Spectral Karyotyping Analysis Research Articles

A new complex translocation t(5;17;15)(q11;q21;q22) in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is associated with the t(15;17)(q22;q21) translocation which causes the fusion of the retinoic acid alpha gene ( RARA) on 17q21 to the promyelocytic leukemia gene ( PML) on 15q22. The two chimeric genes, PML/ RARA and RARA/ PML, are thought to play a role in leukemogenesis. A small proportion of patients with APL have complex or simple variants of this translocation. We report the case of a 22-year-old woman with APL carrying a complex variant translocation t(5;17;15)(q11;q12;q22) confirmed by G-banding, reverse transcription polymerase chain reaction (RT-PCR), fluorescence in situ hybridization(FISH), and spectral karyotyping analysis (SKY). The patient achieved complete remission with all-trans retinoic acid treatment and chemotherapy. These results illustrate the usefulness of combined analysis consisting of G-banding, RT-PCR, FISH, and SKY methods to identify the PML/ RARA fusion gene in cases with variant t(15;17).

Spectral karyotyping and SNP microarray analysis define uniparental disomy (UPD) as a novel mutational mechanism in MSI- and CSI-colorectal cancers ∗

Spectral karyotyping and SNP microarray analysis define uniparental disomy (UPD) as a novel mutational mechanism in MSI- and CSI-colorectal cancers ∗

Spectral Karyotyping and SNP Microarray Analysis Define Uniparental Disomy (UPD) as a Novel Mutational Mechanism in MSI- and CSI-Colorectal Cancers

Spectral Karyotyping and SNP Microarray Analysis Define Uniparental Disomy (UPD) as a Novel Mutational Mechanism in MSI- and CSI-Colorectal Cancers

Immunoglobulin light chain gene translocations in non‐Hodgkin’s lymphoma as assessed by fluorescence in situ hybridisation

In non-Hodgkin's lymphoma (NHL), the majority of translocations involve the immunoglobulin heavy chain gene (IGH) locus, while a few involve the immunoglobulin light chain gene (IGL) locus, consisting of the kappa light chain gene (IGkappa) and the lambda light chain gene (IGlambda). Although many reports have dealt with the translocation and/or amplification of IGH in NHL, only a few have identified IGL translocations. To identify cytogenetic abnormalities and the partner chromosomes of IGL translocations in NHL, we performed dual-colour fluorescence in situ hybridisation (DC-FISH) and spectral karyotyping (SKY) in seven NHL cell lines and 40 patients with NHL. We detected IGL translocations in two cell lines and nine patients: four patients with diffuse large B-cell lymphoma, three with follicular lymphoma, one with extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue and one with mantle cell lymphoma. Five distinct partners of IGlambda translocation were identified by SKY analysis: 3q27 in three patients, and 1p13, 6p25, 17p11.2 and 17q21 in one patient each. Three cases featured double translocations of IGH and IGL. These findings warrant the identification of novel genes 1p13, 6p25, 17p11.2 and 17q21.

Novel 6p rearrangements and recurrent translocation breakpoints in retinoblastoma cell lines identified by spectral karyotyping and mBAND analyses

Gain of the short arm of chromosome 6, usually through isochromosome 6p formation, is present in approximately 50% of retinoblastoma tumors. The minimal region of gain maps to chromosome band 6p22. Two genes, DEK and E2F3, are implicated as candidate oncogenes. However, chromosomal translocations have been overlooked as a potential mechanism of activation of oncogenes at 6p22 in retinoblastoma. Here, we report combined spectral karyotyping), 4',6-diamidino-2-phenylindole banding, mBAND, and locus-specific fluorescence in situ hybridization analyses of four retinoblastoma cell lines, RB1021, RB247c, RB383, and Y79. In RB1021 and RB247c, 6p undergoes structural rearrangements involving a common translocation breakpoint at 6p22. These data imply that 6p translocations may represent another mechanism of activation of 6p oncogene(s) in a subset of retinoblastomas, besides the copy number increase. In addition to 6p22, other recurrent translocation breakpoints identified in this study are 4p16, 11p15, 17q21.3, and 20q13. Common regions of gain map to chromosomal arms 1q, 2p, 6p, 17q, and 21q.

