Obese women fearful of contracting a particularly aggressive type of breast cancer should lose weight to reduce their risk, according to a study conducted in the US.The researchers, headed by Prof. Liza Makowski at the University of North Carolina School of Medicine and just published in Breast Cancer Research and Treatment, found that obese women face a significantly increased risk of developing “basallike” breast cancer. The scientists outlined in their article the biological mechanisms where obesity can create a favorable environment for the growth of basal-like breast cancer tumors.“This may be an important piece of research,” said Prof.Yechezkel Barenholz, a world-renowned cancer and liposome researcher at the Hebrew University-Hadassah Medical Center who has developed important cancer drugs.Makowski said: “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.”Breast cancer is a heterogeneous disease made up of several distinct subtypes. Basallike carcinoma is defined by its gene expression and protein expression profile and classified as ductal carcinoma. The basallike subtype, an aggressive form of breast cancer, is found in 15- 20 percent of women diagnosed with breast cancer, with a high percentage of cases found among young and African-American women.Women diagnosed with the basal-like subtype often have a poor prognosis and cannot be treated with hormonal and targeted therapies.“Our study was fairly unique in that we focused on the role that the surrounding tissue in the breast, known as the stroma, plays in breast cancer onset,” Makowski explained. “Many scientists study the tumor alone, but the stroma ‘soil’ where the cancer ‘seed’ grows is important in helping that tumor grow.”Since HGF levels are increased with obesity, the study indicates that public health efforts to prevent obesity in at-risk populations may be a clinically useful way of preventing the disease.