Supplementary Figure S9 from Determinants of survival in HER2+ metastatic esophagogastric cancer

Serial plasma ctDNA in an individual patient demonstrating pre-treatment genomic heterogeneity and selection for resistant clones. Plasma ctDNA at diagnosis revealed ERBB2 amplification in a patient with HER2+ EG cancer, as well as numerous pre-existing resistance mechanisms including EGFR amplification, PIK3CA amplification, and an FGFR3-TACC3 fusion that was not identified on tumor sequencing (Figure 2b).