Testical Cancer Related to Bike Riding

I am an avid bike rider. I mainly ride for my health but do enter into weekend tours and races. I ride around 100 to 150 miles per week. Occationally my testicals get numb or are numb after riding. I have started using special bike seats for this problem and it seems to be working fine. My question is, Are bike riding and testical cancer related or can the riding cause any testical problems or cancer. I've read alot on Lance Armstrong and with all his riding this has never reoccured with him. I'm 54 years old and have rode for 20 years and plan on continuing my bike exercise program but I always have this question in my mind.