Two Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function

For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. In the case of a CCR, such as the one described here, the probability of gamete formation with a karyotype, showing a balance of chromosome regions, is extremely low. Recommendation for the family in genetic counseling should take into account the obtained result. In the case of an sSMC, it is critically important to identify the original chromosome from which the sSMC has been derived, even if the euchromatin material is absent. Finally, we present our view on the optimal strategy of identifying and describing sSMCs, namely the production of a microdissectional DNA probe from the sSMC combined with a consequent reverse painting.

[Accidental finding of a cri du chat syndrome in an adult patient by means of array-CGH]

INTRODUCTION

The cri du chat syndrome (CDCS) come from a partial or total deletion of the short arm of chromosome 5, being one of the most common deletion syndromes in human beings. The great majority of patients are diagnosed between the first month and first year of life, but herein we report a finding of a CDCS in a woman with a suspect of spinocerebellar ataxia, and a family medical record of ataxia and bipolar disorder. We pay special attention to the clinical features as well as the diagnostics tests, used to identify the CDCS.

CASE REPORT

We report a case of a 46 years-old woman showing a borderline intelligence and bilateral cataract surgery at the age of 43. Beginning of symptoms in childhood included hypoacusia, ataxia, dysarthria, dysphagia, depression, cognitive impairment and bipolar disorder. Physical examination showed microcephaly, micrognathia, talipes equinovarus and ataxia. Karyotype and array-CGH were carried out on peripheral blood. The patient showed a rearrangement involving chromosomes 5 and 15, as well as an inversion of chromosome 9: 45,XX,inv9(p11q13);t(5,15)(p15.33;q11.2). Array comparative genomic hybridization was performed showing a 2.91 Mb deletion at 5p15.33, genomic formula arr 5p15.33 (151537-3057771)x1. The deletion involved 20 genes, including TERT gene.

CONCLUSIONS

The multiple gene deletions confirmed the CDCS diagnosis, being responsible for the patient phenotype. It has been showed up the importance of using the correct diagnosis techniques (array-CGH, peripheral blood karyotype) as well as their appropriate choice.

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.

The incidence of myelodysplastic syndromes in Western Greece is increasing

Descriptive epidemiology of the myelodysplastic syndromes (MDS) is always interesting and may reveal time-dependent and geographical variations, as well as occupational exposure. Epidemiological data in Greece are not available by now. We have collected and analyzed medical records of all patients with a documented diagnosis of MDS, performed by an expert hematologist and/or hematopathologist, in the geographical area of Western Greece, during the 20-year period, defined between 1990 and 2009. We have then calculated and described demographic and clinical features of the diagnosed MDS patient population, and assessed the incidence and prevalence rates of MDS in Western Greece, during the above-mentioned period. A total of 855 patients with newly diagnosed MDS have been identified. Refractory anemia was the most common subtype in both FAB and WHO classification systems and in both genders. Del-5q and RARS were more commonly encountered among females, and the dysplastic subtype of chronic myelomonocytic leukemia among males. Trisomy 8 was the most common single cytogenetic abnormality. The crude mean annual incidence rate of MDS was 6.0 per 100,000 inhabitants aged ≥15 years old (all subtypes according to FAB), and it was 4.8 per 100,000 when CMML and RAEB-T were excluded. Crude incidence rate was higher in rural than in urban areas, but this finding was not confirmed after age standardization. Age-standardized mean annual incidence rate in men was 7.9/100,000 and in women 3.4/100,000. A continuously increasing incidence rate of MDS has been observed throughout the study period.

Myelodysplastic syndromes classification and risk stratification

Myelodysplastic syndromes (MDS) are spectrum of bone marrow failure disorders that share a common pathologic feature: cytologic dysplasia. The classification of MDS reflects the understanding of the disease. It is hoped that in the future classification and risk stratification will be based on underlying pathobiology of different disease subsets and molecular signatures where the pathologic classification represents their phenotype. This article reviews MDS classification and risk stratification highlighting differences between the various systems.

Relationship of differential gene expression profiles in CD34+ myelodysplastic syndrome marrow cells to disease subtype and progression

Microarray analysis with 40 000 cDNA gene chip arrays determined differential gene expression profiles (GEPs) in CD34(+) marrow cells from myelodysplastic syndrome (MDS) patients compared with healthy persons. Using focused bioinformatics analyses, we found 1175 genes significantly differentially expressed by MDS versus normal, requiring a minimum of 39 genes to separately classify these patients. Major GEP differences were demonstrated between healthy and MDS patients and between several MDS subgroups: (1) those whose disease remained stable and those who subsequently transformed (tMDS) to acute myeloid leukemia; (2) between del(5q) and other MDS patients. A 6-gene "poor risk" signature was defined, which was associated with acute myeloid leukemia transformation and provided additive prognostic information for International Prognostic Scoring System Intermediate-1 patients. Overexpression of genes generating ribosomal proteins and for other signaling pathways was demonstrated in the tMDS patients. Comparison of del(5q) with the remaining MDS patients showed 1924 differentially expressed genes, with underexpression of 1014 genes, 11 of which were within the 5q31-32 commonly deleted region. These data demonstrated (1) GEPs distinguishing MDS patients from healthy and between those with differing clinical outcomes (tMDS vs those whose disease remained stable) and cytogenetics [eg, del(5q)]; and (2) molecular criteria refining prognostic categorization and associated biologic processes in MDS.

Treatment of MDS: something old, something new, something borrowed

As opposed to the treatment landscape for myelodysplastic syndromes (MDS) two decades ago, potential therapies now abound for the treatment of lower-risk and higher-risk populations. In lower-risk patients, decision tools can be used to determine the likelihood of response to erythropoiesis stimulating agents (ESAs), which have demonstrated survival advantages in retrospective studies in patients with MDS, and whether these patients should be treated initially with ESAs or non-growth factor ("active") therapies. Lenalidomide has shown good activity in transfusion-dependent patients with the del(5q) cytogenetic abnormality and modest activity in other lower-risk patients. In higher-risk patients, the DNA methyltransferase inhibitors produce complete and partial responses in 20% to 30% of patients, and for the first time, the MDS drug azacitidine has demonstrated a survival advantage when compared with conventional therapies. Newer therapies stimulate platelet production and target novel pathways, while a panoply of combination studies are underway or recently completed and that likely represent the next frontier in MDS therapy.

