Fluorescence in situ hybridization analysis of whole-arm 7;12 translocations in hematologic malignancies

Whole-arm translocation of der(5;17)(p10;q10) with concurrent TP53 mutations in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS): A unique molecular-cytogenetic subgroup

Der(5;17)(p10;q10) is a recurrent but rare aberration reported in myeloid neoplasms (MNs). We report 48 such patients including 19 acute myeloid leukemia (AML) and 29 myelodysplastic syndrome (MDS), to characterize their clinicopathological features. There were 29 men and 19 women, with a median age of 61 years (range, 18-80). 62.5% patients had therapy-related diseases (t-MNs), 70.8% had multilineage dysplasia and 83.3% showed complex karyotypes. In 39 patients tested, FLT3, NPM1, CEBPA, KIT were all wild type and NRAS, KRAS, IDH1, APC, TET2 mutations were detected in single case(s) respectively. TP53 mutations were identified in 8 of 10 cases (80%) tested. Median disease-free survival (DFS) and overall survival (OS) were 3 and 10 months, respectively and did not differ between AML or MDS cases, or between de novo versus therapy-related cases, or between the groups with or without complex karyotypes. In 19 patients who achieved complete remission after chemotherapy, and in 9 patients who underwent stem cell transplantation, the OS was better (14 and 17.5 months, P = 0.0128 and P = 0.0086, respectively). The der(5;17)(p10;q10) represents a unique molecular-cytogenetic subgroup in t-MNs and, associated with complex karyotypes. TP53 inactivation, resulting from 17p deletion coupled with TP53 mutation, likely contributes to the poor clinical outcome of these patients.

der(5;17)(p10;q10) is a recurrent but rare whole-arm translocation in patients with hematological neoplasms: a report of three cases

We report the cases of 3 patients with hematological malignancies and complex karyotypes involving der(5; 17) (p10;q10), which results in the loss of 5q and 17p. Although deletions of 5q and 17p are recurrent abnormalities in hematological disease, only about 20 cases harboring der(5; 17) (p10;q10) have been reported. We address the tumorigenesis and morphological characteristics of hematological malignancies involving der(5; 17)(p10;q10), along with a review of the literature.

Derivative (5;19)(p10;q10): a rare but recurrent whole-arm translocation in acute myeloid leukemia

A previous study of cases of myelodysplastic syndrome harboring der(5;19)(p10;q10) found that they displayed common characteristics including predominance in elderly men, dysplasia involving three hematopoietic lineages and CD7 expression in blasts. However, the whole-arm translocation der(5;19)(p10;q10) has not been fully analyzed because of its rarity. In this study we used flow cytometry to evaluate the immunophenotype of two patients' bone marrow mononuclear cells. Both patients had involved der(5;19)(p10;q10) in their karyotype analyzed by standard G-banding technique. Both patients had the CD7+ and CD41+ phenotype, and the CD41 positivity suggested that the myeloid neoplasms involving der(5;19)(p10;q10) were of megakaryoblastic origin. The der(5;19)(p10;q10) abnormality is associated with unique characteristics of the immunophenotype. We address the clinical, immunophenotypic and morphological aspects of hematological malignancy involving der(5;19)(p10;q10), along with a review of the literature.

A novel unbalanced whole-arm translocation der(3;10)(q10;q10) in acute monocytic leukemia

We describe here a novel unbalanced whole-arm translocation der(3;10)(q10;q10) in a 58-year-old man with acute monocytic leukemia. Bone marrow was massively infiltrated with 22.2% monoblasts, 55.4% promonocytes, and 5.6% monocytes. These monocytic cells were positive for myeloperoxidase and alpha-naphthyl butyrate esterase staining. Surface marker analysis revealed that they were positive for CD4, CD13, CD33, CD56, and HLA-DR but negative for CD14 and CD34. Chromosome analysis of the bone marrow cells showed 46,XY,+3,der(3;10)(q10;q10)[18]/46,XY[2]. Spectral karyotyping confirmed der(3;10)(q10;q10) as a sole structural abnormality. By acquisition of a normal chromosome 3 but not a chromosome 10, the der(3;10)(q10;q10) resulted in trisomy 3q and monosomy 10p. The +3,der(3;10)(q10;q10) is thought to play a crucial role in the pathogenesis of acute monocytic leukemia because of the gain of 3q or the loss of 10p.

