I have heard many times that being obese or overweight increases the risk of developing breast cancer. It also has been said that it shortens the time between the return of the disease.

Why is this? It might be because of a hormone in our bodies called leptin.

Researchers are doing experiments on mice that might prove to be an important influence in developing drugs that target the mechanism that causes obese individuals to have a higher risk of the disease.

Italian researchers speaking at the Experimental Biology 2007 in Washington, DC, report evidence on how leptin, a hormone found in fat cells, significantly influences breast cancer development and progression in mice.

Leptin sends messages to the body that no more food is needed, a process that might not work well for those that are overweight or obese. Leptin also is involved with cell differentiation and proliferation in the body. Leptin has demonstrated to play a significant role in promoting breast cancer in obese women by increasing the amount of estrogen in the breast tissue.

Even though these are experiments done only on mice at this point, this learning process is what leads to new drugs and targeted therapies.