Prenatal origin of separate evolution of leukemia in identical twins

Several studies involving identical twins with concordant leukemia and retrospective scrutiny of archived neonatal blood spots have shown that the TEL-AML1 fusion gene in childhood acute lymphoblastic leukemia (ALL) frequently arises before birth. A prenatal origin of childhood leukemia was further supported by the detection of clonotypic immunoglobulin gene rearrangements on neonatal blood spots of children with various other subtypes of ALL. However, no comprehensive study is available linking these clonotypic events. We describe a pair of 5-year-old monozygotic twins with concordant TEL-AML1-positive ALL. Separate leukemic clones were identified in the diagnostic samples since distinct IGH and IGK-Kde gene rearrangements could be detected. Additional differences characterizing the leukemic clones included an aberration of the second, nonrearranged TEL allele observed in one twin only. Interestingly, both the identical TEL-AML1 fusion sequence and distinct immunoglobulin gene rearrangements were identified on the neonatal blood spots indicating that separate preleukemic clones evolved already before birth. Finally, we compared the reported twins with an additional 31 children with ALL by using the microarray technology. Gene expression profiling provided evidence that leukemia in twins harbours the same subtype-typical feature as TEL-AML1-positive leukemia in singletons suggesting that the leukemogenesis model might also be applicable generally.

Prognostic impact of chromosomal aberrations in Ewing tumours

Although greater than 50% of Ewing tumours contain non-random cytogenetic aberrations in addition to the pathognomonic 22q12 rearrangements, little is known about their prognostic significance. To address this question, tumour samples from 134 Ewing tumour patients were analysed using a combination of classical cytogenetics, comparative genomic and fluorescence in situ hybridisation. The evaluation of the compiled data revealed that gain of chromosome 8 occurred in 52% of Ewing tumours but was not a predictive factor for outcome. Gain of 1q was associated with adverse overall survival and event-free survival in all patients, irrespective of whether the tumour was localised or disseminated (overall survival: P=0.002 and P=0.029; event-free survival: P=0.018 and P=0.010). Loss of 16q was a significant predictive factor for adverse overall survival in all patients (P=0.008) and was associated with disseminated disease at diagnosis (P=0.039). Gain of chromosome 12 was associated with adverse event-free survival (P=0.009) in patients with localised disease. These results indicate that in addition to a 22q12 rearrangement confirmation in Ewing tumours it is important to assess the copy number of 1q and 16q to identify patients with a higher probability of adverse outcome.

Constitutional balanced chromosomal rearrangements and neoplasm in children

A predisposition to tumor development is currently associated with some, but not all, constitutional chromosomal abnormalities. In a series of 578 children, in which conventional cytogenetic investigation was performed on material from various benign and malignant tumors, four boys and one girl were also found to have constitutional balanced chromosomal rearrangements. The figure of 5 in 578 is notable because the reported incidence of balanced rearrangements in newborns is approximately 1 in 450. Thereby suggesting that some, if not all, children with balanced constitutional chromosomal rearrangements have an increased predisposition for neoplasms developing.

Detection of unidentified chromosome abnormalities in human neuroblastoma by spectral karyotyping (SKY)

Spectral karyotyping (SKY) is a novel technique based on the simultaneous hybridization of 24 fluorescently labeled chromosome painting probes. It provides a valuable addition to the investigation of many tumors that can be difficult to define by conventional banding techniques. One such tumor is neuroblastoma, which is often characterized by poor chromosome morphology and complex karyotypes. Ten primary neuroblastoma tumor samples initially analyzed by G-banding were analyzed by SKY. In 8/10 tumors, we were able to obtain additional cytogenetic information. This included the identification of complex rearrangements and material of previously unknown origin. Structurally rearranged chromosomes can be identified even in highly condensed metaphase chromosomes. Following the SKY results, the G-banding findings were reevaluated, and the combination of the two techniques resulted in a more accurate karyotype. This combination allows identification not only of material gained and lost, but also of breakpoints and chromosomal associations. The use of SKY is therefore a powerful tool in the genetic characterization of neuroblastoma and can contribute to a better understanding of the molecular events associated with this tumor.

