ERBB2 and breast cancer: Functional characterization of Chinese and Caucasian gene-clusters, by testing whether gene lists relevant to breast cancer 1,20–22 were over-represented, revealed a number of clusters of correlated genes in both Chinese and Caucasian datasets that were associated with: (1) intrinsic classification 1,20 defining luminal epithelial/ER and ERBB2 clusters and clusters of genes involved in proliferation and epithelial differentiation; (2) ECM components, including structural and adhesion molecules 21; and (3) immunological mechanisms according to Rody et al.