Kidney cancer starts in cells of the kidney. The 2 kidneys are on either side of the backbone, deep inside the upper part of the abdomen and protected by the lower ribs. Attached to the top of each kidney is an adrenal gland. The kidneys make urine by filtering water and waste material from the blood. The ureter is a tube that carries urine from each kidney to the bladder. When the bladder is full, the urine passes out of the body through a tube called the urethra.
