Inversions of chromosome 12 in human malignancies

We present four cases with a malignant hematologic disorder and an inversion (peri- or paracentric) involving chromosome #12. Two cases of myelodysplastic syndrome showed an identical acquired pericentric inv(12)(p12q23). The pertinent literature on constitutional and acquired inversions of chromosome #12 has been revised.     

Cytogenetic changes at 11q11, 11q23, and 17q11 in myelodysplastic syndrome

Cytogenetic studies were performed on two patients with myelodysplastic syndromes. One patient was a 68 year old Japanese male in whose bone marrow cells two translocations were established, i.e., t(4;11)(q13;q23) and t(11;17)(q11?;q11), as well as other karyotypic changes (-6,-18,15p+). The other patient was a 74 year old white male whose bone marrow cells showed six marker chromosomes, i.e., der(5),t(5;17)(q12;q11), der(6),t(6;5)(q27;q22), der(8),t(8;11;?)(q11;q11----q23;?), der(11),t(11;?)(q11;?), an isochromosome of the long arm of chromosome #8, and a small G-group sized marker chromosome of unknown origin. Though the translocation patterns in the abnormal cells in these two cases were different, the breakpoints of the marker chromosomes were almost the same, i.e., 11q11, 11q23, and 17q11. Also, changes of chromosome #6 were observed; the first case showed monosomy 6 and the second a 6q+ marker chromosome. In these two cases of myelodysplastic syndromes, common sites of chromosome breakage and reunion of 11q23 and 17q11 were close to recently established sites of human cellular oncogene homologs, c-ets (11q23) and c-erbA (17q21----24). These associations draw attention to a possible relationship between chromosome changes in myelodysplastic syndromes and oncogene (or other gene) activation and/or dysfunction.     

11q-chromosome is associated with abnormal iron stores in myelodysplastic syndromes

Nine cases of myelodysplastic syndrome with a deletion of the long arm of chromosome #11 (11q-) showed ringed sideroblasts, and three of which had an acquired sideroblastic anemia according to the criteria of the FAB classification. In contrast, among four cases of myelodysplastic syndromes with translocation of extra material to the long arm of chromosome #11 (11q+), only one showed bone marrow sideroblasts. These results strongly indicate that an 11q- chromosome is a marker of iron overload in myelodysplastic syndromes. Within the cases of 11q- associated with sideroblastosis, two cytogenetically different anomalies (i.e., terminal or interstitial deletions) were delineated.     

Unbalanced 6p translocation as primary karyotypic anomaly in secondary acute nonlymphocytic leukemia.

A case of acute nonlymphocytic leukemia after radiochemotherapy for Hodgkin's disease, with a rearrangement of 6p23 region, is described. This chromosome change, which has been previously reported in secondary leukemias or myelodysplastic syndromes, was an isolated karyotypic anomaly in our case, which strongly supports the nonrandom involvement of chromosome 6p in induced leukemias.     

Molecular cytogenetic characterization of rearrangements involving 12p in leukemia

Translocations involving the short arm of chromosome 12 are frequent events among patients with various hematologic malignancies. In approximately half of these patients, fluorescence in situ hybridization (FISH) analysis has shown that the breakpoints are clustered within the ETS-variant gene 6 (ETV6) at 12p13, leading to its fusion with a variety of partner genes on different chromosomes. The remaining patients have breakpoints centromeric or telomeric to ETV6 or, less frequently, interstitial 12p13 deletions that invariably involve this gene. In most cases reported, 12p translocations were found to be associated with other structural and/or numerical abnormalities as part of a complex karyotype. Initially using conventional cytogenetic analysis, we characterized the chromosomal breakpoints of three leukemia patients (two with B-acute lymphoblastic leukemia and one with myelodysplastic/myeloproliferative disorder) presenting a t(5;12)(q13;p13), t(12;15)(p13;q22), and dic(9;12)(p11;p11), respectively, as the only structural abnormalities in the karyotype. These rearrangements were further investigated using FISH and molecular studies. Two cases revealed cryptic three-way translocations that had gone undetected in the conventional cytogenetic analyses. One of the cases presented an ETV6 rearrangement with an unsuspected fusion, with the CBFA2 gene at 21q22. In the other two, small and large 12p deletions that included ETV6 were found. This report illustrates the chromosomal and molecular heterogeneity of rearrangements underlying 12p chromosome translocations in leukemia.     

