A novel tumor marker test that may help predict whether breast cancer is likely to spread or metastasize to the brain, a deadly complication with survival typically measured only in months after diagnosis has been identified by scientists.
The approach was based on prior laboratory experiments by Dr. Vincent Cryns, professor of medicine and study co-leader, on a cell stress protein called alpha B-crystallin. Working initially in mice, Cryns and colleagues found that alpha B-crystallin promoted brain metastasis in aggressive "triple-negative" breast cancers that lack expression of three different receptors, the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2).
Based on these earlier findings, Cryns turned to an international team of scientists to examine whether levels of alpha B-crystallin in breast tumor samples could help identify those patients who would go on to develop metastasis to the brain. The team analyzed nearly 4,000 breast tumor samples from women with long-term clinical follow up, including sites of metastasis.
The researchers found that among women with metastatic disease, women whose breast tumors expressed alpha B-crystallin were nearly three times more likely to develop brain metastasis than women whose breast tumors did not express this protein. Alpha B-crystallin expression also predicted shorter survival after the initial breast cancer diagnosis and after the diagnosis of brain metastasis.
"The results were completely consistent with our predictions based on our prior laboratory studies," says Cryns.
"In addition, our lab is working on strategies to therapeutically target alpha B-crystallin as a strategy to treat or prevent brain metastasis in breast cancer," says Cryns. He cautions that these results need to be validated in additional studies before this test could be used in the clinic.