Serial gene expression analysis in locally advanced breast cancer patients who failed to respond to neoadjuvant chemotherapy. Homo sapiens

To elucidate candidate genes and pathways associated with poor response, we retrospectively analyzed gene expression profiles in serial biopsies from women with locally advanced breast cancer who failed to respond to anthracycline-based chemo followed by taxane in the I-SPY Overall design: Of the 221 patients who completed neoadjuvant chemotherapy, 215 patients had surgery with 73% not achieving a pathologic complete response (pathCR). In these patients, cDNA microarray expression profiles from pretreatment biopsy (T1) were compared to those biopsy specimens obtained 24-72 hours after initiation of treatment (T2) or in tumors surgically removed after chemotherapy (TS). Paired expression data for T1vsT2 and T1vsTS were available for 29 and 39 patients with no pathCR, respectively. Paired differential expression analyses were performed via Significance Analysis of Microarrays (SAM) and differentially expressed genes were subjected to Ingenuity Pathway Analysis