New research from Oklahoma University has uncovered a link between obesity and the spread of breast cancer in women. The study suggests that unique changes in the bodies of women with obesity are helping breast cancer become invasive, typically more advanced, and spreading into surrounding breast tissue.
Key Findings
The researchers observed changes in cancer tumors and the surrounding cells. They found higher levels of an enzyme known as Sulfatase 2 in tumor cells. This enzyme, a protein that accelerates chemical reactions, has previously been linked to breast, lung, liver, and other cancers.
Bethany Hannafon, an assistant professor at the university's College of Medicine, explained: "This could be why women with obesity are at higher risk for invasive breast cancer. The changes that the cancer cells are undergoing are allowing them to survive and thrive."
Inflammation and Tumor Growth
The area surrounding the cancer was more inflamed in women with obesity, as immune cells arrived and sped up tumor growth. Normally, these cells fight off disease, but they can be reprogrammed by tumors to support cancer, according to New York's Memorial Sloan Kettering Cancer Center.
Additionally, the cells that make up their tumors appeared to survive better under stress, with differences noted in both the tumor cells and the cells around them.
Breast Cancer Statistics
The American Cancer Society estimates that about 321,910 new cases of invasive breast cancer will be diagnosed this year. Most breast cancers are invasive, with two common types: invasive ductal carcinoma (80% of cases) and invasive lobular carcinoma (10% of cases). Invasive ductal carcinoma begins in the milk duct cells, breaking through the duct wall into nearby tissue. Invasive lobular carcinoma starts in the milk-producing glands.
Breast cancer is the most common cancer in women in the U.S., excluding skin cancers, accounting for about 30% of new female cancers each year.
Implications for Treatment
Currently, there is no way to determine which women with noninvasive tumors will develop invasive ductal carcinoma. Hannafon noted: "As a result, many women with noninvasive breast cancer receive the same treatments used for invasive ductal carcinoma, including surgery, radiation, and sometimes hormone therapy. Overtreatment is a major concern, but if we had better ways of determining risk, unnecessary treatments could potentially be reduced."
Future research will focus on the role of Sulfatase 2 in invasive breast cancer. Obesity, which affects over 100 million Americans (40% women), is a known risk factor for invasive breast cancer and other diseases.
