title: Acute promyelocytic leukemia M3: cytomorphologic, immunophenotypic, cytogenetic, and molecular variants.
abstract: Acute promyelocytic leukemia (APL) M3 is an acute myeloid leukemia (AML) subtype characterized by proliferation of malignant promyelocytes with mature myeloid immunophenotype and the translocation t(15;17)(q22;q11), which results in the fusion of retinoic acid receptor-alpha (RARalpha) gene on chromosome 17 and the gene PML on chromosome 15. There are three M3 morphologic variants: the typical hypergranular form and the microgranular and basophilic variants. Although most leukemic cells in M3 patients express t(15;17), other cytogenetic abnormalities have also been reported. Also, there are three molecular variants of the PML/RARalpha transcript (bcr1, bcr2, bcr3). Blasts had typical hypergranular appearance (13 patients) with a mature myeloid immunophenotype (HLA-DR(-),CD13(+), and/or CD33(+)) (10 patients) in the majority of patients with M3 followed in this study. The typical translocation [t(15;17)(q22;q11)] was detected by cytogenetic analysis in 5 M3 patients, but PML/RARalpha was positive in 13 out of 15 patients, as assessed by RT-PCR (8 patients with bcr1 and 5 with bcr3 subtype). Cytogenetic diversity was found in three patients (1 with t(17;17), 1 with +8, and 1 with add (7)(q22); -7; +8). According to many studies, leukemic cell heterogeneity in APL influences the clinical outcome of disease. The analysis of certain leukemic cell characteristics on the clinical outcome in our study revealed that patients with bcr3 had shorter medians of first remission and survival in comparison to patients with the bcr1 isoform of PML/RARalpha. Also, the clinical relapse of disease in 4 APL patients with reverted PML/RAR alpha positivity is consistent with the view that detection of PML/RARalpha by RT-RCR in patients in remission implies a poor prognosis. On the contrary, lack of detection of PML/RARalpha by RT-PCR at least three times is a sign of long remission and survival.
authors.affiliation: Division of Cytology of the Clinical Institute of Laboratory Diagnosis, Zagreb University Clinical Hospital Center and School of Medicine, 10000 Zagreb, Croatia. mirna.sucic@zg.tel.hr
authors.forename: Mirna
authors.initials: M
authors.lastname: Sucić
authors.forename: Renata
authors.initials: R
authors.lastname: Zadro
authors.forename: Branka
authors.initials: B
authors.lastname: Burazer
authors.forename: Boris
authors.initials: B
authors.lastname: Labar
authors.forename: Damir
authors.initials: D
authors.lastname: Nemet
authors.forename: Mirando
authors.initials: M
authors.lastname: Mrsić
authors.forename: Igor
authors.initials: I
authors.lastname: Aurer
authors.forename: Sanja
authors.initials: S
authors.lastname: Mrsić
authors.forename: Vlasta
authors.initials: V
authors.lastname: Hitrec
authors.forename: Dubravka
authors.initials: D
authors.lastname: Boban
authors.forename: Mirjana
authors.initials: M
authors.lastname: Marković-Glamocak
authors.forename: Drago
authors.initials: D
authors.lastname: Batinić
authors.forename: Branka
authors.initials: B
authors.lastname: Uzarević
authors.forename: Ana
authors.initials: A
authors.lastname: Stavljenić-Rukavina
mesh_terms: D000328:Adult; D000368:Aged; D048429:Cell Size; D020732:Cytogenetic Analysis; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D015514:Oncogene Proteins, Fusion / Q000032:analysis; D011379:Prognosis; D020033:Protein Isoforms / Q000032:analysis; D012074:Remission Induction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016896:Treatment Outcome
chemical_list: D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D020033:Protein Isoforms; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein