Trisomy 8 as the sole chromosomal aberration in myelocytic malignancies: a comprehensive molecular cytogenetic analysis reveals no cryptic aberrations

Involvement of the MLL gene located at chromosome region 11q23 is a frequent occurrence in both acute myelocytic leukemia and acute lymphoblastic leukemia. More than 30 loci have now been associated with MLL, usually by reciprocal translocation. Deletions, insertions, and more complex rearrangements of MLL are rarely seen. We present three cases of AML M5 showing no cytogenetic evidence of 11q23 rearrangement, in which a commercial MLL dual-color fluorescence in situ hybridization probe revealed a nonstandard abnormal signal pattern, suggesting cryptic insertion of the MLL gene into its partner gene site.     

Trisomy 8 as the sole chromosomal aberration in acute myeloid leukemia and myelodysplastic syndromes

Trisomy 8 as the sole abnormality is the most common karyotypic finding in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), occurring in approximately 5% and 10% of the cytogenetically abnormal cases, respectively. However, despite the high frequency of +8, much remains to be elucidated as regards its epidemiology, etiology, clinical impact, association with other chromosomal abnormalities, cell of origin, and functional and pathogenetic consequences. Here, we summarize and review these various aspects of trisomy 8, focusing on AMLs and MDS harboring this abnormality as a single change.     

Arm-specific multicolor fluorescence in situ hybridization reveals widespread chromosomal instability in glioma cell lines

An investigation of numerical and structural chromosome aberrations using chromosome arm-specific multicolor fluorescence in situ hybridization (armFISH) revealed considerable genetic heterogeneity among and within 11 glioma cell lines. Despite the substantial variation in numerical chromosome alterations among the cell lines, several distinct and glioma growth-associated losses or gains were frequently observed, that is, losses of chromosomes 10, 13, and 22 and gain of chromosome 7 in particular. Structural aberrations frequently affected chromosomes 1, 4, 7, 16, and 19; however, no single structural chromosome aberration common to all or even several glioma cell lines could be found. Structural alterations were often multiform, and a large variety of unstable chromosome structures were detected. Two of the cell lines also harbored small marker chromosomes containing mainly heterochromatin and chromosomal insertions within hetero-chromatic regions. Altogether, the armFISH provides a versatile tool for the identification of chromosomal aberrations as well as their formation patterns in tumors with a complex genome at the level of chromosome arms.     

Recurrent duplication of Xq27-qter in hematological malignancies revealed by multicolor fluorescence in situ hybridization and multicolor banding

Multicolor fluorescence in situ hybridization (M-FISH) experiments were performed to determine the composition of abnormal complex karyotypes in 15 cases of hematological malignancy. Four cases were found to have unsuspected unbalanced X chromosome translocations, which resulted in the presence of extra X chromosome material. We determined the identity of the duplicated chromosome regions using the multicolor banding (mBAND) technique. Xq27-qter was duplicated in three of the four male cases with an X chromosome abnormality (i.e., in one third of male cases and one fifth of all cases). These preliminary results may point to the existence of a recurrent chromosome abnormality, either translocation at a specific Xq27 locus or duplication of Xq27-qter.     

Trisomy 8 as sole karyotypic aberration in an ovarian metastasizing Sertoli-Leydig cell tumor

Sertoli-Leydig cell tumors (SLCTs) represent a rare group of sex-cord stromal tumors of the ovary of unknown pathogenesis. We report a SLCT of intermediate differentiation with peritoneal recurrence and lymph node metastasis 12 months after removal, including cytogenetic analysis by comparative genomic hybridization and fluorescence in situ hybridization, which showed trisomy 8 as sole unbalanced karyotypic aberration. Our results provide evidence that a simple numeric chromosomal abnormality in SLCT may be associated with a malignant phenotype and suggest that the molecular pathogenesis of SLCT may be different from ovarian granulosa-stromal cell tumors.     

Trisomy 2 as the sole chromosomal abnormality in a hepatoblastoma.

Short-term cultures of a fine-needle aspirate from a hepatoblastoma were analyzed cytogenetically. Trisomy 2 was found as the sole abnormality, yielding the karyotype 47,XY, + 2/46,XY. Because trisomy for all or part of chromosome 2 has been described, although together with other aberrations, in seven of the 11 hepatoblastomas hitherto reported, the finding of + 2 as the only anomaly in the present case strongly indicates that additional chromosome 2 material is of pathogenetic significance in this tumor type.     