Expression of Alternative CALM-AF10 Fusions Causes Different Hematological Malignancies in Mice.

The clathrin assembly lymphoid myeloid leukemia gene, CALM, was first described as a translocation partner for AF10 in morphologically distinct subsets of acute leukemia with a recurring 10;11 translocation. As the name implies, CALM is involved in the regulation of clathrin-mediated endocytosis. We hypothesize that expression of the CALM-AF10 protein disrupts endocytosis of growth receptors, leading to constitutive activation and, thereby, contributes to the development of leukemia. The CALM-AF10 fusion transcripts are characterized by two breakpoints in CALM at positions 1926 and 2091. Using the 293T human renal epithelial cell line as a model, we demonstrated that CALM1926-AF10 localized diffusely to the cytoplasm, whereas CALM2091-AF10 had a more prominent punctate appearance. This difference in distribution was likely attributable to protein domains in CALM rather than AF10, which is a transcription factor that localizes to the nucleus. The difference in localization extended to their effects on endocytosis. Whereas ∼4–8% of cells expressing truncated CALM2091, CALM1926, or AF10 displayed impaired transferrin uptake, this value was ∼60% in cells expressing CALM2091-AF10 and only ∼13% in cells expressing CALM1926-AF10. Next, we used a retroviral transduction-transplantation murine model to test the impact of CALM-AF10 expression on the development of leukemia. Mice transplanted with either CALM1926-AF10 or CALM2091-AF10 transduced fetal liver cells developed disease within a short period of time (∼8 to 21 weeks post-transplantation). Interestingly, expression of CALM1926-AF10 led to the development of a myeloproliferative disease (MPD)-like leukemia, with a predominance of mature neutrophils, whereas expression of CALM2091-AF10 led to the development of an acute myeloid leukemia (AML) with >30% immature myeloid blasts, with one exception. One mouse transplanted with progenitor cells expressing CALM2091-AF10 developed a MPD accompanied by a granulocytic sarcoma; however, examination of RNA from the spleen of this diseased mouse revealed that it had undergone a splicing event consistent with the size expected for the 1926 breakpoint. Both diseases were transplantable to secondary recipients confirming the leukemic nature of the CALM-AF10 expressing cells. Previous studies show that patients with the t(10;11) (p13;q14-21) develop either AML or T cell-acute lymphoblastic leukemia (T-ALL). Most of the patients with T-ALL express the CALM1926-AF10 fusion. Although there are differences in presentation between humans and mice, the hematological disease may be a reflection of the conditions of the mouse model. To identify possible secondary cooperating mutations, spectral karyotyping analysis of the mouse AMLs and MPDs was performed. However, to date we have not identified any significant abnormalities. We hypothesize that defective endocytosis synergizes with transcriptional deregulation, leading to an aggressive form of leukemia.

Chromosomal Instability and Supernumerary Centrosomes Represent Precursor Defects in a Mouse Model of T-Cell Lymphoma

A hallmark of carcinogenesis is resistance to cell death. However, recent studies indicate that Bax expression increased apoptosis and promoted oncogenesis. In this study, we hypothesized that Bax promotes tumor formation by increasing chromosomal instability (CIN). Consistent with this hypothesis, spectral karyotype analysis (SKY) of lymphomas derived from Lck-Bax38/1 mice were consistently aneuploid. To determine if CIN precedes tumor formation, quantitative cytogenetic analysis, SKY analysis, and quantitative centrosome staining were done on thymocytes from young premalignant mice. Between 6 and 10 weeks of age, thymi from Bax-expressing mice (either p53+/+ or p53-/-) had an increased percentage of aneuploid cells as well as an increase in cells with supernumerary centrosomes. For 3- to 6-week-old mice, Bax expression increased aneuploidy and supernumerary centrosomes in p53-/- mice but not in p53+/+ animals. Importantly, both aneuploidy and supernumerary centrosomes were attenuated by Bcl-2. Remarkably, SKY analysis showed multiple independent aneuploid populations in the p53-/- Bax-expressing mice between 3 and 6 weeks of age. These results indicate that oligoclonal aneuploidy and supernumerary centrosomes are early hallmarks of Bax-induced lymphoma formation and support a novel link between the Bcl-2 family and CIN. The data provide an attractive model for the paradoxical effects of the Bcl-2 family on carcinogenesis that have been observed in multiple studies of both humans and mice.