Myelodysplastic syndromes associated with interstitial deletion of chromosome 5q: clinicopathologic correlations and new insights from the pre-lenalidomide era

To better estimate prognosis for patients with myelodysplastic syndromes (MDS) associated with clonal interstitial deletions of the long arm of chromosome 5 (del(5q)), we reviewed the medical records of 130 adults with del(5q) MDS seen at our institution over a 15-year period. Overall median survival of this cohort was 9.5 months, shorter than reported in earlier series. The least favorable outcomes are associated with complex cytogenetics, lack of any normal metaphases, normocytic rather than macrocytic erythrocyte indices, and low baseline lymphocyte counts. Lymphopenia but not neutropenia at the time of diagnosis appears to be a new adverse prognostic indicator. Cytogenetic breakpoints defined by G-banded karyotyping correlate poorly with particular disease features. Surprisingly, survival of patients with treatment-related MDS was equivalent to that of de novo MDS with del(5q) in this series. Morphologic features associated with del(5q) are diverse. Most patients with del(5q) MDS do not meet criteria for WHO-defined 5q-syndrome, and the presence of del(5q) does not appear to modify the clinical phenotype otherwise risk-stratified by the International Prognostic Scoring System (IPSS). Additional important prognostic factors not taken into account by the IPSS include the baseline erythrocyte indices, lymphocyte count, and clonal burden.

Cytogenetic features in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) comprise a group of bone marrow diseases characterized by profound heterogeneity in morphologic presentation, clinical course, and cytogenetic features. Roughly 50% of patients display clonal chromosome abnormalities. In several multicentric studies, the karyotype turned out to be one of the most important prognostic parameters and was incorporated into statistical models aiming for a better prediction of the individual prognosis like the International Prognostic Scoring System. However, due to the profound cytogenetic heterogeneity, the impact of many rare abnormalities as well as combinations of anomalies occurring in a substantial portion of patients with MDS is still unknown and can only be delineated on the basis of large international multicentric cooperations. Recently, the German-Austrian MDS Study Group presented cytogenetic findings in 2,072 patients with MDS, which serve as a basis for the characterization of the cytogenetic subgroups discussed in this article. The availability of new therapeutic options for low- and high-risk MDS targeted against distinct entities characterized by specific chromosome abnormalities, like 5q-deletions, monosomy 7, and complex abnormalities underlines the important role of cytogenetics for the clinical management of MDS. This article thus focuses on the clinical and prognostic relevance, the molecular background, and therapeutic perspectives in these three cytogenetic subgroups.

Immunomodulatory drugs in the treatment of myelodysplastic syndromes

PURPOSE OF REVIEW

The aim of this article is to discuss the proposed mechanisms of action, clinical trial data, and clinical implications for use of the immunomodulatory drugs in the treatment of myelodysplastic syndrome.

RECENT FINDINGS

The immunomodulatory drugs are a novel, nonteratogenic class of thalidomide analogues that are more potent and less toxic than the parent compound. Lenalidomide, a second generation immunomodulatory drug, has shown substantial remitting activity in myelodysplastic syndrome that is karyotype-dependent. Its biologic effects include T-cell co-stimulation, promotion of erythropoiesis, angiogenesis inhibition, and modulation of apoptosis. Results from the MDS-003 multicenter deletion 5q registration study show that lenalidomide suppresses the deletion 5q clone, and in higher risk myelodysplastic syndrome patients, may also alter the natural history of disease. Lenalidomide was approved by the US Food and Drug Administration for the treatment of International Prognostic Scoring System low or intermediate-1 risk myelodysplastic syndrome patients with chromosome 5q deletion. The most common adverse events with lenalidomide therapy are neutropenia and thrombocytopenia, the frequency of which is highest in patients with deletion 5q, in whom early clonal suppression is expected. Combination strategies are now in progress, which may improve the therapeutic potential of the immunomodulatory drugs.

SUMMARY

The immunomodulatory drugs show exciting erythropoietic activity in myelodysplastic syndrome that is karyotype-dependent.

Leukaemia-specific chromosome damage detected by comet with fluorescence in situ hybridization (comet-FISH)

Acute myeloid leukaemia (AML) is associated with exposure to benzene and treatment with chemotherapeutic agents. It is thought to arise from damage to specific regions of DNA, resulting in chromosome rearrangements or loss. For instance, a deletion on the long arm of chromosome 5 [e.g. del(5q31)] is common in AML patients previously treated with alkylating agents, such as melphalan, or exposed to benzene. Translocations of the MLL gene at 11q23 are frequently observed in AML arising from treatment with topoisomerase II inhibitors, such as etoposide. Our goal was to determine whether or not breakage at 5q31 and 11q23 is selectively induced by these chemical agents. To address this question, the comet assay combined with fluorescence in situ hybridization (comet-FISH) was used to detect DNA breakage in the specific chromosomal regions in an in vitro model. TK6 lymphoblastoid cells were exposed to melphalan, etoposide or the benzene metabolite, hydroquinone (HQ), at various concentrations. HQ, melphalan and etoposide induced DNA breaks at both 5q31 and 11q23 chromosome regions in a dose-dependant manner. However, HQ produced significantly more DNA damage at 5q31 than at 11q23. Etoposide produce slightly more DNA damage at 11q23 and melphalan had a somewhat greater effect at 5q31, but not significantly so. Thus, HQ and melphalan act similarly, perhaps explaining some similarities between benzene- and alkylating agent-induced AML. Comet-FISH also appears to be a useful approach for detecting and comparing damage to specific chromosome regions of significance in leukaemogenesis.

Molecular characterisation of a mosaicism with a complex chromosome rearrangement: evidence for coincident chromosome healing by telomere capture and neo-telomere formation

BACKGROUND

Broken chromosomes must acquire new telomeric "caps" to be structurally stable. Chromosome healing can be mediated either by telomerase through neo-telomere synthesis or by telomere capture.

AIM

To unravel the mechanism(s) generating complex chromosomal mosaicisms and healing broken chromosomes.

METHODS

G banding, array comparative genomic hybridization (aCGH), fluorescence in-situ hybridisation (FISH) and short tandem repeat analysis (STR) was performed on a girl presenting with mental retardation, facial dysmorphism, urogenital malformations and limb anomalies carrying a complex chromosomal mosaicism.

