Obesity Increases Risk of Basal-Like Breast Cancer Development

Women who are obese have an increased risk of developing an aggressive sub-type of breast cancer, according to researchers from the University of North Carolina. These 'basal-like' cancer cells are formed from a triple-negative phenotype and typically found in younger patients.

"Obesity is widespread and is one of the few risk factors for breast cancer that we may be able to control, hence our intention in this study was to better understand the molecular mechanisms and/or biomarkers of obesity-related basal like breast cancer that could impact disease prevention," Liza Makowski, assistant professor with the UNC Gillings School of Global Public Health and member of the UNC Lineberger Comprehensive Cancer Center said, via a press release. 

The basal-like subtype accounts for 15 to 20 percent of breast cancer diagnoses in women, with a high number of cases found in young and African-American women. Those diagnosed with this sub-type often show a poor prognosis that cannot be treated with hormonal and targeted therapies.

The researchers used a mouse model to help develop the basal-like subtype. They discovered that obesity radically alters cellular microenvironments for the mammary glands so that basal-like tumors are more likely to form.

Excess weight promotes a growth protein and an oncogene known as c-Met that has been liked to basal formations of cancer, as well. In animals, these elevated levels of HGF increased the development of basal-like tumors.

"Our study was fairly unique that we focused on the role that the surrounding tissue in the breast, known as the stroma, plays in the breast cancer onset. Many scientists study the tumor alone, but the stroma 'soil' where the cancer 'seed' grows is important in helping that tumor grow," Makowski said.

More information regarding the study can be found via the journal Breast Cancer Research and Treatment.