A molecule made by fat cells in human breast tissue increases the growth of certain breast-cancer cells. The finding suggests a potential reason why larger breast size seems to correlate with a higher risk of cancer.

Fat cells are thought to interact with cancer cells in the breast. To learn how, Wen-Hwa Lee at China Medical University in Taiwan and his colleagues grew human breast-cancer cells along with fat cells isolated from human breast tumours that had been surgically removed. The team found that the fat cells promoted the growth of cancer cells that made a protein called MCT2. The researchers pinpointed a small molecule, β-hydroxybutyrate, that is secreted by the fat cells and is transported into tumour cells by MCT2. This molecule upregulated several cancer genes, boosting the growth of human breast-tumour cells that express MCT2.

Nature Commun. 8, 14751 (2017)