RESULTS & DISCUSSION

The karyotype showed a de novo chromosome rearrangement with two cell lines: one cell line with a deletion 9pter and one cell line carrying an inverted duplication 9p and a non-reciprocal translocation 5pter fragment. aCGH, FISH and STR analysis enabled the deduction of the most likely sequence of events generating this complex mosaic. During embryogenesis, a double-strand break occurred on the paternal chromosome 9. Following mitotic separation of both broken sister chromatids, one acquired a telomere vianeo-telomere formation, while the other generated a dicentric chromosome which underwent breakage during anaphase, giving rise to the del inv dup(9) that was subsequently healed by chromosome 5 telomere capture.

CONCLUSION

Broken chromosomes can coincidently be rescued by both telomere capture and neo-telomere synthesis.

Clinical Relevance of Cytogenetics in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous stem cell disorders with different clinical behaviors and outcomes. Conventional cytogenetics (CC) studies have demonstrated that the majority of MDS patients harbor clonal chromosome defects. The probability of discovering a chromosomal abnormality has been increased by fluorescence in situ hybridization (FISH), which has revealed that about 15% of patients with a normal chromosome pattern on CC may instead present cryptic defects. Cytogenetic abnormalities, except for the interstitial long-arm deletion of chromosome 5 (5q-), are not specific for any French-American-British (FAB)/World Health Organization (WHO) MDS subtypes, demonstrate the clonality of the disease, and identify peculiar morphological entities, thus confirming clinical diagnosis. In addition, chromosome abnormalities are independent prognostic factors predicting overall survival and the likelihood of progression in acute myeloid leukemia.

Polymorphisms of the CD14 gene and atopic phenotypes in Czech patients with IgE-mediated allergy

IgE-mediated allergy is a common chronic disorder resulting from interactions between genetic and environmental factors. The gene encoding CD14 is a positional candidate gene for allergic diseases as it is localised on chromosome 5q31.1, a region linked to asthma and bronchial hyperresponsiveness. We investigated the relationship among atopic phenotypes and six polymorphisms in the CD14 gene. Polymerase chain reaction with RFLP analyses was used to determine the CD14 genotypes in subjects with IgE-mediated allergic diseases (n=282) and random controls (n=187). No significant differences in allele or genotype frequencies for individual polymorphisms between patients and controls were found. However, when atopic patients were subdivided into subjects with positive and with negative skin prick tests for separate antigens, T allele of the 1341G/T polymorphism was significantly associated with positive reactivity to mites (P=0.007) and moulds (P=0.041). Similarly, the C allele frequency of the -159C/T variant was increased in patients with positive skin prick tests for mites (P=0.046) and moulds (P=0.056). In haplotype analysis, the common -1619A/-1359G/-550C/-159C/+1188G/+1341T haplotype was associated with positive reaction to these antigens (P values: 0.0008-0.0035). Our study supports the idea that CD14 plays a role in IgE-mediated allergic diseases, and its gene polymorphisms can be important for manifestation of these disorders.

Immunomodulatory drugs in myelodysplastic syndromes

This review summarises the mechanism of action of immunomodulatory analogues of thalidomide and their use in myelodysplastic syndromes. Thalidomide was found to have a response rate of approximately 20% in these patients. Lenalidomide--which is more potent and less toxic than thalidomide--has been used in three clinical trials and produced the best responses (60 - > 90%) in low- and intermediate-1-risk transfusion-dependent patients with del(5q). The responses are purely erythroid in nature, and are associated with major cytogenetic responses in > 50% of the del(5q) patients. Non-del(5q) low- and intermediate-1-risk transfusion-dependent patients also had a approximately 25% incidence of transfusion independence following therapy with lenalidomide. Median time to response is approximately 4 weeks and 90% of patients respond within 12 weeks. The precise mechanism of action remains unknown but anticytokine, antiangiogenic and immunomodulatory properties are thought to play a role.

Treatment of myelodysplastic syndrome with isolated del(5q) including bands q31-q33 with a combination of all-trans-retinoic acid and tocopherol-alpha: a phase II study

All-trans-retinoic acid (ATRA) alone or in combination with cytokines and vitamins has been shown to stimulate erythropoiesis in low-risk myelodysplastic syndromes (MDS). We performed a phase II study on 29 patients with MDS and isolated del(5q) including bands q31-q33 to determine the efficacy and safety of ATRA in combination with tocopherol-alpha. All patients had low/intermediate-1 risk MDS according to the international prognostic scoring system. They received 45 mg/m(2) ATRA on days 1 to 90, and 90 mg/m(2) on days 91 to 180. Tocopherol dosage was 600 IU three times daily. Twenty-four patients completed dose level I, and 12 patients dose level II. Eighty-six percent of patients experienced side effects. Thirty discontinued the drug treatment due to such events as skin reactions, cheilitis, conjunctivitis, joint pain, creatinine increase, or CNS symptoms. One patient (3%) achieved a major erythroid response resulting in transfusion independence throughout the study. Four patients (14%) achieved a minor erythroid response with >50% reduction of transfusion needs. None of the participants had a cytogenetic response. There was no significant improvement in quality of life among responding patients as measured by the European Organization for the Research and Treatment of Cancer (EORTC) quality of life questionnaire. Based on these results, the combination of ATRA and tocopherol-alpha is not recommended for the treatment of del(5q) MDS.

High-resolution chromosome arm 5p array CGH analysis of small cell lung carcinoma cell lines

Genomic amplification of regions on chromosome arm 5p has been observed frequently in small cell lung cancer (SCLC), implying the presence of multiple oncogenes on this arm. Although conventional comparative genomic hybridization (CGH) detects gross chromosomal copy number changes, gene discovery requires a higher-resolution approach in order to identify regions of alteration precisely. To identify candidate genes on this chromosome arm, we developed a high-resolution, 10-clone-per-megabase bacterial artificial chromosome CGH array for 5p and examined a panel of 15 SCLC cell lines. Utilization of this CGH array has allowed the fine-mapping of breakpoints to regions as small as 200 kb in a single experiment. In addition to reporting our observations of aberrations at the well-characterized SKP2 and TERT loci, we describe the identification of microdeletions that have escaped detection by conventional screens and the identification TRIO and ANKH as novel putative oncogenes.

