33 patients with CCRCC and compared with those of 11 cases of non-CCRCC. All patients were treated with a partial or radical nephrectomy at St. Olavs Hospital, Trondheim University Hospital, between 2010 and 2016. Thirty-three patients who were diagnosed with CCRCC had a total of 35 tumours, where 34 of the tumours were CCRCC and one was papillary adenoma. Thirty-three (97%) of 34 CCRCCs were positive for erythropoietin, and the same 33 (97%) tumours demonstrated strong expression for neuron-specific enolase (NSE). Two (6%) of 34 CCRCCs had a positive reaction for synaptophysin, and three (9%) of 34 were positive for CD56. Erythropoietin and NSE were negative in non-CCRCCs, and chromogranin A was negative in all tumours. The above findings suggest that there is a strong association between CCRCC and the expression of erythropoietin and NSE.