Tumor entities with highest rates of Napsin A positivity included adenocarcinoma of the lung (85.6%), papillary renal cell carcinoma (40.2%), clear cell adenocarcinoma of the endometrium (42.8%) and the ovary (71.7%) and clear cell (tubulo) papillary renal cell carcinoma (16.7%). The gene discussed is NAPSA; the disease is papillary renal cell carcinoma.