Azacitidine-venetoclax versus azacitidine salvage treatment for primary induction failure or first relapsed acute myeloid leukaemia patients

OBJECTIVES

To compare the efficacy of venetoclax-azacitidine (VEN-AZA) with AZA in the real-life for patients with first relapsed or refractory acute myeloid leukaemia (R/R AML).

METHODS

We retrospectively analysed R/R AML patients treated with VEN-AZA at the Institut Paoli Calmettes between September 2020 and February 2022. We compared them to a historical cohort of patients treated with AZA between 2010 and 2021.

RESULTS

Thirty-five patients treated with VEN-AZA were compared with 140 patients treated with AZA. There were more favourable cytogenetics (25.7% vs. 8.6%; p = 0.01) and less FLT3-ITD mutated AML (8.8% vs. 25.5%; p = .049) in the VEN-AZA group. The overall 30-day mortality rate was 7.4% and the overall 90-day mortality was 20%, with no difference between the groups. The complete remission rate was 48.6% in the VEN-AZA group versus 15% (p < .0001). The composite complete response rate was 65.7% in the VEN-AZA group versus 23.6% (p < .0001). OS was 12.8 months in the VEN-AZA group versus 7.3 months (p = 0.059). Patients with primary refractory AML, poor-risk cytogenetics, prior hematopoietic stem-cell transplantation (HSCT) and FLT3-ITD mutated AML had lower response and survival rates.

CONCLUSION

VEN-AZA was associated with a better response rate and a longer survival than AZA monotherapy in AML patients who relapsed after or were refractory to intensive chemotherapy.

A chemogenomic approach to identify personalized therapy for patients with relapse or refractory acute myeloid leukemia: results of a prospective feasibility study

Targeted next-generation sequencing (tNGS) and ex vivo drug sensitivity/resistance profiling (DSRP) have laid foundations defining the functional genomic landscape of acute myeloid leukemia (AML) and premises of personalized medicine to guide treatment options for patients with aggressive and/or chemorefractory hematological malignancies. Here, we have assessed the feasibility of a tailored treatment strategy (TTS) guided by systematic parallel ex vivo DSRP and tNGS for patients with relapsed/refractory AML (number NCT02619071). A TTS issued by an institutional personalized committee could be achieved for 47/55 included patients (85%), 5 based on tNGS only, 6 on DSRP only, while 36 could be proposed on the basis of both, yielding more options and a better rationale. The TSS was available in <21 days for 28 patients (58.3%). On average, 3 to 4 potentially active drugs were selected per patient with only five patient samples being resistant to the entire drug panel. Seventeen patients received a TTS-guided treatment, resulting in four complete remissions, one partial remission, and five decreased peripheral blast counts. Our results show that chemogenomic combining tNGS with DSRP to determine a TTS is a promising approach to propose patient-specific treatment options within 21 days.

Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR¹–MR⁴), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR^4.5 level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR^4.5 sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.

Acute myeloid leukaemia with 8p11 (MYST3) rearrangement: an integrated cytologic, cytogenetic and molecular study by the groupe francophone de cytogénétique hématologique

Thirty cases of acute myeloid leukaemia (AML) with MYST histone acetyltransferase 3 (MYST3) rearrangement were collected in a retrospective study from 14 centres in France and Belgium. The mean age at diagnosis was 59.4 years and 67% of the patients were females. Most cases (77%) were secondary to solid cancer (57%), haematological malignancy (35%) or both (8%), and appeared 25 months after the primary disease. Clinically, cutaneous localization and disseminated intravascular coagulation were present in 30 and 40% of the cases, respectively. AMLs were myelomonocytic (7%) or monocytic (93%), with erythrophagocytosis (75%) and cytoplasmic vacuoles (75%). Immunophenotype showed no particularity compared with monocytic leukaemia without MYST3 abnormality. Twenty-eight cases carried t(8;16)(p11;p13) with MYST3-CREBBP fusion, one case carried a variant t(8;22)(p11;q13) and one case carried a t(8;19)(p11;q13). Type I (MYST3 exon 16-CREBBP exon 3) was the most frequent MYST3-CREBBP fusion transcript (65%). MYST3 rearrangement was associated with a poor prognosis, as 50% of patients deceased during the first 10 months. All those particular clinical, cytologic, cytogenetic, molecular and prognostic characteristics of AML with MYST3 rearrangement may have allowed an individualization into the World Health Organization classification.

Fluorescence in situ hybridization analysis of 110 hematopoietic disorders with chromosome 5 abnormalities: do de novo and therapy-related myelodysplastic syndrome-acute myeloid leukemia actually differ?