THE APPLICATION OF MICROARRAY BASED COMPARATIVE GENOMIC HYBRIDIZATION IN PRENATAL DIAGNOSIS

Microscopic forms of karyotyping and cytogenetic analysis by means of G-banded chromosome analysis and rapid FISH (fluorescencein situhybridization) on amniotic fluids or chorionic villus samples are at present regarded as the gold standard for prenatal diagnosis of chromosomal anomalies. Nevertheless, up to now the resolution of conventional chromosomal analysis was limited to approximately 4–5 Mb and not smaller than 2 Mb for FISH. Thus numerous common microdeletion syndromes are not detectable by conventional karyotyping. In addition, prenatal cells yield lower band resolution by conventional karyotyping than peripheral white blood cells making detection of subtle abnormalities even more difficult. With the advances in molecular-based techniques, a collaborative effort has led to the standardized method for detection of a restricted set of common chromosomal aneuploidies and microdeletion syndromes such as Down's syndrome, DiGeorge or Angelman syndrome either by rapid FISH and/or quantitative fluorescent PCR (QF-PCR). Even if the presence of particular phenotypic features of microdeletion or duplication syndromes may direct the use of syndrome-specific FISH tests in the postnatal period, syndrome-specific FISH analysis still has a very limited potential and application in the prenatal period due to the limitation in prenatal morphological or imaging diagnosis of many of the syndromes.

Loss of 17p is a major consequence of whole-arm chromosome translocations in hematologic malignancies

To ascertain the distribution of whole-arm translocations (WATs) and their consequential imbalances in hematologic malignancies, we analyzed the imbalances related to chromosomes involved in clonal, acquired WATs in 140 consecutive tumors with WATs and near-diploid karyotypes. Tumors for analysis were obtained from a survey of the cytogenetic database in the Department of Medical Genetics, Henry Ford Health System, Detroit, MI. Of the 140 tumors, 9 had balanced WATs; the remaining 131 had WATs that rarely or never involved chromosome X, Y, 2, 3, 4, 6, 19, or 20. Chromosome arms were lost more often than they were gained, and short arms were lost more often than long arms, except for chromosomes 7 and 16 (more long arms lost than short) and chromosome 11 (both arms equally lost). The long arm of chromosome 1 was the only arm gained with substantial frequency, in 26% of tumors. Of WATs that resulted in gain of 1q, short arm of chromosome 7 and acrocentric long arms were involved in 47 and 24%, respectively. Acrocentric chromosomes were involved in acquired WATs in 45% of tumors (the D-group acrocentrics more than the G-group), and were more likely to be involved in non-Robertsonian than Robertsonian translocations (P < 0.001, normal test). Loss of 17p was the most common short-arm loss (23% of tumors) and often occurred as part of complex karyotypes suggestive of disease progression. The present findings show that acquired whole-arm chromosome translocations in hematologic malignancies are nonrandom, commonly involve acrocentric chromosomes, and often result in loss of 17p, which is often associated with advanced disease and poor prognosis in a wide spectrum of hematologic malignancies.

Isodicentric Philadelphia chromosome in acute lymphoblastic leukemia with der(7;12)(q10;q10)

We describe here the first case of acute lymphoblastic leukemia (ALL) with an isodicentric Philadelphia [idic(Ph)] chromosome. A 35-year-old man was diagnosed as ALL because of the infiltration of CD10(+)CD19(+)CD33(+)CD34(+) lymphoblasts in the bone marrow and the expression of p190-type BCR/ABL fusion transcript. Chromosome analysis showed 45,XY,der(7;12)(q10;q10),der(9)t(9;22)(q34;q11),idic der(22)t(9;22)(q34;q11). The idic(Ph) chromosome was spindle-shaped and supposed to be formed by two Ph chromosomes joined at their q terminals, whereas idic(Ph) chromosomes in chronic myelogenous leukemia (CML) have been shown to be fused at the satellite regions of p arms. The results indicate that the structure of idic(Ph) chromosomes appears to be different between ALL and CML. The patient did not respond to any chemotherapy and could not achieve remission. This chromosome aberration in ALL may suggest poor prognosis as observed in some cases of CML. Furthermore, considering other three reported cases, der(7;12)(q10;q10) may be one of the recurrent translocations in ALL.

