What could cause renal cancer?

Smoking. Cigarette smoking is associated with many cancers including renal cancer. Certain inherited disorders may also increase the risk of developing kidney cancer.
Many things. Smoking, high blood pressure, obesity, exposure to toxic substances, overuse of pain relievers, and cystic changes of the kidneys are risks for getting renal cancer. Cadmium, asbestos, and petroleum-based chemicals (like de-greasers) are the main toxins that cause renal cancer. Chronic hepatitis c infection is linked to causing kidney cancer. There is a strong genetic link as well.