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The MLL gene located at 11q23 has been described as a 'promiscuous' gene due its involvement with a large number of genetic partners. The EU Concerted Action Workshop on 11q23 provided 550 cases for study of which 82 showed abnormalities which did not involve the established translocations or deletion of 11q23. In these 'other' cases, which included inversions and duplications, 11q23 was found to be involved with 25 chromosome partners of which 10 had not been previously reported. These were 1q31, 4p11, 6q13, 8q21, 10q22, 10q25, 11q11, 11q21, 13q34 and 18q23. This study demonstrated the value of the Workshop, in confirming the diversity of chromosomal partner sites involved with 11q23 and in the identification of new partners.

This study prospectively analysed the relationships between immunophenotypic and cytogenetic features of blast cells in 432 acute non-lymphoblastic leukemias (ANLL) at presentation. An abnormal karyotype was detected in 232 cases (54%). These abnormalities were related to immunophenotypic markers as detected using a consensual panel of monoclonal antibodies allowing lineage assignment and investigation of myeloid marker expression on blast cells. In univariate analysis, CD9, CD10, CD15, CD34 and TdT expression appeared significantly associated with chromosomal anomalies. Multivariate analysis identified CD34 and CD9 expression as independently predictive of the presence of at least one cytogenetic abnormality (P < 10(-4) and P < 0.03, respectively). Significant associations between immunophenotypic and karyotypic features were observed both within individual FAB subgroups and independently from morphological criteria. Specific features were seen in five ANLL entities: M0 or M1/B lineage antigen positivity/t(9;22) or del(11)(q23); M2/CD13-/t(8;21); M4/CD13+, CD34+, CD36+/inv(16); M4 or M5/lack of B lineage antigen/del(11)(q23) or t(9;11). More practically, and although the relationships demonstrated only represent a fraction of homogeneous immunophenotypic subgroups, identification of such immunophenotypic features should prompt careful karyotypic examination, eventually using molecular biology analysis on non-growing cells.

As a result of chromosome translocations, the EWS gene is fused to a variety of transcription factors in human solid tumors. Up to now, gene fusions of EWS with 6 different partners have been described. In all fusions presently reported the entire N-terminal domain of EWS (NTD-EWS) composed of 265 amino acids encoded by the first 7 exons of EWS was always included in the chimeric proteins, suggesting that the integrity of this domain was mandatory for the oncogenic property of the fusion proteins. We report the molecular characterization of a Ewing tumor demonstrating a reciprocal t(21;22)(q22;q12) translocation. No EWS/ERG fusion transcript could be detected with previously reported RT-PCR primers. However, Southern-blot experiments demonstrated that the EWS gene was disrupted within a 2-kb PstI genomic fragment including exon 7. PCR amplification and sequence of the translocation junction fragments indicated that the breakpoint was localized within exon 7 of EWS. The resulting fusion gene encoded a chimeric protein in which a truncated NTD-EWS was linked, in frame, to the ETS DNA-binding domain of ERG. This observation indicates that, to avoid false negative results, RT-PCR-based diagnosis of tumors with EWS fusion transcripts should now include the search for such rare variants. It also suggests that the amino-terminal portion of the NTD-EWS, but not its carboxy terminal part, might be fundamental for the oncogenicity of the chimeric proteins.

Cytogenetic study reveals non random chromosomal abnormalities in 50-80% of patients with acute leukemia. These changes are correlated with morphological [t(15;17) closely connected with FAB M3] and (or) immunological findings [t(1;19) with pre-B/early pre-B ALL]. Karyotype in ALL is an independent prognostic factor. Patients with ALL and hyperdiploidy > 50 chromosomes fared the best as well as patients with AML and inv(16). Conversely the Philadelphia chromosome or t(4;11) in ALL, del5q or trisomy 8 in AML have shown an adverse predictive value. Cytogenetic study is a useful tool to detect relapse and residual disease. Cytogenetic abnormalities have also provided focus for molecular studies of leukemogenesis.

The der(16)t(1;16)(q11;q11) is a frequent recurrent rearrangement in solid tumours such as breast carcinomas and Ewings sarcomas. Recently, this abnormality was described also in multiple myeloma. We identified a der(16)t(1;16)(q11;q11) in three patients with myelodysplastic syndrome, either during preleukaemic phase (n = 2) or at the time of blastic transformation (n = 1). Breakpoints were ascertained by fluorescence in situ hybridization (FISH) using specific centromeric alpha-satellite probes and whole chromosome painting for chromosome 1 and chromosome 16. These observations, combined with isolated cases of the literature, suggest that der(16)t(1;16)(q11; q11) is a nonrandom abnormality associated with myelodysplastic syndromes.

