During the four-year Ella Binational Breast Cancer Study, scientists assessed the association between reproductive factors and tumors subtypes in 1,041 Mexican and Mexican-American female cancer patients.
The study looked at the occurrence of three tumor subtypes: luminal A, HER2 and triple negative. The luminal tumor starts in the inner cell lining of the mammary ducts and is most common. The HER2 tumor is so-named because it is positive for human epidermal growth factor receptor 2 (or HER2) — a protein shown to play a role in aggressive breast cancer. Triple negative breast cancer does not have targeted treatment options, making it difficult to treat and giving it the worst prognosis.
“We found that breastfeeding in women of Mexican descent is associated with triple negative breast cancer,” said María Elena Martínez, MPH, PhD, UC San Diego Moores Cancer Center Sam M. Walton Endowed Chair for Cancer Research and co-director of the Reducing Cancer Disparities research program and lead author of the study. “This was quite surprising. No other study has seen this correlation before. Most studies show health benefits of breastfeeding.”