Dicentric chromosome 3 associated with binucleated lymphocytes in atypical B-cell chronic lymphoproliferative disorder

Binucleated lymphocytes on blood smear are known in PPBL characterized by stable and polyclonal lymphocytosis, polyclonal increase of serum IgM, HLA DR7 and strong correlation with additional i(3q) and premature chromosome condensation. In this disorder some reports of clonal Ig rearrangement suggest a follow up of these patients with immunological and genetic studies. Binucleated lymphocytes are rarely described in other clonal B-CLPD as B-CLL or marginal zone B-cell lymphoma (MZL). Chromosome 3 abnormality is never described in B-CLL but trisomy 3 represents the most consistent abnormality characterizing the MZL. We report in a man without previous medical history an unusual B-CLPD with monoclonal lymphocytosis CD5-, characteristic cytology (particularly binucleated lymphocytes) and chromosomic abnormality as dicentric chromosome 3 never previously described in B-CLPD. In this case lymphocytosis is persistent and stable over 24 months, cytologic immunologic and chromosomic abnormalities are unchanged. We discuss the nosologic place of this atypical B-CLPD closely related to PPBL and MZL with at the moment, after 24 months, a quiet evolution that imply nevertheless a careful follow up with regular cytologic, immunological and genetic studies to clarify the issue.

A novel dic(1;10) in a patient with myelodysplastic syndrome

We report on a case of refractory anemia with trilineage dysplasia and an unbalanced der(1)t(1;10) that resulted in trisomy of the long arm of chromosome 1 (1q) and monosomy of the short arm of chromosome 10 (10p). Fluorescence in situ hybridization showed that the rearranged chromosome contained the centromeres of both chromosomes 1 and 10, leading to a dic(1;10). To our knowledge, a dicentric chromosome involving chromosomes 1 and 10 has never been described in hematological malignancies.

Increased frequency of dicentric chromosomes in therapy-related MDS and AML compared to de novo disease is significantly related to previous treatment with alkylating agents and suggests a specific susceptibility to chromosome breakage at the centromere

Dicentric chromosomes are observed in many malignant diseases including myelodysplasia (MDS) and acute myeloid leukemia (AML) and have often been observed in a subset of these diseases, namely therapy-related MDS (t-MDS) and AML (t-AML). Using fluorescence in situ hybridization (FISH) with centromere-specific probes, we investigated the frequency and type of dicentric chromosomes in 180 consecutive patients with t-MDS and t-AML and in 231 consecutive patients with de novo MDS and AML, whose karyotypes had been studied previously by conventional G-banding. Twenty-seven out of 180 patients with t-MDS or t-AML presented dicentric chromosomes compared to only seven out of 231 patients with de novo disease (P = 0.00003). A dic(1q;7p) was observed in 10 cases, a dic(5p;17q) was observed in six cases, whereas various isodicentric chromosomes were observed in six cases. Excluding these six cases with isodicentrics, all 25 patients with dicentric chromosomes had involvement of at least one of the chromosome arms 1q, 5p, or 7p resulting in monosomy for 5q or 7q, and/or trisomy for 1q. Patients with dicentric chromosomes presented significantly more often as t-MDS compared to patients without dicentrics (P = 0.046), and the presence of a dicentric chromosome was significantly related to previous therapy with alkylating agents (P = 0.026). Thus, only one out of 27 patients with a dicentric chromosome had not previously received an alkylating agent. A specific susceptibility to breakage at the centromere after exposure to alkylating agents is suggested and may explain the frequent loss of whole chromosomes, in particular chromosomes 5 and 7 in t-MDS and t-AML, if the breaks are not followed by rejoining. Leukemia (2000) 14, 105-111.

Cytogenetic changes in benign proliferative and nonproliferative lesions of the breast

Cytogenetic analysis of short-term cultures from 69 cases of fibrocystic breast changes and 10 samples of normal mammary tissue revealed clonal chromosome aberrations in six fibrocystic lesions. All the histologically normal tissue samples had a normal karyotype. The frequency of cytogenetically abnormal cases seems to correlate with the degree of histopathologic changes of the tissue; nonproliferative lesions may have clonal chromosome alterations, but at a low frequency. Whether women with karyotypically altered fibrocystic "disease" have a higher risk of developing invasive breast cancer, compared with women without microscopically visible genetic anomalies in fibrocystic lesions, remains unknown.

Childhood myeloproliferative disorders

Disorders classified as paediatric myeloproliferative disorders (MPD), such as juvenile chronic myeloid leukaemia (JCML), and as paediatric myelodysplastic syndrome (MDS), are essentially diseases characterized by abnormal myeloproliferation and they share similar genetic events on chromosome 7. As such, the abnormalities of increased myeloproliferation in childhood (AIMC) should be considered under the same heading. Constitutional and other genetic factors play an essential role in children and include the NF1 gene, whereas toxic exposure is of greater importance in adults. The most common cytogenetic alteration is that of monosomy or deletion of the long arm of chromosome 7. Critical regions have been identified and mapped by fluorescence in situ hybridization (FISH). It appears that the similar critical regions on chromosome 7 are involved, and suggests that these regions may contain genes important in the pathogenesis of AIMC.

Complex structural involvement of chromosome 7 in primary myelodysplastic syndromes determined by fluorescence in situ hybridization

Cytogenetic analysis of 72 consecutive de novo myelodysplastic syndrome patients revealed monosomy 7 in 12 cases. In 4 of these cases, the -7 was the only abnormality, whereas the remaining 8 cases showed additional chromosomal aberrations. Fluorescence in situ hybridization (FISH) utilizing chromosome 7 alpha-satellite and painting probes and other specific probes, when necessary, provided evidence of unusual and unsuspected structural rearrangements involving chromosome 7. FISH analysis showed that the small fragment found in one patient and the ring found in each of two other patients were chromosome 7-derived rings. FISH also revealed the insertion of chromosome 7 sequences into autosomes in three other patients and unusual translocations in the remaining two patients. By comparing the results obtained by using banding techniques to those obtained by using the FISH technique, we deduced the involvement of chromosome 7 with partial deletion of the short arm in all eight examined patients. Our study confirms the ability of FISH to detect chromosomal aberrations that would otherwise not be identified and the tendency of chromosome 7 to be involved in many different rearrangements. From a clinical point of view, we confirm that patients affected by myelodysplastic syndromes with complex karyotypes involving chromosome 7 do not respond to treatment and have a poor prognosis.

Characterization of a malignant eccrine poroma by cytogenetic and fluorescence in situ hybridization techniques

We have cytogenetically and by fluorescence in situ hybridization (FISH) analyzed short-term cultures from a malignant eccrine poroma, a type of tumor in which chromosomal abnormalities have previously not been reported. Combining the results from G-banding and FISH, the karyotype was interpreted as 50,XX,t(3;11;12)(q21;p15;q15),+5,+7,+9, +9,t(12;22)(q13;q13),+del(12)(q15),der(15)t(3;15) (q23;p13),der(17)t(8;17)(q22;p13),-20,add(22)(q13).

FISH investigation of 5q and 7q deletions in MDS/AML reveals hidden translocations, insertions and fragmentations of the same chromosomes

We have studied, by fluorescence in situ hydridization (FISH), chromosomes 5 and 7 in a series of 11 cases with 5q deletion, as sole anomaly (four cases), or in association with 7q deletion (seven cases), in MDS/AML patients. We found that, in some cases, a part of the so-called 'lost' chromosome 5 and 7 material, was actually translocated. These translocations may be either end-arm or whole-arm, as well as small insertions. Chromosomes 5 or 7 may be broken in more than two segments, defining 'fragmentation', giving rise to marker chromosomes. FISH allowed the identification of small material insertion, which is totally unidentified by classical cytogenetics. Chromosome 5 and 7 translocations occur irrespectively of the 'de novo' or 'secondary' type of myelodysplastic syndrome (MDS)/acute myeloid leukaemia (AML) patients.

Unbalanced chromosomal rearrangements in a metastasizing salivary gland tumor with benign histology

Benign metastasizing pleomorphic adenoma (BMPA) is a rare tumor of the salivary glands. Despite benign histopathologic features, it can metastasize and is sometimes lethal. No chromosomal data have been reported for this tumor type. We have by chromosome banding and fluorescence in situ hybridization analysis examined the short-term cultures of three skeletal metastases from a BMPA and identified two related hypodiploid clones: 44,XX,dic(3;22)(p11;q13) or der(3)t(3;22)(p11;q?) add(22)(q?),der(9;21)(q10;q10),der(13)t(1;13)(q11;p13)/45,XX,-3,der(9;21 ) (q10;q10),der(13)t(1;13)(q11; p13),?der(22)t(3;22)(q22;q13), +mar. The karyotypic features of this BMPA thus differ from the characteristic cytogenetic findings in pleomorphic adenomas and carcinomas ex pleomorphic adenoma.

