Sole Cytogenetic Abnormality Research Articles

Leukemogenic mechanisms and targets of a NUP98/HHEX fusion in acute myeloid leukemia

AbstractWe have studied a patient with acute myeloid leukemia (AML) and t(10;11)(q23;p15) as the sole cytogenetic abnormality. Molecular analysis revealed a translocation involving nucleoporin 98 (NUP98) fused to the DNA-binding domain of the hematopoietically expressed homeobox gene (HHEX). Expression of NUP98/HHEX in murine bone marrow cells leads to aberrant self-renewal and a block in normal differentiation that depends on the integrity of the NUP98 GFLG repeats and the HHEX homeodomain. Transplantation of bone marrow cells expressing NUP98/HHEX leads to transplantable acute leukemia characterized by extensive infiltration of leukemic blasts expressing myeloid markers (Gr1+) as well as markers of the B-cell lineage (B220+). A latency period of 9 months and its clonal character suggest that NUP98/HHEX is necessary but not sufficient for disease induction. Expression of EGFP-NUP98/HHEX fusions showed a highly similar nuclear localization pattern as for other NUP98/homeodomain fusions, such as NUP98/HOXA9. Comparative gene expression profiling in primary bone marrow cells provided evidence for the presence of common targets in cells expressing NUP98/HOXA9 or NUP98/HHEX. Some of these genes (Hoxa5, Hoxa9, Flt3) are deregulated in NUP98/HHEX-induced murine leukemia as well as in human blasts carrying this fusion and might represent bona fide therapeutic targets.

A BCR-JAK2 fusion gene as the result of a t(9;22)(p24;q11) in a patient with acute myeloid leukemia

We report the occurrence of a BCR-JAK2 fusion gene in a case of acute myeloid leukemia (AML) resulting from a t(9;22)(p24;q11) translocation as the sole cytogenetic abnormality. The BCR-JAK2 fusion gene has the same breakpoint in BCR as is found in the BCR/ABL p210. The chimeric gene is the result of a reciprocal translocation between chromosomes 9 and 22, which implies a double break on chromosome 9; this has allowed generating an in-frame fusion transcript. Previously, BCR-JAK2 rearrangement was observed in a single case with atypical chronic myelogenous leukemia (CML), but in that case the breakpoint in the BCR was different.

The leukemogenic CALM/AF10 fusion protein alters the subcellular localization of the lymphoid regulator Ikaros

The t(10;11)(p13;q14) translocation leads to the fusion of the CALM and AF10 genes. This translocation can be found as the sole cytogenetic abnormality in acute lymphoblastic leukemia, acute myeloid leukemia and in malignant lymphomas. The expression of CALM/AF10 in primary murine bone marrow cells results in the development of an aggressive leukemia in a murine bone marrow transplantation model. Using a yeast two-hybrid screen, we identified the lymphoid regulator Ikaros as an AF10 interacting protein. Interestingly, Ikaros is required for normal development of lymphocytes, and aberrant expression of Ikaros has been found in leukemia. In a murine model, the expression of a dominant negative isoform of Ikaros causes leukemias and lymphomas. The Ikaros interaction domain of AF10 was mapped to the leucine zipper domain of AF10, which is required for malignant transformation both by the CALM/AF10 and the MLL/AF10 fusion proteins. The interaction between AF10 and Ikaros was confirmed by GST pull down and co-immunoprecipitation. Coexpression of CALM/AF10 but not of AF10 alters the subcellular localization of Ikaros in murine fibroblasts. The transcriptional repressor activity of Ikaros is reduced by AF10. These results suggest that CALM/AF10 might interfere with normal Ikaros function, and thereby block lymphoid differentiation in CALM/AF10 positive leukemias.

Myelodysplastic syndrome with isolated deletion of chromosome 20q: an indolent disease with minimal morphological dysplasia and frequent thrombocytopenic presentation

The present study analysed the clinicopathological features of nine myelodysplastic syndrome (MDS) patients in which del(20q) was the sole cytogenetic abnormality and a control group of 17 adult patients with idiopathic thrombocytopenic purpura (ITP). Seven of nine del(20q) patients were thrombocytopenic and six of nine were mildly anaemic at presentation. There was no significant morphological dysplasia identified in the del(20q) group as compared with the ITP group. These results indicate that MDS with del(20q) commonly presents with thrombocytopenia and has minimal morphological dysplasia. Cytogenetic analysis on adult patients undergoing bone marrow sampling for thrombocytopenia may help avoid misdiagnosis of MDS with del(20q) as ITP.

