Expression of folate sensitive and aphidicolin induced chromosomal fragile sites in familial neuroblastoma

The expression of folate sensitive and aphidicolin induced fragile sites in the blood lymphocyte chromosomes of affected and unaffected members from 2 neuroblastoma families were studied. The subjects included 4 neuroblastoma patients, and 9 of their clinically healthy first degree relatives and corresponding number of age and sex matched controls. Lymphocytes cultured in folate deprived culture medium showed rare fragile sites at band p13.1 of chromosome 1, in a frequency of 3%-5% in all the 4 neuroblastoma patients. In aphidicolin treated cultures, the patients and unaffected members in neuroblastoma families, showed hypersensitivity to aphidicolin, as evidenced by the significant increase in percentage of aberration/cell (ab/c) and damaged cells (dc), over that of controls (P < 0.01). Aphidicolin induced fragile sites were more pronounced in chromosomes 1 and 2. A larger number of subjects have to be studied to prove whether altered fragile site expression may be a cytogenetic evidence for an individual or familial cancer predisposing genetic constitution.     

Procoagulant activity of human neuroblastoma cell lines, in relation to cell growth, differentiation and cytogenetic abnormalities

Procoagulant activity (PCA) was investigated in relation to cell growth, differentiation, and cytogenetics in seven human neuroblastoma cell lines. Before 5-bromodeoxyuridine (BrdUrd) treatment, PCA was notably heterogeneous, with the highest activity in NCG (S-type in morphology) 40- to 100-fold greater than the lowest activity in SK-N-DZ (N-type). PCA was not related to 1p abnormalities. After BrdUrd treatment at 5 micrograms/ml for 6 days, PCA increased 6.8-fold in GOTO and 2.7-fold in SK-N-DZ with associated growth inhibition and morphological changes (I-type morphology converted to S-type in GOTO and N-type converted to an advanced N-type in SK-N-DZ). In contrast, only growth suppression was observed in 2 other cell lines, and no changes in PCA, growth or morphology were induced in the remaining 3 cell lines.     

Favorable cytogenetic abnormalities in secondary leukemia

The authors report on five patients with secondary leukemia (SL) and one of the "specific" chromosomal rearrangements usually encountered in de novo acute nonlymphoblastic leukemia: inv(16), t(15;17), t(8;21), and t(9;11). They were characterized by solid tumor as the primary malignancy in four of five cases, absence of preleukemic phase in all cases, and myelodysplastic features in one of five cases only. All patients achieved complete remission (CR) with aggressive chemotherapy. Only two relapsed, but follow-up is still limited in the three remaining cases. Cytogenetic analysis is important in all younger patients with SL, especially if unusual features (such as absence of preleukemic phase or myelodysplastic features) are found. Aggressive chemotherapy appears to be indicated in those patients if a "specific" rearrangement is found.     

Association of circulating immune complexes with cytogenetic abnormalities but not with prognosis in acute nonlymphocytic leukemia

Sera from 91 adult acute nonlymphocytic leukemia patients were tested for circulating immune complexes by the C1q binding test. In 42 patients tested prior to the initiation of therapy, C1q binding activity was inversely correlated with leukemic infiltrate of the bone marrow (rs = -0.34, p less than 0.02), but it was not related to peripheral white blood cell count or presence of infection. Patients with abnormal C1q binding activities (greater than 6%) were more likely to have cytogenetic abnormalities in their bone marrow (p = 0.02); the most frequent abnormality was an extra No. 8 chromosome. The median survival of 8 patients with abnormal values was 1.5 months as compared to 7.8 months in 34 patients with normal values. However, the C1q binding test did not identify patients likely to achieve remission; and after remission was achieved, it did not identify those likely to relapse. Differences between these findings and those recently published by other investigators are discussed.     

多发性骨髓瘤细胞遗传学异常及预后的研究进展

多发性骨髓瘤(MM)是一种不可治愈的血液系统恶性肿瘤,随着细胞遗传学检测技术的进步,发现细胞遗传学异常几乎发生于全部的MM患者.细胞遗传学异常不仅揭示了MM的本质,而且成为影响MM患者预后最重要的因素.文章就MM遗传学异常及其不同预后意义进行综述.     

