Although TLX1 is not normally expressed in the hematopoietic system, its inappropriate expression due to chromosomal translocations involving T cell receptor (TCR) genes is associated with about 30% of adult and approximately 8% of childhood T-cell acute lymphoblastic leukemia (T-ALL) cases [3,8]. This evidence concerns the gene TLX1 and T-cell acute lymphoblastic leukemia.