I. To compare the combination of doxorubicin hydrochloride and cyclophosphamide (AC) followed by weekly paclitaxel with the combination of AC followed by the combination of weekly paclitaxel and trastuzumab in terms of disease free survival (DFS). (Stage I) II. To compare the combination of AC followed by weekly paclitaxel with the combination of AC followed by the combination of weekly paclitaxel and trastuzumab in terms of the rate of cardiac events. (Stage I) III. To compare the combination AC followed by weekly paclitaxel with the sequential schedule of the combination of AC, weekly paclitaxel, and trastuzumab in terms of DFS. (Stage II) IV. To compare the sequential schedule of the combination of AC, weekly paclitaxel, and trastuzumab with the combination of AC followed by the combination of weekly paclitaxel and trastuzumab in terms of DFS. (Stage II) V. To compare the combination AC followed by weekly paclitaxel with the sequential schedule of the combination of AC, weekly paclitaxel, and trastuzumab in terms of the rate of cardiac events. (Stage II)