background: trastuzumab (herceptin) is a humanized monoclonal antibody (mab) which is used for specific treatment of metastatic breast cancer in patients with overexpression of her2/neu receptor. in this study, we have attempted to develop a biosimilar version of trastuzumab mab. methods: according to in silico studies, the heavy and light chains of trastuzumab mab were designed and constructed...