The expression of fragile sites in lymphocytes of patients with rectum cancer and their first-degree relatives

The present study was designed to clarify the molecules responsible for peritoneal dissemination of cancer cells. We established sublines with high (HP cells) and low (LP cells) passing activity through the membrane of a transwell chamber. The cell lines were established from the human pancreatic cancer cell line, Panc-1. LP cells demonstrated an octagonal shape and tight adhesion, whereas HP cells exhibited a spindle shape and grew with less cell-cell contact in vitro. It was found that HP cells demonstrated a high degree of peritoneal dissemination in nude mice following peritoneal injection of these cells compared to LP cells. We subsequently investigated the expression of certain adhesion molecules. Consequently, we found that LP cells exhibited a stronger expression of E-cadherin than HP cells. On the other hand, there was no difference in the expression of CD44H and beta1 integrin between these two sublines. Passing activity of LP cells through the membrane of the invasion chamber increased to nearly equal levels with HP cells following treatment with anti-human E-cadherin antibody. Moreover, transfection of mouse E-cadherin cDNA into HP cells reduced both passing activity through the membrane of the invasion chamber and peritoneal dissemination in nude mice to levels similar to that of LP cells. In conclusion, these results indicated that loss of E-cadherin facilitates both passing activity in an invasion chamber and peritoneal dissemination, playing a causative role in peritoneal dissemination of cancer cells.     

Evolution of clonal cytogenetic abnormalities in aplastic anemia

Prior to the introduction of effective therapies, the high mortality rates of severe aplastic anemia (AA) precluded recognition of late complications of this disease. Once the survival of AA improved, observation of clonal evolution raised questions as to whether the development of secondary myelodysplastic syndrome (MDS) is a part of the extended natural history of the disease or is related to the therapies applied. Clinical features of myelodysplasia and AA can overlap, and typical MDS may evolve as a complication of AA. Common pathophysiologic elements operate in these diseases and are subject to many studies and theories as to what mechanisms in AA may lead to the late evolution of MDS. Similarly, AA has been hypothesized to be a reflection of an over-reactive immune response triggered by the appearance of genetically altered and/or phenotypically abnormal dysplastic clones. Hypocellular variants of myelodysplasia and responsiveness of certain forms of MDS to immunosuppressive regimens serve as the most appealing examples of the intricate and close pathophysiologic relationship of this disease with AA. The diagnosis of clonal evolution in the course of AA can be obvious if secondary cytopenia involves hypercellularity and a high percentage of blasts. In addition, the occurrence of a new karyotypic defect objectively heralds the progression of disease to MDS. However, the diagnostic imprecision of dysplasia recognition in the context of marrow hypocellularity, inability to obtain informative cytogenetics, and a high proportion of MDS cases with normal karyoptype have hampered studies designed to determine the frequency and timing of MDS evolution in AA. In addition, the diagnostic criteria and definitions used are not unified. While some centers recognize that the abnormal karyotype does not preclude the diagnosis of AA; in others, the diagnosis of AA includes the presence of normal karyoptype. Many typical features of dysplastic evolution in AA have been clarified. For example, karyotypes most frequently encountered in MDS secondary to AA involve chromosomes 6, 7 and 8. The evolution rates seem to be in the range of 10 - 15% in 10 years, but there are no predictive clues as to which patients are at greatest risk for this complication. Study of the mechanisms of clonal evolution in AA may help understand the pathophysiology of other forms of MDS and leukemia and also the mechanisms of antileukemic surveillance. Clinically, identification of patients at increased risk for clonal complications may influence the choice of therapies applied.     