Loss of heterozygosity patterns of sclerosing hemangioma of the lung and bronchioloalveolar carcinoma indicate a similar molecular pathogenesis

CONTEXT

The histogenesis and origin of sclerosing hemangioma (SH) of lung were uncertain for many years. Many immunohistochemical, ultrastructural, and recent molecular studies support the hypothesis that SH is a neoplasm originating from the cells of the terminal lobular unit, similar to the nonmucinous variant of bronchioloalveolar carcinoma (BAC). Most cases of SH are benign, but they can metastasize to the regional lymph nodes.

OBJECTIVE

To compare the patterns of allelic loss of tumor suppressor genes in SH and BAC by microdissection-based genotypic analysis.

DESIGN

Microdissection-based loss of heterozygosity analysis of 9 cases of SH and 14 cases of BAC, using a panel of 7 polymorphic microsatellite markers located on 1p, 5q, 9p, 10q, and 17p. Microsatellite marker and chromosomal arm-based fractional allelic loss (FAL) were calculated in each case.

RESULTS

Our results showed similar patterns of allelic loss between the 2 groups of tumors on an individual case basis. Chromosomal arms 5q and 10q showed frequent allelic loss in SH (66.7% and 62.5%, respectively), whereas in BAC, chromosomal arm 17p (52.6%) was frequently affected. A statistically significant difference in allelic loss between SH and BAC was located only on chromosomal arm 5q (P =.04). Microsatellite marker D5S615 was significantly more frequently affected in SH than in BAC (66.7% vs 28.6%; P =.04).

CONCLUSION

Our molecular data support the hypothesis of common origin of SH and BAC. A putative tumor suppressor gene that might play a role in tumorigenesis of SH may be located on the chromosomal arm 5q.

A new complex rearrangement involving the ETV6, LOC115548, and MN1 genes in a case of acute myeloid leukemia

A new complex rearrangement involving chromosome bands 5q13, 12p13, 22q11, and 3q12 was identified and characterized in a patient with acute myeloid leukemia. Fluorescence in situ hybridization showed the involvement of the ETV6 gene in 12p13. ETV6 primers were specifically designed for 3'- and 5'-RACE-PCR experiments, which led to the identification of the other two rearranged genes. The derivative chromosome 5 harbored a fusion of the ETV6 sequence with that of the LOC115548 gene. The two genes were placed in opposite orientation and did not encode a fusion protein. On the derivative chromosome 12, ETV6 was fused to the MN1 gene on chromosome 22. Also in this case, the insertion, within the MN1 sequence, of a portion of chromosome 3 prevented the formation of a fusion protein. Finally, the derivative chromosome 22 contained the 3' portions of both LOC115548 and MN1, and no fusion transcript with coding potential could be predicted. In conclusion, all chromosome breakpoints led to the truncation of the three involved genes in the absence of predicted fusion proteins. This study lends further support to the hypothesis that gene disruption resulting in either loss of function or haploinsufficiency may be relevant in acute myeloid leukemia pathogenesis.

Lack of response to imatinib mesylate in a patient with accelerated phase myeloproliferative disorder with rearrangement of the platelet-derived growth factor receptor beta-gene

Imatinib mesylate has been reported to produce positive results in atypical chronic myeloproliferative disorders (CMD) with chromosomal translocations that disrupt the platelet-derived growth factor receptor beta gene (PDGFRB). We used imatinib to treat a 49-year old man with atypical CMD in accelerated phase and the H4 (D10S170)-PDGFRB fusion gene. After 3 months of treatment, we observed grade 4 hematologic toxicity and a lack of response.

Prader-Willi syndrome resulting from an unbalanced translocation: characterization by array comparative genomic hybridization

Prader-Willi syndrome (PWS) is caused by lack of expression of paternally inherited genes on chromosome 15q11-->15q13. Most cases result from microdeletions in proximal chromosome 15q. The remainder results from maternal uniparental disomy of chromosome 15, imprinting center defects, and rarely from balanced or unbalanced chromosome rearrangements involving chromosome 15. We report a patient with multiple congenital anomalies, including craniofacial dysmorphology, microcephaly, bilateral cryptorchidism, and developmental delay. Cytogenetic analysis showed a de novo 45,XY,der(5)t(5;15)(p15.2;q13), -15 karyotype. In effect, the proband had monosomies of 5p15.2-->pter and 15pter-->15q13. Methylation polymerase chain reaction analysis of the promoter region of the SNRPN gene showed only the maternal allele, consistent with the PWS phenotype. The proband's expanded phenotype was similar to other patients who have PWS as a result of unbalanced translocations and likely reflects the contribution of the associated monosomy. Array comparative genomic hybridization (array CGH) confirmed deletions of both distal 5p and proximal 15q and provided more accurate information as to the size of the deletions and the molecular breakpoints. This case illustrates the utility of array CGH in characterizing complex constitutional structural chromosome abnormalities at the molecular level.

Protein phosphatase 4 interacts with the Survival of Motor Neurons complex and enhances the temporal localisation of snRNPs

Protein phosphatase 4 (PPP4) is a ubiquitous essential protein serine/threonine phosphatase found in higher eukaryotes. Coordinate variation of the levels of the catalytic subunit (PPP4c) and the regulatory subunit (R2) suggests that PPP4c and R2 form a heterodimeric core to which other regulatory subunits bind. Two proteins that specifically co-purify with Flag-epitope-tagged R2 expressed in HEK-293 cells were identified as Gemin3 and Gemin4. These two proteins have been identified previously as components of the Survival of Motor Neurons (SMN) protein complex, which is functionally defective in the hereditary disorder spinal muscular atrophy. Immuno-sedimentation of the epitope-tagged SMN protein complex from HeLa cells expressing CFP-SMN showed that the SMN protein interacts, as previously reported, with Gemin2 (SIP1), Gemin3 and Gemin4 and in addition associates with PPP4c. The SMN complex has been implicated in the assembly and maturation of small nuclear ribonucleoproteins (snRNPs). Expression of GFP-R2-PPP4c in HeLa cells enhances the temporal localisation of newly formed snRNPs, which is consistent with an association of R2-PPP4c with the SMN protein complex.

