Most prominent examples of mAbs include rituximab (Rituxan) for non-Hodgkin lymphoma and chronic lymphocytic leukemia, targeting CD20 on B cells [48]; trastuzumab (Herceptin) for HER2-positive breast cancer [49]; cetuximab (Erbitux) for colorectal, head, and neck cancers, targeting EGFR [49]; bevacizumab (Avastin) for various cancers by blocking VEGF and inhibiting tumor angiogenesis [49]; and ipilimumab (Yervoy) for melanoma, targeting CTLA-4 to enhance immune response [50]. This evidence concerns the gene CTLA4 and cancer.