Translocation between chromosomes 7 and 11 in nonlymphocytic neoplasia

Three cases with chromosome changes involving bands 7p14 or 7p15 and 11p15 are described: one was a Japanese female with an acute myelomonocytic leukemia, the second was a white female with a 10-year history of paroxysmal nocturnal hemoglobinuria who developed a myelodysplastic syndrome, and the third was a patient with Ph-negative atypical chronic myelogenous leukemia with trisomy 8 and a chromosome change involving bands 7p14 and 11p15. These cases possibly indicate that the t(7;11)(p14 or p15;p15) change may characterize a subset of human nonlymphocytic neoplasia.     

Erythrocyte glutathione reductase activity and acquired trisomy #8 in various hematologic disorders

The gene for erythrocyte glutathione reductase (E-GR) activity has been assigned to chromosome #8. In the present series, we examined the E-GR activity in 14 cases with chronic myelodysplastic syndrome (CMS, preleukemia), atypical acute myelogenous leukemia (AML), or chronic myelogenous leukemia (CML), with and without acquired trisomy #8. No difference in the incidence of high levels of this enzyme was found between two groups, i.e., those with and without trisomy #8 suggesting the existence of a complex regulatory system in addition to chromosome #8.     

Cytogenetics of human malignant melanoma and premalignant lesions

Chromosome studies were done on direct preparations, early passage cultures, and/or cell lines derived from melanocytic lesions of 17 patients. There were 5 nevi (3 dysplastic); 1 early primary melanoma (radial growth phase); 1 advanced primary melanoma (vertical growth phase) with multiple metastases; and 10 metastatic lesions. The 5 nevi had normal karyotypes, while each of the tumors had a predominantly abnormal karyotype. The early melanoma was pseudodiploid, including a 6p;22 translocation. Ten of the 11 advanced melanomas had one or more aberrations involving chromosome #1, with 9 having deletions or translocations of Ip that involved the proximal segment 1p12→1p22 9 times in 8 lesions. Six advanced tumors had additional material involving 7q, including extra #7s (4 cases) and 7q (2 cases). Nine melanomas, including the early tumor, had alterations in chromosome #6. Three had additional copies of 6p (as iso6p or t6p); the others showed no consistent pattern. In one advanced tumor, the primary lesion and 5 metastases (removed seriatim over an 18-month period) had nearly identical karyotypes, indicating the clonal nature of the neoplasm. The nonrandom cytogenetic changes suggest that genes important in melanoma carcinogenesis are located on the proximal portion of 1p, on 7q, and on chromosome #6. More data on early lesions are needed to identify the relation of these various cytogenetic changes to the different stages of malignant melanoma development.     

Cytogenetic and molecular studies of the Philadelphia translocation in myelodysplastic syndromes. Report of two cases and review of the literature.

We report two patients with a myelodysplastic syndrome and the Philadelphia (Ph) chromosome. The first patient was a 73-year-old man who was diagnosed as having a chronic myelomonocytic leukemia in combination with features suggestive of a myeloproliferative syndrome. Chromosomal analysis showed a normal karyotype in the majority of cells, mixed with metaphases containing a standard Ph translocation, t(9;22)(q34;q11), as well as a translocation between chromosome 4 and 6: t(4;6)(p15;p12). Southern blot analysis showed breakpoint cluster region rearrangement as observed in classic chronic myeloid leukemia. The second patient was a 63-year-old man with a myelodysplastic syndrome, type refractory anemia. Cytogenetic study of bone marrow cells at the time of diagnosis revealed a normal karyotype: 46,XY. The initial myelodysplastic syndrome evolved to a myeloproliferative phase with progressive leukocytosis and thrombocytosis. During the terminal phase the Ph chromosome was discovered in 100% of the examined cells. We discuss the correlation between MDS and myeloproliferative diseases, the de novo acquisition of the Ph chromosome during the course of a myelodysplastic syndrome, and review the literature.     