Myxoinflammatory fibroblastic sarcoma showing t(2;6)(q31;p21.3) as a sole cytogenetic abnormality

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade sarcoma characterized by distinctive, large, and bizarre Reed–Sternberg–like cells associated with an intense inflammatory infiltrate. The biology of MIFS is still poorly understood, and only two previous cases had been studied cytogenetically. In the present case, analysis of MIFS in the foot of a 53-year-old man revealed the chromosome translocation t(2;6)(q31;p21.3) as the only cytogenetic abnormality. This finding is distinct from the two cases previously reported. Additional studies are needed to verify whether any of these chromosome rearrangements are involved recurrently in MIFS.

Chromosome 5q deletion: Specific diagnoses and cytogenetic details among 358 consecutive cases from a single institution

The purpose of this study was to define the spectrum of hematologic neoplasms and chromosomal breakpoints associated with del(5q); separate analyses were performed to account for prior cytotoxic treatment. A total of 358 consecutive del(5q) cases were identified; specific diagnoses included myelodysplastic syndrome (MDS; 53%), acute myeloid leukemia (AML; 22%), plasma cell proliferative disorder (PCPD; 9%), myeloproliferative disorder (MPD; 7%), acute lymphoblastic leukemia (ALL; 2%), PCPD with MDS (2%), MDS/MPD (2%), and malignant lymphoma (ML; 2%). The corresponding figures in the absence/presence of prior cytotoxic treatment ( n = 250/108) were 61%/34% for MDS, 24%/19% for AML, 4%/20% for PCPD, 6%/8% for MPD, 1%/4% for ALL, and 2%/4% for ML. del(5q) occurred as the sole cytogenetic abnormality in 88 cases (25%) including 76 without prior cytotoxic therapy. Among the latter, 82% had MDS, 8% AML, 5% MPD, 4% PCPD, and 1% ML. Chromosome 5 breakpoints included q13q33 in 49% of the cases, q15q33 in 22%, q22q33 in 8%, and q13 in 3% and their distribution was not affected by specific diagnosis or treatment history. del(5q)-associated lymphoid disorders featured a higher prevalence of previous cytotoxic therapy and smaller number del(5q)-positive metaphases, when compared to their counterparts with myeloid neoplasms. We conclude that del(5q), although most prevalent in MDS, is seen across the spectrum of myeloid disorders including MPD and its occurrence in lymphoid disorders might signify, for the most part, an occult myeloid clone.

Trisomy 21 as a Sole Acquired Abnormality in an Adult Omani Patient with CD7- and CD9-Positive Acute Myeloid Leukemia

We describe a case of acute myeloid leukemia (AML) in which trisomy 21 was the sole acquired cytogenetic abnormality. The immunophenotype showed positivity for CD7 and CD9 along with CD13, CD33, and CD34. The chromosomal analysis of bone marrow showed 47,XY +21 in all the metaphases analyzed. The constitutional karyotype was normal. The patient was an adult and did not have any features of Down's syndrome. The bone marrow morphology was AML-M2 as per the French-American-British (FAB) criteria. A final diagnosis of CD7- and CD9-positive AML-M2 was established with trisomy 21 as a sole cytogenetic abnormality. The patient responded remarkably well to chemotherapy and achieved complete clinical remission. This is the first case of CD7- and CD9-positive AML with trisomy 21 as a sole abnormality. A putative role for the co-expression of abnormal lymphoid markers in achieving quick remission is discussed.

An inv(16) in Ph-negative cells of a chronic myelogenous leukemia patient after imatinib treatment

Secondary chromosomal changes are known to develop in Philadelphia chromosome-negative (Ph−) cells of chronic myelogenous leukemia (CML) patients after treatment with imatinib mesylate, an ABL kinase inhibitor. We report here a novel case of a pericentric inversion of chromosome 16 as the sole cytogenetic abnormality in Ph− cells after treatment of Ph+ CML with imatinib.

