Precursor T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma and acute biphenotypic leukemias.
Session 4 of the 2005 Society of Hematopathology/European Association for Haematopathology Workshop focused on case presentations of precursor T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma (pre-T ALL/LBL) and acute biphenotypic leukemia. Pre-T ALL represents approximately 15% of childhood and 25% of adult ALL cases. Pre-T LBL comprises 85% to 90% of LBL and frequently manifests as a mediastinal mass. Gene expression studies have shown distinct subtypes of LYL1+, HOX11+, TAL1+, and MLL+ pre-T ALL/LBL. HOX11 overexpression may correlate with a good prognosis in adult pre-T ALL. ABL gene amplification and NOTCH1 gene mutations in subsets of pre-T ALL/LBL suggest patients may benefit from therapy with tyrosine kinase and gamma-secretase inhibitors, respectively. Acute biphenotypic leukemias are characterized by a single population of blasts that express myeloid, T- or B-lineage antigens in various combinations and account for fewer than 4% of all acute leukemias. The blasts have a high incidence of chromosome abnormalities. An accurate diagnosis of pre-T ALL/LBL and acute biphenotypic leukemia requires a multiparametric approach, including examination of morphologic features, immunophenotype, clinical characteristics, and cytogenetic and molecular findings.
Han
Xin
X
The Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Bueso-Ramos
Carlos E
CE
D014408:Biomarkers, Tumor / Q000032:analysis*; D002869:Chromosome Aberrations; D003937:Diagnosis, Differential; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D007945:Leukemia, Lymphoid / Q000145:classification / Q000175:diagnosis* / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification / Q000175:diagnosis* / Q000235:genetics
D014408:Biomarkers, Tumor