Smoking has long been the biggest cause of cancer in the United States, but obesity; now the second leading cause, has gained ground. A new study from researchers at the University of Chicago finds that women with breast cancer; the most common cancer among women are at even higher risk from obesity. Breast cancers occur in adipose tissue, better known as fat. Triple-negative breast cancer (TNBC) is a type of breast cancer that is particularly difficult to treat.
None of the three most appealing drug target the estrogen receptor, the progesterone receptor; human epidermal growth factor receptor 2 are present on TNBC cells. These cancers can be particularly aggressive. “For patients with TNBC, there are few therapeutic options. The survival rate is quite low. And cancer tends to be dramatically elevated in patients who are overweight or obese.”
Cancer prevention measure
Unfortunately, once cancer has detected there may not time to lose weight prior to treatment. “So our bottom line,” Rosner said, is to “promote weight loss as a cancer prevention measure, incorporate weight loss; as a component of therapy for patients with breast cancer; develop specific drug targets that could leverage to address the obesity component of the disease.”
The biology of how obesity promotes TNBC. They show that obesity reprograms macrophages scavenger white blood cells that can devour invaders such as bacteria, viruses or tumor cells into pro-inflammatory; metabolically-activated macrophages. Instead of fighting breast cancer, these immune cells actually promote it. Their studies, in mice and humans,” Becker added, implicate these metabolically-activated adipose tissue macrophages.
Therefore they accumulate in mammary adipose tissue. They release interleukin 6, a pro-inflammatory cytokine which can fuel tumorigenesis. And they thrive on obesity. So interleukin 6 binds to a receptor on the surface of existing cancer cells. That can create “an even more aggressive stem cell phenotype. These cancer stem cells are able to encourage tumor growth and metastasis; enabling them to travel to other sites.
The metastatic cancer
Patients with advanced or metastatic cancer have higher levels of IL-6 in their blood; which is correlated with poor survival rates. Obesity, the study authors wrote, is a pathological state that “facilitates tumorigenesis by creating tumor permissive conditions in multiple tissues.” This suggests that chronic inflammation and its effects on tumorigenesis may reversed by targeted anti-inflammatory therapies or by weight loss.
Indeed, the researchers found that inducing weight loss in obese mice by feeding them a healthier low-fat diet reversed macrophage inflammation and TNBC tumor formation in mammary fat; even though their body weight remained elevated. These findings highlight the potential value of weight loss; not only as a preventive intervention but even after patients develop breast cancer.