Kidney Cancer is one of the most prevalent types of cancer that affects the kidneys. It is caused by aberrant cell proliferation in the renal tissue, which causes the cells to multiply and divide uncontrolled. These extra cells eventually become cancerous and develop a tumor in one or both kidneys. Kidneys are two bean-shaped organs found beneath the ribcage that take excess water and salt from the blood and convert these waste products into urine, which is expelled from the body by urination.