Past exposure to densely ionizing radiation leaves a unique permanent signature in the genome

Speculation has long surrounded the question of whether past exposure to ionizing radiation leaves a unique permanent signature in the genome. Intrachromosomal rearrangements or deletions are produced much more efficiently by densely ionizing radiation than by chemical mutagens, x-rays, or endogenous aging processes. Until recently, such stable intrachromosomal aberrations have been very hard to detect, but a new chromosome band painting technique has made their detection practical. We report the detection and quantification of stable intrachromosomal aberrations in lymphocytes of healthy former nuclear-weapons workers who were exposed to plutonium many years ago. Even many years after occupational exposure, more than half the blood cells of the healthy plutonium workers contain large (>6 Mb) intrachromosomal rearrangements. The yield of these aberrations was highly correlated with plutonium dose to the bone marrow. The control groups contained very few such intrachromosomal aberrations. Quantification of this large-scale chromosomal damage in human populations exposed many years earlier will lead to new insights into the mechanisms and risks of cytogenetic damage.

The status of the chromatin of human preimplantation embryos with good morphology

The data about the relation and succession of blastomere fragmentation, cleavage rate and chromatin anomalies in preimplantation mammalian embryos are empirical and controversial at present. In this work we studied the proportion of nuclear fragmentation and condensation in 3-5-cell stage human embryos with no or minimal blastomere fragmentation (morphological class A and B, respectively) and the possibilities to perform FISH chromosomal analyses with them. We observed different stages of chromatin damage in blastomere nuclei corresponding to the steps of nuclear apoptotic changes well known in many cell types. The ploidity analysis of chromosomes 1, 5, 19 and X was determined as successful in embryos which had at least 2 out of 3, 3 out of 4 or 3 out of 5 normal nuclei with an equal number of FISH signals. There was no difference in the percentage of abnormal nuclei among the A- and B-class embryos. Tendencies noted by us suggest that the minimal blastomere fragmentation (up to 20% of perivitelline space) does not preclude the normal nuclear status allowing successful ploidy testing. The presence of condensed chromatin is a critical factor for interphase cytogenetic analysis of single early blastomeres.

Periventricular heterotopia associated with chromosome 5p anomalies

Periventricular heterotopia (PH) is characterized by neuronal nodules along the lateral ventricles. Whereas mutations in X-linked FLNA cause such cortical malformations, the authors report two cases of PH localizing to chromosome 5p. Both subjects have complex partial seizures. MRI demonstrated bilateral nodular PH, with subcortical heterotopia or focal gliosis. FISH identified a duplication of 5p15.1 [46,XX,dup(5)(p15.1p15.1)] and a trisomy of 5p15.33 [46,XY,der(14)t(5;14)(p15.33;p11.2) mat]. These findings suggest a new PH locus along the telomeric end of chromosome 5p.

A unique clone involving multiple structural chromosome rearrangements in a myelodysplastic syndrome case

In a young female patient presenting with a myelodysplastic syndrome (MDS), a unique clone involving six structural chromosome rearrangements was identified using G-banding and molecular cytogenetic techniques. Fifty GTG-banded metaphases from bone marrow were initially analyzed and all metaphases contained all of the six structural chromosome rearrangements. To further define the GTG-banded karyotype, a series of fluorescence in situ hybridization and primed in situ labeling experiments were performed and the karyotype was then characterized as: 46,XX,r(5)(p13q13),der(20)t(5;20),dup(11)(p11.2p15), r(11)(p15q25),del(13)(q14),idic(22)(p11). The patient quickly progressed to acute nonlymphocytic leukemia three months after the diagnosis and died of a hemorrhage in the brain parenchyma two months later. In this case, the multiple structural chromosome rearrangements conferred an obvious cellular proliferative advantage and indicated a very poor prognosis. Considering that multiple chromosome abnormalities associated with MDS transformation are often polyclonal, this unique clone involving six structural chromosome rearrangements make our case highly unusual.

Genetic susceptibility to oral cancer and the expression of common fragile sites. a study of 100 patients

The expression of bleomycin-induced fragile sites (FS) in the blood lymphocytes of 150 individuals (100 oral cancer patients and 50 age and sex matched controls) is described. FS expression frequencies in oral cancer patients were significantly higher when compared with controls. FS expression was site specific in oral cancer patients. Chromosome 5 was the most affected, with four of its FS expressing in high frequencies. Enhanced expression of FS at the centromeric region was observed in the patient group. This study emphasizes the role of FS in the genetic susceptibility to oral cancer.

Fas-mediated apoptosis is important in regulating cell replication and death in trisomy 8 hematopoietic cells but not in cells with other cytogenetic abnormalities

Increased apoptosis of hematopoietic progenitor cells has been implicated in the pathophysiology of cytopenias associated with myelodysplastic syndromes (MDSs), and inhibition by immunosuppression may account for the success of this treatment in some patients. We examined bone marrow and peripheral blood of 25 patients with chromosomal abnormalities associated with MDS (monosomy 7, trisomy 8, and 5q-) for evidence of apoptosis. When fresh bone marrow was examined, the number of apoptotic and Fas-expressing CD34 cells was increased in patients with trisomy 8, but decreased in monosomy 7, as compared with healthy control donor marrow. Fas expression was increased in the trisomy 8 cells and decreased in the monosomy 7 cells when compared with normal cells from the same patient. Trisomy 8 cells were more likely to express activated caspase-3 than were normal cells. For bone marrow cells cultured with Fas agonist or Fas antagonist, the percentage of cells with trisomy 8 was significantly decreased in most cases after Fas receptor triggering and increased by Fas ligand (Fas-L) antagonist (P < 0.01), suggesting increased Fas susceptibility of cells with trisomy 8. No such changes were seen in cultures of cells with 5q- or monosomy 7. Fas antagonist facilitated the expansion of cells with trisomy 8 only. Cells with trisomy 8 appear to be more susceptible to Fas-mediated apoptosis. Clinical data demonstrating the responsiveness of some patients with trisomy 8 to anti-thymocyte globulin (ATG) and cyclosporine (CsA) would favor an active role of the immune system in this syndrome.

