"Our data indicate that HSET represents a potential new biomarker for poor breast cancer outcome among African-American women with the disease," said Ritu Aneja, Ph.D., associate professor in the Department of Biology at Georgia State University in Atlanta. "Using this biomarker effectively could give oncologists critical new information and potentially save lives by allowing earlier recognition of more aggressive breast cancers in African-American women, with the subsequent use of more customized treatment regimens to better manage disease."

African-American women are often diagnosed with breast cancer at a younger age than non-Hispanic white women and are more likely to have cancers that spread, recur, or result in death. Identification of biomarkers that can help clinicians predict if African-American women will have aggressive cancer is a high priority, according to Aneja.

Prior research has linked HSET overexpression to lung cancer metastasis to the brain, and has shown that HSET is upregulated in a particularly aggressive form of breast cancer that most commonly occurs in African-American women, triple-negative breast cancer.

To evaluate whether HSET could be a clinical breast cancer biomarker in ethnically distinct populations, Aneja and colleagues analyzed breast tumor samples from 149 African-American women and 44 non-Hispanic white women, looking for levels of HSET.

Breast tumor samples from African-American women were three times more likely to show high levels of HSET in a region of cells called the nucleus when compared with breast tumor samples from non-Hispanic white women. In addition, higher levels of nuclear HSET were linked to poorer outcomes among African-American women, but not non-Hispanic white women. African-American women with the highest levels of HSET were three to four times more likely to have shorter overall survival, progression-free survival, and metastasis-free survival when compared with African-American women with the lowest levels of HSET.

"We were surprised to find that HSET levels appeared to be a better predictor of cancer outcome than other routinely used breast cancer predictors, such as assigning triple negative status," said Aneja. "We are working around the clock to define ways in which this new biomarker can be used most effectively and as soon as possible in the clinical setting."