Spreading of mammalian DNA-damage response factors studied by ChIP-chip at damaged telomeres

Phosphorylated histone H2AX (gammaH2AX) is generated in nucleosomes flanking sites of DNA double-strand breaks, triggering the recruitment of DNA-damage response proteins such as MDC1 and 53BP1. Here, we study shortened telomeres in senescent human cells. We show that most telomeres trigger gammaH2AX formation, which spreads up to 570 kb into the subtelomeric regions. Furthermore, we reveal that the spreading patterns of 53BP1 and MDC1 are very similar to that of gammaH2AX, consistent with a structural link between these factors. Moreover, different subsets of telomeres signal in different cell lines, with those that signal tending to equate to the shortest telomeres of the corresponding cell line, thus linking telomere attrition with DNA-damage signalling. Notably, we find that, in some cases, gammaH2AX spreading is modulated in a manner suggesting that H2AX distribution or its ability to be phosphorylated is not uniform along the chromosome. Finally, we observe weak gammaH2AX signals at telomeres of proliferating cells, but not in hTERT immortalised cells, suggesting that low telomerase activity leads to telomere uncapping and senescence in proliferating primary cells.

A Transgenic Mouse Model of Plasma Cell Malignancy Shows Phenotypic, Cytogenetic, and Gene Expression Heterogeneity Similar to Human Multiple Myeloma

Multiple myeloma is an incurable plasma cell malignancy for which existing animal models are limited. We have previously shown that the targeted expression of the transgenes c-Myc and Bcl-X(L) in murine plasma cells produces malignancy that displays features of human myeloma, such as localization of tumor cells to the bone marrow and lytic bone lesions. We have isolated and characterized in vitro cultures and adoptive transfers of tumors from Bcl-xl/Myc transgenic mice. Tumors have a plasmablastic morphology and variable expression of CD138, CD45, CD38, and CD19. Spectral karyotyping analysis of metaphase chromosomes from primary tumor cell cultures shows that the Bcl-xl/Myc tumors contain a variety of chromosomal abnormalities, including trisomies, translocations, and deletions. The most frequently aberrant chromosomes are 12 and 16. Three sites for recurring translocations were also identified on chromosomes 4D, 12F, and 16C. Gene expression profiling was used to identify differences in gene expression between tumor cells and normal plasma cells (NPC) and to cluster the tumors into two groups (tumor groups C and D), with distinct gene expression profiles. Four hundred and ninety-five genes were significantly different between both tumor groups and NPCs, whereas 124 genes were uniquely different from NPCs in tumor group C and 204 genes were uniquely different from NPCs in tumor group D. Similar to human myeloma, the cyclin D genes are differentially dysregulated in the mouse tumor groups. These data suggest the Bcl-xl/Myc tumors are similar to a subset of plasmablastic human myelomas and provide insight into the specific genes and pathways underlying the human disease.

MCT-1 oncogene downregulates p53 and destabilizes genome structure in the response to DNA double-strand damage

Tumor suppressor p53 protein mediates checkpoint controls and the apoptotic program that are critical for maintaining genomic integrity and preventing tumorigenesis. Forced-induction of MCT-1 decreased p53 expression before and after genomic insults. While inhibiting protein synthesis, the levels of ubiquinated-p53 and the phospho-MDMA2 were significantly increased in ectopic MCT-1 cells. Abrogation of the proteosome degradation process attenuated p53 destabilization and p21 down-regulation by MCT-1. Concomitantly, MCT-1 overexpression enhanced the phosphorylation status of MAPK (ERK1/ERK2). While MCT-1 gene knockdown or MEK/ERK pathway inhibition dramatically reduced MAPK phosphorylation, the genotoxin-induced p53 and p21 production were noticeably elevated. Upon Etoposide treatment, ectopic MCT-1 cells relaxed S-phase and G2/M checkpoints followed by G1 phase progressing. Moreover, cells inducing with MCT-1 abridged accumulations of G2/M populations in the response to gamma-irradiation. The polyploidy (DNA content >4N) populations were increased in association with p53 loss in MCT-1 oncogenic cells. Alkaline comet assay validated that ectopic MCT-1 cells were less susceptibility to the genotoxicity. Furthermore, the allocation of nuclear MCT-1 induced by the genotoxic stress was moderately coincided with γ-H2AX appearances. Throughout damage-repairing process, ectopic MCT-1 cells displayed many larger chromosomes and multiple chromosomal fusions compared to the controls that showed increase in chromosomal breaks/gaps and minute chromosomal fragments. Spectral karyotyping analysis precisely identified the acquisition of a single extra copy of chromosome 14 together with a complex genome organizations in ectopic MCT-1 cells, including extra copies of chromosome segments that had been translocated to derivative chromosomes 6 [der(6)] and 9 [der(9)]. In conclusion, MCT-1 deregulates p53–p21 network and impairs the damage checkpoints those are robustly connected to oncogenic chromosomal abnormalities.

Characterization of trisomy 8 in pediatric undifferentiated sarcomas using advanced molecular cytogenetic techniques

Pediatric undifferentiated soft tissue sarcomas (USTS) are a rare group of neoplasms that are unclassifiable despite the application of immunohistochemical, cytogenetic, and molecular techniques. To date, there is a dearth of studies looking at the cytogenetic and molecular genetic alterations in such tumors. Trisomy 8, a frequent molecular alteration in neoplasia, is seen in several soft tissue sarcomas, including Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET), synovial sarcoma, and leiomyosarcoma. Because USTS share several clinicobiological features with the aforementioned tumors, the occurrence of alterations in chromosome 8 was studied in 11 pediatric USTS using a combination of interphase fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), and genomic profiling with oligonucleotide array comparative genomic hybridization (aCGH). The copy number status of MYC was also assessed on the same tumors using dual-color FISH, with the aim of delineating the degree and intratumoral distribution of MYC amplification in this tumor. A near-uniform presence of an increase in MYC copy number was observed, along with an increase in chromosome 8 copy number in all the tumors. SKY and aCGH analysis of tumors exhibiting trisomy 8 confirmed the numerical imbalances. The occurrence of trisomy 8 in a subset of pediatric USTS confirms a shared genomic alteration with several other soft tissue sarcomas. Further studies are required to determine the clinical implications of such a finding.

Establishment and characterization of the new splenic marginal zone lymphoma-derived cell line UCH1 carrying a complex rearrangement involving t(8;14) and chromosome 3

A new cell line, designated UCH1, was established from a patient with splenic marginal zone lymphoma (SMZL). UCH1 cells feature a mature B-cell phenotype, characterized by surface IgM +, κ+, CD5−, CD10−, CD19+ and CD20+. The BCL2 and BCL6 genes retained their germ-line configurations and overexpression of cyclin D1 was not detected. UCH1 cells carry numerical and structural aberrations in chromosome 3, but these were too complex to be analyzed with the conventional G-banding method. Spectral karyotyping (SKY) and fluorescence in situ hybridization analysis clearly demonstrated the presence of a balanced translocation between chromosomes 8 and 14 [t(8;14)(q24;q32)] in the complex aberrations involving chromosome 3. The results of Southern blot analysis supported this finding by showing rearrangement of the c-myc gene in UCH1 cells. SKY analysis also identified a translocation involving chromosome band 18q21, to which BCL2 and MALT1 genes were assigned, suggesting their implication in the development or progression of SMZL.

