A correlation between early changes in the tumor maximum standardized uptake value (SUVmax) on FDG-PET after one or two cycles of neoadjuvant chemotherapy (NAC) and the pathological response after 6 to 8 cycles has been demonstrated in several independent small series of patients.

Breast tumor proliferation status has previously been demonstrated to be a good predictive factor of response to chemotherapy. The best method for assessing proliferation status is unclear. Proportion of cells staining for nuclear Ki67 antigen is the most widely used assay for comparing the proliferation status between tumors. However major variations in analytical procedure and interpretation limited its clinical value. Taking into account the prognosis and predictive value of proliferation gene as a common "signature" in breast cancer transcriptome analysis, quantitative assessment of mRNA expression of genes involved in proliferation has been developed by the investigators team and others. The evaluation of these parameters is quantitative and reliable and can be standardized for a clinical use.

The main objective of the investigators study is to early predict pathological response to anthracycline-based neoadjuvant chemotherapy (NAC) using a combination of parameters based on FDG-PET imaging performed at baseline and after 2 cycles, and molecular markers of proliferation measured on pre-treatment biopsy (Ki67 protein level by immunohistochemistry and Ki67 mRNA level and the mRNA (messenger RNA) expression of the most pertinent genes of the Genomic Grade Index (GGI) component by RT (reverse transcriptase) - qPCR).

Inclusion Criteria:

• Women aged ≥ 18 years
• Newly diagnosed invasive breast cancer
• Stage-II or stage-III
• Neoadjuvant anthracycline-based chemotherapy
• Primary breast biopsy must be available
• Non metastatic, M0
• No prior systemic therapy for the presFrance: Direction Generale de la Sante ent tumor
• Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other trial procedures

Exclusion Criteria:

• Metastatic breast cancer
• Uncontrolled diabetes
• Limited breast cancer immediately accessible to conservative surgery and not candidate for neoadjuvant chemotherapy
• Previous homolateral breast cancer and/or contralateral breast cancer except if treated by surgery +/- radiation therapy alone without any systemic treatment
• Any surgery (not including minor procedures such as lymph node biopsy, primary tumor core biopsy, fine needle aspiration) within 12 weeks of start of study treatment; or not fully recovered from any side effects of previous procedures.
• Diagnosis of any previous malignancy within the last 5 years, except for adequately treated basal cell carcinoma, or squamous cell skin carcinoma, or in situ cervical carcinoma

Stage II-III Breast cancer