A retrospective cytogenetic study of acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS) was conducted by the Groupe Francophone de Cytogénétique Hématologique (GFCH) to evaluate the structural abnormalities of chromosome 5 associated with other chromosomal abnormalities, in particular of chromosome 7, in these pathologies. In all, 110 cases of AML/MDS were recruited based on the presence of chromosome 5 abnormalities under conventional cytogenetics and supplemented by a systematic fluorescence in situ hybridization study of chromosomes 5 and 7. The abnormalities of the long arm of chromosome 5 (5q) were deletions of various sizes and sometimes cryptic. The 5q abnormalities were associated with translocations in 54% of cases and were simple deletions in 46%. In 68% of cases, 5q deletions were associated with chromosome 7 abnormalities, and 90% of these presented a complex karyotype. Of the 110 patients, 28 had a hematopoietic disorder secondary to chemotherapy, radiotherapy, or both. Among 82 patients with de novo AML/MDS, 63 were older than 60 years. Chromosomal abnormalities often associated hypodiploidy and chromosome 5 and 7 abnormalities in complex karyotypes, features resembling those of secondary hemopathies. Systematic investigation of the exposure to mutagens and oncogenes is thus essential to specify the factors potentially involved in MDS/AML with 5q abnormalities.

NUP98 rearrangements in hematopoietic malignancies: a study of the Groupe Francophone de Cytogénétique Hématologique

The NUP98 gene is fused with 19 different partner genes in various human hematopoietic malignancies. In order to gain additional clinico-hematological data and to identify new partners of NUP98, the Groupe Francophone de Cytogénétique Hématologique (GFCH) collected cases of hematological malignancies where a 11p15 rearrangement was detected. Fluorescence in situ hybridization (FISH) analysis showed that 35% of these patients (23/66) carried a rearrangement of the NUP98 locus. Genes of the HOXA cluster and the nuclear-receptor set domain (NSD) genes were frequently fused to NUP98, mainly in de novo myeloid malignancies whereas the DDX10 and TOP1 genes were equally rearranged in de novo and in therapy-related myeloid proliferations. Involvement of ADD3 and C6ORF80 genes were detected, respectively, in myeloid disorders and in T-cell acute lymphoblastic leukemia (T-ALL), whereas the RAP1GDS1 gene was fused to NUP98 in T-ALL. Three new chromosomal breakpoints: 3q22.1, 7p15 (in a localization distinct from the HOXA locus) and Xq28 were detected in rearrangements with the NUP98 gene locus. The present study as well as a review of the 73 cases previously reported in the literature allowed us to delineate some chromosomal, clinical and molecular features of patients carrying a NUP98 gene rearrangements.

Cytogenetic study of 75 erythroleukemias

Chromosomal abnormalities of erythroleukemia (EL) are often described as complex and unspecific. A retrospective study of 75 EL defined following the WHO classification was performed by the Groupe Francophone de Cytogénétique Hématologique (GFCH) in order to reexamine the cytogenetics of this infrequent leukemia subtype. Clonal chromosomal abnormalities were found in 57 patients (76%), distributed in 4 subgroups according to their ploidy status: pseudodiploid (16%), hypodiploid (47%), hyperdiploid (19%), and 18% mixed cases associating 2 different clones (hypodiploid+hyperdiploid) or (pseudodiploid+hyperdiploid). Complex rearrangements and hypodiploid chromosome number were widely dominant (50%). Partial or entire monosomies represented 56% of abnormalities. Chromosomes 5 and 7 were the most frequently involved (41 and 33 times, respectively), followed by chromosomes 8, 16, and 21 (19 times each). Unbalanced abnormalities were more frequent than balanced. All these kinds of abnormalities were observed in de novo as well as in secondary EL. Four out of 7 cases of "pure erythroid" leukemia were associated with a BCR-ABL fusion. Lastly, no chromosome abnormality specific to EL could be established. However, the large overlap of chromosomal abnormality patterns of EL (pure erythroid form excepted) and refractory anemia with excess of blasts in transformation (RAEB-t) favors the hypothesis of similarities between these 2 hematologic disorders.

Gene expression profiling identifies molecular subgroups among nodal peripheral T-cell lymphomas

The classification of peripheral T-cell lymphomas (PTCL) is still a matter of debate. To establish a molecular classification of PTCL, we analysed 59 primary nodal T-cell lymphomas using cDNA microarrays, including 56 PTCL and three T-lymphoblastic lymphoma (T-LBL). The expression profiles could discriminate angioimmunoblastic lymphoma, anaplastic large-cell lymphoma and T-LBL. In contrast, cases belonging to the broad category of 'PTCL, unspecified' (PTCL-U) did not share a single molecular profile. Using a multiclass predictor, we could separate PTCL-U into three molecular subgroups called U1, U2 and U3. The U1 gene expression signature included genes known to be associated with poor outcome in other tumors, such as CCND2. The U2 subgroup was associated with overexpression of genes involved in T-cell activation and apoptosis, including NFKB1 and BCL-2. The U3 subgroup was mainly defined by overexpression of genes involved in the IFN/JAK/STAT pathway. It comprised a majority of histiocyte-rich PTCL samples. Gene Ontology annotations revealed different functional profile for each subgroup. These results suggest the existence of distinct subtypes of PTCL-U with specific molecular profiles, and thus provide a basis to improve their classification and to develop new therapeutic targets.