Trisomy 6 in Merkel cell carcinoma: a recurrent chromosomal aberration

We retrospectively investigated 17 cases of primary and metastasizing Merkel cell carcinomas (MCC) from 14 patients using chromosomal in-situ hybridization (CISH) to study the occurrence of trisomy 6 in these lesions. METHODS AND RESULTS: Histological diagnosis on all tumour samples was obtained on haematoxylin and eosin stained sections. Immunohistochemistry was performed with antibodies against pancytokeratin (CAM 5.2), cytokeratin 20 (CK20), MIC2 antigen (CD99), neuron-specific enolase (NSE), and chromogranin A (chrA). Sections (4 microm) of the paraffin-embedded tumours were analysed with alpha-satellite centromeric probes for chromosome 6 or 17 using CISH. The signal was amplified by the Tyramide Signal Amplification (TSA) assay. Immunohistochemically, the tumours showed the same general epithelial neuro-endocrine pattern: 11/13 expressed cytokeratin 20, and 47% exhibited trisomy 6, with no significant difference between primary and metastatic lesions. Incomplete follow-up data did not allow us to establish a prognostic value of trisomy 6, however, this aberration might be an additional diagnostic tool in distinguishing MCC from other small round blue cell tumours. CONCLUSIONS: CISH seems to be a promising adjunctive method to diagnose Merkel cell carcinoma. Trisomy 6 should be investigated more closely in these cases, as has been done for chromosomes 1 and 11. Of particular interest would be identification of modifications in proto-oncogene(s) located on chromosome 6.     

Two balanced and novel chromosomal translocations in myeloid malignancies. characterization by multiplex fluorescence in situ hybridization

We describe two novel chromosomal translocations in two cases of leukemia in which these translocations were further characterized as the sole acquired karyotypic abnormality by mutliplex fluorescence in situ hybridization (M-FISH). They comprised a case of acute myeloid leukemia with t(6;10)(q21;p12) and a case of chronic myelomonocytic leukemia with t(5;12)(q34;q24). To the best of our knowledge, these two balanced translocations are novel and are hitherto unrecognized in hematologic malignancies. While the clinical and pathogenic significance of these translocations remains to be defined, the present report illustrates that M-FISH technology contributes to the exclusion of subtle or cryptic translocations in sole karyotypic aberrations and the confirmation of novel chromosomal arrangements in neoplastic disorders.     

Trisomy 8 in stage I and stage III ovarian cancer detected by fluorescence in situ hybridization.

Ovarian cancer is the leading cause of death from gynecologic maligancy among women in the United States. In 1997, there were nearly 27,000 ovarian cancer cases with over 14,000 deaths. Recent attempts at early detection of ovarian cancer have been aimed at the identification of biomarkers that would indicate an underlining malignant process or reflect the biological behavior of the tumor. Our previous studies revealed that chromosome 8 copy number abnormality, especially trisomy, is common in several cancers. Archival tissues from 24 cases of papillary serous ovarian carcinoma (10 stage I and 14 stage III) were analyzed by fluorescence in situ hybridization (FISH) with a chromosome 8-specific alpha-satellite probe (Oncor, Gaithersburg, MD). The analysis was done according to standard protocols of the Lifespan Academic Medical Center Cytogenetics Laboratory at Rhode Island Hospital. Twenty-one of 24 cases (87.5%) were found to be trisomic for chromosome 8, if a cutoff point of >/=15% cells with three signals is adopted. Overall, 80% of stage I and 93% of stage III tumors had trisomy 8. This study confirms the presence of a high frequency of trisomy 8 in both early and late stages of the disease and suggests that trisomy 8 may be an early event in the multistep process leading to ovarian cancer. It is of interest to note that a higher frequency of trisomy 8 was found in a higher stage of disease, consistent with our previous results on breast cancer. Thus, additional FISH studies of ovarian tumors for chromosome 8 copy number assessment may be warranted.     

Genomic alterations in lung adenocarcinomas detected by multicolor fluorescence in situ hybridization and comparative genomic hybridization

We used two molecular cytogenetic techniques, multicolor fluorescence in situ hybridization (M-FISH) and comparative genomic hybridization (CGH), to analyze three established lung adenocarcinoma cell lines (A549, H1650, and SPC-A-1) and primary lung adenocarcinoma samples, to identify common chromosomal aberrations. M-FISH revealed numerous complex chromosomal rearrangements. Chromosomes 5, 6, 11, 12, and 17 were most frequently involved in interchromosomal translocations. CGH revealed regions on 1q, 2p, 3q, 5p, 5q, 7p, 8q, 11q, 12q, 14q, 16p, 17p, 19q, 20q, 21q, and 22q to be commonly overrepresented and regions on 2q, 3p, 4p, 5q, 7q, 8p, 9p, 13q, 14q, and 17p to be underrepresented. The most common gains were found in 16p13 (in 50% of samples), and 16p13 amplification was associated with relatively poor differentiation and late stage. M-FISH and CGH can be a powerful tool in identification of genomic alterations in lung cancer, as well as in diagnosis. The overrepresented regions may harbor potential candidate genes involved in lung adenocarcinoma pathogenesis.     

