CD22 and leukemia: Third, CD22 expression is present in 60–80% of B-cell lymphomas or leukemias (Alderson et al. 2009; Cesano and Gayko 2003), including hairy cell leukemia (HCL), chronic lymphoblastic leukemia (CLL), non-Hodgkin’s lymphoma (NHL), and acute lymphoblastic leukemia (ALL) (Kreitman and Pastan 2011).