African ancestry and higher prevalence of triple-negative breast cancer: findings from an international study.
BACKGROUND
The study of breast cancer in women with African ancestry offers the promise of identifying markers for risk assessment and treatment of triple-negative disease.


METHODS
African American and white American women with invasive cancer diagnosed at the Henry Ford Health System comprised the primary study population, and Ghanaian patients diagnosed and/or treated at the Komfo Anokye Teaching Hospital in Kumasi, Ghana constituted the comparison group. Formalin-fixed, paraffin-embedded specimens were transported to the University of Michigan for histopathology confirmation, and assessment of estrogen and progesterone receptors and HER-2/neu expression.


RESULTS
The study population included 1008 white Americans, 581 African Americans, and 75 Ghanaians. Mean age at diagnosis was 48.0 years for Ghanaian, 60.8 years for African American, and 62.4 for white American cases (P=.002). Proportions of Ghanaian, African American, and white American cases with estrogen receptor-negative tumors were 76%, 36%, and 22%, respectively (P<.001), and proportions with triple-negative disease were 82%, 26%, and 16%, respectively (P<.001). All Ghanaian cases were palpable, locally advanced cancers; 57 (76%) were grade 3. A total of 147 American women were diagnosed as stage III or IV; of these, 67.5% (n=46) of African Americans and 44.6% (n=29) of white Americans were grade 3. Among palpable, grade 3 cancers, Ghanaians had the highest prevalence of triple-negative tumors (82.2%), followed by African Americans (32.8%) and white Americans (10.2%).


CONCLUSIONS
Our study demonstrates progressively increasing frequency of estrogen receptor-negative and triple-negative tumors among breast cancer patients with white American, African American, and Ghanaian/African backgrounds. This pattern indicates a need for additional investigations correlating the extent of African ancestry and high-risk breast cancer subtypes.
Stark
Azadeh
A
Department of Pathology, Ford Health System, Detroit, Michigan, USA.
Kleer
Celina G
CG
Martin
Iman
I
Awuah
Baffour
B
Nsiah-Asare
Anthony
A
Takyi
Valerie
V
Braman
Maria
M
Quayson
Solomon E
SE
Zarbo
Richard
R
Wicha
Max
M
Newman
Lisa
L
D000368:Aged; D044383:Black People; D001943:Breast Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000473:pathology; D047628:Estrogen Receptor alpha / Q000032:analysis; D005260:Female; D006801:Humans; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000453:epidemiology / Q000208:ethnology; D015995:Prevalence; D001741:Black or African American
D047628:Estrogen Receptor alpha