1/44. Complete remission of t(11;17) positive acute promyelocytic leukemia induced by all-trans retinoic acid and granulocyte colony-stimulating factor.The combined use of retinoic acid and chemotherapy has led to an important improvement of cure rates in acute promyelocytic leukemia. Retinoic acid forces terminal maturation of the malignant cells and this application represents the first generally accepted differentiation-based therapy in leukemia. Unfortunately, similar approaches have failed in other types of hematological malignancies suggesting that the applicability is limited to this specific subgroup of patients. This has been endorsed by the notorious lack of response in acute promyelocytic leukemia bearing the variant t(11;17) translocation. Based on the reported synergistic effects of retinoic acid and the hematopoietic growth factor granulocyte colony-stimulating factor (G-CSF), we studied maturation of t(11;17) positive leukemia cells using several combinations of retinoic acid and growth factors. In cultures with retinoic acid or G-CSF the leukemic cells did not differentiate into mature granulocytes, but striking granulocytic differentiation occurred with the combination of both agents. At relapse, the patient was treated with retinoic acid and G-CSF before reinduction chemotherapy. With retinoic acid and G-CSF treatment alone, complete granulocytic maturation of the leukemic cells occurred in vivo, followed by a complete cytogenetical and hematological remission. Bone marrow and blood became negative in fluorescense in situ hybridization analysis and semi-quantitative polymerase chain reaction showed a profound reduction of promyelocytic leukemia zinc finger-retinoic acid receptor-alpha fusion transcripts. This shows that t(11;17) positive leukemia cells are not intrinsically resistant to retinoic acid, provided that the proper costimulus is administered. These observations may encourage the investigation of combinations of all-trans retinoic acid and hematopoietic growth factors in other types of leukemia.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/44. Terminal deletion of the long arm of chromosome 9 in acute promyelocytic leukemia with a cryptic PML/RAR alpha rearrangement.Deletions of the long arm of chromosome 9 (9q-) are rare aberrations specifically found in acute myeloid leukemia (AML). Here we describe the first case of acute promyelocytic leukemia (APL) with a terminal 9q deletion as a sole abnormality. Chromosome analysis of the bone marrow cells showed 46,XX,del(9)(q22) in all 20 metaphases. fluorescence in situ hybridization (FISH) analysis with painting probes of chromosomes 15, 17, and 9 revealed only two normal chromosomes 15 and 17, normal chromosome 9, and del(9)(q22). FISH with cosmid dna probes flanking the breakpoints of t(15;17) did not show the retinoic acid receptor alpha (RAR alpha)/PML fusion signal usually generated on the der(17) t(15;17). However, rearrangement of the RAR alpha gene and expression of the PML/RAR alpha chimeric transcript were identified by Southern blot and reverse transcriptase-polymerase chain reaction analyses, respectively. These results suggested that the PML/RAR alpha fusion gene was generated by submicroscopic interstitial insertion of the RAR alpha gene into the PML gene. Therefore, 9q- was interpreted as a secondary aberration following the PML/RAR alpha rearrangement. The patient died during induction therapy because of intracerebral hemorrhage. Considering other reported cases of APL with 9q-, 9q- may be an adverse prognostic factor in APL as observed in AML with t(8;21).- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/44. Two new 3' PML breakpoints in t(15;17)(q22;q21)-positive acute promyelocytic leukemia.In the present article, two new types of PML/RARA junctions are described. Both were identified in diagnostic samples from two t(15;17)(q22;q21)-positive acute promyelocytic leukemia (APL) patients who failed to achieve complete remission. By using different sets of primers, reverse transcriptase polymerase chain reaction (RT-PCR) of PML/RARA junctions showed atypical larger bands compared with those generated from the three classical PML breakpoints already described. sequence analysis of the fusion region of the amplified cDNAs allowed us to determine the specificity of these fragments in both patients. This analysis showed two new hybrid transcripts that were 53 and 306 base pairs (bp) longer than