Differential expression of TCL1 during pre-B-cell acute lymphoblastic leukemia progression

Nonrandom, recurring chromosomal translocations are critical events in the pathogenesis of leukemia. The recently identified TEL/AML1 (CBFA2/EVT6) fusion gene occurs as a result of the t(12;21)(p13;q22) in approximately 25% of children with diagnosed pre-B-cell acute lymphoblastic leukemia (PBC-ALL). To identify changes in gene expression patterns that occur during PBC-ALL disease progression, we used cDNA microarrays to compare expressed sequences from the AT-1 and AT-2 cell lines. These cell lines, from the same patient, were established from two distinct stages of PBC-ALL disease progression, namely, first and second relapse. Analysis of both cell lines with spectral karyotying (SKY) revealed an insertion of chromosome 8 into chromosome 5 and a previously undetected translocation in AT-2 involving chromosomes 1 and 17. Hybridization of cDNA microarrays identified the TCL1 transcript as being overexpressed in the AT-2 cell line relative to AT-1. Northern blot analysis showed an eightfold increase of the TCL1 transcript in AT-2 over AT-1 cells. Western blot analysis showed that the TCL1 protein was expressed more than 50-fold higher in AT-2 than AT-1 cells. TCL1 expression was correlated with TEL expression by reintroducing TEL into AT-2 cells and demonstrating that those cells expressing TEL at high levels showed a decreased expression of endogenous TCL1.

Genetics of adenocarcinomas of the small intestine: frequent deletions at chromosome 18q and mutations of the SMAD4 gene

The small intestinal mucosa makes up about 90% of the total surface of the gastrointestinal tract. However, adenocarcinomas arise rarely in this location. To elucidate genetic alterations underlying tumour development in the small intestine we investigated 17 sporadic adenocarcinomas. By comparative genomic hybridization recurrent gains of chromosomal material were found at chromosomes 7, 8, 13q, and 20 (5/17, each), while non-random losses were seen at 8p, 17p (4/17, each), and 18 (8/17 cases). Deletions at 5q, the location of the APC tumour suppressor gene, were seen in three cases. Microsatellite analysis with markers on chromosomal arms 1p, 5q, 8p, 17p, 18q, 19p, and 22q revealed a microsatellite instable phenotype in two cases and a high frequency of loss at 18q21-q22 (80%). Given the high incidence of 18q21-q22 deletions, we performed sequencing analysis of SMAD4, a downstream component of the TGFbeta-pathway, located at 18q21. Four tumours displayed mutations in highly conserved domains of the gene indicating disruption of TGFbeta-signalling. Our data reveal complex genetic alterations in sporadic small intestinal carcinomas. However, most tumours share deletions of 18q21-q22, which frequently target SMAD4. This indicates that disruption of TGFbeta-signalling plays a critical role in small intestinal tumorigenesis.

Periodic morphologic, cytogenetic and clonality evaluation after autologous peripheral blood progenitor cell transplantation in patients with lymphoproliferative malignancies

BACKGROUND AND OBJECTIVES

Myelodysplastic syndrome (MDS), secondary acute myeloid leukemia (sAML) and clonal karyotypic abnormalities, have been recognized as relatively frequent and potentially serious complications of autologous peripheral blood progenitor cell transplantation (PBPCT) for Hodgkin's disease (HD), non-Hodgkin's lymphoma (NHL) or multiple myeloma (MM).

DESIGN AND METHODS

We analyzed 66 patients, undergoing PBPCT for HD, NHL, MM or chronic lymphocytic leukemia (CLL). Patients reported in this study had to be in continuous complete remission after transplantation without receiving chemo-radiotherapy or other biological response modifiers, had to show absence of cytogenetic abnormalities and myelodysplastic features at transplantation and had to have at least 12 months of follow-up. We evaluated the bone marrow, peripheral blood, cytogenetics and clonality (HUMARA) 12 months after the transplant and thereafter every 12 months or every 6 months if lineage dysplasia, clonal or cytogenetic abnormalities were detected.

RESULTS

We did not observe MDS/sAML, according to the FAB classification, in 163 assessments of 66 patients over a median follow-up of 25 months (range 12-106) after PBPCT. Twelve patients showed lineage dysplasia: six patients had dyserythropoiesis, 2 patients dysgranulopoiesis, one dysmegakaryocytopoiesis, two patients showed double lineage dysplasia (erythroid and granulocytic), and one patient showed dysgranulopoiesis at the first control acquiring dyserythropoiesis at the next follow-up. We found three cytogenetic abnormalities in the absence of concomitant dysplastic features: transient -5q, -Y, fra(10)(q25). The female patient with the cytogenetic abnormality -5q showed transient unbalanced clonality by HUMARA assay; further controls documented normalization of both clonality and cytogenetics.

INTERPRETATION AND CONCLUSIONS

The occurrence of MDS/sAML depends on a variety of risk factors such as the number and type of prior courses of chemo-radiotherapy, total body irradiation in conditioning regimen, cytogenetic and morphologic alterations prior to transplant. This may account for the difference in reporting MDS/sAML after transplantation. The lack of exposure to recognized risk factors for MDS/sAML in our patients may account for the absence of this complication in this study. We consider that the use of stringent morphologic criteria, especially during the first period after PBPCT, combined with cytogenetic, clonality and FISH analyses are necessary for a correct diagnosis of MDS and to overcome the limitations of the FAB and WHO classifications in this setting.

Translocation t(5;14)(q35;q32) in three cases of childhood T cell acute lymphoblastic leukemia: a new recurring and cryptic abnormality

We report three cases of T-ALL in which conventional cytogenetic analysis yielded normal karyotypes, but for which a new M-FISH technique (IPM-FISH) was able to detect a translocation. For these patients this technique highlighted a new, recurring and cryptic translocation t(5;14)(q35;q32) in childhood T-ALL which might be phenotypically restricted. The most innovative part of this technique is the use of interspersed polymerase chain reaction (IRS-PCR) painting probes that show an R-band pattern simultaneous with the combinatorial labeling. Contrary to the DOP-PCR, IRS-PCR-derived probes provide stronger hybridization signals at the telomeric ends that potentially increase the possibility of detecting cryptic translocations. All the IPM-FISH findings were validated by FISH with whole chromosome painting and unique sequence probes. These results demonstrate the efficient use of IPM-FISH as an improved, single-step method for the identification of cryptic chromosomal abnormalities. This new IPM-FISH technique is a good tool to display cryptic chromosomal abnormalities.

