Biomarker in African American Women With Triple-Negative Breast Cancer Indicates Poor Outcome

March 3, 2017
Lauren Evoy Davis

Scientists have discovered that African American patients with triple-negative breast cancer who carry a specific biomarker, nKIFC1, experience a dismal prognosis.

Scientists have discovered that African American patients with triple-negative breast cancer (TNBC) who carry a specific biomarker, nKIFC1, experience a dismal prognosis. The scientific community has become more aware that this patient population, due to socioeconomic issues, is diagnosed with later stage breast cancer so this finding is important.

This was first published in the journal Nature.

The expression was assessed by immunohistochemistry in 163 African American and 144 white TNBC tissue microarrays (TMAs) pooled from four hospitals. The nKIFC1 biomarker correlated significantly with Ki67 in white TNBCs, but not in African American TNBCs, suggesting that nKIFC1 is not just a surrogate for proliferation in African American TNBCs. High nKIFC1 weighted index (WI) was associated with significantly worse overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) (hazard ratios [HR], 3.5, 3.1, and 3.8, respectively; P = .01, .009, and .007, respectively) in multivariable Cox models in African American TNBCs, but not white TNBCs.

“We looked at the levels of nuclear KIFC1 in their tumors, and interestingly, we found that African American women had slightly higher levels, but it was only within African American patients that the levels mattered for their outcome,” said Angela Ogden, lead author of the study and a PhD candidate in Dr. Ritu Aneja’s laboratory in Georgia State’s Biology Department. “African American women with high nuclear KIFC1 levels tended to do poorly, whereas in white women, it didn’t matter if they had high or low levels. It had no effect on their outcomes.”

The researchers further investigated why the biomarker only seems to matter in African American patients by studying triple-negative breast tumor cells from African American and white patients.

“We found that if we silence the KIFC1 gene, it had a greater impact on the migration of the African-American cells than it did on the white cells,” Ogden said. “It may be that for whatever reason, in African-American breast cancer tumors, KIFC1 helps the cells to migrate and spread to other parts of the body. And for reasons that we currently don’t know, that’s not the case in white tumors. Ultimately, it may even be that African-American patients could potentially be treated with a KIFC1 inhibitor to help prevent metastasis, but that’s for future studies.”

TNBC accounts for 15% to 20% of all breast cancers, and is more prevalent in African American and Hispanic women, and women younger than 40 years of age. This oftentimes deadly cancer is also likely to metastasize early. These findings may lead to biomarkers that could identify differences in tumor biology between racial groups to predict risk and to help lessen health disparity in African American women who have this diagnosis.

Although it is not completely clear about whether African American women with TNBC is a molecularly distinct disease or whether African American women have a higher incidence of aggressive biology driven by disparities. However, it is important to learn how biology and disparities affect survival rate of African American women with TNBC.