The investigation of karyotypic instability in the high-hyperdiploidy subgroup of acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) of childhood has been cytogenetically well characterized, and approximately 25% of cases will have a high-hyperdiploid (51-68) chromosome complement. In a 5 year period a consecutive series of 152 presentation ALL's were karyotyped. In all cases a result was obtained and 138 (91%) had a detectable abnormal clone of which 44 (29%) were high-hyperdiploid. Within the high-hyperdiploidy group karyotypic cell to cell variation was observed in many cases. To provide further evidence of this phenomenon a dual-color fluorescence in-situ hybridization (FISH) experiment was performed on stored fixed suspension from 14 ALL's with such a karyotype. In each case 4-6 probes were investigated, employing probes to centromeres of chromosomes X, 4, 6, 8, and 10 and a locus specific probe to chromosome 21q22. It was found that the FISH produced results that were generally in good agreement with the G-banding findings and supported the notion of karyotypic cell to cell variation. FISH further showed that most of cases would have two extra copies of chromosome 21 in the majority of leukemic cells and a single extra copy in the minority. A further finding was that fewer cells contained extra copies of chromosomes 6, 8 and 10 than was expected based on the comparison of the signal number of the other probes investigated. In contrast chromosomes X, 4, and 21 seldom displayed this feature. We have demonstrated that karyotypic instability as defined by karyotypic cell to cell variation is a feature of the high-hyperdiploid subgroup in childhood ALL. It is questioned whether the underlying defect resulting in the observed karyotypic instability of this subgroup is one of the primary causative events in the formation of the leukemia.

Loss of X chromosome in childhood acute lymphoblastic leukemia

We present six cases of childhood acute lymphoblastic leukemia (ALL) in which an acquired loss of the X chromosome was detected. The cases derive from a consecutive series of 178 childhood ALL, consisting of 80 girls and 98 boys. In five cases the presence of the TEL-AML1, t(12;21), fusion product was detected by FISH. The single negative case had an unusual t(1;19)(p13;q13). In addition, this was the only case that did not have a cytogenetically visible rearrangement involving one of the chromosome regions 6q, 9p, or 12p. The six cases showed the typical presentation features of an ALL of FAB type L1, a common ALL immunophenotype with myeloid marker co-expression, and a median presenting age of 7 years. We, therefore, conclude that loss of chromosome X may be a secondary event in older girls with TEL-AML1-positive ALL.

Inv(11)(p13p15) and myf-3(MyoD1) in a malignant extrarenal rhabdoid tumor of a premature newborn

We present a premature newborn of 32 wk of gestation with a congenital malignant extrarenal rhabdoid tumor (MERT) on the right shoulder with generalized metastases. Standard histologic, immunohistochemical, molecular and cytogenetic methods were used in the evaluation of diagnostic material. Biopsy of a skin lesion showed the histologic features of a malignant rhabdoid tumor. Cytogenetic analysis of the tumor cells revealed an inv(11)(p13p15) and additionally, an increased expression of myf-3 (myogenic determination factor, MyoD1) and PAX3 was detected. These results suggest an origin of the neoplasm derived from a pluripotent cell with the potential of myogenic differentiation. Tumor suppressor genes located on chromosome 11p13 and 11p15 may play an important role for malignant rhabdoid tumor development and progression.

