Genomic profiling of breast cancer in African-American women.

Abstract

11054 Background: Molecular profiling of breast cancer (BC) identifies intrinsic subtypes with distinct gene expression and clinical characteristics. In the US, BC is less frequent in African-American females (AAF); however mortality is higher, particularly among younger women. Unfavorable subtypes of BC seem to be more frequent in premenopausal AAF. Methods: Tumor gene expression in AAF presenting with early stage or locally advanced BC was performed using the Symphony platform on fresh and paraffin-embedded tissue (Agendia inc), a microarray-based method which classifies tumors according to prognosis (MammaPrint, MP), molecular subtype (BluePrint, BP) and estrogen receptor (ER), progesterone receptor (PR) and Human Epidermal Growth Factor Receptor 2 (HER2) mRNA levels (TargetPrint, TP). Genomic information is correlated with clinical and pathologic characteristics and Oncotype DX recurrence score (RS) when available. We plan to enroll 100 patients. Results: Results available in 46 patients. Median age 62 years (range 24-100), 20 stage I, 15 stage II, 11 stage III disease. There was no significant association between MP risk and stage, but MP risk was significantly associated with grade 3 disease (p=.006). 9 cancers were triple negative by IHC; using BP, 8 of these were Basal-type and 1 HER2-type. Basal-type was the most common subtype in patients ≤ 40 years old (p < .001). In the 6 cases ER positive by IHC but negative by TP, 3 were Basal-type and 3 were HER2-type.14 patients had Oncotype RS results available: 2 were High Risk by Oncotype and MP; 3 had intermediate RS, 2 of which were High Risk by MP; 9 had a low RS, 4 of which were High Risk by MP. Conclusions: African-American women with stage I to III BC often present with High-Risk disease irrespective of stage. BP classified all young patients (≤40) as Basal-type. Molecular subtyping confirmed the biologic heterogeneity in triple negative and hormone positive tumors. Oncotype RS and MP offered different prognostic information. Follow up will be needed to determine correlation with outcome. Funding: MP, BP and TP test provided by Agendia. Biostatistical support by GHUTTCS-CTSA. [Table: see text]