Cryptic insertion and translocation or nondividing leukemic cells disclosed by FISH analysis in infant acute leukemia with discrepant molecular and cytogenetic findings

An Evaluation of a Fluorescence In Situ Hybridization Strategy Using Air-dried Blood and Bone-marrow Smears in the Risk Stratification of Pediatric B-Lineage Acute Lymphoblastic Leukemia in Resource-limited Settings

Cytogenetic abnormalities (CAs), one of the strongest influencers of therapeutic outcome in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL), can be identified by different techniques. Despite several technological advances, many centers with resource-limited settings continue to use either reverse-transcriptase polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH) to identify prognostically relevant CAs. We evaluated a simple and cost-effective triple-probe FISH strategy on air-dried blood and bone-marrow smears and compared its performance with a multiplex RT-PCR-based approach in the prognostication of pediatric BCP-ALL patients. Three hundred twenty BCP-ALL patients were tested prospectively and in parallel by FISH on air-dried blood or bone-marrow smears and RT-PCR. The FISH strategy correctly diagnosed all genetic abnormalities identified by RT-PCR. Prognostically relevant genetic abnormalities were missed by RT-PCR in 24 (8.1%) patients. In another 20 children (6%), with samples inadequate for RT-PCR testing (dry taps or due to poor sample quality), a successful FISH testing could be performed on bone-marrow aspirate or trephine-imprint smears. In addition, FISH detected ploidy changes, which could be confirmed by FxCycle Violet-based flow-cytometry. FISH testing on air-dried smears identified more prognostically relevant CAs, provided information on the ploidy status, and could be successfully performed in children with difficulty in bone-marrow sampling.

Involvement of AF1q/MLLT11 in the progression of ovarian cancer

The functional role of AF1q/MLLT11, an oncogenic factor involved in a translocation t(1;11)(q21;q23) responsible for acute myeloid leukaemia, has been investigated in hematological and solid malignancies and its expression was found to be linked to tumor progression and poor clinical outcome. In addition to its oncogenic function, AF1q has been shown to play a role in the onset of basal and drug-induced apoptosis in cancer cells of different histotypes, including ovarian cancer. Through in vitro, ex vivo, and in silico approaches, we demonstrated here that AF1q is also endowed with protumorigenic potential in ovarian cancer. In ovarian cancer cell lines, stable AF1q overexpression caused activation of epithelial-to-mesenchymal transition and increased motility/migratory/invasive abilities accompanied by gene expression changes mainly related to Wnt signaling and to signaling pathways involving in ERK/p38 activation. The potential role of AF1q in ovarian cancer progression was confirmed by immunohistochemical and in silico analyses performed in ovarian tumor specimens which revealed that the protein was absent in normal ovarian epithelium and became detectable when atypical proliferation was present. Moreover, AF1q was significantly lower in borderline ovarian tumors (i.e., tumors of low malignant potential without stromal invasion) than in invasive tumors, thus corroborating the association between high AF1q expression and increased migratory/invasive cell behavior and confirming its potential role in ovarian cancer progression. Our findings demonstrated, for the first time, that AF1q is endowed with protumorigenic activity in ovarian cancer, thus highlighting a dual behavior (i.e., protumorigenic and proapoptotic functions) of the protein in the malignancy.

Cytogenetic Profile of De Novo B lineage Acute Lymphoblastic Leukemia: Determination of Frequency, Distribution Pattern and Identification of Rare and Novel Chromosomal Aberrations in Indian Patients

BACKGROUND

Chromosomal aberrations identified in acute lymphoblastic leukemia (ALL) have an important role in disease diagnosis, prognosis and management. Information on karyotype and associated clinical parameters are essential to physicians for planning cancer control interventions in different geographical regions.

MATERIALS AND METHODS

In this study, we present the overall frequency and distribution patterns of chromosomal aberrations in both children and adult de novo B lineage ALL Indian patients using conventional cytogenetics, interphase FISH and multiplex RT-PCR.

