Renal cell carcinoma (also known as hypernephroma) is the most common form of kidney cancer arising from the proximal renal tubule. The tissue of origin for renal cell carcinoma is the proximal renal tubular epithelium. Renal cell carcinoma can be classified as 1) clear cell carcinoma, 2) papillary carcinoma, 3) chromophobe renal carcinoma, and 4) collecting duct carcinoma.