Since deregulated expression of NKL homeobox genes in T-ALL is primarily caused by chromosomal aberrations, we analyzed the karyotype of SU-DHL-5 by SKY, FISH and in a genomic array with respect to the NKX2-1 gene which is located at 14q13 (36.9 Mb). Here, NKX2-1 is linked to acute lymphoblastic leukemia.