Abstract: The invention relates generally to the field of cancer prognosis and treatment. More particularly, the present invention relates to methods and compositions that utilize a particular panel of gene products (“biomarkers”) and their differential expression patterns (“expression signatures”), wherein the expression patterns correlate with responsiveness, or lack thereof, to chemotherapy treatment. The invention is based on the identification of a specific set of biomarkers that are differentially expressed in chemotherapy-treated tumors and which are useful in predicting the likelihood of a therapeutic response, including residual disease persistence and subsequent tumor recurrence in cancer patients receiving chemotherapy. The gene panel is also useful in designing specific adjuvant modalities with improved therapeutic efficiency. Also disclosed are methods for characterizing tumors according to expression of the biomarkers described herein.