Purpose. To evaluate whether changes in genomic expression that occur beginning with breast cancer (BC) diagnosis and through to tumor resection after neoadjuvant chemotherapy (NCT) reveal biomarkers that can help predict therapeutic response and survival. Materials and Methods. We determined gene expression profiles based on microarrays in tumor samples from 39 BC patients who showed pathologic complete response (pCR) or therapeutic failure (non-pCR) after NCT (cyclophosphamide-doxorubicin/epirubicin). Based on unsupervised clustering of gene expression, together with functional enrichment analyses of differentially expressed genes, we selected NUSAP1, PCLAF, MME, and DST. We evaluated the NCT response and the expression of these four genes in BC histologic subtypes. In addition, we study the presence of tumor-infiltrating lymphocytes. Finally, we analyze the correlation between NUSAP1 and PCLAF against disease-free survival (DFS) and overall survival (OS). Results. A signature of 43 differentially expressed genes discriminated pCR from non-pCR patients (|fold change >2|, false discovery rate <0.05) only in biopsies taken after surgery. Patients achieving pCR showed downregulation of NUSAP1 and PCLAF in tumor tissues and increased DFS and OS, while overexpression of these genes correlated with poor therapeutic response and OS. These genes are involved in the regulation of mitotic division. Conclusions. The downregulation of NUSAP1 and PCLAF after NCT is associated with the tumor response to chemotherapy and patient survival.

Background: Studies of molecular changes occurring before and after neo-adjuvant chemotherapy (NCT) for breast cancer may unveil genetic biomarkers to predict therapy response. This study aimed at identifying genomic changes in breast primary tumors of patients under NCT. Gene expression changes were correlated with pathological response and survival.Methods: Gene expression profiles in tissue samples from pre and post NCT were obtained by a non-supervised classification analysis. Thirty-nine patients were classified according to their response to the chemotherapy as pathologic complete responders or non-responders (pCR and no-pCR, respectively). Overall survival was assessed by comparing gene expression values before NCT using the Log-rank (Mantel-Cox) test. Results: A signature constituted by 43 genes was obtained to stratify pCR and no-pCR patients after NCT (FC = + 3, FDR p -value < 0.0298). These genes were involved in regulation of the mitotic nuclear division and the anaphase-promoting complex-dependent catabolic process. Remarkably, over-expression of NUSAP1 and KIAA0101 were associated to poor overall survival. Conclusions: A new expression signature evaluating response for the neo-adjuvant chemotherapy stratified pathological response. The expression levels of NUSAP1 and KIAA0101 before and after the neo-adjuvant therapy may be useful to predict overall survival.