About 15 percent of breast cancers are classified as triple-negative, lacking receptors for estrogen, progesterone, and Her2. These cancers do not respond to targeted hormonal therapies, and they tend to be particularly aggressive, often resisting systemic chemotherapy and metastasizing to other tissues.
Researchers had observed that triple-negative breast cancer (TNBC) patients who had higher numbers of a type of immune cell called myeloid-derived immunosuppressor cells (MDSCs) in their bloodstream had poorer outcomes. But until now it wasn’t clear how MDSCs are recruited to the primary breast tumor and how they contributed to its progression and spread.
A new report led by the University of Pennsylvania School of Veterinary Medicine’s Rumela Chakrabarti, an assistant professor of biomedical sciences, and Sushil Kumar, a postdoctoral researcher in Chakrabarti’s lab, fills in crucial details about the connection between MDSCs and aggressive disease. In the Journal of Clinical Investigation, Chakrabarti, Kumar, and colleagues identify a protein, deltaNp63, on tumor cells that directs MDSCs to the tumor and metastatic sites, where they promote tumor growth and metastasis. Blocking either this protein or the MDSCs themselves reduced tumor growth and metastasis in a mouse model of TNBC.
“We’re excited because we think our findings could make
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