Significant inter-individual variation exists in tumor response and chemotherapy toxicity because of unique tumor and patient factors. Individual drugs with distinct mechanisms of action may induce specific genomic and proteomic changes that may be used as predictor for response. We plan to study serial genomic and proteomic profiles in primary breast tumor treated with one of two sequences of alternating adriamycin (A) and docetaxel (T), A>T>A>T>A>T, or T>A>T>A>T>A, at 75mg/m2 3 weekly for each drug. Pharmacokinetic analysis of both drugs will be performed; amplified tumor RNA will be hybridized on Affymetrix® HG-U133+2 array; tumor proteins will be fractionated and profiled with ProteinChip® Array SELDI MS (Ciphergen). Tumor gene expression and proteomic changes will be correlated with treatment response to identify biomarkers that may predict chemotherapy sensitivity.