T-ALL with CD1a+, CD4+, and CD8+ immunophenotype includes several subgroups, such as rearrangements of TLX1, TLX3, NKX2-1, reflecting a differentiation arrest in early stages of cortical thymocyte maturation and confers a relatively favorable prognosis [144,145]. The gene discussed is NKX2-1; the disease is acute lymphoblastic leukemia.