Supplementary Figs. 2–5 compare the CNS failure free survival and overall survival between the Early Progression group vs. Non-Early Progression group subdivided into three breast cancer subtypes: estrogen receptor-positive (ER + ), HER2 non amplified (HER2-) group, HER2 + group, and the triple negative (ER-/HER2-) group. This evidence concerns the gene ERBB2 and breast cancer.