Monosomy 7 and 7q--associated with myeloid malignancy

An association between the complete or partial loss of chromosome 7 and preleukaemic myelodysplasia or acute myeloid leukaemia has been recognized from the early days of tumour cytogenetic analysis. Detection of such abnormalities usually heralds a poor prognosis. The loss of DNA on chromosome 7 has led to speculation that tumour-suppressor genes may play a significant role in this form of leukaemogenesis, although it may be part of a multistep process. A further association with leukaemia secondary to carcinogen exposure including previous chemotherapy or a number of congenital anaemias has increased the interest in discovering the gene or genes on chromosome 7. Banded chromosome analysis has suggested that there are two broad critical regions on the long arm of chromosome 7 at bands 7q22 and 7q34-q36 that may contain the relevant genes. Initial molecular analysis has confirmed these two regions to be of significance. The advent of fluorescence in-situ hybridization techniques has facilitated some definition of the 7q22 region, with identification of candidate genes for further functional analysis. It is becoming clear that there will be more than one gene on chromosome 7 involved in the leukaemic process and with the definition of these genes it may be possible to look for associations with different phenotypes and prognosis. As for the reason for chromosome 7 showing a particular predisposition to total or partial loss we may speculate that the DNA sequence and structure may confer a 'fragility' on the chromosome. A greater understanding of the DNA structure of the long arm may provide real insight into the mechanisms of leukaemia. We would like to speculate in the long term that this could lead to the ability to screen for leukaemia susceptibility and avoidance of 'inducers' in those at risk.

Chromosome 7 and Haematological Malignancies

Abnormalities of chromosome 7 are the most common clonal chromosomal changes observed in myelodysplasia (MDS) and the second most frequent in acute myeloid leukaemia (AML) [1-5]. These changes may consist of long arm deletion (7q-) or total loss of the whole chromosome (monosomy 7) from bone marrow cells [1, 4, 6-24] and was first reported in association with myeloid disease in 1964 with the report of 3 cases of refractory anaemia, granulocytic hyperplasia [25]. The association between chromosome 7 alterations, MDS and AML in children and adults is clear, however, a rare association with lymphoid malignancies has also been recently reported. The abnormalities may occur in de novo MDS/AML, secondary cases following exposure to drugs, radiotherapy and toxins and in addition in a range of constitutional disorders including Fanconi's anaemia, congenital neutropenia and neurofibromatosis type 1 (NF1). The broad spread of conditions in which this consistent genetic change can occur leads one to speculate that there is an underlying instability in chromosome 7 and that genes on this chromosome play a role in the development of malignancy. The loss of DNA associated with malignant progression suggests the presence of a tumour suppressor gene (or genes) [26, 27]. Patients with monosomy 7 usually present as classical MDS with abnormal erythroid, megakaryocyte and myeloid differentiation [7, 28]. From a mechanistic perspective, increased cell proliferation and apoptosis is a common feature possibly induced by the failure of normal haematopoietic maturation. In all groups the presence of chromosome 7 abnormalities defines a poor prognostic group [29]. The majority of patients with MDS transform to a form of acute leukaemia resistant to therapy, including bone marrow transplantation (BMT). Although fluorescence in situ hybridization (FISH) has accelerated the study of these disorders at the cytogenetic and molecular levels, [4, 30, 31, 32, 33] no gene has been clearly implicated. A few candidate genes are under investigation. While the loss of chromsome 7 material is crutial in the malignant process it is almost certainly not the primary molecular abnormality. An initiating event genetic event predisposing to chromosome breakage and loss probably occurs in haematopoietic cells permitting chromosome 7 loss and progression to clonal malignancy as a secondary event.

Dicentric (9;20)(p11;q11) identified by fluorescence in situ hybridization in four pediatric acute lymphoblastic leukemia patients

Four children with acute lymphocytic leukemia (ALL) and a dic(9;20) are described. All four patients were diagnosed with pre-B-cell All, and the three for whom information was available were CD10+. Age at diagnosis ranged from 23 months to 12 years. All patients achieved remission, with two in continuous remission for 2 years 6 months and 3 years, one patient relapsed, dying 3 years 2 months after diagnosis, and one patient was lost to follow-up. These four patients were initially diagnosed as having a deletion of 9p and loss of one chromosome 20. Re-examination of the karyotypes indicated a possible dic(9;20). The dicentric chromosome was verified using dual-color fluorescence in situ hybridization (FISH) with centromeric probes for chromosomes 9 and 20 on interphase nuclei. Three of the four patients had multiple chromosomal abnormalities in addition to the translocation; one was hypodiploid, one was pseudodiploid, and two were hyperdiploid. This dicentric chromosome was recently described in four adult and nine pediatric patients with ALL [8, 9]. All reported patients had CD10+ pre-B-cell All, and achieved remission, as was the case for our four pediatric dic(9;20) patients. Two of our three patients for whom follow-up is available are in continuous remission as were two adults and five pediatric patients in the previous reports. These studies confirm the dic(9;20) as a recurring abnormality in ALL. Due to the subtle nature of the translocation, FISH is very useful in confirming the chromosomal abnormality.