Establishment and characterization of an arsenic-sensitive monoblastic leukaemia cell line (SigM5)

Few human monoblastic cell lines have been characterized to date. We have established the SigM5 cell line from a patient with acute monoblastic leukaemia (FAB M5a). Original leukaemic cells had a karyotype of 47,XY,+8, whereas the cell line showed a stemline clone of 81,XX,Y,Y,1,4,6,7,+8,+8,9,10,10,11,13,16,19[cp], with a minor sideline also present. Cytochemical staining was strongly positive with alpha-naphthylbutyrate acetate esterase, particulate positive with Sudan black and weakly positive for myeloperoxidase. Cells were positive for CD13, CD15, CD18, CD23, CD33, CD38, CD45, CD68 and myeloperoxidase. CD14 expression was 3-15%. SigM5 constitutively secreted interleukin (IL)-2, IL-8, IL-10, tumour necrosis factor (TNF)-alpha, ferritin, lysozyme, N-elastase and neopterin upon stimulation with interferon (IFN)-gamma. Cells expressed the proinflammatory mediator macrophage migration inhibitory factor (MIF). All NADPH oxidase subunits were constitutively present, but nitroblue tetrazolium reduction was only detectable upon activation with IFN-gamma. SigM5 monoblasts were sensitive to arsenic trioxide (As2O3) previously not described to induce apoptosis in monoblastic cells. Differing considerably in morphology, immunophenotype and sensitivity to arsenics from the widely used cell lines U937, HL-60 and THP-1, SigM5 is a new monoblastic cell line useful for studying leukaemogenesis, monocyte differentiation and tumour cell susceptibility to arsenic compounds.

Molecular features of a human rhabdomyosarcoma cell line with spontaneous metastatic progression

A novel human cell line was established from a primary botryoid rhabdomyosarcoma. Reverse transcription polymerase chain reaction investigations of this cell line, called RUCH-2, demonstrated expression of the regulatory factors PAX3, Myf3 and Myf5. After 3.5 months in culture, cells underwent a crisis after which Myf3 and Myf5 could no longer be detected, whereas PAX3 expression remained constant over the entire period. Karyotype analysis revealed breakpoints in regions similar to previously described alterations in primary rhabdomyosarcoma tumour samples. Interestingly, cells progressed to a metastatic phenotype, as observed by enhanced invasiveness in vitro and tumour growth in nude mice in vivo. On the molecular level, microarray analysis before and after progression identified extensive changes in the composition of the extracellular matrix. As expected, down-regulation of tissue inhibitors of metalloproteinases and up-regulation of matrix metalloproteinases were observed. Extensive down-regulation of several death receptors of the tumour necrosis factor family suggests that these cells might have an altered response to appropriate apoptotic stimuli. The RUCH-2 cell line represents a cellular model to study multistep tumorigenesis in human rhabdomyosarcoma, allowing molecular comparison of tumorigenic versus metastatic cancer cells.

Trisomy 1q generating translocations in Wilms tumor

Unbalanced translocations generating trisomy of 1q are common in Wilms tumor (WT). We present eight unbalanced 1q translocations from seven tumors and a review of the literature. An unbalanced translocation that results in a der(16)t(1q;16q) chromosome represents more than half of the published +1q generating translocations in WT. This translocation is also common to many other tumor types. Four of the tumors presented here contained this chromosome and,in two cases, it was the primary acquired cytogenetic abnormality within the tumor. The other four translocations involved 9q31, 9q34, 17p1?, and 21p11 as the partner to 1q. The chromosome 17 and 21 translocations occurred within the same tumor as apparently independent events. In contrast with the 16q translocations, these other translocations were secondary cytogenetic events, thereby indicating a role in tumor progression rather than initiation. Probes mapping to 1q12 and 1q21 were employed for fluorescence in situ hybridization and it was demonstrated that different 1q breakpoints are possible. In this series, the majority of breakpoints either mapped to 1q12 or were centromeric to this region.

Gain of chromosome arm 17q and adverse outcome in patients with neuroblastoma

BACKGROUND

Gain of genetic material from chromosome arm 17q (gain of segment 17q21-qter) is the most frequent cytogenetic abnormality of neuroblastoma cells. This gain has been associated with advanced disease, patients who are > or =1 year old, deletion of chromosome arm 1p, and amplification of the N-myc oncogene, all of which predict an adverse outcome. We investigated these associations and evaluated the prognostic importance of the status of chromosome 17.