RESULTS

Among the 215 subjects, cytogenetic results were achieved in 172 (80%) patients; normal karyotype represented 37.2% and abnormal 62.8% with a distribution as follows: 15.3% hypodiploidy; 10.3% hyperdiploidy; 15.8% t(9;22); 9.8% t(1;19); 3.7% t(12;21); 2.8% t(4;11); 2.8% complex karyotypes. Apart from these, we observed several novel, rare and common chromosomal rearrangements. Also, FISH studies using LSI extra-signal dual-color probes revealed additional structural or numerical changes.

CONCLUSIONS

These results demonstrate cytogenetic heterogeneity of ALL and confirm that the incidence of chromosomal abnormalities varies considerably. To the best of our knowledge, this is one of the largest reported series of cytogenetic investigations in Indian B-lineage ALL cases. In addition, ongoing cytogenetic studies are warranted in larger groups of B-lineage ALL cases to identify newly acquired chromosomal abnormalities that may contribute to disease diagnosis and management.

Gene expression profile analysis of an isogenic tumour metastasis model reveals a functional role for oncogene AF1Q in breast cancer metastasis

To study the molecular mechanisms underlying breast cancer metastasis, gene expression profile analysis was performed on two well-established breast cancer cell lines with high and low metastatic potentials: MDA-MB-435HM and MDA-MB-435LM. The analysis was conducted using cDNA microarrays containing 8000 genes. Of 60 differentially expressed genes, ALL1-fused gene from chromosome 1q (AF1Q), a putative oncogene not described previously in breast cancer, was identified and found to be over-expressed in MDA-MB-435HM cells compared with MDA-MB-435LM cells. The results indicate that AF1Q may play an important role in breast cancer metastasis. To test this hypothesis, we generated an AF1Q high-expression cell line by stable transfection of AF1Q cDNA into MDA-MB-435LM cells. Results showed that over-expression of AF1Q led to a marked increase in the invasive and metastatic potential of MDA-MB-435LM cells in vitro and in vivo, accompanied by the up-regulation of matrix metalloproteinase-2 (MMP-2), MMP-9, transcription factor Ets-1, and RhoC expression in both mRNA and protein levels. Consistent with this observation, reduced AF1Q expression in MDA-MB-435HM cells by small interfering RNA (siRNA) resulted in a significant decrease in the invasive potential of MDA-MB-435HM cells in vitro and in the protein expression of MMP-2, MMP-9, Ets-1, and RhoC, compared with either parental or non-silencing control cells. These data provide functional evidence that oncogene AF1Q may be a novel mediator of metastasis promotion in human breast cancer through regulation of the MMP pathway and RhoC expression.

Translocation (10;11)(p12;q23) in childhood acute myeloid leukemia: incidence and complex mechanism

Using both conventional and molecular cytogenetic methods, we found five new cases of t(10;11)(p12;q23). This translocation represented 28% of all cases of childhood AML treated at our center in 2004, and 63% of AML with rearrangements of 11q23. We describe three mechanisms for the translocation. Different fragments of 11q were involved in four of the five cases. One patient showed a cytogenetically cryptic insertion of 5' part of MLL into the 3' part of MLLT10 in 10p12. The median event-free survival of patients was 8.1 months, and we conclude that the t(10;11)(p12;q23) is associated with unfavorable prognosis in childhood acute myeloid leukemia.

Temporary blast reduction after immunoglobulin administration for congenital cytomegalovirus infection masking infant leukemia with cryptic MLL rearrangement

Differentiation between reactive bone marrow suppression due to viral infection and early stages of leukemia can be difficult particularly in young infants. We report on a 2-month-old girl presenting with pancytopenia and positive markers for congenital cytomegalovirus (CMV) infection. Definitive diagnosis of coexisting pro-B cell infant leukemia with cryptic MLL rearrangement was delayed by the transient regeneration of normal hematopoiesis and reduction of abnormal blastoid cells in the bone marrow following immunoglobulin administration. Molecular diagnosis could only be established using interphase fluorescence in situ hybridization (FISH) analysis which may be considered as a valuable additional diagnostic tool in similar cases.

