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This study reports 10 patients with hematological malignances with t(20;21)(q11;q11) resulting from del(20q) (for example, der(20)del(20)(q11q13)t(20;21)(q11;q11) and der(21)t(20;21)(q11;q11)) and described their clinical features and the possible prognostic significance of this abnormality. The t(20;21)(q11;q11) was a rare but recurrent abnormality secondary to del(20q) besides i(20q-). The frequency of der(20)del(20)(q11q13)t(20;21)(q11;q11) among our patients with del(20q) was 2.4%. It was considered that the 20q deletion preceded translocation with chromosome 21. This abnormality is often cryptic, occurs predominantly in older men and is observed most often in myelodysplastic syndromes. Patients with this abnormality have an unfavorable prognosis, similar to patients with i(20q-). The molecular consequences of der(20)del(20)(q11q13)t(20;21)(q11;q11) may be different from patients with i(20q-). To the best of our knowledge this is the largest dataset published to date., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Deletion of the long arm of chromosome 20 is a common abnormality underlying hematological malignancy. We analyzed 21 patients with hematologic diseases confirmed to carry the del(20q) by conventional cytogenetics and fluorescence in situ hybridization using microarray comparative genomic hybridization (aCGH). Seventeen patients were positive for del(20q), but this deletion was not detected in four patients. All deletions detected were interstitial of which continuous deletions were seen in 12 patients and discrete deletions in five. Three commonly deleted regions (CDRs) and two commonly retained regions (CRRs) were defined: CDR1 spanning 3.05Mb (34560497-37608229) within 20q11.23, CDR2 spanning 1.76Mb (37851501-39615698) within 20q12, CDR3 spanning 116Kb (48120412-48236791) within 20q13.13, CRR1 spanning 1.1Mb (29374726-30428250) within 20q11.21, and CRR2 spanning 2.5Mb (60484668-62963548) within 20q13.33. Duplications of retained regions (20q11.21) were found in five cases with similar erythroid hyperplasia (2 M6, 3 MDS). Moreover, duplication of 20p13-p11.21 was also found in two cases with M6. Using the CDRs and CRRs, we identified the candidate genes we searched for using the UCSC Genome Browser. Our data suggest that aCGH analysis is useful for more precisely defining breakpoints on 20q. Further work is required to identify candidate pathogenic genes within these CDRs and CRRs.

The clinical and hematological characteristics and the prognostic significance of del(20q) were investigated in a consecutive series of 213 myeloid malignancies. In the analyses, the cases were divided into three subgroups according to diagnosis or four subgroups according to cytogenetic data. Patients in the myeloproliferative neoplasms subgroup had high WBCs and platelet counts at initial diagnosis. The del(20q) occurred predominantly in older men. Sole del(20q) was observed most often in myelodysplastic syndromes, while del(20q) as a part of complex karyotypes was observed predominantly in acute myeloid leukemia. The most frequent additional abnormalities accompanying del(20q) were -5/del(5q), -7/del(7q) and +8; t(20;21)(q11;q11) and double del(20q) were two rare but recurrent abnormalities secondary to del(20q). In all types of diseases, patients with a sole del(20q) had a favorable prognosis. The presence of any additional abnormality with del(20q) had an unfavorable outcome. Patients with i(20q) had an unfavorable prognosis. Patients with the minor del(20q) clone had a better median survival than those with the major del(20q) clone., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Secondary pulmonary alveolar proteinosis (PAP) is a rare lung disease that has been reported in 13 cases of myelodysplastic syndromes (MDS). A dicentric isochromosome of deleted chromosome 20q, idic(20q-), is a newly recognized rare, but recurrent, cytogenetic anomaly that has been described in 28 cases of MDS. Recently, we encountered an interesting MDS patient with idic(20q-) and secondary PAP. At presentation, she was a 40-year-old woman with pancytopenia and dysplasia involving 2 cell lineages that were compatible with refractory cytopenia with multilineage dysplasia. A chromosome analysis of bone marrow cells using the R-banding technique revealed a karyotype of 46,XX,-20 and +a small metacentric marker chromosome. Fluorescence in situ hybridization demonstrated this marker chromosome to be idic(20q-). Three years after presentation, her disease was complicated by secondary PAP that was confirmed by chest computed tomographic scans and a thoracoscopic lung biopsy, revealing the characteristic periodic acid Schiff stain-positive materials filling the alveoli. The patient subsequently died of respiratory failure 45 months after diagnosis. To our knowledge, this is the first MDS patient with idic(20q-) and secondary PAP to be reported in the literature. Moreover, this patient is also the 29th MDS case with idic(20q-)., (Copyright (c) 2009 S. Karger AG, Basel.)

