Molecular biology of myeloma

Multiple myeloma (MM) is a B-cell malignancy characterised by the accumulation of clonal plasma cells (PC) in the bone marrow (BM). The molecular bases for this incurable disease have been widely investigated in the last years, and the development of modern genomic technologies has contributed to the understanding of the pathogenesis of MM. The molecular mechanisms that explain the cellular origin of myeloma cells, the cytogenetic abnormalities and their clinical implications, and the biological information provided by gene expression profiling analysis are reviewed in this paper. In addition, a molecular classification of MM in seven groups based on the relationship between gene expression profiling, chromosomal translocations and prognostic outcome is also presented. And finally, the recent hypothesis of a potential unifying event in the pathogenesis of MM, supported by cyclin D deregulation in virtually all MM tumours, will be summarised.     

应用左炔诺孕酮硅胶棒避孕者后代细胞遗传学研究

目的　探讨左炔诺孕酮硅胶棒对应用者后代细胞遗传学的影响。方法　 1997年 1月至 2 0 0 1年 12月沈阳市生殖医学中心等检测了平均埋棒 3 86年、取药 1 0 1年后妊娠夫妇的后代及正常夫妇的后代染色体随体联合发生率及细胞分裂指数。结果　观察组和对照组染色体随体联合率的平均值比较差异无显著性 (P >0 0 5 ) ,淋巴细胞分裂指数的平均值在统计学上差异有显著性 (P <0 0 5 ) ,但由于观察组淋巴细胞分裂指数平均值高于对照组 ,所以在统计学上虽然有意义 ,却无临床意义。结论　左炔诺孕酮硅胶棒对应用者后代不产生潜在的细胞遗传学损伤效应     

Cytogenetic evaluation of human oocytes that failed to complete meiotic maturation in vitro

OBJECTIVE: To determine the cause of infertility in a couple whose oocytes failed to mature in two consecutive fertility treatments. DESIGN: Case report. SETTING: University-based IVF program. PATIENT(S): A 32-year-old woman with unexplained infertility. INTERVENTION(S): Cytogenetic evaluation of oocytes that failed to reach meiotic metaphase II stage of maturation. MAIN OUTCOME MEASURE(S): Observation of oocyte maturity and chromosome composition after fixing and staining with Orcein stain. RESULT(S): Cytogenetic analysis revealed that the oocytes had successfully resumed meiosis. Germinal vesicle breakdown was also indicated, and chromosomes were at metaphase II stage of development. However, meiotic reduction of those chromosomes failed. CONCLUSION(S): Infertility in this couple seems to be attributed to the failure of the chromosomes to complete the reduction phase of metaphase II of meiosis.     

Genetic analysis of a group of mentally retarded children

Genetic analysis of 169 mentally retarded (MR) children from Madras, revealed chromosomal abnormalities in 17%. Down syndrome was the major chromosomal anomaly (24/169=14.2%). These included three cases of trisomy-21 mosaics, and one case ofde novo Robertsonian translocation. MR children with chromosomal abnormalities were either mildly or moderately retarded. Syndromes with known etiology occurred in 3% of the MR cases. Microcephaly, neonatal anoxia, perinatal stress and pharmacological attempt for abortion were found to be important pathogenic factors associated with MR. Most of the microcephalies (11/ 169=6.5%) were severely retarded, whereas those associated with neonatal anoxia and perinatal stress were either mildly or moderately retarded. Birthorder effects were found only among Down syndrome patients. Segregation analysis of the three groups of proband families (viz. mild, moderate and severe MR) indicated that autosomal recessive mode of inheritance is compatible in moderate and severe MR proband families. The proportion of X-linked instances of MR is estimated to be about 22% of the cases.     

Outcomes of Patients With Relapsed Core Binding Factor-Positive Acute Myeloid Leukemia

Purpose

To determine the factors associated with outcomes in patients with core binding factor acute myeloid leukemia (CBF-AML) in first relapse.

Cytogenetic analysis in patients with primary myelodysplastic syndromes in leukaemic transformation: A report on 94 cases

A series of 94 patients presenting primary refractory anaemia with excess of blasts in transformation or acute myeloid leukaemia occurring after a myelodysplastic stage was submitted to retrospective cytogenetic analysis by the Groupe Français de Cytogénétique Hématologique. The aim of this collaborative study was to analyze the patterns of chromosome abnormalities appearing in primary myelodysplastic syndromes (MDS) in leukaemic transformation. As previously described in the literature, the most common chromosome aberrations involved del(5q), -7, +8, 17, 11, 12p and del(20q), while abnormalities of chromosome 17p were more frequently detected during the leukaemic transformation of MDS. The translocations t(2;3)(p22–23;q26–28) and whole arm t(17;18) were confirmed to be nonrandom events in these myeloid disorders.GFCH: Brest, D Rivière, Pluchon-Rivière; Nantes, Talmant; Chambéry, Pedron, Lespinasse; Nice, Raynaud, Taillan, Thyss, Bayle, Ayraud; Dijon, Mugneret; Paris, Verdier, Eclache; Lille, Laï, Fenaux, Zandecki; Paris, St-Antoine, van den Akker, Pérot; Louvain UCL, Michaux, Michaux; Paris, St-Louis, Berger, Jonveaux; Lyon, Charrin; Toulouse, Dastugue; Marseille, Lafage, Mozziconacci, Brunel, Arnoulet, Sainty; Strasbourg, Uettwiller, Ruch, Oberling; Nancy, Grégoire, Buisine, Guerci; Villejuif, Bernheim, Venuat     

Improvement of preparative conditions for cytogenetic studies by short-term liquid culture of haemopoietic cells