Cytogenetic studies in 112 cases of untreated myelodysplastic syndromes.

Cytogenetic studies were performed in 112 untreated cases of myelodysplastic syndrome (MDS) between 1985 and 1990. Among 112 patients who were examined at the time of diagnosis, 54 had an abnormal karyotype (48%). The highest frequency of chromosome abnormalities was observed in refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-t) and the lowest in refractory anemia with ring sideroblasts (RARS) and chronic myelomonocytic leukemia (CMMoL). Numerical changes were observed in 19 cases and structural in 17; chromosome 8 was most frequently gained (11 cases), whereas chromosome 7 was most frequently lost (6 cases), 5q- in 14 (4 as a sole anomaly); involvement of 7q22 was seen in 3 cases, 11p in 2 patients, 11q in 3 (one patient as a sole anomaly), 12p in 4 (2 patients as a sole anomaly), i(17q) in 4 (3 patients as a sole anomaly), and complex chromosomal defects in 10 patients. If one takes into account the prognosis value, a complex karyotype and the presence of ring chromosomes were correlated with the worst prognosis, followed by -7/7q-; an intermediate prognosis corresponds to i(17q), 12p as a sole anomaly, +8 (as a sole anomaly or plus other anomalies), and involvement of 12p. Patients with a 5q- as a sole anomaly or with a normal karyotype, had the best prognosis.     

Translocation t(6;9) occurring in acute myelofibrosis, myelodysplastic syndrome, and acute nonlymphocytic leukemia suggests multipotent stem cell involvement

The cytological and cytogenetic features of six patients with myeloid neoplasia and t(6;9)(p23;q34) including a case of acute myelofibrosis (AMF), a refractory anemia with excess of blasts (RAEB), and four cases of acute nonlymphocytic leukemia (ANLL) are described. Two patients in this series, both affected by ANLL type M2, presented an increase of bone marrow basophils, suggesting that this cytological-cytogenetic association is not absolute and that it may be more frequently observed in ANLL with maturation. All patients with de novo ANLL showed associated myelodysplastic features, and one patient presented a dysmyelopoietic syndrome, later evolving into ANLL. The presence of the t(6;9) in a range of myeloid neoplasias, with either concurrent myelodysplastic features or a preleukemic phase in cases of ANLL, provide evidence that this chromosome aberration may always involve a multipotent myeloid stem cell. Data on toxic exposure of the patients suggests that myeloproliferative disorders with the t(6;9) may frequently represent environmentally induced neoplasias.     

A new case of myelodysplastic syndrome with 6p rearrangement

Bone marrow cells from a patient with refractory anemia with ringed sideroblasts were studied cytogenetically. All metaphases analyzed revealed an abnormal karyotype with complex defects. The most prominent defect consisted of a rearrangement of the short arm of chromosome 6. Until now, 6p rearrangements have been preferentially observed in myelodysplastic patients with a history of previous exposure to toxic products such as alkylating agents or environmental factors of occupational origin. Although our patient was not exposed to alkylating agents, for about 20 years he has regularly consumed important quantities of analgesics, tranquilizers, and nonsteroidal antiinflammatory drugs. The eventual relationship between sideroblastic anemia and drug abuse, as well as the existence of chromosome sites preferentially rearranged in the bone marrow cells of myelodysplastic patients, are discussed.     

伴t(1;7)易位骨髓增生异常综合征的双色荧光原位杂交研究

目的 通过对5例伴有t（1；7）易位的骨髓增生异常综合征（myelodysplastic syndromes,MDS）患者进行研究，并进一步确定易位杂色体着丝粒的组成和来源。方法 采用骨髓细胞直接法或短期培养法制备染色体，应用R显带技术进行核型分析，应用荧光素SpectrumRed标记的1号染色体着丝粒特异性α卫生DNA探针和荧光素SpectrumGreen标记的7号染色体着丝粒特异性α卫星DNA探针，对其中3例患者进行双色荧光原位杂交（fluorescence in situ hybridization,FISH）研究。结果 5例患者均有t(1;7)易位。双色FISH显示其中3例患者t（1;7) 位所致衍生染色体的着丝粒均由红绿两个信号融合而成。结论 双色FISH证实MDS患者t(1;7）易位染色体着丝粒由1号和7号染色体着丝粒共同组成。     

