A Crystal Ball for Cancer Spread?

Breast cancer is one of the most common sources of brain metastasis (BM), and affects 10-30 percent of patients (1). It goes without saying that this has a significant effect on mortality, and the ability to predict which patients will go on to develop BM could be used to better manage the disease. Now, a team of US researchers have found a biomarker which may help oncologists predict which breast cancers will spread to the brain – αB-crystallin expression.

“BM is associated with the shortest survival time compared with other sites of metastatic spread. If, using primary tissues, we can identify a subgroup of patients who may be of higher risk to develop BM, this could potentially be very valuable for clinical management,” says co-leader of the associated study (2), Maggie Cheang.

The researchers analyzed αB-crystallin protein expression in 3,987 specimens from breast cancer patients using immunohistochemistry, and tissue samples were recorded as positive for the protein if there was any staining above background levels. They found that, in women whose cancer had already begun to spread, those who tested positively were around three times more likely to develop BM, and that the protein was also linked with poorer survival rates. A test of this kind could have clear applications in both disease monitoring and management, and in selecting patients for clinical trials.

However, it remains unclear whether gene or protein levels of αB-crystallin provide the best predictive power, Cheang warns. “We hope to add αB-crystallin to established clinical trials in metastatic breast cancer to validate our findings. We also plan to see if expression of this protein contributes to BM in other types of solid tumors, like lung cancer and melanoma, which commonly metastasize to the brain,” she says.