Summary In patients with haemopoietic failure, the low incidence of cells in mitosis often prevents successful chromosome preparations. By performing liquid cultures of myeloid cells a high incidence of mitoses could be obtained even in those cases failing to provide mitoses when the direct preparation technique was used. The cytogenetic studies demonstrated that the mitoses achieved by culture techniques were aneuploid and, thus, there is evidence that they are of leukaemic origin. The combination of short-term liquid culture and chromosome analysis appears to be a diagnostic approach in selected cases of hemopoietic insufficiency.Supported by Deutsche Forschungsgemeinschaft, SFB 112¹ and SFB 68²     

No elevated genomic damage in children and adolescents with attention deficit/hyperactivity disorder after methylphenidate therapy

Background and objective

Attention-deficit/hyperactivity disorder (ADHD) is the most frequent psychiatric disorder in children and adolescents and is often treated with methylphenidate (MPH), resulting in MPH exposure in more than 1% of all children in many countries. A 2005 report on cytogenetic effects in peripheral lymphocytes from 12 ADHD children treated for 3 months with MPH raised questions about its genetic toxicity and potential carcinogenicity. In 2007, we described no elevated micronucleus frequency in 21 children after 3 months of MPH-treatment; since the difference between the two studies could not be explained we now enlarged the overall sample size, and added a healthy control group, a new chronically treated group and positive control slides. Furthermore, micronuclei were analyzed in a second tissue, buccal mucosa.

Study participants

A healthy control group (23 individuals), a chronically MPH-treated (>12 months) group (21 patients), and a drug naïve group of ADHD-affected children (26 patients), which was analyzed again after 3 months (17 patients) and 6 months (11 patients), provided samples for analysis of micronucleated lymphocytes. With inclusion of 14 previously obtained blood samples, an overall group size of 31 patients was reached for the comparison of the 3 months observation time with before for micronucleated lymphocytes. For buccal mucosa cells, an additional inclusion of 10 more chronically treated patients (no lymphocytes donated) yielded sample numbers of 22 (healthy), 17 (chronically treated), 23 (ADHD drug naïve), 14 (3 months) and 11 (6 months).

Results

No significant alteration in genomic damage as seen as micronucleus frequency in peripheral lypmphocytes or buccal mucosa cells was detected after MPH treatment.

Conclusions

No indication for genomic damage induced by MPH was obtained in this study, as in our previous study. Together with our previous study, our overall number of MPH-treated patients is now 68 (30 chronically treated, 38 prospectively followed), plus 23 healthy controls. Ongoing studies in the USA, as well as continuation of recently published epidemiological cancer incidence analysis should provide additional reassurance for MPH-treated ADHD patients.     

Cytogenetic methods for detection of oxidative stress and evaluation of antioxidant therapy in hepatitis C infection

The plasma of patients with hepatitis C contains chromosome-damaging substances, the so-called "clastogenic factors" (CFs), as this is the case for other chronic inflammatory diseases and after radiation exposure. These endogenous clastogens, formed as a consequence of increased superoxide production by inflammatory cells, can be detected with cytogenetic methods, as they are used for exogenous clastogens. The long-lived, autosustained DNA-damaging effects of CFs are risk factors for the development of cancer and leukemia. In hepatitis C, the highest clastogenic scores has been observed in patients with hepatocellular carcinoma. In agreement with the link to inflammation, clastogenic score are correlated with necro-inflammatory scores in liver biopsies. Antioxidant therapy with a powerful superoxide scavenger resulted in normalization of clastogenic scores and significant decreases in aminotransferase levels, but did not influence the virus load. Preliminary results of our study on a limited number of patients suggest that pre-treatment with antioxidants may improve the outcome of interferon/ribavirin treatment. A comparison of a three-month treatment with either interferon alone or the antioxidant alone, yielded similar results for reduction of ALT levels, but only complete normalization of clastogenic scores for the antioxidant. Further studies have to be conducted to see whether a combination of an antiviral agent with an appropriate antioxidant would allow to reduce interferon and its side effects.Combination of antioxidants with IFN/RIBA was also reported by other authors with discordant results. The CF-test can be useful in clinical trials for the choice of the appropriate antioxidant.     

Radiation-induced meningiomas: clinical, cytogenetic, and microarray features

Limited information exists about the clinical and biological features of radiation-induced meningiomas (RIMs), particularly those that follow high-dose therapeutic radiation. We report our experience with 20 patients with RIMs (16 following high-dose radiotherapy) treated at our institution from 1993-2006. Patients (14 female, 6 male) had intervals from first radiotherapy to RIM diagnosis of 11-63 years; 12 had at least one RIM occur at an interval of 30 years or more after initial radiotherapy. Multiple RIMs were seen in six patients, with one patient developing his six RIMs sequentially over a 22-year interval. Most RIMs could be managed surgically, either with a single extensive resection or additional resection(s). Adjuvant stereotactic radiosurgery, external beam radiation, or chemotherapy were required in a minority (n = 6). Most were WHO grade I meningiomas. Complex karyotypes were found in three of four cases and abnormalities of chromosome 1p and/or LOH 1p36 were identified in five of 11 informative cases. Gene-expression microarray analysis of RIMs (n = 5) compared to non-RIMs (MEN, n = 6) and a panel of other tumors (n = 62) showed that RIM gene-expression was similar to that seen in MEN, and by clustering analysis did not separate from them. However, microarray comparative gene-expression analysis did demonstrate a few genes with significant differences in the expression level in RIM versus MEN. Of note, NF2 was under-expressed in four of five RIMs (P = 0.0065), at a similar level as measured in MEN.