Light micrograph of a clear cell adenocarcinoma of the kidney. This is a cancer of the tubules in the kidney that filter waste from blood. It is so named because the cancer cells appear clear under a microscope. It makes up around 80 % of renal cell carcinomas, the most common form of kidney cancer, and surgical removal of the tumour or entire kidney is the typical treatment. This tissue is stained with haematoxylin-eosin saffron (HES). Magnification: 1667x when printed 10 centimetres wide.