Correlating breakage-fusion-bridge events with the overall chromosomal instability and in vitro karyotype evolution in prostate cancer

Chromosomal instability (CIN) is thought to underlie the generation of chromosomal changes and genomic heterogeneity during prostatic tumorigenesis. The breakage-fusion-bridge (BFB) cycle is one of the CIN mechanisms responsible for characteristic mitotic abnormalities and the occurrence of specific classes of genomic rearrangements. However, there is little detailed information concerning the role of BFB and CIN in generating genomic diversity in prostate cancer. In this study we have used molecular cytogenetic methods and array comparative genomic hybridization analysis (aCGH) of DU145, PC3, LNCaP, 1532T and 1542T to investigate the in vitro role of BFB as a CIN mechanism in karyotype evolution. Analysis of mitotic structures in all five prostate cancer cell lines showed increased frequency of anaphase bridges and nuclear strings. Structurally rearranged dicentric chromosomes were observed in all of the investigated cell lines, and Spectral Karyotyping (SKY) analysis was used to identify the participating rearranged chromosomes. Multicolor banding (mBAND) and aCGH analysis of some of the more complex chromosomal rearrangements and associated amplicons identified inverted duplications, most frequently involving chromosome 8. Chromosomal breakpoint analysis showed there was a higher frequency of rearrangement at centromeric and pericentromeric genomic regions. The distribution of inverted duplications and ladder-like amplifications was mapped by mBAND and by aCGH. Adjacent spacing of focal amplifications and microdeletions were observed, and focal amplification of centromeric and end sequences was present, particularly in the most unstable line DU145. SKY analysis of this line identified chromosome segments fusing with multiple recipient chromosomes (jumping translocations) identifying potential dicentric sources. Telomere free end analysis indicated loss of DNA sequence. Moreover, the cell lines with the shortest telomeres had the most complex karyotypes, suggesting that despite the expression of telomerase, the reduced telomere length could be driving the observed BFB events and elevated levels of CIN in these lines.

Efficient immortalization of primary human cells by p16INK4a‐specific short hairpin RNA or Bmi‐1, combined with introduction of hTERT

Activation of telomerase is sufficient for immortalization of some types of human cells but additional factors may also be essential. It has been proposed that stress imposed by inadequate culture conditions induces senescence due to accumulation of p16(INK4a). Here, we present evidence that many human cell types undergo senescence by activation of the p16(INK4a)/Rb pathway, and that introduction of Bmi-1 can inhibit p16(INK4a) expression and extend the life span of human epithelial cells derived from skin, mammary gland and lung. Introduction of p16(INK4a)-specific short hairpin RNA, as well as Bmi-1, suppressed p16(INK4a) expression in human mammary epithelial cells without promoter methylation, and extended their life span. Subsequent introduction of hTERT, the telomerase catalytic subunit, into cells with low p16(INK4a) levels resulted in efficient immortalization of three cell types without crisis or growth arrest. The majority of the human mammary epithelial cells thus immortalized showed almost normal ploidy as judged by G-banding and spectral karyotyping analysis. Our data suggest that inhibition of p16(INK4a) and introduction of hTERT can immortalize many human cell types with little chromosomal instability.

Spectral karyotyping analysis of human and mouse chromosomes.

Classical banding methods provide basic information about the identities and structures of chromosomes on the basis of their unique banding patterns. Spectral karyotyping (SKY), and the related multiplex fluorescence in situ hybridization (M-FISH), are chromosome-specific multicolor FISH techniques that augment cytogenetic evaluations of malignant disease by providing additional information and improved characterization of aberrant chromosomes that contain DNA sequences not identifiable using conventional banding methods. SKY is based on cohybridization of combinatorially labeled chromosome-painting probes with unique fluorochrome signatures onto human or mouse metaphase chromosome preparations. Image acquisition and analysis use a specialized imaging system, combining Sagnac interferometer and CCD camera images to reconstruct spectral information at each pixel. Here we present a protocol for SKY analysis using commercially available SkyPaint probes, including procedures for metaphase chromosome preparation, slide pretreatment and probe hybridization and detection. SKY analysis requires approximately 6 d.

