In this study, we temporally characterised the mutational, gene expression, pathway enrichment and tumour-infiltrating lymphocytes (TILs) dynamics across different timepoints over a 12-week period in HER2-negative primary breast cancers enrolled in the single-arm SOLTI-1007 NEOERIBULIN phase II clinical trial (NCT01669252). The gene discussed is ERBB2; the disease is neoplasm.