Katharina Buczek
According to the American Cancer Society, triple-negative breast cancer (TNBC) accounts for about ten to fifteen percent of all breast cancers in the U.S.
But, a new study conducted by Weill Cornell Medicine in New York City has found a concrete biological link between African ancestry and TNBC disease processes.
TNBC is distinct since the cancer cells do not have progesterone or estrogen receptors and produce only a little or no HER2 protein.
This makes the tumor cells more challenging to treat because they do not respond to anti-HER2 drugs or hormone therapies.
The cancer subtype also accounts for about thirty-three percent of all breast cancer diagnoses in African nations; meanwhile, TNBC makes up less than twenty percent in other countries.
But, this study is the first of its kind to determine TNBC’s ancestral links via not only African descent but also specific African regions.
The researchers first conducted ancestry estimation on a hundred and thirty-two patients’ breast tissue samples. Then, RNA sequencing was performed on twenty-six cases.
And after the team identified gene expression associated with African ancestry at both the national and regional levels, the researchers analyzed biological pathway impact and were able to estimate the number of immune cells in tumors.
In other words, the study revealed that women with a high degree of African ancestry– particularly East Africans from Ethiopia– and who have TNBC exhibit much greater immune cell populations infiltrating tumors. This is compared to women with lower degrees of African ancestry– mainly West Africans from Ghana and African Americans.
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