Shared cytogenetic abnormalities in lung-tumors and corresponding peripheral-blood lymphocytes

We analyzed chromosomal alterations in primary lung tumours and peripheral blood lymphocytes (PBLs) from 10 lung cancer patients (nine with non-small cell lung carcinoma and one with small cell lung carcinoma) to determine whether there were shared chromosomal changes in the normal and diseased tissue of these cases. This study revealed that each paired sample had at least three chromosomes and two chromosomal regions in common for structural rearrangements. The chromosomes most frequently found structurally altered in paired analysis were 1 and 3 (60% each), 5 (50%), 6, 7, and 9 (40% each), and 14 (30%). Chromosome region 3p13-3p21 was structurally rearranged in both the normal and tumour tissues of three patients. Chromosome 3 was structurally rearranged in all ten tumours. The chromosome arms most commonly affected in the tumours were 3p (nine times), 9p and 5q (eight times each), Ip and 7q (six times each), 10q and 11q (five times each), 14q and 6q (four times each). The most frequently affected chromosomal regions in these tumours were (in decreasing order) 9p23-p24, 3p21-3p13, 5q11, 1p34, 7q22, and 11q13. Frequent polysomy of 7 and 12 and loss of D-group chromosomes were also observed in the tumours analyzed. Comparing the changes found only in tumours with those found in both PBLs and tumours was helpful in shedding some light on the probable sequence of genetic events leading to lung cancer. This investigation also offered compelling evidence that genomic instability at the chromosomal level in PBLs corresponds with the genetic changes observed in tumours indicating that PBL analysis can help identify the early chromosomal changes in lung cancer. PBL chromosomal analysis thus has a promising future in the genetic analysis of lung cancers.     

Genetic alterations in cancer as a result of breakage at fragile sites

The organization and replication of DNA render fragile sites (FSs) prone to breakage, recombination as well as becoming preferential targets for mutagens-carcinogens and integration of oncogenic viruses. For many years, attempts to link FSs and cancer generated mostly circumstantial evidence. The discoveries that chromosome translocations, amplification of proto-oncogenes, deletion of tumor suppressor genes, and integration of oncogenic viruses all result from the specific breakage of genomic DNA at FSs, however, have provided compelling support for such a link, further suggesting a causative role for FSs in cancer.     

The molecular basis of common and rare fragile sites

Fragile sites are specific loci that form gaps and constrictions on chromosomes exposed to partial replication stress. Fragile sites are classified as rare or common, depending on their induction and frequency within the population. These loci are known to be involved in chromosomal rearrangements in tumors and are associated with human diseases. Therefore, the understanding of the molecular basis of fragile sites is of high significance. Here we discuss the works performed in recent years that investigated the characteristics of fragile sites which underlie their inherent instability.     

Racial differences in primary cytogenetic abnormalities in multiple myeloma: a multi-center study

We examined four clinically assessed cytogenetic subtypes (t(11;14), t(4;14), monosomy 13/del13q and monosomy 17/del17p in 292 black patients with newly diagnosed multiple myeloma (MM) from four medical centers, who had fluorescent in situ hybridization testing results available in their medical records. We then compared the prevalence of these abnormalities with a previously characterized Mayo Clinic cohort of 471 patients with MM. We found a significant difference in the prevalence of the t(11;14) immunoglobulin heavy chain (IgH) translocation between blacks and whites, 6.5% versus 17.6%, respectively, P<0.0001. Blacks also had lower rates of the t(4;14) IgH translocation, (5.5% versus 10%); monosomy 13/del13q (29.1 versus 49.3%); and monosomy 17/del17p (7.9% versus 13%). Consequently, 63.4% of blacks versus 34.6% of whites did not have any of the four abnormalities that we studied, P<0.001. As almost all MM is associated with either an IgH translocation or trisomies, we hypothesize that MM in blacks is associated with either excess prevalence of either the trisomic (hyperdiploid) form of MM or an IgH translocation besides t(11;14) or t(4;14). We conclude that there are significant differences in the cytogenetic subtypes of MM that occur in blacks and whites.     