Multicolour-banding fluorescence in situ hybridisation (mbanding-FISH) to identify recurrent chromosomal alterations in breast tumour cell lines

Recurrent chromosome breakpoints in tumour cells may point to cancer genes, but not many have been molecularly characterised. We have used multicolour-banding fluorescence in situ hybridisation (mbanding-FISH) on breast tumour cell lines to identify regions of chromosome break created by inversions, duplications, insertions and translocations on chromosomes 1, 5, 8, 12 and 17. We delineate a total of 136 regions of break, some of them occurring with high frequency. We further describe two examples of dual-colour FISH characterisation of breakpoints, which target the 1p36 and 5p11–12 regions. Both breaks involve genes whose function is unknown to date. The mbanding-FISH strategy constitutes an efficient first step in the search for potential cancer genes.

A diagnostic biochip for the comprehensive analysis of MLL translocations in acute leukemia

Reciprocal rearrangements of the MLL gene are among the most common chromosomal abnormalities in both Acute Lymphoblastic and Myeloid Leukemia. The MLL gene, located on the 11q23 chromosomal band, is involved in more than 40 recurrent translocations. In the present study, we describe the development and validation of a biochip-based assay designed to provide a comprehensive molecular analysis of MLL rearrangements when used in a standard clinical pathology laboratory. A retrospective blind study was run with cell lines (n=5), and MLL positive and negative patient samples (n=31), to evaluate assay performance. The limits of detection determined on cell line data were 10(-1), and the precision studies yielded 100% repeatability and 98% reproducibility. The study shows that the device can detect frequent (AF4, AF6, AF10, ELL or ENL) as well as rare partner genes (AF17, MSF). The identified fusion transcripts can then be used as molecular phenotypic markers of disease for the precise evaluation of minimal residual disease by RQ-PCR. This biochip-based molecular diagnostic tool allows, in a single experiment, rapid and accurate identification of MLL gene rearrangements among 32 different fusion gene (FG) partners, precise breakpoint positioning and comprehensive screening of all currently characterized MLL FGs.

Report of 34 patients with clonal chromosomal abnormalities in Philadelphia-negative cells during imatinib treatment of Philadelphia-positive chronic myeloid leukemia

Imatinib mesylate (Gleevec), an inhibitor of the BCR-ABL tyrosine kinase, was introduced recently into the therapy of chronic myeloid leukemia (CML). Several cases of emergence of clonal chromosomal abnormalities after therapy with imatinib have been reported, but their incidence, etiology and prognosis remain to be clarified. We report here a large series of 34 CML patients treated with imatinib who developed Philadelphia (Ph)-negative clones. Among 1001 patients with Ph-positive CML treated with imatinib, 34 (3.4%) developed clonal chromosomal abnormalities in Ph-negative cells. Three patients were treated with imatinib up-front. The most common cytogenetic abnormalities were trisomy 8 and monosomy 7 in twelve and seven patients, respectively. In 15 patients, fluorescent in situ hybridization with specific probes was performed in materials archived before the initiation of imatinib. The Ph-negative clone was related to previous therapy in three patients, and represented a minor pre-existing clone that expanded after the eradication of Ph-positive cells with imatinib in two others. However, in 11 patients, the new clonal chromosomal abnormalities were not detected and imatinib may have had a direct effect. No myelodysplasia was found in our cohort. With a median follow-up of 24 months, one patient showed CML acceleration and two relapsed.

t(5;14)/HOX11L2-positive T-cell acute lymphoblastic leukemia. A collaborative study of the Groupe Français de Cytogénétique Hématologique (GFCH)

To accurately estimate the incidence of HOX11L2 expression, and determine the associated cytogenetic features, in T-cell acute lymphoblastic leukemia (T-ALL), the Groupe Français de Cytogénétique Hématologique (GFCH) carried out a retrospective study of both childhood and adult patients. In total, 364 patients were included (211 children </=15 years and 153 adults), and 67 (18.5%) [47 children (22.4%) and 20 adults (13.1%)] were shown to either harbor the t(5;14)q35;q32) translocation or express the HOX11L2 gene or both. Most of the common hematological parameters did not show significant differences within positive and negative populations, whereas the incidence of CD1a+/CD10+ and cytoplasmic CD3+ patients was significantly higher in positive than in negative children. Out of the 63 positive patients investigated by conventional cytogenetics, 32 exhibited normal karyotype, whereas the others 31 showed clonal chromosome abnormalities, which did not include classical T-ALL specific translocations. Involvement of the RANBP17/HOX11L2 locus was ascertained by fluorescence in situ hybridization in six variant or alternative (three-way translocation or cytogenetic partner other than 14q32) translocations out of the 223 patients. Our results also show that HOX11L2 expression essentially occurs as a result of a 5q35 rearrangement, but is not associated with another identified T-ALL specific recurrent genetic abnormality, such as SIL-TAL fusion or HOX11 expression.