that expressed by the NB4 cell line (PML breakpoint within intron 6), and are the result of the direct joining of RARA exon 3 with PML exon 7a (patient 2) or the 5' portion of PML exon 7b (patient 1), respectively. In patient 1, RT-PCR analysis of the reciprocal RARA/PML junction showed a smaller transcript than that expected in bcr1 cases, while in patient 2 no amplified fragment was obtained. cytogenetic analysis and/or fluorescence in situ hybridization (FISH) showed that both patients had the t(15;17) translocation. The clinical and hematological profiles expressed by the two patients carrying these unexpected types of PML/RARA rearrangement did not differ significantly from that commonly seen in other APLs with the exception of the poor outcome. genes chromosomes Cancer 27:35-43, 2000.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/44. Submicroscopic insertion of RARalpha gene into chromosome 15 in two cases of acute promyelocytic leukemia.Acute promyelocytic leukemia (APL) is characterized by a specific translocation (15;17)(q22;q21), resulting in the formation of PML/RARalpha chimeric transcripts. We report two female patients with PML/RARalpha-positive classical APL, whose leukemic cells expressed a variant translocation, t(5;15)(q13;q22) and t(15;17)(q22;p13), respectively. Both translocations were confirmed by whole chromosome painting which revealed no apparent involvement of 17q. A two-color fluorescence in situ hybridization with a 5' PML and a 3' RARalpha probe showed, in both cases, the presence of a PML-RARalpha fusion gene, on the der(15)t(5;15) long arm, and on the der(17)t(15;17) short arm, respectively. These two complex rearrangements resulted most probably from a two-step mechanism: (1) a submicroscopic insertion into 15q of a 17q segment including the 3' part of the RARalpha gene; (2) a reciprocal translocation between der(15) and a variable chromosome arm, with a breakpoint distal and proximal to RARalpha insertion in the case of t(5;15) and t(15;17), respectively. Molecular and prognosis significance of these variant translocations are discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/44. A PML/RARA chimeric gene on chromosome 2 in a patient with acute promyelocytic leukemia (M3) associated with a new variant translocation: t(2;15;17)(q21;q22;q21).We describe a patient with acute promyelocytic leukemia (APL) carrying a new complex variant translocation of t(2;15;17)(q21;q22;q21). The karyotypic interpretation was confirmed by fluorescence in situ hybridization (FISH) with the use of painting probes of chromosomes 2, 15, and 17 and a PML/RARA dual color DNA probe. FISH showed a PML/RARA fusion gene on the der(2) instead of the der(15). These results suggest that the critical event in the development of APL is the formation of a PML/RARA chimeric gene, regardless of its locus in the genome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/44. Molecular characterization of der(15)t(11;15) as a secondary cytogenetic abnormality in acute promyelocytic leukemia with cryptic PML-RAR alpha fusion on 17q.A case of acute promyelocytic leukemia (APL) with cryptic PML-RAR alpha fusion on 17q and add(15p) as a secondary abnormality was characterized using molecular cytogenetic techniques. spectral karyotyping (SKY) showed that chromosome 11 material was added to 15p, forming a der(15)t(11;15), which was refined to der(15)t(11;15)(q13.2;p13) with information obtained by comparative genomic hybridization (CGH). Interstitial insertion of chromosome 15 material into chromosome 17q was found by fluorescence in situ hybridization (FISH) with whole chromosome painting (WCP) probes. This study illustrates the necessity of a combination of molecular cytogenetics to decipher complex karyotypic abnormalities and cryptic translocations in leukemia.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