Biochemical differences between SUDHL-1 and KARPAS 299 cells derived from t(2;5)-positive anaplastic large cell lymphoma are responsible for the different sensitivity to the antiproliferative effect of p27(Kip1)

An inverse correlation between p27(Kip1) expression and proliferation has been recently established in tissues derived from human lymphomas. The nucleophosmin-anaplastic lymphoma kinase (NPM-ALK)/phospholipase C-gamma (PLCgamma) complex also appears to play an important role in cell proliferation and malignant transformation of anaplastic large cell lymphoma (ALCL). In this study, we report that SUDHL-1 and KARPAS 299 ALCL-derived cell lines present different sensitivity to the antiproliferative effect of recombinant adenovirus-mediated p27(Kip1) expression or to serum-starvation in culture media. The results indicate that exogenous p27(Kip1) may interact with the NPM-ALK/PLCgamma pathway in SUDHL-1 but not in KARPAS 299 cells. This interaction correlates with changes in cell cycle and cell morphology observed mainly in SUDHL-1 cells. The percentage of SUDHL-1 cells in S phase declines, whereas it is almost unchanged in KARPAS 299 cells as compared to the controls after 96 h of infection with the recombinant adenovirus. Furthermore KARPAS 299 cells are resistant to serum-starvation due to deficient p27(Kip1)-upregulation and G1 arrest, whereas SUDHL-1 cells respond with increased G1 phase and p27(Kip1)-upregulation after 48 h of serum-starvation. Both cell lines express appropriate variation of levels of cyclins E and A, and Rb-phosphorylation as expected by growing them in culture media with different FBS content. Although both cell lines express cyclin D2, SUDHL-1 cells only present high level of cyclin D3. Moreover SUDHL-1 cells express high level of PTEN and the PKB/Akt pathway is constitutively activated in both cell lines. Lastly SUDHL-1 cells show higher levels of phosphotyrosine-containing proteins that is correlated with a higher NPM-ALK-associated autophosphorylation activity compared to KARPAS 299 cells. Our study clearly identifies some of the biochemical differences that may explain the difference in sensitivity to antiproliferative stimuli shown by two cell lines derived from the same type of lymphoma.

Follicular thyroid cancer cells: a model of metastatic tumor in vitro (review)

We used a thyroid metastatic tumor model to analyze some of the mechanisms of invasion and metastasis in culture. Chronic TSH stimulation (thyroid stimulating hormone) was associated with enhanced tumor proliferation and aggressiveness. We present a unique metastatic tumor model including three follicular thyroid cancer cell lines using a human primary tumor and two metastases of the same patient. They contain thyroglobulin, have intact thyroid functions and response to TSH. Investigating growth factor sensitivity we found that the amplitude of stimulation or inhibition of invasion was significantly smaller in both metastatic cell lines. Unstimulated cells of the lung metastasis had the highest basal invasive potential, but were only minimally affected by the stimulation of growth factors. In contrast, the parental cell line had the lowest basal invasiveness, but was considerably stimulated by growth factors.

Insights into the biologic and molecular abnormalities in adult acute lymphocytic leukemia

The last 3 decades have seen much progress in the treatment and outcome of patients with ALL. Unfortunately, the success that has been achieved in children with ALL has not yet been translated into adult patients. Insight into the biologic and molecular abnormalities in ALL may, however, provide the necessary clues that allow a clearer understanding of the crucial differences in the behavior of ALL in different groups of patients. As the molecular basis of the disease is deciphered, new targets are discovered that may prove useful for therapeutic interventions in the future.

Submicroscopic insertion of RARalpha gene into chromosome 15 in two cases of acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is characterized by a specific translocation (15;17)(q22;q21), resulting in the formation of PML/RARalpha chimeric transcripts. We report two female patients with PML/RARalpha-positive classical APL, whose leukemic cells expressed a variant translocation, t(5;15)(q13;q22) and t(15;17)(q22;p13), respectively. Both translocations were confirmed by whole chromosome painting which revealed no apparent involvement of 17q. A two-color fluorescence in situ hybridization with a 5' PML and a 3' RARalpha probe showed, in both cases, the presence of a PML-RARalpha fusion gene, on the der(15)t(5;15) long arm, and on the der(17)t(15;17) short arm, respectively. These two complex rearrangements resulted most probably from a two-step mechanism: (1) a submicroscopic insertion into 15q of a 17q segment including the 3' part of the RARalpha gene; (2) a reciprocal translocation between der(15) and a variable chromosome arm, with a breakpoint distal and proximal to RARalpha insertion in the case of t(5;15) and t(15;17), respectively. Molecular and prognosis significance of these variant translocations are discussed.

Interstitial deletion of the short arm of chromosome 12 during clonal evolution in myelodysplastic syndrome with t(5;12)(q13;p13) involving the ETV6 gene

We report here a 65-year-old man with a myelodysplastic syndrome (MDS), refractory anemia with excess of blasts. He had received chemotherapy with tegafur for renal carcinoma. Chromosome analysis of bone marrow cells revealed complex karyotypes; del(5)(q13) was observed in all 20 metaphase spreads, and two related aberrations, add(12)(p11) and add(12)(p13), were detected in 13 and 7 cells, respectively. Fluorescence in situ hybridization (FISH) analysis with chromosome-specific DNAs revealed that these alterations originated from a reciprocal translocation (5;12)(q13;p13). Therefore, del(5)(q13), add(12)(p11), and add(12)(p13) were revised as der(5)t(5;12)(q13;p13), der(12)del(12)(p11p13)t(5;12)(q13;p13), and der(12)t(5;12)(q13;p13), respectively. Fluorescence in situ hybridization with a series of cosmid probes spanning the ETV6 gene showed that the 12p13 breakpoint on the der(12)t(5;12)(q13;p13) was located in intron 1, but the exon 1 signal was deleted. Our results suggest that a fusion gene was generated between the 5'-end of an unidentified partner at 5q13 and the 3'-end of ETV6 by t(5;12)(q13;p13), and that the interstitial deletion (12)(p11p13) occurred following t(5;12) during clonal evolution. del(12)(p11p13), including the rearranged ETV6 gene, may be implicated in the progression of MDS.

