PAMELA is a non-randomized, open label, multicentric translational research study of neoadjuvant dual HER2 blockade therapy without chemotherapy. Although efficacy and safety will be investigated, the primary goal is to identify profiles predictive of clinical benefit from targeted therapy. Eligible patients must be women with untreated primary HER2-overexpressing and/or amplified breast tumors of more than 1 cm in diameter amenable to definitive surgery (stage I-IIIA).