These include CD3/CD19 and CD3/CD20 BSABs for B-cell lymphoma/leukemia; CD3/BCMA, CD3/FcRH5, and CD3/GPRC5D BSABs for MM; CD3/EpCAM BSABs for peritoneal carcinoma and malignant ascites, CD3/gp100 BSABs for UV; CD3/HER2 BSABs for HER2-positive tumors; and CD3/PSMA BSABs for prostate cancer, etc. (Fig. 1a). The gene discussed is CD19; the disease is leukemia.