The cytogenetic anomaly der(20)del(20)(q11.2q13.3)idic(20)(p11), or idic(20q-) in short form, has been reported in 13 cases of myelodysplastic syndrome, one case of chronic myelomonocytic leukemia, and one case of acute myeloid leukemia since 2004. To our knowledge, it has not previously been described in lymphoid diseases. Here we report the cases of two patients with B-cell acute lymphocytic leukemia (ALL) having a novel idic(20q-). One was a 34-year-old man with B-cell ALL whose leukemic cells at presentation had a karyotype of 45,XY,dic(9;20)(p11;q11.2); at relapse, a small marker chromosome was found coexisting with the dic(9;20). The other was a 39-year-old woman with Ph-positive B-cell-ALL whose leukemic cells contained both t(9;22)(q34;q11.2) and a small marker chromosome. A series of FISH analyses using the appropriate probes revealed the small marker chromosome in both patients to be an idic(20q-), confirming the dic(9;20)(p11;q11.2) in one case and revealing a BCR/ABL fusion gene in the other. One patient achieved complete remission but relapsed; the other did not achieve complete remission. Both patients died with a short survival time, despite receiving intensive chemotherapy. These two cases show that idic(20q-) can appear not only in myeloid diseases but also in lymphoid diseases.

Fluorescence in situ hybridization (FISH) analyses were performed on six of seven patients who had been reported in 2004 to have an i(20q-) anomaly expressed as ider(20)(q10)del(20)(q11q13). The i(20q-) was investigated with a series of probes: a centromere-specific probe for chromosome 20, two paint probes for 20p and 20q, and a panel of locus-specific probes prepared from BAC/PAC clones mapped to 20p. The results showed that: (1) i(20q-) was a dicentric chromosome; (2) both of its arms comprised a deleted 20q and a small part of 20p near the centromere of chromosome 20; and (3) the breakpoints and reunion sites of i(20q-) differed, residing in the region 20p11.21-20p11.22 delineated by BAC/PAC clones RP11-96L6 and RP13-401N8. Thus, i(20q-) could be more precisely described as a der(20)del(20)(q11q13)idic(20)(p11)., ((c) 2006 Wiley-Liss, Inc.)

We report on seven patients with myeloid diseases characterized by i(20q-) anomaly. Four patients were male and three were female, their median age was 57 years. The diagnosis at presentation was myelodysplastic syndrome in six patients, acute myeloid leukaemia in one patient. Four died but three survived and remain anaemic. The survivals were 6 months for patient 1, 7 months for patient 2, 17 d for patient 4 and 28 d for patient 5. Chromosome specimens were prepared by direct and/or short-term culture of bone marrow cells. Karyotype analysis was performed by R- and G-banding technique, which showed that one of the normal chromosomes 20 was substituted by one or two small metacentric chromosomes in all seven patients. The karyotype was ider(20)(q10)del(20)(q11q13), i.e. i(20q-) in six patients by dual-colour fluorescence in situ hybridization assay using two probes (a subtelomeric probe for 20q and an unique probe for 20q12). As far as we know, this anomaly has not been reported previously. Thus, we consider that i(20q-) is a novel and rare recurrent chromosomal abnormality that is specifically associated with myeloid diseases and may indicate a poor prognosis.

A rare chromosomal translocation, (11;20)(p15;q11), was detected in a 29-year-old male patient diagnosed with acute monocytic leukemia (AMoL) according to the French-American-British classification criteria. Whole chromosome painting analysis with paints for chromosomes 11 and 20 confirmed the result of conventional cytogenetic analysis. Reverse transcriptase polymerase chain reaction revealed the NUP98-TOP1 fusion transcript. To our knowledge, this is the second report of the translocation involving NUP98 and TOP1 genes in AMoL. On reviewing the literature, we suggest that t(11;20)(p15q11) is associated with myelocytic disorders rather than lymphocytic proliferative diseases.