Aneuploidy is a frequent feature in multiple myeloma. Cytogenetic analyses have shown that a 14q+ chromosome resulting from either a t(8;14)(q24;q32) or a t(11;14)(q13;q32) was the most consistent abnormality but no specific chromosomal aberration has been identified in this disease. Bone marrow cells from 121 consecutive patients with multiple myeloma were analyzed cytogenetically by standard banding techniques including RHG, GTG and CBG banding. Cells were cultured for 24-96 h in the presence or in the absence of interleukin-6. Clonal abnormalities were detected in 41 of the 121 patients (34%). A der(16)t(1;16)(q10;p10) abnormality was identified in nine of these 41 patients (22%). Der(16) was identified at diagnosis in five patients, during disease progression in two additional patients, and at the time of a relapse in the two last cases. The t(1;15)(q10;p10) translocation was always unbalanced, resulting in a monosomy 16q in all cases. The CBG banding did not demonstrate dicentric chromosomes and the whole chromosome painting confirmed the der(16). A large number of other chromosomal abnormalities were associated with der(16), including chromosomal rearrangements involving the 8q24 band in five cases. Four of these five cases were Burkitt's-type translocations. This observation suggests that der(16)t(1;16)(q10;p10) could be one of the most frequent chromosomal abnormalities that can be identified in multiple myeloma cells.

The polymerase chain reaction (PCR) was used to amplify cDNA in order to characterize normal and hybrid T-cell receptor (TCR) gene rearrangements derived from a T-cell acute lymphoblastic leukemia (T-ALL) bearing a chromosome 7 inversion. The nucleotide sequence analysis of the amplified product showed the presence of an out-of-frame V beta/J gamma/C gamma transcript and an in-frame V gamma/J gamma/C beta transcript which result from an interlocus recombination between the TCR-beta and gamma loci and the transcription of the reciprocal hybrid TCR gene. The sequence analysis of the reciprocal DNA segment directly involved in the breakpoint of the inversion showed a recombination between a J gamma-sequence heptamer signal and a coding J beta gene segment. The exonuclease nibbling of each DNA extremity and the non-templated nucleotide insertion observed at both coding and reciprocal joints demonstrate that the inversion is mediated by the lymphocyte recombinase complex. During T-cell differentiation, TCR-beta genes are rearranged prior to TCR-alpha genes. In the present case of T-ALL, we have shown that TCR-delta genes are rearranged at both loci, excluding productive rearrangements of TCR-alpha genes. The molecular analysis of the normal TCR genes derived from the leukemic cells revealed the presence of productively rearranged TCR-beta, gamma, and delta genes. Cell surface staining of these cells showed the presence of CD3 molecules and of a TCR-beta chain corresponding to the normal beta allele expressed in a disulfide-linked complex with a protein which is not TCR-alpha, gamma, or delta. This could represent the cell surface expression of the hybrid TCR-V gamma/C beta protein or the expression of a TCR-beta homodimer.

A case of bone marrow necrosis associated with a serologically documented recent Parvovirus B 19 infection which preceded the development of PH1+ acute lymphoblastic leukemia is reported. No conclusions can be drawn on the basis of a single case but the question of the role of human Parvovirus B19 in the pathogenesis of bone marrow necrosis is discussed. It is suggested that the virus may act as a co-factor for the induction of bone marrow necrosis, in some cases.

A new case of t(3;17)(q26;q22) was observed in a Philadelphia-positive (Ph+) chronic myelogenous leukemia in acceleration 1 month before occurrence of the blastic phase. Abnormal megakaryocytopoiesis and thrombopenia were noted, but blast cells did not express platelet markers. The same translocation was previously reported in three myeloproliferative disorders in acceleration or in the process of becoming acute. Translocations or inversions of chromosome 3 with breakpoint involving the band 3q26 were specifically associated with megakaryoblastic acute phase or abnormal megakaryocytopoiesis. This report confirms that the t(3;17)(q26;q22) is a specific nonrandom chromosomal abnormality associated with the acute nonlymphoblastic phase of myeloproliferative disorders and megakaryocytopoiesis dysfunction.

Four cases of XX patients with testis development are reported. The aim of this study was to describe their clinical features and to see if there was any relationship between phenotypes and the presence of Y material. Several human Y-derived sequences including the SRY probe were used to analyze the DNA of the patients. Yp material including the pseudo-autosomal region and SRY was detected. The cases reported in this study confirm that XX true hermaphrodites cannot be distinguished from XX males on the basis of their genotypes. There is no relationship between clinical and anatomical phenotypes and the presence of Y material. SRY does not warrant a complete and normal testis differentiation. Although similar in some features with Klinefelter's syndrome patients, XX males exhibit specific clinical manifestations due to the lack of Y-specific genes.