Acute lymphoblastic leukemia with 4;11 translocation analyzed by a multi-modal strategy of conventional cytogenetics, FISH, morphology, flow cytometry and molecular genetics, and review of the literature

We report a case of acute lymphoblastic leukemia (ALL) with a 4;11 translocation. Metaphase cells and interphase nuclei derived from a routine unstimulated culture of bone marrow were analyzed using a combined strategy of G-banding and fluorescent in situ hybridization (FISH) in addition to hematopathological analysis, flow cytometry, and molecular genetics. This multimodal approach enables a successful correlation of pathology and cytogenetics to support a comprehensive diagnosis of the patient. Meaningful prognostication and appropriate therapeutic considerations are possible only when accurate diagnostic information is given. We further search and review the literature for the most up-to-date information currently available for this subtype of ALL in the constantly evolving field of molecular cytogenetics.

Characterization of fusion partner genes in 114 patients with de novo acute myeloid leukemia and MLL rearrangement

The fusion transcripts of MLL rearrangement [MLL(+)] in acute myeloid leukemia (AML) and their clinicohematologic correlation have not be well characterized in the previous studies. We used Southern blot analysis to screen MLL(+) in de novo AML. Reverse transcriptase-polymerase chain reaction was used to detect the common MLL fusion transcripts. cDNA panhandle PCR was used to identify infrequent or unknown MLL partner genes. MLL(+) was identified in 114 (98 adults) of 988 AML patients. MLL fusion transcripts comprised of 63 partial tandem duplication of MLL (MLL-PTD), 14 MLL-AF9, 9 MLL-AF10, 9 MLL-ELL, 8 MLL-AF6, 4 MLL-ENL and one each of MLL-AF1, MLL-AF4, MLL-MSF, MLL-LCX, MLL-LARG, MLL-SEPT6 and MLL-CBL. The frequency of MLL-PTD was 7.1% in adults and 0.9% in children (P<0.001). 11q23 abnormalities were detected in 64% of MLL/t11q23 and in none of MLL-PTD by conventional cytogenetics. There were no differences in remission rate, event-free survival and overall survival between adult MLL-PTD and MLL/t11q23 groups. Adult patients had a significantly poorer outcome than children. The present study showed that cDNA panhandle PCR can identify all rare or novel MLL partner genes. MLL-PTD was rare in childhood AML. MLL(+) adults had a poor outcome with no difference in survival between MLL-PTD and MLL/t11q23 groups.

Del(5q) and MLL amplification in homogeneously staining region in acute myeloblastic leukemia: a recurrent cytogenetic association

We report here a 71 year-old female presenting with acute myeloblastic leukemia (FAB-M1) after treatment of essential thrombocythemia with Vercyte. Conventional cytogenetic techniques showed a complex karyotype, 44,XX,-5,-7,-11,add(11)(q23),-14,+mar,+r. The use of several fluorescent in situ hybridizations (FISH) lead to the identification of these complex rearrangements. The marker was found to be tricentric, with pericentromeric material of chromosome 7 inserted in the short arm of chromosome 5, resulting in monosomy 5q and 7q. The derivative chromosome 11 was dicentric and had subtelomeric sequences of 11p on both ends; several copies of the MLL gene were located in two different regions separated by a centromere of chromosome 11. Twenty-one cases, including ours, of myelodysplastic syndromes and acute myelogenous leukemia with MLL amplification present in hsr or dmin were found in the literature. Most of these patients shared some characteristics: they were old, they had de novo acute myeloid leukemia (AML) with a complex karyotype and a short survival, 90% of them having also a del(5q). Therefore, the simultaneous presence of MLL amplification and del(5q) appears to be a nonrandom association that could be the signature of AML in elderly patients with a poor prognosis.

