ABSTRACT
Objective To analyze gene expression profiles of biopsy specimens from breast cancer patients who were treated with neoadjuvant chemotherapy(NAC) after biopsies, and to identify the genes which are closely associated with the efficacy of neoadjuvant chemotherapy with T/FAC [docetaxel(Taxotere), 5-fluorouracil, doxorubicin and cyclophosphamide] or T/FEC (Taxotere, 5-fluorouracil, epirubicin and cyclophosphamide) regimen.Methods We retrieved and collected gene expression profiles from publicly available databases.Four datasets, a total of 844 samples, were finally retained because all the patients had received a uniform neoadjuvant chemotherapy regimen.Response to neoadjuvant chemotherapy was categorized as a pathological complete response (pCR) or residual invasive cancer (RD).The differentially expressed genes (adjusted P-value<0.05) and therapeutic efficacy were analyzed and explored.Results After differential analysis, genes whose expressions were higher or lower in pCR group than in RD group were identified in each of the four datasets, respectively.There were 34 and 42 genes which were simultaneously more highly expressed or more lowly expressed in pCR group than in RD group in the four datasets.The unsupervised clustering, based on the 76 intersection genes, showed that the pCR specimens tended to form one cluster and the RD tended to form the other.Conclusion The seventy-six differentially expressed genes are associated with the efficacy of neoadjuvant chemotherapy and are likely to be novel predictive biomarkers for the efficacy of neoadjuvant chemotherapy.