MAF Regulates Bone Metastases in Breast Cancer

The bone is often the first site of breast cancer metastases and nearly 15% to 20% of advanced stage breast cancer (BC) patients present with bone metastases. The 5-year survival in these stage IV patients is estimated at 22% by the American Cancer Society, while patients who have a less invasive disease (stage III or lower), fare much better. Now, a group of research scientists in Spain have identified a gene that triggers the bone metastasis. The findings have been published in the Journal of the National Cancer Institute.

In the paper, the authors report having analyzed over 900 primary breast tumor samples to identify copy number aberrations (CNA) associated with bone metastases. This led to the identification of a gain-of-function mutation (16q23) in the MAF gene, as well as overexpression of the MAF protein. The authors found a significant correlation between these aberrations in MAF and an increased risk of relapse in patients with early BC. Patients expressing a mutated MAF were also at a greater risk of presenting with bone metastases but not to any other sites.

Previous work with this gene has shown that MAF regulates a set of genes that together support BC cell metastases to the bone. These results suggest that MAF could be an ideal marker to predict disease progression in early stage BC patients.

"This gene reliably predicts metastasis to the bone. Studying whether it is highly expressed in breast cancer patients to determine whether this also happens in a clinical setting is an important next step. It could improve the quality of life of these patients and the way clinicians manage their cancer. And this is exactly what we are doing," said Roger Gomis, PhD, the senior author on the study.

This discovery has been patented and transferred to Inbiomotion, a company led by the venture investor Ysios Capital. Efforts are underway to validate the marker in clinical trials.