METHODS

We compiled molecular cytogenetic analyses of chromosome 17 in primary neuroblastomas in 313 patients at six European centers. Clinical and survival information were collected, along with data on 1p, N-myc, and ploidy.

RESULTS

Unbalanced gain of segment 17q21-qter was found in 53.7 percent of the tumors, whereas the chromosome was normal in 46.3 percent. The gain of 17q was characteristic of advanced tumors and of tumors in children > or =1 year of age and was strongly associated with the deletion of 1p and amplification of N-myc. No tumor showed amplification of N-myc in the absence of either deletion of 1p or gain of 17q. Gain of 17q was a significant predictive factor for adverse outcome in univariate analysis. Among the patients with this abnormality, overall survival at five years was 30.6 percent (95 percent confidence interval, 21 to 40 percent), as compared with 86.0 percent (95 percent confidence interval, 78 to 91 percent) among those with normal 17q status. in multivariate analysis, gain of 17q was the most powerful prognostic factor, followed by the presence of stage 4 disease and deletion of 1p (hazard ratios, 3.4, 2.3, and 1.9, respectively).

CONCLUSIONS

Gain of chromosome segment 17q21-qter is an important prognostic factor in children with neuroblastoma.

Primary pleomorphic adenoma of the external auditory canal diagnosed by fine needle aspiration cytology. A case report

BACKGROUND

Pleomorphic adenoma (PA) arising in the external auditory canal (EAC) is a very rare neoplasm, thought to be derived from ceruminous glands.

CASE

A 43-year-old male presented with a slowly growing mass in the right EAC. Clinical and radiologic examinations showed a well-circumscribed tumor limited to the EAC, without a connection to the parotid gland. Fine needle aspiration cytology (FNAC) revealed the typical cytologic findings of PA. The diagnosis was confirmed by histologic examination.

CONCLUSION

This case illustrates that together with clinical and radiologic findings, primary PA of the EAC can confidently be diagnosed by FNAC.

Cytogenetic abnormalities in Langerhans cell histiocytosis

We present the cytogenetic investigations of five histiocytic tumour lesions from children. In four cases there was a confirmed diagnosis of Langerhans cell histiocytosis (LCH) and one case of histiocytosis that did not fulfil all the criteria for true LCH. All five cases showed cytogenetic abnormalities, including the first report of an abnormal clone in LCH. The clone showed a t(7;12)(q11.2;p13) translocation and was detected in only a small percentage of cells. This case and a further three also contained non-clonal abnormalities and an increase in chromosome breakage. The fifth case, the only one in which no acquired abnormalities were seen, had a constitutional paracentric inversion of chromosome 13q.

A further case of a t(11;20)(p15;q11.2) translocation in an acute myeloid leukemia (FAB M2)

PURPOSE

The clinical implications of many cytogenetic abnormalities in acute myeloid leukemia (AML) are now well established. However, questions about the significance of rarer abnormalities still exist, particularly in childhood disease.

PATIENTS AND METHODS

We report a case of a 9 1/2-year-old girl who had AML of the FAB M2 subtype. A diagnostic bone marrow aspirate and subsequent bone marrow aspirates were investigated using conventional cytogenetic methods.

RESULTS

Cytogenetic analysis of the diagnostic bone marrow aspirate showed a t(1;20)(p15;q11.2) translocation as the sole acquired abnormality. After one course of chemotherapy, the patient achieved hematopoietic and cytogenetic remission which has been sustained for 1 year after presentation.

CONCLUSION

This report demonstrates that rare non-random cytogenetic abnormalities are still to be described in AML, and that care should be taken when ascribing clinical significance to cytogenetic findings in childhood disease based on those of older patients.

