A new study found that anti-inflammatory drugs, like ibuprofen, could reduce the severity of postpartum breast cancers in animal models.
Breast involution is the process by which milk-producing cells that are no longer needed are killed and replaced with fat cells. During this time of change, the breast is especially susceptible to the development of cancer.
University of Colorado research team discovered that breast involution shares similarities with wounds, and wounds can cause cells to become cancerous in addition to promoting metastasis of otherwise localized tumour cells.
Two wound-like changes that occur in the postpartum breast are an increase in fibrous collagen (the protein that gives our flesh structure) and increase of an enzyme called COX-2.
In short, breast involution leads to COX-2, which leads to fibrous collagen, which promotes the release of more COX-2, and this positive feedback loop can help a tumour grow and push into other tissues.
It's a vicious chain, but one with a weak link: many drugs exist that inhibit COX-2. These include the non-steroidal anti-inflammatories (NSAIDs), such as ibuprofen, or celecoxib, which is a more targeted COX-2 inhibitor used in other inflammatory diseases like arthritis.
"Inhibition of COX-2 slows the formation of fibrillar collagen and thus both tumour growth and the tumour's travel into the lung," wrote Pepper Schedin, PhD, investigator at the University of Colorado Cancer Centre and collaborators.
Schedin and the research team found that in postpartum mice, ibuprofen and celecoxib treatment reduced mammary tumour size, collagen architecture, COX-2 expression, and breast tumour cell spreading into the lung.
However, they say recommending ibuprofen for women undergoing breast involution is premature.
The study was published online on Aug. 7, 2011, the journal Nature Medicine.