HR+/HER2+ breast cancer belongs to a special type of tumor with dual-channel signal activation. However, in clinical treatment, the preferred approach is usually the inhibition of the HER2 signaling pathway. Therefore, the non-pCR rate after neoadjuvant therapy is relatively high (about 60%). To optimize the neoadjuvant treatment strategy for HR+/HER2+ breast cancer, increase the pCR rate of neoadjuvant treatment, and improve the prognosis of patients, our research group intends to conduct a prospective clinical and translational study. By observing the clinical efficacy and changes in biomarkers, individualized treatment for HR+/HER2+ breast cancer will be carried out. Patients who respond well to HER2-targeted therapy will be identified early, and for those without early relief, targeted combined dual-channel inhibition therapy with endocrine treatment will be adopted. The effectiveness and safety of the individualized neoadjuvant treatment strategy for HR+/HER2+ breast cancer patients will be evaluated. In addition, this study aims to focus on the neoadjuvant chemotherapy mechanism of HR+/HER2+ breast cancer, and combine the establishment and validation of effective disease models to provide theoretical basis and experimental support for achieving precise treatment and clinical transformation.

Inclusion Criteria:

• The patient must meet all of the following criteria to be included in the study:

  1. The tumor stage must be in accordance with the 8th edition of the AJCC standard, being stage II-III for the initial diagnosis;
  2. The age must be between 18 and 75 years (inclusive of 18 and 75), and the patient must be female;
  3. All patients must have been pathologically confirmed as HR+/HER2+. The estrogen receptor (ER) must be positive (>10%) or the progesterone receptor (PR) must be positive (>10%), and the HER2 must be positive. HER2 positivity is defined as an immunohistochemistry (IHC) score of 3+, or a score of 2+ and positive in in situ hybridization (ISH) (ISH amplification rate ≥ 2.0);
  4. The ECOG score must be 0-1;
  5. According to the RECIST 1.1 standard, there must be at least one measurable lesion;
  6. The functional levels of the organs must meet the following requirements: (a) Blood routine: ANC ≥ 1.5×109/L; PLT ≥ 90×109/L; Hb ≥ 90g/L; (b) Blood biochemistry: TBIL ≤ 1.5×ULN; ALT and AST ≤ 3×ULN; BUN and Cr ≤ 1.5×ULN and creatinine clearance rate ≥ 50 mL/min; (c) Cardiac echocardiography: Left ventricular ejection fraction ≥ 50%:
  7. The subject voluntarily joins this study, signs the informed consent, has good compliance and is willing to cooperate with follow-up.

Exclusion Criteria:

• (1) Has received any form of anti-tumor treatment (chemotherapy, radiotherapy, molecular targeted therapy, endocrine therapy, etc.) in the past; (2) Is currently receiving other anti-tumor drug treatment; (3) Has had any other malignant tumor within the past 5 years, except for cured cervical carcinoma in situ, basal cell carcinoma or squamous cell carcinoma of the skin, or minimally invasive papillary thyroid cancer after radical surgery; (4) Has severe dysfunction of important organs such as the heart, liver, and kidneys; (5) Has difficulty swallowing, chronic diarrhea, and intestinal obstruction, and has multiple factors that affect the administration and absorption of the drugs; (6) Has participated in other drug clinical trials within 4 weeks before enrollment and has received the investigational drugs; (7) Has a history of immunodeficiency diseases, including positive HIV test, HCV, active viral hepatitis, or having other acquired or congenital immune deficiency diseases, or having a history of organ transplantation; (8) Has a known history of allergic reaction to the components of this study drug; (9) Has had any heart disease, including: requiring drug treatment or clinically significant arrhythmia; myocardial infarction; heart failure; any other heart disease judged by the investigator as unsuitable for participation in this trial; (10) Pregnant or lactating female patients, female patients with reproductive capacity and positive baseline pregnancy test results; (11) According to the investigator's judgment, has serious accompanying diseases that endanger the patient's safety or affect the patient's completion of the study (including but not limited to severe hypertension that cannot be controlled by drugs, severe diabetes, active infection, etc.); (12) Has a clear history of neurological or mental disorders, including epilepsy or dementia; (13) The investigator deems that the patient is not suitable for participating in this study in any other circumstances.