Neoadjuvant Study of DV in Combination Toripalimab or Sequence Chemotherapy in HR-negative, HER2 Low-expressing Breast Cancer

Voluntarily participate and sign the informed consent form;

Ages≥18 years;

Invasive breast tumour tissue with low HER2 expression confirmed by the central laboratory, defined as HER2 protein expression of IHC 1+ or IHC 2+ with no amplification by in situ hybridisation (ISH) (according to the Breast Cancer HER2 Detection Guidelines, 2019 edition) by immunohistochemistry; and specimens from the primary site of the tumour for HER2 detection (wax blocks, biopsies, or fresh tissues are acceptable) are available for HER2 detection

Tumour hormone receptor (HR)-negative, defined as IHC-stained invasive carcinoma with a proportion of cells positive for both ER and PgR nuclear staining of <1% according to ASCO/CAP guideline 2020;