There is not always a clear cause of kidney cancer. As with most cancers, it is commonly a combination of factors, including age. However a number of risk factors have been identified with tend to be associated with somewhat higher rates of kidney cancer.
There is an excellent discussion of this topic from Cancer Research UK.
The strongest risk factors are genetic changes that can run in families. If there are multiple people with kidney cancer — or any other cancer — in your family, it would be wise to work with a genetic counselor to explore whether there may be a genetic change in your family that might increase your risk for cancer.
Click here for the WebMD discussion of increased risk of kidney cancer.