Chemotherapy of secondary leukemias

Chemotherapy of secondary leukemias is currently still considered to be associated with poor results. However, recent data suggest that the response to remission induction may substantially differ according to the previous medical history of the patients. Therapy related leukemia, arising following exposure to previous alkylating agents or radiotherapy, is often associated with chromosomal abnormalities involving chromosomes 5 and 7 and has a particularly bad response, whereas AML after exposure to epipodophyllotoxins or topoisomerase-II active agents could have a somewhat better response. Acute promyelocytic leukemia secondary to treatment of a primary malignant neoplasm seems to be associated with a better response if compared to other cytotypes of AML or to AML arising after transformation of myelodysplasia. However, here the literature data are not in full agreement, as different kinds of approaches have been applied. In fact, even if the problems encountered in treating patients with secondary leukemia are similar to those seen in patients with AML arising in a background of myelodysplasia (resistant disease and prolonged cytopenia after treatment), there are data suggesting that the use of high dose ara-C, with or without fludarabine, can circumvent resistance in a small but significant number of cases. One of the unsolved problems which still remains is how to consolidate the CR induced with high dose ara-C or with cycles based on anthracycline derivatives. In addition, another question relates to the categories of patients in whom chemotherapy may change the expected survival. Intensive post-remission chemotherapy, with or without autologous HSCT, may constitute an appropriate alternative for patients lacking a suitable sibling donor or for older patients who are in remission after chemotherapy and also able to tolerate other cycles of intensive chemotherapy. In this respect, the specific cytogenetic abnormality involved should be considered the most important prognostic factor for response and disease free survival; patients with abnormalities of chromosome 5 and 7 have a particularly low possibility of response and duration of CR. Furthermore, it is still debatable whether patients, especially the elderly, with these characteristics should go through a series of conventional treatments or just receive supportive treatment. On the other hand, patients with better prognostic factors should be entitled to further intensive treatments, taking into account possible delayed recovery and/or possible less successful collection of peripheral or marrow stem cells.

Anaplastic large cell lymphoma: a clinicopathologic analysis

The clinicopathologic features of anaplastic large cell lymphoma (ALCL) are reviewed. ALCL is a heterogeneous group of tumours, and histologic examination alone is not adequate in providing useful prognostic information. However, using a combination of clinical, phenotypic, and genotypic features, several distinct clinicopathologic entities have been identified. A subset of ALCL as presently defined is characterized by a balanced translocation, t(2;5)(p23;q35), resulting in a novel fusion protein (NPM-ALK) that can be readily detected by immunohistochemical methods using antibodies against the ALK protein. Detection of ALK protein, along with other methods for demonstrating the t(2;5), has assisted in identifying a distinct biologic entity within the heterogeneous group of ALCL with significant prognostic implications. It is important to separate these from cases of ALK-negative ALCL, which have a poorer prognosis, and cases of primary cutaneous ALCL, which have an excellent prognosis.

A new recurrent translocation, t(5;11)(q35;p15.5), associated with del(5q) in childhood acute myeloid leukemia. The UK Cancer Cytogenetics Group (UKCCG)

Partial deletion of the long arm of chromosome 5, del(5q), is the cytogenetic hallmark of the 5q-syndrome, a distinct subtype of myelodysplastic syndrome-refractory anemia (MDS-RA). Deletions of 5q also occur in the full spectrum of other de novo and therapy-related MDS and acute myeloid leukemia (AML) types, most often in association with other chromosome abnormalities. However, the loss of genetic material from 5q is believed to be of primary importance in the pathogenesis of all del(5q) disorders. In the present study, we performed fluorescence in situ hybridization (FISH) studies using a chromosome 5-specific whole chromosome painting probe and a 5q subtelomeric probe to determine the incidence of cryptic translocations. We studied archival fixed chromosome suspensions from 36 patients with myeloid disorders (predominantly MDS and AML) and del(5q) as the sole abnormality. In 3 AML patients studied, this identified a translocation of 5q subtelomeric sequences from the del(5q) to the short arm of an apparently normal chromosome 11. FISH with chromosome 11-specific subtelomeric probes confirmed the presence of 11p on the shortened 5q. Further FISH mapping confirmed that the 5q and 11p translocation breakpoints were the same in all 3 cases, between the nucleophosmin (NPM1) and fms-related tyrosine kinase 4 (FLT4) genes on 5q35 and the Harvey ras-1-related gene complex (HRC) and the radixin pseudogene (RDPX1) on 11p15.5. Importantly, all 3 patients with the cryptic t(5;11) were children: a total of 3 of 4 AML children studied. Two were classified as AML-M2 and the third was classified as M4. All 3 responded poorly to treatment and had short survival times, ranging from 10 to 18 months. Although del(5q) is rare in childhood AML, this study indicates that, within this subgroup, the incidence of cryptic t(5;11) may be high. It is significant that none of the 24 MDS patients studied, including 11 confirmed as having 5q-syndrome, had the translocation. Therefore, this appears to be a new nonrandom chromosomal translocation, specifically associated with childhood AML with a differentiated blast cell phenotype and the presence of a del(5q).

Acute myeloid leukemia with t(5;11): two case reports

A case of acute monocytic leukemia (AMoL) with t(5;11)(q31;q23) and a case of acute myelomonocytic leukemia (AMMoL) with t(5;11)(q35;q13.1) are reported. The translocation between the long arm of chromosome 11q and that of chromosome 5q with leukemia have been rarely reported. Though breakpoint of both cases were subtlety different, they had morphologically monocytic character and showed hyperleukocytosis and chemoresistance.

Congenital leukemia: successful treatment of a newborn with t(5;11)(q31;q23)

A male neonate presented with a high white cell count, an 11q23 translocation, and M5b leukemia. He was treated at 3 days of age with intensive combination chemotherapy after progressing despite exchange transfusions. The patient achieved complete remission at 28 days of age. Therapy was completed at the age of 6 months. At the time of this report, the patient is 17 months old and remains in remission. Twenty-nine patients with congenital acute myeloid leukemia were also reviewed. Twenty of these patients received varying therapies. Ten of the treated patients achieved complete remission; two died of toxicity; and eight died of progressive disease. Two patients had a translocation affecting 11q23. Congenital leukemia is a rare and usually fatal condition in patients without Down syndrome. The patient reported here shows that survival may be achieved with very intensive chemotherapy plus supportive care, despite extremely high white blood cell counts and unfavorable translocation.