Fig. 4: Evolution of HER2 expression according to breast cancer subtype.

These Sankey diagramas show the evolution of HER2 expression from baseline biopsy to residual disease after neoadjuvant chemotherapy in patients failing to achieve pCR in the HER2-negative cohort according to breast cancer phenotype. a Evolution of HER2 expression in HR+/HER2+subtype; b Evolution of HER2 expression in TN subtype. HR+ hormone-receptor positive, TN triple-negative.