Two unrelated mentally retarded patients were found to have an interstitial deletion of 18q12. They were a 2-year-old, short, macrocephalic and autistic girl, and a 5-year-old boy. Six other liveborn patients with comparable deletion have been so far identified. The common findings are mild dysmorphic features (telecanthus, epicanthal folds, flaring eyebrows, small mouth with thin upper lip), hypotonia, behavioural disorders, mental retardation with speech delay and lack of major malformation.

The expression of the P-glycoprotein which is associated with the development of multidrug resistance in various cell lines was investigated in 87 fresh acute leukaemia and multiple myeloma samples using the specific mouse monoclonal antibody MRK16 in an indirect immunofluorescence assay. Considering a 10% positive cell cut-off value, a heterogeneous expression of P-glycoprotein was observed in 5/22 (22.7%) de novo acute leukaemias, 7/22 (31.8%) relapse or secondary acute leukaemias, 14/27 (51.8%) acute transformation of myeloproliferative or myelodysplastic syndromes and 5/16 (31.2%) multiple myelomas. This expression was not associated with specific cytogenetic abnormalities, especially alterations of chromosome 7q. Verapamil, a calcium channel blocker, has been demonstrated to circumvent the multidrug resistance in cell lines, possibly by interfering with P-glycoprotein function. Using the microculture tetrazolium assay, verapamil was demonstrated to increase the sensitivity of fresh leukaemic or myeloma cells to doxorubicin in 19/43 (43.1%) samples. The doxorubicin IC50 level and the capacity of verapamil to increase the sensitivity of blast cells to doxorubicin in vitro did not correlate with the expression of P-glycoprotein. We conclude that high non-cytotoxic concentrations of verapamil were able to increase the in vitro doxorubicin sensitivity of fresh acute leukaemia and myeloma cells without detectable expression of the P-glycoprotein.

Chromosomal data from 82 informative, unrelated Ewing's sarcoma (ES) specimens (including 20 personal specimens) were reviewed for secondary changes additional to the t(11;22)(q24;q12). Additional numerical and/or structural changes were found in 75 specimens. Trisomy 8 was observed consistently in half of the 43 cases selected for analysis of numerical changes. A nonrandom der(16) was observed as a result of an unbalanced t(1;16) in 18% of the 82 analyzed for structural changes. Consistent involvement of chromosome #16 in rearrangements with chromosome #1 may be an additional chromosome change specifically associated with ES.

A review on the association between acute leukemias (AL) and constitutional chromosome abnormalities (CCA) is presented. AL, myeloblastic or lymphoblastic according to age are 18 to 20 times more frequent in Down Syndrome (DS) children than in non DS children. The incidence of acquired chromosome abnormalities is similar in leukemic cells of DS and non DS patients but the type of anomalies, in the leukemic myeloblastic cells of DS, are different : hyperdiploidy, excess of C, F and G. Gain of chromosomes 8, 19 and 22 would characterize leukemic myeloblasts in an early stage of differentiation. Recent data on transient leukemoid reactions show that a 21 in DS appears to be predisposing factor in the development of AL. Association between AL and other balanced or unbalanced CCA appears until now to be fortuitous.

The histogenesis of Ewing's sarcoma (ES) remains uncertain. Mesenchymal and neuroectodermal origins were the most recent hypotheses. In an attempt to test these two hypotheses, frozen sections of an ES with the chromosomal translocation t(11;22) have been studied using a panel of antibodies directed against monocytes/macrophages cell surface antigens (Leu M1, Leu M2, Leu M3, and MO1), and against neural components (NSE, S-100, T4, and HNK-1). None of these antigens were detected. Positive reactions were obtained with antibodies recognizing HLA II antigen and B2-microglobulin. From a panel of various intermediate filaments only vimentin was shown to be present. None of the two hypotheses could be supported by the results obtained from the immunohistological analysis of the tumor studied. In the absence of a specific immunological pattern, the chromosomal t(11;22)(q24;q12) marker remains the only diagnostic criterion of ES.

