The goal of this clinical trial is to identify cellular and molecular determinants of response to neoadjuvant immunochemotherapy in women aged 18 or older with early-stage triple-negative breast cancer (TNBC). The main questions it aims to answer are:

• Can detailed immune profiling of the tumor and its microenvironment predict pathological complete response (pCR, RCB-0) versus partial/non-response (RCB-I, II, III) to neoadjuvant immunochemotherapy?
• Are there specific immune or molecular biomarkers (e.g., TILs, CD3/8/20, FoxP3, PDL1, transcriptomic signatures) associated with progression-free survival and overall survival in this population? Researchers will compare patients achieving pCR (RCB-0) to those with residual disease (RCB-I, II, III) to determine if immune and molecular profiles can discriminate responders from non-responders and guide personalized treatment strategies.

Inclusion Criteria:

• Female.
• Age ≥ 18 years.
• Histologically confirmed invasive triple-negative breast cancer (ER and PR < 10% by IHC, HER2 0, 1+, or 2+ with negative SISH), stage II or III.
• Eligible for neoadjuvant immunochemotherapy according to the Keynote-522 regimen.

Indication for intra-tumoral clip placement.

- Signed written informed consent

Exclusion Criteria:

• Pregnant or breastfeeding women.
• Hematoma requiring Grade II analgesics after diagnostic biopsy.
• Known coagulation disorders.
• Adults under guardianship, curatorship, or legal protection, or deprived of liberty.
• Not affiliated with a social security system.

Patients treated in the neoadjuvant setting for triple-negative breast cancer