Identification of precursors of leukemic dendritic cells differentiated from patients with acute myeloid leukemia

Dendritic cells (DC) can facilitate immune responses that might help in the induction of effective antitumor T cell responses. We reported previously that leukemic blasts from selected patients with acute myeloid leukemia (AML) were able to differentiate in vitro into cells with mature DC features. However, despite the use of a wide variety of cytokine combinations, leukemic DC could not be obtained from all AML patients. In this study, we investigated in a wide range of AML patients (n = 30), the nature and functional characteristics of the blast compartment that can be induced to acquire DC features in vitro. Our results demonstrate that leukemic DC generated in the presence of GM-CSF, IL-4 and matured with CD40L, are composed of two major subsets: DC derived from CD14(+) leukemic cells and leukemic DC derived from in vivo expanded circulating blood myeloid DC (MDC). Leukemic DC of both subsets exhibited DC morphology, had a phenotype of mature DC, and could induce a potent proliferative response of naive CD4(+) T cells. Moreover, both subsets produced large amounts of IL-12p70 and leukemic CD14(+)-derived DC could induce a potent Th1 response. These results can be considered as a prerequisite before the design of vaccine immunotherapy protocols for the adjuvant treatment of AML patients.

Large deletions 5' to the ETO breakpoint are recurrent events in patients with t(8;21) acute myeloid leukemia

Recurrent chromosomal rearrangements are observed in many leukemia subtypes. Recently, it has been shown that several of these translocations/inversions were associated with the loss of sequences located in the vicinity of the chromosomal breakpoints. So far, such deletions have not been described for the t(8;21) translocation. We have analyzed a series of 65 patients with t(8;21) using several probes specific for the ETO and AML1 regions. We have found six patients (9%) with deletion of the region 5' to ETO. In all six patients, the deletion encompassed at least 260 kb, and was even larger in two patients (up to 2 Mb). A similar analysis of the 21q22 region did not reveal any deletion of the 3'AML1 region. In conclusion, cytogenetically undetectable small deletions located immediately 5' to the ETO breakpoint were found to accompany the t(8;21) translocation in a significant percentage of cases. The clinical significance, if any, of these deletions remains to be determined.

Large granular lymphocytes (LGL) following non-myeloablative allogeneic bone marrow transplantation: a case report

We report here the first case of large granular lymphocytes (LGL) expansion following non-myeloablative allo-BMT for chronic myeloid leukemia. We characterized the morphologic, phenotypic and functional features of the LGL subset amplified in vivo 14 months after allo-BMT. Our results indicate that LGL can mediate in vitro a cytolytic activity on tumor cells. In vivo, the timing of the LGL expansion was associated with a sustained complete molecular remission. These observations suggest that LGL are a subset with the properties of effector lymphocytes which may contribute to the graft-versus-tumor effect.

Characterization of acute promyelocytic leukemia cases lacking the classic t(15;17): results of the European Working Party. Groupe Français de Cytogénétique Hématologique, Groupe de Français d'Hematologie Cellulaire, UK Cancer Cytogenetics Group and BIOMED 1 European Community-Concerted Action "Molecular Cytogenetic Diagnosis in Haematological Malignancies"

Acute promyelocytic leukemia (APL) is typified by the t(15;17), generating the PML-RAR alpha fusion and predicting a beneficial response to retinoids. However, a sizeable minority of APL cases lack the classic t(15;17), prompting the establishment of the European Working Party to further characterize this group. Such cases were referred to a workshop held in Monza, Italy and subjected to morphologic, cytogenetic, and molecular review, yielding 60 evaluable patients. In the majority (42 of 60), molecular analyses revealed underlying PML/RAR alpha rearrangements due to insertions (28 of 42) or more complex mechanisms, including 3-way and simple variant translocations (14 of 42). Metaphase fluorescence in situ hybridization (FISH) demonstrated that insertions most commonly led to formation of the PML-RAR alpha fusion gene on 15q. In 11 of 60 workshop patients, PLZF/RAR alpha rearrangements were identified, including 2 patients lacking the t(11;17)(q23;q21). In one case with a normal karyotype, FISH analysis revealed insertion of RAR alpha into 11q23, and PLZF-RAR alpha was the sole fusion gene formed. Two patients were found to have t(5;17), one with a diffuse nuclear NPM staining pattern and with NPM-RAR alpha and RAR alpha-NPM transcripts detected. In the other with an unbalanced der(5)t(5;17)(q13;q21) and a nucleolar NPM localization pattern, an NPM/RAR alpha rearrangement was excluded, and FISH revealed deletion of one RAR alpha allele. In the remaining 5 workshop patients, no evidence was found for a rearrangement of RAR alpha, indicating that in rare instances, alternative mechanisms could mediate the differentiation block that typifies this disease. This study highlights the importance of combining morphologic, cytogenetic, and molecular analyses for optimal management of APL patients and better understanding of the pathogenesis of the disease. (Blood. 2000;96:1297-1308)

