Triple-negative Breast Cancer (TNBC), Stage II-III

The goal of this study is to investigate whether specific metabolic profiles can predict response to neoadjuvant chemo-immunotherapy in patients with stage II and III triple-negative breast cancer (TNBC). The main objectives are to determine: * whether targeted metabolic pathways, specifically tryptophan and diacetylspermine metabolism, are associated with histological response to neoadjuvant treatment; * whether untargeted metabolomics combined with machine learning approaches can identify novel biomarkers predictive of treatment response. Participants will: * undergo image-guided tumor sampling during the standard-of-care placement of the tumor localization clip, prior to initiation of neoadjuvant chemo-immunotherapy, in accordance with routine clinical practice at the study center; * provide a blood sample before initiation of neoadjuvant chemo-immunotherapy; * provide a second blood sample during the course of standard treatment; continue to receive routine clinical care, including imaging assessments and surgical management, according to standard clinical practice. The study does not modify the patient's standard therapeutic management.