ERBB2 and breast cancer: To explore how tumor subtypes identified in ctDNA data perform when applied to tumor tissue DNA, the scores of the 150 DNA-based signatures were determined and evaluated using tumor DNAs from 1,689 patients with early-stage breast cancer from the publicly available METABRIC dataset29, and 381 patients with advanced HR+/HER2- breast cancer from the MSK-IMPACT dataset (Fig. 5a and Supplemental Fig. 22a).