Screening by fluorescence in situ hybridization for MLL status at diagnosis in 239 unselected patients with acute myeloblastic leukemia

A large number of abnormalities involving the MLL gene have been associated with hematological malignancies, including acute myeloblastic leukemias (AML). Given the overall unfavorable prognosis of AML with an MLL abnormality, its reliable and accurate detection is needed for informed treatment decision. We therefore investigated the occurrence of MLL abnormalities in 239 unselected consecutive AML patients, using conventional cytogenetic and fluorescent in situ hybridization (FISH) analyses. FISH analysis for MLL was performed using a commercial dual-color probe. Of the 239 patients, 30 (12.6%) showed MLL abnormalities under FISH analysis, 10 (4.2%) showed a split signal indicating the disruption of the MLL gene by translocation or insertion, and 20 (8.4%) showed overrepresentation of the MLL gene without evidence of rearrangement. MLL abnormalities were more frequently found in AML-M5 and M4, mainly as rearrangements, and in AML-M2, mainly as overrepresentation. Our results are in agreement with those reported in other studies. All M2, M4, and M5 AML patients without known recurrent translocations, such as t(8;21) and inv(16), should be investigated by FISH with an MLL probe because it allows the detection of MLL rearrangement that would go undetected by conventional cytogenetics and because it has the ability of detecting multiple copies of the MLL gene in, for example, marker chromosomes and double minutes.

Polysomy 8 defines a clinico-cytogenetic entity representing a subset of myeloid hematologic malignancies associated with a poor prognosis: report on a cohort of 12 patients and review of 105 published cases

Tetrasomy, pentasomy, and hexasomy 8 (polysomy 8) are relatively rare compared to trisomy 8. Here we report on a series of 12 patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or myeloproliferative disorder (MPD) associated with polysomy 8 as detected by conventional cytogenetics and fluorescence in situ hybridization (FISH). In an attempt to better characterize the clinical and hematological profile of this cytogenetic entity, our data were combined with those of 105 published patients. Tetrasomy 8 was the most common presentation of polysomy 8. In 60.7% of patients, polysomy 8 occurred as part of complex changes (16.2% with 11q23 rearrangements). No cryptic MLL rearrangements were found in cases in which polysomy 8 was the only karyotypic change. Our study demonstrates the existence of a polysomy 8 syndrome, which represents a subtype of AML, MDS, and MPD characterized by a high incidence of secondary diseases, myelomonocytic or monocytic involvement in AML and poor overall survival (6 months). Age significantly reduced median survival, but associated cytogenetic abnormalities did not modify it. Cytogenetic results further demonstrate an in vitro preferential growth of the cells with a high level of aneuploidy suggesting a selective advantage for polysomy 8 cells.

Increased AF1q gene expression in high-risk myelodysplastic syndrome

The AF1q gene is expressed in normal haematopoietic progenitors, but less so in differentiated blood cells. In 47 patients with myelodysplastic syndrome (MDS), AF1q copy numbers were 0-6.8 x 10(6)/microg RNA compared with 1.5-2.4 x 10(5)/microg RNA in normal marrow. AF1q levels correlated with international prognostic scoring system (IPSS) scores (P = 0.004) and the risk of post-transplant relapse (P = 0.05). Among IPSS high-risk patients, survival correlated inversely with AF1q levels (P = 0.04). Thus, AF1q levels correlate with high-risk MDS and may provide a marker for risk stratification.

