Our prior studies using an anti-HER2 IgG3 antibody–endostatin fusion protein showed that replacement of native endostatin in the fusion with a human endostatin containing a proline to alanine mutation at position 125 (E-P125A) demonstrated enhanced anti-angiogenic and anti-tumor activity in both murine (EMT6-HER2) and human HER2 expressing SK-BR-3 xenograft models compared to fusions incorporating native endostatin [16]. This evidence concerns the gene IGHG3 and neoplasm.