荧光原位杂交在恶性血液病中的研究进展

荧光原位杂交(fluorescence in situ hybtidization,FISH)可对分裂中期及间期的细胞进行染色体与基因异常检测,具有直观、快速、敏感性和特异性高以及方便灵活等优点,对白血病、淋巴瘤、多发性骨髓瘤、骨髓增生异常综合征等恶性血液病的诊断、分型、临床治疗选择和预后判断提供重要依据.     

荧光原位杂交在恶性血液病中的研究进展

荧光原位杂交(fluorescence in situ hybtidization,FISH)可对分裂中期及间期的细胞进行染色体与基因异常检测,具有直观、快速、敏感性和特异性高以及方便灵活等优点,对白血病、淋巴瘤、多发性骨髓瘤、骨髓增生异常综合征等恶性血液病的诊断、分型、临床治疗选择和预后判断提供重要依据.     

Molecular cytogenetic analysis of breast cancer: a combined multicolor fluorescence in situ hybridization and G-banding study of uncultured tumor cells

In six patients with breast cancer, uncultured tumor cells were investigated with G-banding and multicolor fluorescence in situ hybridization (M-FISH). A large number of numerical and structural aberrations could be analyzed. Among other structural abnormalities, reciprocal, hidden and complex translocations were found. Recurrent t(1;10) and t(6;16), not previously described, were identified, as well as t(15;22). The latter was also found in additional cases among our unpublished breast carcinomas. The significance of t(15;22) for breast cancer is discussed, taking into account also data drawn from the literature. Reciprocal translocations were a prominent feature in a pseudodiploid lobular carcinoma. Hidden translocations on 6p22-p24 were detected with M-FISH. Involvement of 6p22-p24 was observed in five cases. The analysis of various other translocations and different structural abnormalities revealed the following common breakpoints (according to frequency of involvement): 1p34-p36, 3p12-p13, 4p13-->q11, 14p11-->q11, 1q42, 8p11, 8q24, 10q22, 11q13, 11q23-q24, 13q13, and 18p10-p11. Loss of 3p and 1p34-p36-->pter and complete or partial loss of 13q and chromosome 17 were also found. With the combination of G-banding and M-FISH techniques, chromosome misclassification is avoided and the characterization of complex tumor karyotypes is more effective.     

多色荧光原位杂交检测人卵细胞染色体非整倍体方法的建立

目的 建立多色荧光原位杂交技术检测人卵细胞染色体非整倍体的方法。方法 取试管婴儿助孕技术后未能受精成功的卵细胞，于取卵后13d固定，采用多色荧光原位杂交方法检测卵细胞13，16，18。21和22号染色体的情况。结果 正常未受精卵细胞中期染色体显示一个成对的杂交信号，每条染色单体显示一个单个信号；分裂相中多出或缺少一个成对杂交信号表明多余或缺少一条染色体；分裂相中多出或缺少一个单个信号表明多余或缺少一条染色单体；两个单个信号分离表明两条姐妹染色单体分离。结论 采用多色荧光原位杂交方法可以有效检测人卵细胞染色体非整倍体异常。     

The incidence of trisomy 8 as a sole chromosomal aberration in myeloid malignancies varies in relation to gender, age, prior iatrogenic genotoxic exposure, and morphology

Although trisomy 8 as a sole change is one of the most common chromosomal abnormalities in myeloid malignancies, it is largely unknown if the incidence of this aberration is influenced by other factors of clinical importance. In the present study, the frequencies of isolated +8 in relation to gender, age, previous treatment with chemo- or radiotherapy, and morphologic subtype were ascertained in published, as well as in our own unpublished, cases of acute myeloid leukemia (AML; n=4,246), myelodysplastic syndromes (MDS; n=1,817), and chronic myeloproliferative disorders (MPD; n=530). The frequencies of +8 were higher in MDS and MPD than in AML (7.5% vs. 5.6%; P<0.01) and varied among the morphologic subtypes of AML and MDS (P<0.001 and P<0.05, respectively). Trisomy 8 was more common in women than in men with MPD (11% vs. 5.1%; P<0.05). Furthermore, the frequencies of +8 were higher in de novo AML and MDS than in treatment-related cases (6.0% vs. 2.8%; P<0.01 and 8.6% vs. 1.5%; P<0.001, respectively). The incidence also varied significantly with age in AML (P<0.001), being more common in elderly patients. Although the causes for this frequency heterogeneity remain to be elucidated, possible explanations may include different environmental exposures affecting the origin of +8 in AML, MDS, and MPD and the presence of different underlying cryptic primary aberrations.     

