MicroRNA expression profile in HER2-positive breast cancer patients submitted to neoadjuvant chemotherapy.

e11511 Background: In the neoadjuvant setting, trastuzumab associated with chemotherapy significantly improves pathologic complete response (pCR) when compared to chemotherapy alone. There are currently no conclusive biomarkers for patient response to trastuzumab in clinical practice. We investigate predictive factors of response to neoadjuvant treatment in HER2-positive breast cancer patients. Methods: We evaluated clinical, histological and immunohistochemical characteristics of 54 patients with histologically confirmed HER2-positive, stage II and III, breast cancer, treated with preoperative trastuzumab/chemotherapy combination. MicroRNA expression profile from 8 invasive ductal carcinomas was analyzed using Human MicroRNA Cards v.3 A and B (Applied Biosystems). Samples were collected using an ultrasound guided core-needle biopsy prior to neoadjuvant treatment. Samples from patients who achieved pCR were used as basal expression level. The cards were processed and analyzed using a QuantStudio 12K-Flex ...