Clinical significance of PML/RAR alpha isoforms in acute promyelocytic leukemia / 대한내과학회지

BACKGROUND/AIMS: There are three types of PML-RAR alpha mRNA fusion transcripts associated with acute promyelocytic leukemia (APL): the short (S)-form, the long (L)-form and the variable (V)-form. No study on the Korean population has addressed the clinical significance of the specific types of PML-RAR alpha mRNA fusion transcripts for APL patients who receive the combination therapy of all-trans-retinoic-acid and idarubicin (AIDA regimen). METHODS: We performed a retrospective analysis on 94 patients with APL to evaluate differences in the therapeutic outcomes, such as the response rate, an event-free survival (EFS), and overall survival (OS), after remission following the induction of chemotherapy. We also analyzed whether differences in the pretreatment clinical characteristics depend on the PML-RAR alpha isoform. RESULTS: The median age of the patients was 41 years (range 15-85). Among the 94 patients, there were 58 L-form cases (62.1%), 32 S-form cases (34.0%), and 4 V-form cases (4.3%). The CR rate following remission induction treatment was 84.9%. The CR rate was higher in patients with an initial WBC <10.0x109/L, as compared to patients with an initial WBC higher than 10.0X109/L (93.5% vs. 65.4%, p=0.001). The AIDA induction regimen was associated with a better EFS than non-AIDA induction regimens (81.9% vs. 49.6%, p=0.006). The induction group was also a significant prognostic factor for EFS in the multivariate analysis (p=0.020). There were no differences in OS and EFS in patients with either isoform L or isoform S in the AIDA induction group. CONCLUSIONS: This retrospective study demonstrated that pretreatment clinical characteristics and treatment outcomes were not significantly different among patients with varying PML-RAR alpha isoform types in the AIDA induction group.

Do PML/RAR-alpha isoforms have clinical significance in patients with acute promyeloctyic leukemia? / 대한내과학회지

Acute promyelocytic leukemia (APL) is characterized by a specific t (15;17) translocation which produce a PML/RAR-alpha fusion messenger RNA and by effectiveness of all-trans retinoic acid (ATRA) differentiation therapy. Breakpoints within PML intron 3 (bcr 3) produce a short PML/RAR-alpha isoform (S-isoform), whereas breakpoints within PML intron 6 (bcr 1) result in a longer form (L-isoform). Additionally, breakpoints within PML exon 6 (bcr 2) make a variable length transcript (V-isoform) in a small number of patients. The influence of breakpoint site on patient outcome remains controversial. Previous reports showed that patients with S-isoform have an increased incidence of clinical relapse and shorter survival compared to those with L-isoform. Others reported no difference in DFS between these patients groups. In this issue, Lee et al. reported that there were 58 L-isoform (62.1%), 32 S-isoform (34.0%), 4 V-isoform (4.3%) and, no significant prognostic factor for EFS from induction therapy using anthracycline plus ATRA among 94 patients with APL. They concluded pretreatment clinical characteristics and treatment outcomes were not significantly different according to PML/RAR-alpha isoform types in this induction group. Recently, it was reported that FLT3/ITD mutation was frequently associated with S-isoform and with the M3v form of leukemia and CNS relapse in APL was mostly related to S-isoform. With previous studies including this article, outcomes of different types of PML/RAR-alpha isoforms are not conclusive. Future researches need to be focused not only on clinical outcomes of different types of PML/RAR-alpha isoforms, but also clinical relevance of PML/RARA-alpha mRNA isoforms with other prognostic factors and particular clinical characteristics.

Study PML/RAR alpha fusion gene on 21 patients diagnosed with acute promyelocytic leukemia (AML \u2013 M3)

Background: In Vietnam, there are a number of studies on the application of ATRA in treating acute promyelocytic leukemia (AML \u2013 M3) but they have still faced with certain difficulties. Objectives: (1). Study PML/RAR alpha fusion gene on the patients diagnosed with AML \u2013 M3. (2). Study the index of hematology of the PML/RAR alpha positive group. Subject and Method: 21 patients with acute promyelocytic leukemia (M3) were studied. All patients were examined with morphology, coagulation and cytogenetic tests and RNA were extracted from leukemic cells and PCR for PML/RAR alpha fusion transcript. Result and conclusion: PML/RAR alpha positive in 67% including 4 patients which were not discovered t(15; 17) by cytogenetic technique. Rates of three subtype (bcr1, bcr2 and bcr3) of PML/RAR alpha were 7 patients (50%), 3 patients (21,5%) and 4 patients (28,5%), respectively. WBC and bone marrow cells of PML/RAR alpha positive group were 5.08+/-3.87 and 155.82+/-106.21. D \u2013 Dimer level was 1954.89+/-1575.28; 93% of patients in the PML/RAR alpha positive group had DIC.

A Case of Acute Promyelocytic Leukemia with Phenotypic Change at Relapse / 대한진단검사의학회지

Early diagnosis of acute promyelocytic leukemia (APL) depends primarily on morphological recognition before the presence of t(15;17) or PML-RAR gene rearrangement is confirmed. But the diagnosis is difficult to be made, if typical APL morphologic features are not found. Here, we describe a 32- year old man who had been diagnosed as APL. He relapsed with AML M1 like phenotype, lacking the typical features of APL. At relapse, t(15;17) and PML-RAR alpha gene rearrangement were detected. After 14 days of chemotherapy and all-trans retinoic acid, the phenotype changed from the AML M1 like features to the typical hypergranular APL. Awareness of atypical morphologic subtypes found in APL is important. And identification of t(15;17) or PML/RAR alpha rearrangement will be helpful in diagnosis of atypical APL.