ICR - The Institute of Cancer Research: Global Foundation

Institute of Cancer Research (ICR) scientist Dr. Janine Erler, working in collaboration with Professor Valerie Weaver from the University of California, San Francisco, has identified an enzyme that is crucial for turning abnormal but non-malignant breast tissue into tumors. Blocking the enzyme lysyl oxidase (LOX) reduced the chance a tumor would form, and also meant tumors that did develop were smaller and less aggressive.

"This is the crucial missing piece in the jigsaw that scientists have been searching for,” says Dr. Janine Erler.  “Our study shows that stiffening of the breast tissue controlled by enzymes such as LOX is a key factor in cancer development, suggesting these enzymes are promising candidate drug targets.”

Dr. Erler’s previous studies have already highlighted the importance of LOX in cancer spread, showing that it promotes metastasis by sending out signals that prepare a new area of the body for invasion. The new study shows that LOX is also crucial for primary tumor progression.

Although both studies were carried out in breast cancer, Dr. Erler says it is likely a similar mechanism occurs in other cancer types, as LOX levels are known to be elevated in many cancer types.

What makes the current study unique is that the investigators showed that it is the cells within the connective tissue surrounding the growing tumors that express the LOX enzyme.  These cells induce the tissue stiffening and fibrosis that then, through mechanical forces, promote the tumor cells to become invasive. These observations are significant because they emphasize the need to treat tumors early and to focus on the tissue microenvironment – not just the tumor but the surrounding area too.

Scientists from the University of Pennsylvania, University of California, San Francisco, Stanford University School of Medicine, University of Hawaii at Manoa and the University of North Carolina also contributed to this study.