In the present study, we examined the expression patterns of Notch1 and Jagged1 in 10 normal blood samples, 8 bone marrow samples, 11 leukemia/lymphoma cell lines and leukemia cells from 22 patients with acute myeloid leukemia (AML), mature T-cell neoplasms or B-cell chronic lymphocytic leukemia (B-CLL) using FCM. This evidence concerns the gene JAG1 and B-cell chronic lymphocytic leukemia.