Structural aberrations of chromosome 7 revealed by a combination of molecular cytogenetic techniques in myeloid malignancies

In bone marrow cells of 33 patients with myelodysplastic syndrome and acute myeloid leukemia, structural rearrangements of chromosome 7 were found with conventional G-banding: 8 with deletions 7q and 25 with translocations. In 29 of the patients, complex karyotypes were confirmed using multicolor fluorescence in situ hybridization (mFISH). Commercial probes (Abbot Molecular) were used for 7q22, 7q31, and 7q35, the regions most frequently deleted in myeloid malignancies. In three cases without deletions, high-resolution multicolor banding (mBAND) for chromosome 7 revealed other aberrations. Five groups of chromosomal rearrangements were established: (a) deletion 7q as a sole aberration (2 cases), (b) deletion 7q and complex karyotypes (6 cases), (c) combined translocations and deletions of 7q (17 cases), (d) combined translocation and deletion 7p (5 cases), and (e) translocation of chromosomes 7 without deletion 7p or 7q (3 cases). Deletions of all three FISH-screened regions were the most frequent, with heterogeneous breakpoints. The region 7p13.2 approximately p15.2 was most commonly deleted. Most of the deletions were cryptic, not detectable with conventional cytogenetics. Aberrations of chromosome 7 are associated with a very poor outcome; survival time in our cohort was short (median 7 months).     

Translocation t(1;3)(p36;q21) in malignant myeloid stem cell disorders

A t(1;3)(p36;q21) translocation was found in bone marrow samples of two patients with hematologic disorders. One patient had a myelodysplastic syndrome evolving into acute nonlymphocytic leukemia (ANLL) M1 and the second patient had ANLL-M6 secondary to treatment for Hodgkin's disease. Because myelodysplastic syndromes and secondary leukemia are stem cell disorders, the t(1;3)(p36;q21) appears to be a chromosome abnormality in malignant myeloid stem cells.     

Four patients with myelodysplastic syndrome with translocation (1;7)(p11;p11) including one patient with independent clones del(7)q22) [corrected] and t(1;7)(q21;q11)

A translocation involving the short arm of chromosome #1 and the short arm of chromosome #7, [t(1;7)(p11;p11)] was present in four patients with myelodysplastic syndrome (MDS). Two of these patients had prior lymphoproliferative disorders and developed MDS following prolonged therapy with alkylating agents. One of the patients with prior therapy history has two additional independent abnormal clones: one with a partial deletion of the long arm of #7 and the other with t(1;7)(q21;q11). A third patient had a family history of leukemia in both the father and a brother, both of whom developed acute nonlymphocytic leukemia following an MDS phase. The last patient was an elderly woman with no predisposing features.     

The 5q-anomaly

A deletion of the long arm of chromosome #5 (5q-) occurs nonrandomly in human malignancies. As a rule, the deletion is interstitial; the distal breakpoint by conventional techniques is usually in band q32, the proximal breakpoints in q12 or q14. Variant breakpoints occur in less than 10% of all cases. As the sole anomaly, 5q- is characteristically found in refractory anemia with or without excess of blasts. It can occur as the sole anomaly in de novo or secondary acute nonlymphocytic leukemia, but is usually accompanied in those disorders by other chromosome changes that are also nonrandomly distributed. In addition, it can be found in lymphoproliferative disorders, and occasionally, also in solid tumors. The 5q- myelodysplastic syndrome typically occurs in older age groups, particularly in females. Characteristic features are macrocytic anemia, normal or elevated platelets in the presence of megakaryocytic anomalies, and a mild clinical course. In cases with 5q- only, transformation into ANLL occurs rarely. Additional chromosome anomalies and male sex are prognostically unfavorable signs. Sex ratio is also at the disadvantage of females in de novo 5q- ANLL, and the latter disorder can occur without being preceded by a myelodysplastic phase. A myelodysplastic phase usually precedes 5q- secondary leukemia, in males as well as in females, and additional chromosome anomalies, especially of chromosome #7, are almost invariably present in those cases. We conclude that 5q- is the most frequently occurring single chromosome anomaly in secondary leukemia. Furthermore, the resemblance between de novo and secondary 5q- MDS and ANLL is striking; clinically, as well as cytogenetically, they are indistinguishable, suggesting that all de novo cases may be due to environmental (chemical) carcinogens. Response to treatment and prognosis are very poor with current therapeutic regimens in de novo as well as in secondary 5q- ANLL. Morphologically, these ANLLs fall into all FAB categories. There is considerable evidence to show that the 5q- anomaly occurs in a myeloid precursor stem cell. The occasional occurrence in lymphoid malignancies, of B cell as well as T cell type, suggests that, as in Ph-positive disorders, a common progenitor stem cell may be affected in 5q- also. The 5q- lymphoid malignancies, however, are much more rare; it is not clear at the present time whether or not a 5q- counterpart of Ph-positive ALL exists, and mixed lymphoid-myeloid 5q- disorders have not yet been documented.(ABSTRACT TRUNCATED AT 400 WORDS)     