Routine karyotyping in Wilms tumor

We describe the karyotypes of nine Wilms tumors (WT). Four tumors were initially karyotyped from diagnostic needle core biopsies, 3 after postchemotherapy tumor resection and the remainder from xenografts grown in nude mice. The 9 nephroblastomas were composed of 7 with favorable histology (intermediate-grade malignancy) and 2 with unfavorable histology (anaplastic or high-grade malignancy). The 7 tumors with favorable histology had karyotypes typical of WT, with the previously described nonrandom abnormalities +1q, +6, +7, +8, +12, +13, +18 and structural abnormalities of 1p and 16q present in at least 1 case. The most common abnormalities were trisomy 18 (4 cases) and +1q (3 cases). The 2 tumors with unfavorable histology both had complex karyotypes atypical for WT. We suggest that cytogenetics can act as a marker when histologic grade is in doubt. Karyotypic analysis from needle core biopsies was attempted in 6 samples, including 1 from a nephrogenic rest (NR) of the nonaffected kidney and provided a result on 5 occasions. The NR were present in the sole case with a constitutional abnormality, a mosaic partial duplication of 8q. However, both the tumor and the NR were apparently derived from the normal cell line. Here we demonstrate that a cytogenetic result can be routinely obtained from needle core biopsies and will thus facilitate true diagnostic tumor karyotypes in both WT and other tumors.

A childhood fibrolamellar hepatocellular carcinoma with increased aromatase activity and a near triploid karyotype

We report a 15-year-old boy with hepatocellular carcinoma (HCC) of the fibrolamellar type. He presented with advanced disease and a non-resectable tumor. Clinical features included marked gynecomastia which had been present for 3 years, failure to enter puberty, and failure to thrive. These features might have been due to a high aromatase activity of the tumor. The course of the illness suggested that the tumor had been present for at least 3 years prior to diagnosis. At diagnosis the patient had multiple metastases which included infiltrated ascites. Cytogenetic analysis of the ascites revealed a near triploid karyotype with cell-to-cell variation and an abnormality of chromosome 1 q. This to our knowledge is the first karyotype report of fibrolamellar HCC in a child.

Cytogenetic analysis in a case of intraocular medulloepithelioma

We report the cytogenetic analysis of a medulloepithelioma, a rare neuroectodermally-derived tumor of childhood, which to our knowledge is the first reported karyotype of this tumor. The tumor sample was received at diagnosis and was mechanically dissociated to create cell suspension cultures. The primary cytogenetic abnormality was a der(16)t(1;16) chromosome, which was typical of that reported in a wide range of other tumor types. The other abnormalities seen were a del(6q) and monosomy 15.

Severe hypodiploidy with karyotype instability in a case of acute myeloid leukemia

We present a case of acute myeloid leukemia (AML) in an elderly male. A severe hypodiploid karyotype (chromosome range 29-39) was detected with a large amount of cell-to-cell variation, suggesting that the leukemic cells are primarily characterized by chromosomal loss due to karyotypic instability. Severe hypodiploidy is a rare finding in AML but previous similar cases indicate that it confers a very poor prognosis.

Cytogenetics in acute myeloid leukaemia

A wealth of literature spanning 20 years describing cytogenetic abnormalities in acute myeloid leukaemia (AML) already exists. It ranges from single case reports of unusual abnormalities to large multicentre studies of hundreds of cases. A landmark publication was the Fourth International Workshop on Chromosomes in Acute Leukaemia which established a base line for diagnosis, prognosis and frequency of chromosome abnormalities in AML. Two large sources of information are a book, 'The Chromosomes in Human Cancer and Leukemia' and a catalogue of chromosome abnormalities, which aims to list all chromosome abnormalities described in the scientific and medical literature from 1973, when the widespread use of banding techniques, enabled the precise definition of the chromosome breakpoints. In this review the common cytogenetic abnormalities seen in AML with reference to associations with the French-American-British (FAB) classification, their possible prognostic significance and their associated molecular biology are summarized.