Spectral karyotyping demonstrates genetically unstable skin‐homing T lymphocytes in cutaneous T‐cell lymphoma

We initially established cell lines from skin biopsies from four patients (MF8, MF18, MF19 and MF31) in early stages of cutaneous T-cell lymphoma (CTCL) in 1999. After 3 weeks of culture, skin-homing T lymphocytes were stimulated with phytohaemagglutinin. Metaphase spreads were analysed using spectral karyotyping (SKY), a molecular cytogenetic technique. MF18 and MF19 had predominantly normal karyotypes. MF8 had recurrent numerical aberrations resulting in two T lymphocyte clones: one with trisomy 21 (12/20 cells) and the other with monosomy chromosome 22 (3/20 cells). MF8 also exhibited a clonal deletion, del(5)(p15.1), as well as multiple non-clonal structural aberrations. MF31 had a clonal deletion, del(17)(p12) and other non-clonal deletions involving chromosomes 2, 5, 10, 11. MF18 had a single abnormal cell that contained two reciprocal translocations t(1;2)(q32;p21) and t(4;10)(p15.2;q24). In 2001, three of the original patients had new skin biopsies taken and cell lines were established. SKY analysis revealed the continued presence of a T-cell clone in MF8 with trisomy 21 (4/20 cells). Additionally, a new clone was seen with a del(18)(p11.2) (17/20 cells). MF31 had only one aberrant cell with a del(17)(p12). MF18 had a clonal deletion, [del(1)(p36.1) in 3/20 cells] and non-clonal aberrations involving chromosomes 3, 4, 5, 6, 12, 13, 17 and 18. Thus, three of four patients continued to show numerous numerical and structural aberrations, both clonal and non-clonal, with only MF8 having a recurring T lymphocyte clone (+21). Our findings demonstrate high genetic instability among skin-homing T lymphocytes even in early stages of CTCL. We did not see genetic instability or evidence of clones in cell lines from a patient with atopic dermatitis and one with psoriasis.

Characterization of Bortezomib Resistant Human Multiple Myeloma Cell Line (HMCL): A Clinically Relevant Model for Novel Drug Development in Multiple Myeloma (MM).

Introduction: Bortezomib (B) is the first in class proteasome inhibitor that received FDA approval for the treatment of MM patients with relapsed or refractory disease. Despite impressive clinical activity all patients develop resistance to B. The underlying mechanism of resistance to B remains undetermined. Mechanisms to overcome B resistance or development of new therapeutic agent(s) with activity in context of B resistance are limited due to unavailability of established preclinical B resistant MM models. To overcome this challenge we developed a B resistant HMCL.Methods: we chronically exposed the OPM-2 HMCL to sub-lethal doses of B. Surviving cells were harvested, re-cultured and dose of B incrementally increased over prolong period of time. The resulting resistant cells were further characterized using array Comparative Genomic Hybridization (aCGH), spectral karyotyping (SKY) and gene expression profiling.Results: After several passages we were able to induce B resistance in this HMCL. Final clone (OPM-2BR) demonstrate resistance to 2 × IC50 dose of B. While SKY and aCGH analysis demonstrated significant differences when compared with parent OPM-2WT (wild type) HMCL, gene expression profiling of the resistant and parental lines demonstrated significant upregulation in the expression of a number of ATP-binding cassette transporters. For example, the breast cancer resistance protein (ABCG2) is upregulated 4-fold in the resistant cell line compared to the parental cell line. This data suggests that drug efflux mediated by drug transporters represents one potential mechanism of resistance to B.Conclusion: Chronic in vitro B exposure results in induced resistance in HMCL-OPM-2BR. Resistant cell line demonstrates cytogenetic variability when compared to the parent cell line. Induction of resistance is stable and provides an important preclinical tool to investigate mechanism(s) of B resistance as well as new drug development for B resistant myeloma patients. Detailed analysis of this cell lines including therapeutic interventions investigating resistance reversal will be presented at the meeting.

