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BREAST CANCER SUBTYPES: Association Between Aggressive Breast Cancer Subtypes and African Ancestry. Lisa A. Newman, M.D., M.P.H., F.A.C.S. Professor of Surgery Director, Breast Care Center University of Michigan Ann Arbor, MI. Goals of Breast Cancer Treatment.
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BREAST CANCER SUBTYPES:Association Between Aggressive Breast Cancer Subtypes and African Ancestry Lisa A. Newman, M.D., M.P.H., F.A.C.S. Professor of Surgery Director, Breast Care Center University of Michigan Ann Arbor, MI
Goals of Breast Cancer Treatment • Local/Regional Treatment: to control/eliminate disease in breast and regional lymph nodes • Surgery • Radiation Therapy • Systemic Treatment: to control/eliminate disease in distant organs • Chemotherapy • Endocrine/Hormonal Therapy • Other Targeted Therapy (e.g. Herceptin)
Breast Cancer Treatment • All breast cancer patients are at risk for having metastatic disease in distant organs (liver, lungs, bones, etc) • Early-stage breast cancer pts more likely to have microscopic metastases (microscopic, invisible disease; micrometastases) • Highest risk in pts with bulky, locally-advanced, node-positive breast cancer • Systemic therapy can control distant organ metastases • Staging information (TNM) provides clues regarding risk of micrometastatic disease • Systemic therapy most likely to be successful if: • Micrometastatic burden is low (early-stage disease) • Systemic therapy is TARGETED to individual tumor biology
Systemic Therapy for Breast Cancer • Chemotherapy • “generic” systemic therapy: kills any rapidly-dividing cells in the body • Endocrine/Hormonally-active therapy • Tamoxifen; Aromatase Inhibitors • Target ER-positive and/or PR-positive breast cancer cells • Herceptin/Trastuzamab • Targets HER2/neu-positive breast cancer
Systemic Therapy for Breast Cancer • Appropriate systemic therapy can improve breast cancer survival by 20-30% • Preoperative (neoadjuvant) systemic therapy • can convert locally-advanced/inoperable breast cancer to resectable disease • can improve ease of surgery for any bulky cancer • Success of systemic therapy: • COMPLETELY dependent upon having information regarding tumor markers (ER, PR, and HER2/neu)
What are breast cancer subtypes? • What is the relationship between breast cancer subtypes and systemic therapy for breast cancer?
“Basal-like” breast cancer • Gene expression profile • Most tightly clustered subgroup in gene expression arrays • CK 5/6 and 17 expression • P53 mutations • EGFR overexpression • Mostly “triple negative” • Morphology • High grade • Mainly ductal or medullary • High mitotic count • Scant stroma • Central necrosis • Pushing border • Lymphocytic infiltrate • Apoptotic figures BRCA1 connection • Gene expression similar • Morphology similar
Sorlie et al. PNAS 2003 ER++, PR++, G1,2 HER2 ISH pos “triple neg,” CK5/6+
Triple-Positive Breast Cancer ER-Pos HER2/neu-Pos H&E PR-Pos Triple-Negative Breast Cancer PR-Neg ER-Neg H&E HER2/neu-Neg
Relevance of “Triple-Negative” Breast Cancer • Tumors that do not express the ER, PR, and HER2/neu markers are more likely to be basal-subtype tumors • Inherently aggressive biologic behavior • Triple-negativity used as a surrogate for basal subtype • Tumors that do not express the ER, PR, and HER2/neu markers have fewer systemic therapy options • Endocrine/hormonal therapy will be ineffective • Herceptin therapy will be ineffective • Chemotherapy IS effective
BREAST CANCER SUBTYPES:Association Between Aggressive Breast Cancer Subtypes and African Ancestry Association initially suggested by observations of disparities in the breast cancer burden of African Americans and White/European Americans Most available data therefore based upon studies of African American breast cancer pts and ER status
BREAST CANCER IN AFRICAN AMERICANS • Overall lower lifetime incidence • Higher mortality • More advanced stage distribution • Younger age distribution • Increased frequency of adverse prognostic tumor features • Higher incidence of male breast cancer
NCDB: Frequency of ER-Negative Tumors by Age, Stage, and Income 1998; N=170K; approximately 10% AA
Frequency of ER-Neg Breast Cancer NOT Explained by Stage Distribution: Age-specific incidence rates by ER status and race Hance, K. W. et al. J. Natl. Cancer Inst. 2005 97:966-975
Frequency of ER-Negative Breast Cancer NOT Explained by Poverty: International Data on SES and ER Status • Glasgow, Scotland (Thomson et al, J Epi & Comm Health, 2001) • 35% ER-negative for affluent women compared to 52% ER-negative for impoverished women • ER status missing for one-third of cases • Glasgow, Scotland (Carnon et al, BMJ 1994) • 51% ER-negative for affluent women compared to 52% ER-negative for impoverished women • Sweden National Health Care System (Halmin et al Acta Oncologica, 2008) • 37% ER-negative; no differences by SES • London, England (Bowen et al Br J Cancer, 2008) • 34% ER-neg for British Black women compared to 25% ER-neg for British White women; results unchanged by SES stratification
High-Risk Breast Cancer and African Ancestry • Parallels between hereditary breast cancer and breast cancer in women with African ancestry • younger age distribution • increased prevalence of ER-neg, aneuploid tumors • higher risk of male breast cancer • Is African ancestry associated with a heritable marker for high-risk breast cancer subtypes? • Unique opportunity to gain insights regarding etiology of breast cancer disparities and the pathogenesis of triple-negative breast cancer
Breast Cancer in African American, Sub-Saharan African, and White American Women
Research Project: KATH-UM International Breast Cancer Registry To systematically evaluate African ancestry as a risk factor for ER/triple-negative, early onset breast cancer • Multicenter/international study • African Americans (UM; Henry Ford Hospital) • White Americans (UM; Henry Ford Hospital) • Ghanaians (Komfo Anoyke Teaching Hospital) • Document correlation between quantified extent of ancestry (via genotyping) and risk for ER-negative/triple-negative breast cancer (via tumor studies)
Other African Datasets • Huo et al (Olopade) JCO 2009 • 378 breast cancers from Nigeria and Senegal • 1996-2007 • Mean age 45 yrs • 76% ER-negative • 73% triple-negative • Bird et al Ann Surg Onc 2008 • 120 breast cancers from Kenya • 2001-2007 • Median age 47 yrs • 76% ER-negative • 44% triple-negative (subset of 34 tumors)
ALDH1 as a Breast Cancer Stem Cell Marker Article ALDH1 Is a Marker of Normal and Malignant Human Mammary Stem Cells and a Predictor of Poor Clinical Outcome Christophe Ginestier, Max S. Wicha and Gabriela Dontu, et al University of Michigan, Ann Arbor MI Laboratoire d'Oncologie Moléculaire, Centre de Recherche en Cancérologie de Marseille, France November 2007, Pages 555-567
ALDH-1 Staining by Race/Ethnicity • Ghanaian Cases: • 20/23 (87%) • University of Michigan White American cases: • 24/146 (19%) • French/European cases: • 102/345 (30%) • White American/European ER-negative cases • 39/80 (50%)