A new morphologic classification system for acute promyelocytic leukemia distinguishes cases with underlying PLZF/RARA gene rearrangements

Acute promyelocytic leukemia (APL) is typified by the t(15;17) translocation, which leads to the formation of the PML/RARA fusion gene and predicts a beneficial response to retinoids. However, approximately 10% of all APL cases lack the classic t(15;17). This group includes (1) cases with cryptic PML/RARA gene rearrangements and t(5;17) that leads to the NPM/RARA fusion gene, which are retinoid-responsive, and (2) cases with t(11;17)(q23;q21) that are associated with the PLZF/RARA fusion gene, which are retinoid-resistant. A key issue is how to rapidly distinguish subtypes of APL that demand distinct treatment approaches. To address this issue, a European workshop was held in Monza, Italy, during June 1997, and a morphologic, immunophenotypic, cytogenetic, and molecular review was undertaken in 60 cases of APL lacking t(15;17). This process led to the development of a novel morphologic classification system that takes into account the major nuclear and cytoplasmic features of APL. There were no major differences observed in morphology or immunophenotype between cases with the classic t(15;17) and those with the cryptic PML/RARA gene rearrangements. Auer rods were absent in the t(5;17) case expressing NPM/RARA. Interestingly, this classification system distinguished 9 cases with t(11;17)(q23;q21) and, in addition, successfully identified 2 cases lacking t(11;17), which were subsequently shown to have underlying PLZF/RARA fusions. The PLZF/RARA cases were characterized by a predominance of blasts with regular nuclei, an increased number of Pelger-like cells, and by expression of CD56 in 4 of 6 cases tested. Use of this classification system, combined with an analysis for CD56 expression, should allow early recognition of APL cases requiring tailored molecular investigations. (Blood. 2000;96:1287-1296)

Translocation and coamplification of loci from chromosome arms 8p and 11q in the MDA-MB-175 mammary carcinoma cell line

Rearrangement and coamplification of the 8p12 and 11q13 chromosomal regions occurs in a significant proportion of breast cancers. It usually involves a complex hybrid structure in which the FGFR1 and CCND1 genes are amplified. We report here a different type of 8p12-11q13 rearrangement in the MDA-MB-175 mammary carcinoma cell line. This amplification contains the NRG1/HGL (from 8p12-21) and DOC4 (from 11q13) genes, encoding respectively a ligand for ERBB receptors and a stress-induced protein which is a mammalian ortholog of Drosophila Tenm/Odz. It has been shown previously (Wang et al, Oncogene 18: 5718-5721, 1999) that these two genes are rearranged and fused by a translocation event. This type of event was not found in 30 tumors tested that showed coamplification of the 8p12 and 11q13 regions.

Fluorescence in situ hybridization analysis of chromosome 1 abnormalities in hematopoietic disorders: rearrangements of DNA satellite II and new recurrent translocations

Using fluorescence in situ hybridization analysis, breakpoints involving the long arm of chromosome 1 (1q) were localized in 36 patients with various hematopoietic disorders and rearrangements of the proximal part of 1q, as ascertained with banding techniques. The breakpoint was localized within the satellite II (sat II) domain in 14 patients with various abnormalities, between the sat II domain and the BCL9 locus in eight, between the BCL9 and ARNT loci in two, between sat II and ARNT in two others, and distal to ARNT in seven. A dicentric chromosome 1 was present in two patients. A high incidence of heterochromatin heteromorphism of chromosome 1 was present in this series. Two recurrent translocations were identified, t(1;2)(q12;q37) in three patients suffering from three different acute leukemia subtypes, and t(1;16)(q12;q24) in two patients with different diseases. Two patients had jumping translocations. Most of the rearrangements of 1q were secondary abnormalities, included in complex karyotypes. The roles of methylation, interactions with the proteins interfering with heterochromatin and possible gene silencing due to heterochromatin rearrangements are discussed.

