A review of more than a thousand studies has found solid evidence that being overweight or obese increases the risk for at least 13 types of cancer. The study was conducted by a working group of the International Agency for Research on Cancer, part of the World Health Organization.
http://well.blogs.nytimes.com/2016/08/24/obesity-linked-to-at-least-13-types-of-cancer/?_r=0
Obesity Is Linked to at Least 13 Types of Cancer