A review on the association between acute leukemias (AL) and constitutional chromosome abnormalities (CCA) is presented. AL, myeloblastic or lymphoblastic according to age are 16 to 20 times more frequent in Down Syndrome (DS) children than in non DS children. The incidence of acquired chromosome abnormalities is similar in leukemic cells of DS and non DS patients but the type of anomalies, in the leukemic myeloblastic cells of DS, are different: hyperdiploidy, excess of C, F and G. Gain of chromosomes 8, 19 and 22 would characterize leukemic myeloblasts in an early stage of differentiation. Recent data on transient leukemoid reactions show that a 21 in DS appears to be predisposing factor in the development of AL. Association between AL and other balanced or unbalanced CCA appears until now to be fortuitous.

By the registry of hematopoietic malignancies in Côte d'Or we studied the 177 cases of myeloproliferative disorders diagnosed between 1980 and 1986, divided into 4 groups: chronic myelogenous leukemia, idiopathic myelofibrosis, polycythemia vera, essential thrombocythemia. The global standardized rates based on the world population were 3.5 per 100,000 in men and 1.9 in women (sex ratio = 1.8). The mean age for myeloproliferative disorders was 61 +/- 16 years. Incidence was slightly higher in urban than in rural areas (NS). The most common means of detection were routine hemogram, fatigue and thrombosis. Five-year survival curves showed large differences in prognosis, from 30% for chronic myelogenous leukaemia to 83% for polycythaemia vera.

A t(X; Y) was discovered in 32 year-old female patient who has had three consecutive miscarriages. Molecular analysis of the loci DXS 31 and DYS 22 was performed which confirmed and precise the breakpoints at Xp22.3 and Yq11. Genetic counselling was based upon the accurate definition of the chromosome rearrangement and the analysis of the outcomes of similar published observations.

A chromosomal study of short-term cultured tumor cells from a benign uterine leiomyoma showed a clonal insertion, dir ins(14;6)(q23;p23p25) as a unique change. This finding supports the hypothesis of a specific association of the breakpoint 14q23 with uterine leiomyoma.

Since our initial reports on chromosomal studies in eight Ewing's sarcomas (ES), we have carried out similar investigations on 23 additional ES specimens following short-term culture of tumor cells (16 cases), and established in vitro cell lines (three cases) and on xenografted tumors in nude mice (four cases). We demonstrated the presence of the reciprocal t(11;22)(q24;q12) in every case except one that exhibited a complex t(11;22;14)(q24;q12;q11). On the basis of results from these additional 23 cases, we confirm the consistency of the t(11;22)(q24;q12) in ES. Moreover, we reviewed 54 ES cases reported by other investigators; when added to our 31 cases, this brings the total number to 85 unrelated cases of ES available for an evaluation of the frequency of involvement of bands 11q24 and 22q12 in translocations in ES. The standard t(11;22)(q24;q12) proved to be a remarkably consistent event, present in 83% of the cases. Five percent of the cases exhibited complex translocations involving a third chromosome in addition to chromosomes #11 and #22. In 4% of the cases variant translocations involved 22q12 but with a chromosome(s) other than #11. The breakpoint on chromosome 22q12 appears to be the most consistently observed event in 92% of the cases, whereas, the breakpoint at chromosome 11q24 was observed in 88% of the cases.

Using immunocytological techniques, neuroectodermal markers were identified on Ewing's sarcoma cell lines established in vitro and carrying the chromosomal translocation t(11;22). Eight cell lines were tested using a panel of monoclonal antibodies. The presence of cell surface antigens recognized by HNK-1 antibody was confirmed. The cells showed also positive reactions using antibodies directed against Neuron-Specific-Enolase and neurofilament proteins. The presence of these neural markers in the Ewing's sarcoma cells tested is an additional argument substantiating the putative neural origin of this tumor.

We report a de novo double reciprocal translocation, involving three chromosomes in a 25 year-old female patient, who has had twelve miscarriages.

Among number of women having consulted for repeated miscarriages about sixty have a gonosomic mosaicism involving chromosome X for which abnormal clones (monosomy and/or excess) are always the minority. A retrospective study of the obstetrical follow up these patients have shown that 23% of them will give birth to a child with a chromosomic abnormality (21 trisomy, 13 trisomy, 45,X, 45,X/46,X iso X (q), 48,XXXX, 49 XXXXXY, del 5 p-). The hypothesis of a tendency toward non-disjunction is pushing for an prenatal diagnosis for patients with X mosaicism. However one can question about the real meaning of this abnormality regarding to the fact that the patients referred are not representative of the general population. Should interchromosomic interaction be taken for responsible? Is the risk for having a child chromosomic abnormality, especially X aneuploidy the same than for the overall population. It certainly would be rewarding to look after these different hypothesis in a multicentric collaborative study.