gamma-heregulin is the product of a chromosomal translocation fusing the DOC4 and HGL/NRG1 genes in the MDA-MB-175 breast cancer cell line

gamma-heregulin is a recently described novel isoform of the heregulin/neuregulin class of EGF-like ligands that bind to and activate receptors of the ErbB family. Deregulated signaling through the heregulin-ErbB pathway is thought to be implicated in the development of a subset of human breast cancers. gamma-heregulin has been found to be expressed in the culture supernatant of MDA-MB-175, a breast carcinoma cell line. gamma-heregulin is characterized by the presence of a large N-terminal peptide extension that is not found in other heregulin isoforms. Here we report that this unique N-terminal extension of gamma-heregulin is identical to the N-terminus of DOC4, a product of a recently identified CHOP-dependent stress-induced gene. Human DOC4 and the heregulin-encoding genes map to different chromosomes and the MDA-MB-175 cell line contains a chromosomal translocation that leads to the fusion of DOC4 and HGL, on chromosomes 11 and 8, respectively. Thus, gamma-heregulin is a product of a mutant fusion gene and not a bona fide normal isoform. We speculate that the mutation may be selected for by virtue of its ability to activate ErbB signaling through the production of an autocrine ligand.

A case of inv(8)(p11q24) associated with acute myeloid leukemia involves the MOZ and CBP genes in a masked t(8;16)

We report on a novel chromosomal aberration, inv(8)(p11q24), in an M5 acute myeloid leukemia. We show by fluorescence in situ hybridization and Southern blot analyses that a t(8;16)(p11;p13) is masked by this inversion. The translocation targets the MOZ gene from the 8p11 and the CBP gene from the 16p13 chromosomal regions. The breakpoints occur in the MOZ region encoding the acidic domain and in the 5' end of the CBP gene. These results provide further evidence for the multiple contribution of both MOZ and CBP genes in acute leukemias. Genes Chromosomes Cancer 26:161-165, 1999.

Atypical response to all-trans retinoic acid in a der(5)t(5;17) acute promyelocytic leukemia

Typical acute promyelocytic leukemia (APL) is associated with the t(15;17) translocation, expression of a PML/RARA fusion transcript, and responsiveness to all-trans retinoic acid (ATRA). Rare APL cases implicating the RARA but not the PML gene have been reported. Cases with t(11;17)(q23;q21) which fuses the PLZF and RARA genes do not respond to ATRA. In contrast, cases with t(11;17)(q13;q21) and t(5;17)(q35;q21) which fuse RARA with NuMA and NPM, respectively, were reported to be sensitive to ATRA. We described previously an APL case with an unbalanced t(5;17) implicating RARA but neither PML nor PLZF. Here, we show that in this case: (1) the NPM gene is not involved, as demonstrated by RT-PCR and Southern blot; (2) response to ATRA in vitro is atypical, as demonstrated by morphological and functional maturation assays; and (3) PML nuclear bodies are not disrupted, as evidenced by immunofluorescence staining.

Constitutional balanced pericentric inversions of chromosomes X, 2, and 5 in myeloid malignancies

We report four cases of unrelated adult males carrying constitutive balanced pericentric inversions of chromosome X (one case), chromosome 2 (one case), and chromosome 5 (two cases) and presenting with myeloid malignancies. We discuss the potential contribution of these abnormalities to a background of susceptibility to hematologic malignancies.

In vitro response to all-trans retinoic acid of acute promyelocytic leukemias with nonreciprocal PML/RARA or RARA/PML fusion genes

Acute promyelocytic leukemia (APL) is characterized by the t(15;17) cytogenetic abnormality leading to the expression of two fusion genes, PML/RARA and RARA/PML, and by its sensitivity to all-trans retinoic acid (ATRA) differentiating treatment. Rare APL cases lacking the t(15;17) have been described. We have previously reported two cases presenting with submicroscopic insertions of RARA or PML into chromosome 15 or 17, respectively. These insertions lead to the formation of potentially functional, nonreciprocal, PML/RARA or RARA/PML fusion genes, providing the unique opportunity to investigate in a human noncell-line model the respective role of PML/RARA or RARA/PML in retinoid signaling. Here, we report the in vitro response to ATRA of these two cases as well as of a third case presenting with submicroscopic insertion (15;17) and expressing exclusively PML/RARA, by morphological, functional, and immunological assays. The two cases expressing PML/RARA presented with an immunostaining pattern typical of APL and a positive response to ATRA, whereas the APL case expressing only a RARA/PML fusion transcript exhibited an immunostaining pattern typical of non-APL cells, and was resistant to ATRA. Our results confirm that sensitivity to ATRA requires expression of PML/RARA and strongly correlates with immunostaining, and demonstrate that expression of RARA/PML alone is sufficient for a cytological APL phenotype, but does not confer sensitivity to ATRA.

