RUNX1 and B-cell chronic lymphocytic leukemia: We present here a case of CLL with secondary myelodysplasia in which the del(21)(q22) detected by G-banding analysis of leukemic cells turned out to correspond to a novel t(5;21)(p15;q22) leading to fusion of RUNX1 from 21q22 with PDCD6 from 5p15.