Additional file 1 of HER2 expression, copy number variation and survival outcomes in HER2-low non-metastatic breast cancer: an international multicentre cohort study and TCGA-METABRIC analysis

Additional file 1: Table S1. Database information and details of HER2 testing by study centre. Table S2. Sensitivity analysis of relapse-free survival and overall survival by HER2 and hormone receptor status. Figure S1. Flowchart of patients included in the ABCCG cohort analysis. Figure S2. Estimated heterogeneity between study centres in (A) relapse-free survival, and (B) overall survival (based on pooling univariable HR estimate from each centre with a random effect restricted maximum likelihood estimation model. HR, hazard ratio; I2, index of heterogeneity). Figure S3. Association of ERBB2 mRNA expression with HER2 IHC and ERBB2 CNV by hormone receptor status (TCGA-BRCA): (A-D) Hormone receptor-positive subgroup of TCGA-BRCA dataset: ERBB2 mRNA expression by (A) HER2-low and HER2-zero, (B) HER2 IHC score, (C) ERBB2 CNV; (D) ERBB2 CNV against HER2 IHC. (E-H) Hormone receptor-negative subgroup of TCGA-BRCA dataset: ERBB2 mRNA expression by (E) HER2-low and HER2-zero, (F) HER2 IHC score, (G) ERBB2 CNV; (H) ERBB2 CNV against HER2 IHC. Figure S4. Relapse-free survival by ERBB2 mRNA expression levels in combined TCGA-BRCA and METABRIC dataset (Quartile 1: lowest; Quartile 4: highest)