Adipose tissue or the fat tissue produces an excess amount of estrogen which is associated with cancers of breast, endometrial, and ovarian.
Obese people have higher levels of insulin and insulin like growth factors in the blood. This condition known as hyperinsulinemia is a cancer threat. It might lead to cancer in the colon, kidney and prostate.
Obesity leads to inflammatory conditions which cause oxidative stress, DNA damage and increases the risk of several diseases including cancer.