The goal of this trial (DAPHNe: De-escalation to Adjuvant antibodies Post-pCR to Neoadjuvant THP) was to assess the feasibility of de-escalating therapy from a multi-agent to a single-agent chemotherapy backbone plus HP in select patients with anatomic stage II-III HER2+ breast cancer, based on pCR as a prognostic biomarker. The gene discussed is ERBB2; the disease is breast cancer.