Characterization of t(6;11)(p21;q12) in a renal‐cell carcinoma of an adult patient

Renal-cell carcinoma (RCC) constitutes a heterogeneous group of tumors with specific chromosome aberrations. Recently, a new small group of RCC, occurring in children and young adults, has been described as characterized by t(6;11)(p21;q12). It has been shown that this translocation results in the fusion of the 5' portion of the ALPHA gene (11q12) with the transcription factor gene TFEB (6p21). Herewith, we report the first complete cytogenetic and molecular characterization of a t(6;11)-positive RCC of an adult patient, a 54-year-old woman. The tumor was histologically defined as RCC with peculiar features and it was negative for epithelial markers and positive for melanocytic markers. Chromosome QFQ banding analysis of short-term cultured cells from the RCC showed t(6;11)(p21;q12) as the sole cytogenetic abnormality. The translocation was confirmed by FISH analysis. RT-PCR analysis, performed on total RNA isolated from both neoplastic and normal tissue samples, revealed an ALPHA-TFEB chimeric transcript in the tumor sample; sequencing of the RT-PCR product defined a novel TFEB gene breakpoint cluster region, broader than the one reported thus far. Western blot analysis showed a band at the expected size of wild-type TFEB in the neoplastic tissue compared to the normal sample, supporting that the fusion gene does not encode for a chimeric protein but it causes an upregulation of the wild-type TFEB. Our data contribute to define better this rare RCC type, which is typical not only of childhood but can also be found in adulthood.

Trisomy 8 as sole cytogenetic abnormality in a case of chronic lymphocytic leukemia

A 49-year-old man, who had been diagnosed with chronic lymphocytic leukemia (CLL) in 2002, had a normal karyotype in his bone marrow. Trisomy 8 was demonstrated in his peripheral blood in 2005. Fluorescence in situ hybridization using an LSI CEP 8 probe performed on the archival bone marrow specimen showed three hybridization signals in 40% of 200 interphase cells scored. This confirmed that the trisomy 8 abnormality was present in both the blood and bone marrow samples. Trisomy 8 as the sole chromosomal abnormality in CLL is a very rare finding. The prognostic significance of trisomy 8 in CLL remains to be seen.

Patterns of Clonal Evolution in Ph'-Positive Chronic Myelogenous Leukemia (CML) during Chronic Phase: Overall Incidence, Type, Multiplicity, Development Time, Effect on Subsequent Genetic Instability, Sokal Risk, Type of bcr/abl Transcript and Hematological Evolution.

Fifty-two kariotypic abnormalities additional to Philadelphia chromosome (Ph') were documented at the time of diagnosis or during the course of the disease in 114 CML patients. Five were evaluated only once at the time of diagnosis, while 109 were repeatedly studied overtime during a median period of 138 (1–275)months. A clonal evolution was already present at diagnosis (early clonal evolution) in 12, while in 23 patients, it was documented in the course of the disease (late clonal evolution). Simultaneous appearence of multiple chromosome abnormalities (4/12 and 4/23) and a tendency to acquire further alterations (5/12 and 2/23, respectively) were associate with both early and late secondary clones. Partial or complete chromosome losses (-1, -6, 6q-, 7p-, 11q-, 12p-, -14, -16, -17,-18, -21) other than -Y (11 events), + 8 (9) and loss of Y chromosome (8) were the most commonly cytogenetic abnormalities, irrespective of the time of their occurrence. Translocations other than Ph' (5 events), complex Ph' translocations (5), duplication of Ph' (5), single iso(Ph') (4), duplication of iso(Ph') (1) or iso17q (2) were found with a decreasing frequency. The type of kariotypic alteration varied with the time of onset. In fact, partial or complete chromosome monosomies and duplication of iso(Ph') never represented early, but only late events. Duplication of Ph' was a late (4/5) rather than an early event (1/5). Similarly, the presence of the iso(Ph') was documented either in early or late clonal evolution in 1 and 3 instances respectively. Furthermore, +8 developed several months after diagnosis in all, but 2 cases. Complex Ph' translocations or loss of Y chromosome do not correlate with any specific phase of the leukemic course. Cytogenetic abnormalities neither correlated with Sokal risk nor with the type of break-points (b3a2,b2a2) documented at diagnosis. However all 3 clones bearing p230 chimeric protein showed early cytogenetic evolution. Secondary clones seem to have different impact on disease history. The occurrence of partial or complete deletions, the iso17q and the late, but not early, loss of Y chromosome were all predictive of a rapid disease progression. Early secondary clones with additional translocations had no effect on the chronic behaviour of the disease, while such clones were associated with a rapid progression (2/3) to blastic phase when they occurred during the course of disease. The presence of +8 as the sole cytogenetic abnormality and complex translocations, irrespective of the time of their onset, did not correlate with leukemia evolution. Finally,simple Ph' duplication of or single and double iso(Ph'), when not associated with other cytogenetic abnormalities, did not correlate with an aggressive course, even if it can be assumed that these cytogenetic events are responsible for an increased concentration of the p210 oncoprotein. In conclusion, regardless of whether bcr/abl has a direct or an indirect role in promoting genomic instability, in our cohort of CML patients additional non random chromosomal abnormalities frequently characterize both early and late phase of the disease and some of them may represent crucial steps in development and progression of leukemia.