Askin tumor and acute myeloid leukemia in a patient with constitutional partial Y disomy

We report the case of a young adult male carrying a constitutional unbalanced t(Y;13)(q11-12;p13) leading to a partial Y disomy, and presenting successively, in a 39-month interval, with an Askin tumor and a t(8;21) acute myeloid leukemia. The origin of the two neoplasias in this patient is discussed.

Cytogenetic and molecular biology for acute leukemias at diagnosis: a cost/effectiveness comparison

This article presents a cost-effectiveness study comparing cytogenetic and molecular analyses for detection of chromosomal abnormalities which are prognostic factors in acute leukemia. The aim of the study was to determine how these two techniques could substitute or complement one another. The study sample consisted of 107 adult patients with de novo myeloid or lymphoid acute leukemias, tested by both techniques in 1994 and 1995, for identification of translocations t(9;22), t(8;21), t(15;17), t(4;11), t(1;19), the inversion of chromosome 16 and for monosomy 5 or 7 (or deletion of their long arms) and trisomy 8. The criterion for diagnostic effectiveness of these strategies was the rate of detection of true positive anomalies which are clinically relevant, according to the current state of knowledge. On the basis of these observations six alternative strategies at diagnosis were compared (each technique alone or different combinations of the two techniques). The study shows that:-for ALL, PCR alone appears the most cost-effective strategy;-for AML, cytogenetic analysis alone is the best strategy;-sequential strategies are more cost effective than simultaneous use of both techniques for minimising risk of false negatives.

Early establishment of chimerism in the B and T lymphoid lineages after transplantation of allogeneic mobilized blood cells in leukemic patients

BACKGROUND

The use of allogeneic recombinant human granulocyte colony-stimulating factor (rhG-CSF)-mobilized blood cells was recently evaluated in patients with malignancies.

METHODS

Ten patients with leukemia were transplanted with allogeneic blood cells from HLA-identical sex-mismatched siblings; blood cells were mobilized with recombinant rhG-CSF. Up to 6 months after transplantation, blood and bone marrow samples were obtained from the recipient and analyzed for the presence of donor cells, using fluorescence in situ hybridization with specific probes hybridizing to sex chromosomes.

RESULTS

Analysis of blood and bone marrow smears demonstrated a complete chimera, as early as day 15 after transplantation. Furthermore, marrow and blood CD4+, CD8+, CD19+, and CD34+ cells were sorted using direct immunofluorescence and flow cytometry: fluorescence in situ hybridization analysis on sorted cells demonstrated that most progenitors and most cells in the T- and B-cell lineages were of donor origin as early as day 15 after transplantation.

CONCLUSIONS

Together with recently reported results, this study demonstrates that allogeneic rhG-CSF-mobilized blood cells contain primitive hematopoietic progenitors that can repopulate all lymphoid and myeloid lineages. Establishment of chimerism seems to be quick and stable, including the T- and B-cell lineages. Although establishment of chimerism in mitogen-responsive T cells is readily assayable with conventional cytogenetics, our study provides additional insight on the reconstitution of the B lineage and T-cell subsets after allogeneic transplantation in patients with leukemia.

Detection of CBFbeta/MYH11 fusion transcripts in acute myeloid leukemia: heterogeneity of cytological and molecular characteristics

Pericentric inversion of chromosome 16, translocation (16;16) and del(16q), resulting in a chimerical fusion of CBFbeta and MYH11 genes, are typically seen in the M4Eo French-American-British (FAB) classification subset of acute myelogenous leukemia (AML). In this study, we analyzed 70 cases of acute non-lymphoblastic leukemia, mainly of the M4 or M5 type. We report the very unusual presence of the t(16;16) and CBFbeta/MYH11 fusion transcript in an M7 patient. Ten M4Eo and four non-M4Eo patients presented an inv(16), t(16;16) or CBFbeta/MYH11 fusion transcript. In most cases, the common 'A-type' CBFbeta/MYH11 fusion transcript was detected. In addition to the eight different breakpoints and the three alternative splicing variants already described, evidence of a new CBFbeta/MYH11 fusion transcript was found which involves a 785-bp deletion of MYH11. Moreover, two patients had an unusual transcript, to our knowledge only observed once. Only one patient had abnormal eosinophilic differentiation without chromosome 16 cytogenetic abnormalities or detectable CBFbeta/MYH11 fusion. Conversely, only one patient presented CBFbeta/MYH11 fusion without abnormal eosinophilic differentiation. Altogether, our data suggest a correlation between the CBFbeta/MYH11 fusion transcript and characteristic abnormal eosinophilic differentiation, whatever the FAB subtype or the percentage of abnormal eosinophils

[Contamination of cytapheresis by tumor cells: apropos of 39 breast cancer cases]