Identical reconstitution after bone marrow transplantation in twins who received fresh and cryopreserved grafts harvested at the same time from their older brother

We report here the reconstitution after bone marrow transplantation (BMT) in identical infant twins with acute myelogenous leukemia (AML). They were diagnosed at 8 and 9 months of age. Complete remission was induced after two courses of chemotherapy. After four and five courses of chemotherapy, respectively, they received BMT at 2-month interval from the same HLA-identical older brother. The total dose of marrow nucleated cells (NC) harvested was 77.7 x 10(8). The first patient was transplanted with half of the total dose of NC. The remaining cells were cryopreserved without the use of a programmed freezer and transplanted into the second patient 2 months later. The number of days for neutrophil (>0.5 x 10(9)/L), platelet (>50 x 10(9)/L), and reticulocyte (>1%) recovery were, respectively, 15, 21, and 14 in the first case and 12, 21, and 15 in the second case. The clinical courses after BMT were uneventful in both cases, except for mild acute GVHD, and complete remission has been maintained >4 yr with full recovery of immune and marrow function. Based on the results in these cases, we confirmed that marrow cells that have been cryopreserved without the use of a programmed freezer could reconstitute immune and marrow function as well as non-cryopreserved cells.

Gene mining: a novel and powerful ensemble decision approach to hunting for disease genes using microarray expression profiling

Current applications of microarrays focus on precise classification or discovery of biological types, for example tumor versus normal phenotypes in cancer research. Several challenging scientific tasks in the post-genomic epoch, like hunting for the genes underlying complex diseases from genome-wide gene expression profiles and thereby building the corresponding gene networks, are largely overlooked because of the lack of an efficient analysis approach. We have thus developed an innovative ensemble decision approach, which can efficiently perform multiple gene mining tasks. An application of this approach to analyze two publicly available data sets (colon data and leukemia data) identified 20 highly significant colon cancer genes and 23 highly significant molecular signatures for refining the acute leukemia phenotype, most of which have been verified either by biological experiments or by alternative analysis approaches. Furthermore, the globally optimal gene subsets identified by the novel approach have so far achieved the highest accuracy for classification of colon cancer tissue types. Establishment of this analysis strategy has offered the promise of advancing microarray technology as a means of deciphering the involved genetic complexities of complex diseases.

MLL translocations with concurrent 3? deletions: Interpretation of FISH results

Rearrangements involving the MLL gene at 11q23 occur in a clinically relevant subgroup of patients with acute lymphoblastic leukemia (ALL) at all ages, and therefore their accurate identification at diagnosis is important. It has become commonplace to screen ALL patients for rearrangements of MLL using a dual-color fluorescence in situ hybridization (FISH) assay. We report on 12 ALL patients with an unusual FISH result consisting of the following signal pattern: one 5' green, no 3' red, and one/two fusion signals. This configuration is consistent with a MLL translocation and simultaneous deletion of 3' MLL-a well-established phenomenon-which has been interpreted as a positive result. G-banded and complementary metaphase FISH analyses confirmed an 11q23/MLL translocation in 8 of the 12 cases, whereas in one case, the identification of a del(11)(q23) was restricted to G-banded analysis only. In three cases, an MLL rearrangement was excluded by extensive FISH analysis and/or Southern blotting. In conclusion, the loss of the 3' MLL signal should not be assumed to be the result of a concurrent translocation and deletion event, and such aberrant FISH signal patterns should be investigated further by alternative methods for determining their MLL status.

MLL/AF-1p Fusion in Therapy-Related Early Pre-B Acute Lymphoblastic Leukemia with t(1;11)(p32;q23) Translocation Developing in the Relapse Phase of Acute Promyelocytic Leukemia

We report the development of therapy-related early pre-B acute lymphoblastic leukemia in a patient administered a topoisomerase II inhibitor, etoposide, a consolidation therapy agent for acute promyelocytic leukemia. Our case is of interest because of simultaneous relapse of the original leukemia and onset of therapy-related leukemia and relatively rare t(1;11)(p32;q23) translocation with confirmed MLL/AF-1p fusion. This case suggests that careful monitoring for MLL gene rearrangements is necessary after administration of topoisomerase II inhibitors.