Moreover, the use of an animal model in which human CD22 is only expressed on implanted tumor cells and not on normal cells precluded comprehensive assessment of "on-target, off-tumor" effects. Radioimmunotherapy (RIT) has long been pursued to improve outcomes of patients with B-cell lymphomas and leukemias [[1]]. Here, we investigated whether CD22, a cell surface glycoprotein broadly expressed on malignant cells across B-cell malignancies and normal B cells but not on other hematopoietic cell lineages [[9]], could serve as target for relatively tumor-selective SP 211 sp At-based RIT. [Extracted from the article]