Chromosome changes in metastatic human melanoma

Cytogenetic studies were performed on human malignant melanoma cells from eight metastatic lesions. Five tumors displayed near-triploid and three near-diploid chromosome numbers. Chromosomes #1,#6,#7, followed by #2 and #9, were found to be most frequently involved in structural aberrations. Aberrations involving chromosome #1, with deletions or translocations of 1p, involving region 1p12-1p22 in seven of eight breakpoints of the p arm were observed. Seven of nine breakpoints of 6q were located at region 6q15-6q21. Most of the breakpoints on chromosome #7 occurred near the centromeric region. All tumors had additional chromosome material involving 1q, chromosome #7 (7q in two tumors), and in five tumors an increased dose of chromosome #6 (6p in one tumor). The nonrandom breakpoints of these and other chromosomes involved diverse bands, including loci of oncogenes and fragile sites. The observation of nonrandom chromosomal changes in advanced malignant melanoma suggests that genes important in the progression of melanoma are located on chromosomes #1,#6, and #7.     

Novel der(1)t(1;19) in two patients with myeloid neoplasias

Cytogenetic studies can be useful in the clinical management of patients with leukemia. They may also give a clue to leukemogenesis and/or pathogenesis. Numerous disease-specific chromosomal aberrations have been and continue to be identified. Translocation (1;19)(q21 through q23;p13.3) involving the long arm of chromosome 1 and the short arm of chromosome 19 is usually associated with acute lymphoblastic leukemia. We found a new translocation involving one virtually identical breakpoint 19p13 and one distinct 1p13 in two cases of myeloid neoplasms. Studies of bone marrow and peripheral blood specimens specified in one of our patients acute myeloid leukemia and in an other myelodysplastic syndrome. Conventional cytogenetics was supplemented by spectral karyotyping (SKY), microdissection, and fluorescence in situ hybridization. Our first case showed a der(1)t(1;19)(p13;p13.1) as the sole chromosomal change. In addition to this translocation, a pericentric inversion within chromosome 10 and with a cryptic t(10;11) were detected by SKY in the second case. Translocation (1;19)(p13;p13.1) may play a role in the leukemogenesis of myeloid diseases.     

A new nonrandom unbalanced t(17;20) in myeloid malignancies

Deletions of chromosomes 17 and 20 are well-described abnormalities in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) but translocations involving these two chromosomes are uncommon. We present five male patients, one with MDS and four with AML, in whom a new, nonrandom unbalanced dicentric t(17;20), resulting in deletions of 17p and 20q, was identified. Conventional cytogenetics showed additional karyotypic abnormalities in most of the patients, including deletions of 5q, deletions or monosomy of chromosome 7, and deletions of 18q. Fluorescence in situ hybridization showed a deletion of the tumor suppressor gene TP53 on 17p. Of the four cases with follow-up data available, only two had received combination chemotherapy. Overall survival in these two cases was 6 and 7 weeks, respectively. Two other patients who had no active therapy administered died 6 weeks and 9 months after diagnosis, respectively. These five cases highlight a rare but recurrent abnormality in MDS and AML, potentially involving genes on 17p and 20q of importance in myeloid leukemogenesis.