Monosomy 7, diabetes insipidus and acute myeloid leukemia in childhood

The triad of diabetes insipidus (DI), monosomy 7, and acute myeloid leukemia in a 7-year-old boy is described. This triad has been described in adults but not in children. The DI ran a transient, self-limiting course and required no specific therapy. The pathogenesis of DI remains unknown, and its transient nature may result in this component of the triad going unnoticed.

Isolated follicular lymphoma cells are resistant to apoptosis and can be grown in vitro in the CD40/stromal cell system

Low-grade follicular non-Hodgkin's lymphomas are characterized by the presence of a t(14;18) chromosomal translocation that results in deregulation of the B-cell lymphoma (Bcl-2) gene. Studies in cell lines and transgenic animal models have suggested that this results in the suppression of apoptotic cell death in germinal centers. B lymphocytes from normal germinal centers and lymph nodes infiltrated by follicular lymphoma were isolated by immunomagnetic depletion of cells bearing CD4, CD8, or slgD for study in vitro. Follicular lymphoma cells expressing Bcl-2 protein were shown to resist apoptosis after isolation, and could be induced to proliferate in a culture system previously described for the growth of normal B lymphocytes. By the use of a mouse fibroblast monolayer transfected with the CDw32 Fc receptor to present CD40 monoclonal antibody in the presence of interleukin-4, prolonged culture was possible. Karyotypic analysis of cultured lymphoma cells showed the t(14;18) translocation, with clonal identity confirmed by polymerase chain reaction amplification of the breakpoints and direct sequence analysis. These findings support the hypothesis that resistance to apoptosis is an influence on the initiation of follicular lymphoma, and provide a novel means of studying in vitro the intercellular reactions that may be important in progression of the disease.

Abnormalities of chromosome 16q in myeloid malignancy: 14 new cases and a review of the literature

Fourteen patients with abnormalities of chromosome 16q, 13 with acute myelogenous leukaemia (AML), and one with refractory anaemia with excess of blasts (RAEB), are described. Seven patients had inv(16)(p13q22), two had del(16)(q22), and five had other abnormalities of 16q. Six of the seven patients with inv(16) had AML M4Eo and, following treatment with adriamycin, cytosine arabinoside, and 6-thioguanine, all achieved complete remission (CR). Neither patient with del(16)(q22) had typical M4Eo morphology at diagnosis; CR was achieved in one and one had resistant leukaemia. Patients with other abnormalities of 16q had blasts of diverse morphology and, although morphologically abnormal eosinophils were seen in three patients, this was not as marked as in the patients with inv(16). CR was achieved in two of the four patients with other abnormalities of 16q but duration of remission was short in both cases. These results suggest that most patients with del(16)(q22) and other abnormalities of 16q22 do not have typical AML M4Eo. Such patients tend to have a worse prognosis, and are more likely to have complex karyotypes typical of secondary leukaemia.

Deletion 14q (q22q23) associated with anophthalmia, absent pituitary, and other abnormalities

A fetus is described with anophthalmia, absent pituitary, hypoplastic adrenal glands and kidneys, absent left horn of the uterus, underdeveloped genitalia, and clinodactyly, with a deletion of 14(q22q23). A review of published reports found no similar deletion cases.

Monosomy 20: a nonrandom finding in childhood acute lymphoblastic leukemia

We describe four cases of childhood acute lymphoblastic leukemia with monosomy 20 as the sole cytogenetic abnormality. These cases represent 3.4% of cytogenetically abnormal childhood ALL studied in our institute at diagnosis. The patients presented at similar age, ranging from 31 to 36 months. All four patients remain in first remission with survival time being at least 20 months from the time of diagnosis.

A 45,X/69,XXY fetus

Post-mortem examination of a 20-week fetus showed incompletely masculinised external genitalia, hypoplastic adrenal glands and minor physical stigmata suggestive of a chromosome abnormality. Gonad and skin were karyotyped and both were found to contain two cell lines, 45,X and 69,XXY. It appears this fetus is a true 45,X/69,XXY mosaic.