The purpose of the present study was the detection of tumor cells in aphereses after mobilization of peripheral blood stem cells (PBSCs) with G-CSF from 39 breast cancer patients. Circulating tumor cells were searched using sensitive immunocytochemical technique (APAAP) with three anticytokeratin monoclonal antibodies. Counting of mononuclear cells and CD34 progenitor cells was also performed. Circulating tumor cells were detected in 35% of the patients. Cytokeratin-positive cells were detected in 45% of the patients of the metastatic group compared with 20% of the non metastatic one. Aphereses contamination was not correlated with lymph node involvement. Numbers of mononuclear cells and CD34 cells were not significantly different in positive and negative PBSCs collections. In our study, presence of tumor cells was associated with advanced clinical stage and could not be related to a higher CD34 cells mobilization by G-CSF.

Unbalanced translocation t(5;17) in an typical acute promyelocytic leukemia

Acute promyelocytic leukemia (APL; M3 in the FAB classification) is specifically associated with the t(15;17)(q23;q12) and the consequent formation of a PML/RARA fusion gene. A few cases of APL with a t(11;17)(q23;q12) and a PLZF/RARA fusion gene have recently been reported. In addition, a new variant, t(5;17)(q32;q12), with a RARA rearrangement was described in a child with atypical APL. We report an unbalanced der(5)t(5;17) in an atypical APL case showing unusual dysgranulopoiesis and some M2 features. The breakpoints were difficult to localize precisely on chromosome 5, because the translocation may have occurred on a previous del(5q). The karyotype also showed del(8q) and multiple double-minutes (dmin). Molecular studies evidenced RARA rearrangement but showed neither PML rearrangement nor PML/RARA fusion. Fluorescence in situ hybridization revealed that the dmin were of chromosome 8 origin and that they accounted for the MYC amplification observed in Southern blots. The patient did very poorly despite chemotherapy and all-trans retinoic acid (ATRA) treatment. Thus, the t(5;17) could represent a second type of variant translocation in APL that, like the disease associated with t(11;17), does not seem to respond to ATRA therapy. Whereas RARA rearrangement appears sufficient for an APL-like phenotype, it seems that the presence of a classical PML/RARA is required for typical APL with response to ATRA.

Translocation of BCR to chromosome 9 in a Philadelphia-negative chronic myeloid leukemia

We report the case of a patient having Philadelphia-negative, bcr-abl-positive chronic myeloid leukemia. In situ hybridization showed the presence of the bcr-abl fusion on the chromosome 9 long arm in all mitoses observed. Stability of the disease was very difficult to obtain because of serious adverse effects to interferon and chemotherapy, mainly grade IV neutropenia, and a blast crisis occurred 12 months after diagnosis. Only three other patients with such presentation (Philadelphia negative, bcr-abl positive with bcr-abl fusion on the chromosome 9 long arm) have been reported, with a poor therapeutic response and outcome in two of them. Translocation of BCR to chromosome 9 may therefore have a worse prognosis than translocation of ABL to chromosome 22 in Philadelphia-negative chronic myeloid leukemia.

Minor breakpoint cluster region (m-BCR) positive chronic myeloid leukaemia with an acute lymphoblastic leukaemia onset: a case report

m-BCR chronic myeloid leukaemia (CML) is a rare entity. We report a patient presenting with Philadelphia (Ph)-positive, m-BCR-positive acute lymphoblastic leukaemia (ALL) who achieved complete remission after induction chemotherapy, but showed a majority of Ph-positive mitoses during this remission. A diagnosis of m-BCR CML was established and the patient was given interferon alpha therapy. This is the first m-BCR CML presenting as ab initio ALL. This report emphasizes the importance of karyotyping Ph-positive ALL during remission so as not to misdiagnose CML patients who can benefit from Interferon therapy.

Direct evidence for dissociated megakaryocytic chimaerism in a Wiskott-Aldrich patient successfully allografted

We report a Wiskott-Aldrich patient who underwent allogeneic bone marrow transplantation from his HLA-identical sister at the age of 25. Conditioning regimen consisted of cyclophosphamide (180 mg/kg) and thoraco-abdominal irradiation (6 Grays). Cytogenetic follow-up revealed rapid and complete lymphoid chimaerism, but prolonged mixed bone marrow chimaerism. Correlative interphase cytogenetics performed on bone marrow smears using dual-colour fluorescence in situ hybridization with X and Y specific probes showed that the proportion of donor cells was significantly higher within megakaryocytes than in other lineages. This patient therefore presented with dissociated lineage engraftment, which is not exceptional in congenital diseases and aplastic anaemia, but has not previously been described in Wiskott-Aldrich syndrome. Bone marrow transplantation was successful despite this delayed engraftment which ensured adequate production in the involved cell lines.