Deletion (21)(q21.2q22.12) as a sole clonal cytogenetic abnormality in a lobular capillary hemangioma of the nasal cavity

A clonal deletion (21)(q21.2q22.12) was detected as a sole cytogenetic abnormality in a lobular capillary hemangioma (pyogenic granuloma) of the nasal cavity. This finding supports a neoplastic, rather than reactive, nature for this lesion. To our knowledge, these rare lesions have not previously been studied by cytogenetics.

Polysomy 13 in a canine prostate carcinoma underlining its significance in the development of prostate cancer

The dog is a well-accepted model for prostate cancer in man because of the striking similarities between both species with respect to the clinical course of the disease as well as to its similar histopathology. Cytogenetic investigations of human prostate cancers has revealed the frequent occurrence of trisomies 7, 8, and 17. In this report, we present a case of prostate carcinoma in a dog characterized by polysomy 13 as the sole cytogenetic abnormality. Along with the known homology between canine chromosome 13 and human chromosome 8 these findings suggest that a homologous area on both chromosomes plays a crucial role in subsets of prostate cancer in both species.

Unusual course of an acute lymphoblastic leukemia case with i(9q) as a sole cytogenetic abnormality

Chromosomal changes are necessary in determining the classification, prognosis and using the appropriate therapeutic regimen in acute leukemia. Isochromosomes are uncommon chromosome aberations in childhood acute lymphoblastic leukemia (ALL) and the effect of i(9q) is not well established. We present an 8-year-old male case of pre-B ALL who has an unusual course at diagnosis. He was hospitalized three times in three different hospitals and blastic cells disappeared after the first hospitalization following blood transfusion without chemotherapy. In the following two hospitalizations no blastic cell was observed and transfused with a pack of erythrocyte suspension each time. In the fourth hospitalization, bone marrow aspiration revealed L1 type of lymphoid blast cell infiltration. The remission was achieved on the 15th day of the induction therapy and he has been in remission for the last 6 months. This unusual presentation and early remission achieved by induction therapy in this patient may support the literature that isochromosome 9q has a favourable outcome in childhood ALL.