Trisomy 12 is a consistent chromosomal aberration in benign ovarian tumors

Clonal karyotypic abnormalities were detected in 7 of 42 cytogenetically analyzed benign ovarian tumors. An adenofibroma had -X and a mucinous cystadenoma had t(1;11)(q25;q23) as the sole abnormality. Trisomy 12 was found in the remaining five tumors. It was the only change in two fibromas and a serous cystadenoma; the fourth tumor, a mucinous cystadenoma, had one clone with +12 and one with +12 and +10, and the fifth tumor, a fibrothecoma, had +4,+9,+12. The finding of trisomy 12 in five of seven karyotypically aberrant tumors suggests that this aberration characterizes a hitherto unrecognized cytogenetic subgroup of benign ovarian neoplasms.     

用荧光原位杂交技术研究人类未受精卵细胞的染色体非整倍体

目的　探讨人类未受精卵细胞非整倍体的产生机制。方法　取未受精卵细胞固定后行多色荧光原位杂交 ,分析卵细胞中 13、16、18、2 1和 2 2号染色体的核型情况。结果　 4 7%的卵细胞核型正常 ,5 3%的卵细胞为异常核型 ,其中 18%为同源染色体不分离 ,12 %为姐妹染色单体非平衡性过早分离 ,36 %为姐妹染色单体平衡性过早分离 ;在体外培养 >2 4小时的卵细胞中 ,姐妹染色单体平衡性过早分离的发生率明显高于体外培养≤ 2 4小时的卵细胞 ( P<0 .0 1)。结论　同源染色体不分离和姐妹染色单体平衡性及非平衡性过早分离这三种机制均参与了卵细胞非整倍体的产生。姐妹染色单体平衡性过早分离与体外培养时间具有相关性     

Interphase fluorescence in situ hybridization overcomes pitfalls of G-banding analysis with special reference to underestimation of chromosomal aberration rates

Fluorescence in situ hybridization (FISH) is suitable for detecting different types of chromosome aberrations on interphase nuclei even in specimens with no or few chromosome metaphases. However, it is not known why FISH is superior to conventional G-banding analysis. The sensitivity of interphase FISH was compared to that of G-banding analysis in 288 leukemia/lymphoma patients for 10 different types of chromosome aberrations: t(9;22) (M- and m-BCR), t(8;21), 11q23 abnormalities, t(15;17), del(5)/-5, del(13)/-13, +8, -7, and +12. The results revealed that t(15;17) positive cells could not proliferate well in culture, leading to underestimation of abnormality by G-banding. Monosomy 7 in acute myelocytic leukemia (AML) and myelodysplastic syndrome (MDS) as well as trisomy 12 and deletion chromosome 13 in chronic lymphocytic leukemias (CLL) were also severely underestimated by G-banding. On the other hand, no discrepancies were observed in t(8;21), t(9;22), translations involving 11q23, or in trisomy 8. These findings indicate the superiority of interphase FISH over conventional cytogenetics for detecting chromosome abnormalities in small clones, especially for monosomy 7 or (15;17) translocations.     

恶性血液病8号染色体数目异常的间期荧光原位杂交检测

目的　探讨间期荧光原位杂交 (fluorescenceinsituhybridization ,FISH)技术在检测恶性血液病 8号染色体数目异常中的价值。方法　采用常规细胞遗传学 (conventionalcytogenetics ,CC)和 8号染色体着丝粒特异性探针间期FISH技术对 8例CC检测显示 8号染色体数目异常的急性髓细胞样白血病患者、10例慢性髓细胞样白血病加速期或急变期患者和 3名正常人骨髓进行 8号染色体数目检测。结果9例CC检测为三体 8的患者中 ,FISH检测结果均与其一致 ,其中例 5经CC检测仅发现存在二体 8、三体8和四体 8克隆 ,而FISH检测不但证实了三体 8和四体 8克隆的存在 ,还发现存在一个较小的五体 8克隆。例 3和例 17经CC检测只发现一个细胞有三体 8,无法确定是否为三体 8克隆性畸变 ,FISH检测证实有三体 8克隆存在。例 9经CC检测未发现三体 8,FISH检测发现有三体 8克隆存在。与CC检测结果相比 ,除例 16三体 8检出率FISH结果明显高于CC检测结果外 ,其余均低于或接近CC检测结果。结论　间期FISH技术对检测 8号染色体数目异常具有重要价值 ,当CC检测正常、不肯定或中期分裂相质量差、数量少时作用更大 ,是CC的重要补充。     

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.