Lipocalin 2 triggers the epithelial to mensenchymal transition (EMT) in breast cancer, which occurs when tumors are about to metastasize, according to researchers at Children’s Hospital Boston. They also found that the same protein, when measured in tissues and urine, can predict a cancer's invasiveness.
The investigators also noticed that lipocalin 2 decreases the levels of estrogen receptor alpha, which triggers the EMT pathway. Reducing the cells' response to estrogen has been associated with poor prognosis of breast cancer.
The team induced human breast cancer cells to make large amounts of lipocalin 2 and showed that cell motility and invasiveness increased significantly. They then took cells from aggressive breast cancers and silenced lipocalin 2, which greatly inhibited cell migration.
Additionally, when investigators transplanted human breast cancer cells into animals, those from tumors making lipocalin 2 were more locally invasive and more likely to metastasize to lymph nodes.
The scientists also discovered that urine and tissue samples from women with invasive breast cancer consistently showed elevated lipocalin 2 levels, suggesting that testing for the protein may be a way of detecting cancer progression.
Lipocalin 2 and other urine biomarkers of cancer identified by the group have been licensed to Predictive Biosciences, which reportedly did not fund these studies. The findings were published online February 23 by the Proceedings of the National Academy of Sciences.
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