T(3;21)(q26;q22) in myeloid leukemia

The t(3;21)(q26;q22) translocation is associated with myeloid leukemias and results in a chimeric oncoprotein containing AML1/RUNX1 variably fused to EAP, MDS1, and/or EVI1. The current study describes what to the authors' knowledge is the first large case series reported to date of 26 t(3;21)(q26;q22)-associated leukemias, in which 24 cases arose after chemotherapy. Conventional G-band karyotyping and flow cytometry immunophenotyping were performed. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to detect fusion transcripts between AML1 and EAP, MDS1, or EVI1, followed by DNA sequencing. In all 16 patients with chronic myeloproliferative disorders, including 14 with chronic myelogenous leukemia (CML), the occurrence of t(3;21) heralded myeloid blast transformation. Fifteen (93%) patients had been previously treated with hydroxyurea. Eight patients with chronic myeloproliferative disorders (CMPD) were found to have t(3;21) with t(9;22) as the sole cytogenetic abnormality; in 5 other patients this was accompanied by trisomy 8. Among 10 cases of t(3;21)-associated acute myeloid leukemia, 8 were secondary tumors after chemotherapy for other neoplasms that had been treated with regimens including fludarabine and 5-fluorouracil in 3 patients each and etoposide in 2 patients. The immunophenotype of the blasts in all 22 tested cases was similar, with uniform expression of myeloid markers and CD34 and variable expression of CD7 and CD9, but minimal morphological myeloid maturation. Dysplastic micromegakaryocytes and bone marrow fibrosis were observed predominantly in CMPD cases. RT-PCR followed by DNA sequencing showed that the AML1-/MDS1-/EVI1 (AME) fusion transcript was detected in all 5 cases assessed. Among the patients with CMPD, 8 died of disease (at a median of 6.5 mos) and 5 achieved disease remission with bone marrow transplantation. Among patients with acute myeloid leukemia/myelodysplastic syndrome, 7 died of disease (at a median of 2 mos) and 2 had persistent leukemia with short follow-up. Activation of AME through t(3;21) defines a highly aggressive, therapy-related leukemic blast syndrome. Prior treatment with hydroxyurea or other antimetabolites is implicated as a contributory cause.

Hematological Responses to Megesterol Acetate in Patients with Myelodysplastic Syndrome Involving an Abnormal Chromosome 6.

The presence of an abnormal chromosome (chr) 6 often confers a poor prognosis on patients with myelodysplastic syndrome (MDS), particularly therapy related-MDS (t-MDS). We report two patients with MDS and an abnormal chr 6 who achieved significant improvements in their hematological parameters after being subjected to megesterol actetate at 80mg/d; one patient achieved a complete cytogenetic remission, albeit based on a limited study. The first patient, a 73 y female presented with a monocytopenia (thrombocytopenia; 43K/dl), a bone marrow consistent with MDS, blasts 6% and an abnormal chr 6 (sole cytogenetic abnormality) in February 2003. In July 2005 she was asymptomatic with a platelet count of 353K/dl and is due to have cytogenetics shortly. The second patient, a 72 y female presented in December 2004 with trilineage cytopenias, a bone marrow consistent with MDS and a complex karyotype, including an abnormal chr 2, 5, 6, 7 & 16. She had had a history of primary (essential) thrombocythemia of 25 y duration and had received P 32 and intermittent courses of hydroxyurea and was on hydroxyurea at the penultimate presentation and probably had t-MDS. This therapy was promptly discontinued and megesteral acetate commenced at 80mg/d. In July 2005 her hematological parameters had improved significantly (W 3.3K/dl; Hb 11.3g/dl;Platelets 135K/dl); her bone marrow remained hypercellular with reticulin fibrosis and cytogenetic studies revealed a 46XX kayotype in a limited sample. At the time of this report, both patients remain well on megesterol acetate with normal or near normal hematological parameters. MDS is a heterogeneous stem cell disorder and hematological and possible cytogenetic responses are noteworthy. The patient with the sole abnormal chr 6 has remained in hematological remission for over 18 months; the second patient with the complex karyotype is also, remarkably, maintaining near normal hematological parameters. We speculate that megesterol acetate, a relatively inexpensive progestational agent with a defined palce in the management of malignancy-related anorexia may have a role in selected patients with MDS. Updated observations and suggested hypotheses will be presented.

Early and Sustained Response to Azacytidine in High-Risk MDS Patients with Monosomy 7 Correlates with Increased Apoptosis and Not CDKN2B Demethylation.

