Predicting Response to Immunochemotherapy in Early Triple Negative Breast Cancer

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.