SKY analysis of childhood neural tumors and cell lines demonstrates a susceptibility of aberrant chromosomes to further rearrangements

Malignant solid tumors are commonly characterized by a large number of complex structural and numerical chromosomal alterations, which often reflect the level of genomic instability and can be associated with disease progression. The aim of this study was to evaluate whether chromosomes that harbor primary aberrations have a higher susceptibility to accumulate further alterations. We used spectral karyotyping (SKY), to compare the individual chromosomal instability of two chromosome types: chromosomes that have a primary aberration and chromosomes without an aberration, in 13 primary childhood neural tumors and seven cell lines. We found that chromosomes that contain a primary aberration are significantly ( p-value < 0.001) more likely to gain further structural rearrangements or to undergo numerical changes (22.6%, 36 of 159 chromosomes) than chromosomes with no initial aberration (4.9%, 54 of 1099 chromosomes). These results are highly suggestive that aberrant chromosomes in solid tumors have a higher susceptibility to accumulate further rearrangements than “normal” chromosomes.

A case of acute myelogenous leukemia with MLL–AF10 fusion caused by insertion of 5′ MLL into 10p12, with concurrent 3′ MLL deletion

Structural abnormalities involving the mixed-lineage leukemia ( MLL) gene on 11q23 have been associated with hematological malignancies. The rearrangement of MLL occurs during translocations and insertions involving a variety of genes on the partner chromosome. We report a rare case of acute myelogenous leukemia (AML-M2) with 11q23 abnormalities. Fluorescence in situ hybridization (FISH) using a commercial dual-color MLL probe detected an atypical signal pattern: one fusion signal, two green signals smaller than those usually detected, and no orange signals. Spectral karyotyping (SKY) analysis indicated that one green signal was detected on the short arm of derivative chromosome 10, and the other green signal on the long arm of a derivative chromosome 11, on which no orange signal was detected. A long-distance inverse polymerase chain reaction (LDI-PCR) identified the fusion partner gene, in which intron 6 of MLL was fused with intron 8 of AF10 on 10p12 in the 5′ to 3′ direction. Our observations indicated that the MLL– AF10 fusion gene resulted from the insertion of part of the region that included the 5′ MLL insertion into 10p12; this was concurrent with the deletion of 3′ MLL.

Primary ovarian failure in a mentally retarded woman with a de novo unbalanced X;autosome translocation

To describe the clinical findings of a patient with a de novo unbalanced X;autosome translocation. Descriptive case study. Mackay Memorial Hospital, National Yang-Ming University, China Medical University, China Medical University Hospital, and Chung Shan Medical University. A 33-year-old woman with primary ovarian failure, moderate mental retardation, and mild phenotype of facial dysmorphism. None. Ultrasound, cytogenetic analysis, and laboratory studies of hormones. Laboratory studies revealed the following values: FSH level 72.48 mIU/mL (normal women: <40 mIU/mL), LH level 32.87 mIU/mL (normal women: <21 mIU/mL), and E(2) level <20 pg/mL (normal women up to 375 pg/mL), confirming primary ovarian failure. The PRL level was normal. Spectral karyotyping and G-banding cytogenetic analysis revealed a derivative X chromosome containing additional chromosomal material derived from the distal long arm of chromosome 5. The derived chromosome X had break points at Xq27.3 and 5q32, resulting in monosomy Xq (Xq27.3-->qter) and partial trisomy 5q (5q32-->qter). The patient's karyotype was 46,X,der(X)t(X;5)(q27.3;q32). The parental karyotypes were normal. This is the first report of partial monosomy Xq (Xq27.3-->qter) and partial trisomy 5q (5q32-->qter). The present case provides evidence for the occurrence of primary ovarian failure and mental retardation in females with unbalanced X;autosome translocations.