Renal Cell Carcinoma as First and Second Primary Cancer: Etiological Clues From the Swedish Family-Cancer Database

High risk was found for histology concordant renal cell carcinoma pairs and contralateral renal cell carcinoma. Bidirectional associations of renal cell carcinoma with many other cancers may imply etiological sharing. von Hippel-Lindau syndrome may explain the excess of renal cell carcinoma after brain hemangioblastoma.