Genomic profiling of breast cancer in African-American women using MammaPrint

Breast cancer in African-American females (AAF) has a less favorable outcome than that in Caucasians. More information is needed regarding its biology. We evaluated gene expression in tumors from AAF presenting with early stage or locally advanced breast cancer using MammaPrint^®, BluePrint ^® (molecular subtype) and TargetPrint ^® [estrogen receptor (ER), progesterone receptor, and Human Epidermal Growth Factor Receptor 2 (HER2) mRNA levels]. Genomic information was correlated with clinical and pathologic characteristics and Oncotype DX^® Recurrence Score^® (RS). One hundred Patients were enrolled, 1 not evaluable by BluePrint. The median age was 60 years (range 22–98), and eighty-four (84 %) patients had stage I or II disease. High Risk MammaPrint was present in 66 % of patients and in 52 % of patients with stage I disease. High Risk MammaPrint was associated with young age (p = 0.02), high grade (p < 0.0001), HER2 expression (p = 0.016), and triple-negative phenotype (p < 0.001). Sixty-four tumors (65 %) were Luminal type (47 % of these were classified as High Risk), 26 (26 %) were Basal type, and 9 (9 %) HER2 type. Twenty-two cancers were triple negative (TN) by IHC and 19 (90 %) Basal type. Among the 15 tumors HER2 positive by IHC/FISH, 8 (53 %) were HER2 type by BluePrint. Eleven tumors with ER expression of 1–9 % were ER negative by TargetPrint and none of these was Luminal type. None of the seven tumors HER2 positive by IHC/FISH but negative by TargetPrint was HER type. RS results were available in 29 patients: two had High Risk both by RS and MammaPrint; eight had intermediate RS, with four High Risk by MammaPrint; 19 had a low RS, with eight High Risk by MammaPrint. AAF with stage I to III breast cancer often present with High Risk disease. Molecular heterogeneity is present within TN, HER2-positive, and ER-positive breast cancer. RS and MammaPrint offer different prognostic information.