A study by researchers at Tufts University School of Medicine, the Sackler School of Graduate Biomedical Sciences at Tufts, and Tufts Medical Center improves our current understanding of the origins of breast cancer. The researchers propose a new model for breast cell differentiation that identifies two populations of progenitor cells, one of which appears to be the cell of origin for luminal-like breast cancer, the most common form of the disease. The study, published in the January 19 issue of Cancer Cell, identifies a possible target for breast cancer drugs.
Breast cancers are generally classified in one of two categories. Luminal-like cancers, which are sensitive to hormones, are the most common form of breast cancer and tend to grow more slowly. Basal-like cancers, which are not sensitive to hormones, are more aggressive and tend to have a poorer prognosis. While scientists have predicted that these cancers might arise from different types of progenitor cells, it has been difficult to identify these cells of origin.
A team of researchers led by Charlotte Kuperwasser and Philip Hinds identified different types of breast stem and progenitor cells using a novel mouse model. Previously, researchers had been unable to functionally distinguish between stem cells that make the entire mammary tissue and other progenitor cells due to the shared molecular features of these cell populations.
"It wasn't clear that breast tissues did in fact contain functionally distinct progenitor cells. Our findings, however, show that luminal-like breast cancer originates from one type of progenitor cell, lobule progenitors, which are the self-renewing cells required to generate the milk-producing structures in breast tissue during pregnancy and lactation. Inhibiting a protein essential to these cells prevented the formation of breast tumors in mice," said co-senior author Charlotte Kuperwasser, PhD, associate professor in the anatomy and cellular biology department at Tufts University School of Medicine (TUSM) and member of the cell, molecular, and developmental biology and genetics program faculties at Sackler.