Disease progression in MDS is associated with CDKN2B (encodes p15INK4b) promoter methylation and an inhibition of apoptosis. We therefore studied predominantly high-risk MDS patients treated with azacitidine in order to determine whether clinical responses correlated with changes in CDKN2B promoter methylation and bone marrow apoptosis. In all, 24 patients (19 male) with a median age of 66.7 years were treated with azacitidine (75mg/m2/day x 7 days, every 28 days). Patients were FAB RA (n=2), RAEB (n=7), RAEB-T (n=13) and AML (n=2) with 18/24 having an IPSS risk of Int-2 or High. Cytogenetic abnormalities were present in 17 patients (4 patients with monosomy 7; 1 with der(7) as the sole cytogenetic abnormality and 1 as part of a complex karyotype; 4 with trisomy 8; 1 with 11q abnormalities; 1 with 5q-, 1 with 20q, 1 with iso 17p; and the remaining -y or misc). A median of 5 courses of azacitidine was administered (range: 1–13). Complete remission was achieved in 6 patients: 2 with trisomy 8, 3 with monosomy 7, and 1 with der(7). Haematological Improvement (HI) in Platelets occurred in 6 patients, HI-E in 2 patients, and HI-N in 3 patients. Five patients had a reduction in blast percentage. Importantly, even in complete cytogenetic remission bone marrow dysplasia persisted. All patients with monosomy 7/der(7) are in complete remission (median follow up of 10 months) whereas those with trisomy 8 relapsed their response at 2 and 5 months. CDKN2B promoter methylation in patients pre-treatment and at hematological remission was studied by bisulfite genomic sequencing (region: −263 to +243). There was no difference in CDKN2B methylation in CD34+ or CD33+ cells of responders and non-responders (both had low level, heterogeneous methylation patterns). However, CDKN2B was unmethylated in lymphocytes of responders and methylated in non-responders. Demethylation was not evident following treatment. Baseline bone marrow mononuclear cell apoptosis of 16 patients (12 RAEB, 2 RAEB T, 2 AML) analysed by PI/Annexin V staining (6% mean, 4.06% median); was not significantly different from normal controls (2%: mean, 0.77%; median, n=3) (2 sample T-test 0.103). From 12 treated patients, 8 patients responding to azacitidine (6 CR; 2 blast reduction with HI-E major and HI-N major, regardless of cytogenetic subtype), the mean apoptosis at the time of remission (11.61% mean; 9% median) was significantly higher than the mean apoptosis of 1.82% (median, 1.095%) in 4 non- responders (2 sample t-test p = 0.006). Azacitidine treatment induced sustained responses in all patients with monosomy 7, in whom the CDKN2B promoter is unmethylated. We propose that increased bone marrow apoptosis disrupts the leukaemic clone and leads to disease regression to an earlier stage.

A der(14)t(1;14)(q12;p11) in chronic myelomonocytic leukemia

Duplication of the long arm of chromosome 1 (1q) is widely reported in human neoplasia, including the myelodysplastic syndromes (MDS). So far, it has not been described as a single aberration in the chronic myelomonocytic leukemia (CMML), a subtype of MDS. Rather, trisomy 1q was always a part of complex chromosome changes affecting the subtypes of MDS other than CMML. We report on a patient with CMML with an unbalanced translocation of the entire 1q onto the short arm of chromosome 14 as a sole cytogenetic abnormality. Fluorescence in situ hybridization (FISH) analysis with an α-satellite probe for the paracentric region of the long arm of chromosome 1 confirmed the presence of trisomy 1q in a derivative chromosome, der(14)t(1;14)(q12;p11). The discrepant results between the metaphase cytogenetics (100% abnormal) and interphase cytogenetic (71% nuclei with 3 signals) suggest that trisomy 1q, even in the absence of additional cytogenetic changes, has a sufficient leukemogenic potential to confer a proliferative advantage on hematopoietic cells committed to monocyte stemline both in vitro and in vivo. The literature data on partial and complete trisomy 1q in CMML is reviewed.

Trisomy 8 as the sole cytogenetic abnormality in a case of extraskeletal mesenchymal chondrosarcoma

Mesenchymal chondrosarcoma is a rare malignant tumor that comprises about 3–10% of all sarcomas. Reports of cytogenetic studies of mesenchymal chondrosarcoma are limited and no consistent cytogenetic abnormality has surfaced. Some mesenchymal chondrosarcomas have a t(11;22) translocation suggesting a relationship with the PNET/Ewing tumor family. We report what to our knowledge is the first case of trisomy 8 as the sole cytogenetic abnormality in a mesenchymal chondrosarcoma.

A clonal reciprocal t(2;7)(p13;p13) in plantar fibromatosis

Cytogenetic reports of plantar fibromatosis are rare, and to our knowledge no clonal reciprocal translocations have been reported in these lesions. Reciprocal chromosome translocations have been identified in a number of solid tumors and in some cases have helped identify genes involved in their pathogenesis. We report a case of plantar fibromatosis with the novel finding of a t(2;7)(p13;p13) balanced reciprocal translocation as the sole cytogenetic abnormality.