7/44. Acute promyelocytic leukemia with additional chromosome abnormalities in a renal transplant case.Some cases of acute myeloid leukemia following organ transplant (PT-AML) have been published in the literature. We report the second case of acute promyelocytic leukemia (APL), which developed post-transplant and immunosuppressive treatment, in a 50-year-old male who had undergone a renal transplant. At diagnosis he presented typical t(15;17)(q12;q13) with additional abnormalities, including 8,t(13;22)(q12;q13) and an abnormal chromosome 1 which was better characterized by fluorescence in situ hybridization (FISH). He obtained cytological, karyotypic and molecular complete remission (CR) with induction treatment according to the all-trans retinoic acid idarubican (AIDA) protocol; after 12 months, he relapsed (molecular relapse) and achieved molecular remission with all-trans retinoic acid (ATRA) plus mitoxantrone and cytosine arabinoside. After a further 14 months, he was treated with arsenic trioxide for cytological relapse and obtained a third CR; at the cytological relapse the karyotype showed 47,XY, 8, t(15;17)(q22;q21),t(13;22)(q12;q13),der(22)t(1;22)(p22;q13). He is alive 3.3 years after diagnosis of APL. Cyclosporin A (CsA) was given during all cycles of chemotherapy. We did not observe any severe infections or kidney failure during treatments. The use of conventional cytogenetic analysis plus FISH may identify complex karyotype also in transplanted patients receiving immunotherapy, and may also contribute to a better assessment of PT-AL.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/44. Acute myeloblastic leukaemias of FAB types M6 and M4, with cryptic PML/RARalpha fusion gene formation, relapsing as acute promyelocytic leukaemia M3.Demonstration of either the translocation t(15;17)(q22;q21) or the fusion of PML and RARalpha genes is regarded as diagnostic for acute myeloid leukaemia (AML) of FAB type M3, but has occasionally been seen in other FAB types. We present two such cases. Case 1 presented with FAB type M6 and a complex karyotype involving chromosomes 1, 2, 11 and 17. Bone marrow relapse of FAB type M3 followed autologous bone marrow transplantation. Subsequent marrow dysplasia and an M6 relapse were accompanied by a new cytogenetic clone involving chromosomes X, 2, 4, 6, 7 and 16. fluorescence in situ hybridization (FISH) of metaphase chromosomes at diagnosis showed insertion of material from chromosome 17 into a 'normal' 15 with juxtaposition of PML and RARalpha. Case 2 presented as AML M4 and relapsed as M3. cytogenetic analysis at diagnosis and in relapse showed 46,XY,t(15;17)(q22;q11),del(16)(q22). FISH analysis showed this to be a three-way translocation involving chromosomes 15, 16 and 17 again with juxtaposition of PML and RARalpha. reverse transcription-polymerase chain reaction (RT-PCR) revealed PML/RARalpha fusion at diagnosis, in remission and in first relapse. These examples strengthen the case for RT-PCR screening of all AML patients for these fusion genes.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/44. Acute promyelocytic leukemia with apparently normal karyotype: molecular findings and response to all-trans retinoic acid.Acute promyelocytic leukemia (APL) is specifically associated with a reciprocal translocation, t(15; 17)(q22; q21), leading to the formation of a fusion of the retinoic acid receptor-alpha (RARA) gene and the promyelocytic leukemia (PML) gene. However, there are several reports describing APL cases lacking the t(15; 17). Many such cases are those bearing variant translocations involving chromosomes 15 or 17, and those with no chromosomal aberrations have rarely been reported. We have studied a patient with APL showing an apparently normal karyotype which was confirmed by spectral karyotyping (SKY). A submicroscopic PML-RARA fusion was identified by reverse transcriptase-polymerase chain reaction (RT-PCR) and fluorescent in situ hybridization (FISH). All-trans retinoic acid (ATRA) was effective as the initial therapy for remission induction and as the reinduction therapy after a relapse. The present study shows the key role of the fusion of PML-RARA in the responsiveness to ATRA as well as in the leukemogenesis of APL.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/44. New cytogenetic variant, insertion (15;17)(q22;q12q21), in an adolescent with acute promyelocytic leukemia.We present the case of a 15-year-old female with acute promyelocytic leukemia and a new variant chromosome rearrangement identified as ins(15;17)(q22;q12q21) by conventional cytogenetic analysis. This finding was confirmed by fluorescence in situ hybridization using the PML-RARA DNA probe and whole chromosome paints 15 and 17. A typical PML-RARA fusion transcript consistent with a breakpoint in intron 3 of the PML gene and intron 2 of the RARA gene was identified by reverse transcription polymerase chain reaction.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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