Creation and Characterization of a Breast Cancer Tissue Microarray Including Black and White Patients from Florida and Hispanic Patients from Puerto Rico and Florida

Breast cancer is a leading cause of cancer-related mortality among women worldwide and is known to have higher mortality among women with African ancestry. Herein, we describe the creation and characterization of a multiethnic breast cancer tissue microarray (ME-BrTMA) representing tumors from non-Hispanic White (n = 41), non-Hispanic Black (NHB; n = 45), and Hispanic patients from Puerto Rico (n = 36) and Florida (n = 52). This ME-BrTMA comprises five blocks with a total of 610 cores: 371 breast cancer tumor cores, 93 breast stromal cores, 96 normal breast tissue cores, 30 non-breast cancer tumor cores, and 20 cores representing normal tissues. Initial characterization of the ME-BrTMA includes standard IHC staining of well-characterized clinical biomarkers, including the estrogen hormone receptors and progesterone hormone receptors, HER2, and Ki-67, interpreted by the coauthoring pathologist (Marilin Rosa). The IHC results indicated good but imperfect alignment with clinical diagnoses. Cores from breast cancer tumors from the NHB cohort most frequently scored negative for estrogen receptor (63%, P < 0.005) and progesterone receptor (80%, P < 0.005) and most frequently have high expression of the Ki-67 proliferation marker (38%, P < 0.05). Prediction Analysis of Microarray 50 (PAM50) analysis using RNA from secondary patient blocks showed that the NHB group also most frequently scored in the basal-like category (61%, P < 0.05). Taken together, the initial characterization of the ME-BrTMA suggests that it may serve as a representative resource to understand the underlying biology of breast cancer and its relationship to patient outcomes. SIGNIFICANCE:The ME-BrTMA described herein provides a resource that may serve as a tool to understand the underlying biology of breast cancer.