Is it true that chocolate can cause cancer?

I just got an email forwarded by my friend says about several food that can cause cancer. Chocolate is included on the list... I couldn't believe it.. I eat chocolate almost my whole life.. And sometimes I eat chocolate too much till I dont want to eat it again for few days.. I hope it is not true, because if it is true I have to reduce my chocolate. Nobody wants to get cancer Any of you ever heard about this too?