Background: Acute Myeloid Leukemia (AML) is a malignant clonal disorder of immature hematopoietic cells. Leukemic blasts may express abilities for maturation to a variable degree, which leads to morphologic heterogeneity. AIM: This study aimed at detection of PML-RAR by real-time quantitative polymerase chain reaction (RQ-PCR) for monitoring minimal residual disease (MRD) in patients with acute promyelocytic leukemia (APL),and to study the clinical application of RQ-PCR of APL for detection of risk of relapse in different phases of treatment, comparing these data with those yielded by conventional qualitative reverse transcriptase-PCR.PATIENTS AND METHODS: Twenty one consecutive patients diagnosed as acute myeloid leukemia (M3) were included in this prospective study. Patients with cardiac and respiratory diseases were excluded. All patients were subjected to the following: full history taking, complete clinical examination, some laboratory tests(complete blood picture &serum creatinine &serum alanine aminotransferase and serum bilirubin).Bone marrow asprite (BMA)for morphology and imunophenotyping (IPT) and cytogenetic studies as well as Real —time Qualitative PCR (RT-PCR)for detection of PML-RAR a gene in BMA at diagnosis and after consolidation were done.Quantitative PCR ( RQ-PCR) in BMA sample after induction phase and consolidation phase to detect normalized copy number (NCN) of PML-RAR a was also done. Samples were taken after informed consent, bone marrow (BM) samples were collected from APL patients into tubes containing EDTA anticoagulant before treatment for RT-PCR, after the induction therapy and after consolidation therapy for RQ-PCR. All patients received AML M3 protocol in the form of Induction phase: ATRA: 45mgm2 divided into two doses orally till complete remission or maximally for 90 days; and Dounroubicin or doxorubicin: 60 mg/m2 I.V. for 3days (1 course).Also, consolidation phase protocol was given in two courses of dounrobicin or doxorubicin: 60 mg/m2 IV for 3 days every month for two months. According to RQ-PCR results after consolidation phase; patients were divided into two groups, group (A): NCN OF PML-RAR a 1(these patients will be kept on follow up without treatment with ATRA),and group (B): NCN of PML —RAR. a >1 or leukocyte cotmt at diagnosis >10000/cmm(These patients received maintenance treatment in the form of oral mercaptopurine, inethotreitate and intermittent ATRA for up to 2 years). During this period; patients were kept on follow up for detection of relapse or remission which is defined as: Hematological remission in the form of normalization of peripheral blood and BMA0.05).There was statistical difference between the two groups as regarding DFR, in group A it was (12+24.00) and group B was (8.014+ 2) _There was no statistical correlation between OS & DFR and hemoglobin levels, platelets count, TLC,PB promyelocyte mean serum fibrinogen level , NCN 1 and BM promyelocyte. There was statistical correlation between OS& DFR and NCN2 (post consolidation)(p0.05).CONCLUSIONS:These data suggested that RT-PCR could be used as a complementary assay for the RQ-PCR approach, especially within the subgroup with 1-10 NCN.Furthermore, it is important to note that the relatively high specifity of RT-PCR assay is not reason enough to substitute a highly sensitive, standarized mad high through-put technology such as RQ-PCR. |