A review and interpretation of cytogenetic abnormalities identified in Hodgkin's disease

The nature of the cell which gives origin to Hodgkin's disease remains unclear after years of intensive investigation. Cytogenetic data, which are very scarce in Hodgkin's disease, could contribute information which might help elucidate this problem. Review of our own data and others shows that the most frequent abnormalities in this disorder involve chromosomes 14q in 35 per cent of cases, 11q in 32 per cent, 6q in 32 per cent, and 8q in 18 per cent. The most common breakpoint in chromosome 14 occurred at 14q32 where the IgH chain genes reside thus suggesting that in these cases the cell of origin might be a B lymphocyte. The 11q and 6q structural abnormality have also been frequently seen in lymphoid disorders such as ALL and large cell lymphoma. Of interest also is the fact that in a certain type of childhood pre-B cell acute lymphoblastic leukemia which shows cytogenetic abnormalities on 11q23, aberrant myeloid and monocytic markers are seen. This suggests that in Hodgkin's disease a similar phenomenon might occur which could help to explain why the Reed-Sternberg cell expresses myeloid-monocytic antigens such as Leu M-1.     

急性粒-单核细胞白血病的细胞遗传学异常研究

背景与目的：2001年WHO分型特别提出4种伴再现性遗传学异常的急性髓细胞白血病（AML），其中inv（16）（p13：q22）与急性粒一单核细胞白血病（M4）密切相关，是预后好的标志。本研究旨在探讨M4的细胞遗传学特征。方法：采用直接法及短期培养法制备骨髓细胞染色体，并以R显带技术对89例M4患者进行核型分析，并应用间期荧光原位杂交（I-FISH）技术对其中伴有＋22异常的患者进行inv（16）检测。结果．89例M4患者中，异常染色体检出率为40．4％（36／89），共12种主要异常核型，其中5种为特异性染色体异常，见于25例患者，占核型异常患者的69．4％。单纯＋8（10例）为最常见的数目异常；结构异常最多见的是inv（16）（5例）；t（8；21）者3例；伴t（9；22）者有1例；其中5例inv（16）及3例＋22均只见于M4Eo患者。3例＋22患者FISH检测inv（16）均阳性。结论：细胞遗传学研究对于急性粒一单核细胞白血病的诊断具有重要价值，但是细胞遗传学对inv（16）检测阳性低，对怀疑病例及所有＋22异常的患者，应尽可能进行FISH检测。     

Frequent occurrence of cytogenetic abnormalities in sporadic nonmedullary thyroid carcinoma

Cytogenetic studies may provide important clues to the molecular pathogenesis of thyroid neoplasia. Thus, the authors attempted cytogenetic studies on 12 thyroid carcinomas: seven papillary, three follicular, and two anaplastic. Successful cytogenetic results were obtained on all 12 tumors; nine (75%) had one or more chromosomally abnormal clones. Four of the papillary carcinomas had a simple clonal karyotype, and three had no apparent chromosome abnormality. All four abnormal papillary tumors contained an anomaly of a chromosome 10q arm. In one instance, an inv(10)(q11.2q21.2) was observed in a Grade 2 papillary carcinoma as the sole acquired abnormality. In another case, an inversion or insertion involving 10q21.2 was found in a Grade 1 papillary tumor. The karyotype of a third tumor, a Grade 1 papillary carcinoma, was 46,XX,der(5)t(5;10)(p15.3;q11),der(9)t(9;?)(q11;?). A fourth abnormal papillary carcinoma, a Grade 1 tumor, had a t(6;10)(q21;q26.1) as the sole abnormality. Each of the five follicular or anaplastic carcinomas had a complex clonal karyotype. The three follicular carcinomas contained an abnormality of 3p25-p21, along with several other chromosome abnormalities.     

微小RNA在伴遗传学异常的急性白血病中的研究进展

微小RNA（miRNA）是一类长度为19～25 nt的单链小分子非编码RNA,通过与靶基因mRNA 3＆#39;端非翻译区结合引起mRNA的剪切、降解及翻译抑制,参与基因的转录后调控.近年来的研究发现,miRNA的异常表达可参与部分癌基因或抑癌基因的表达调控,影响造血细胞的发育和分化,导致血液肿瘤的发生和发展.不同的miRNA表达谱与特异的遗传学异常及编码基因突变相关,能够为不同类型白血病的生物学研究提供新的依据.文章就近年来miRNA在伴不同细胞及分子遗传学异常的急性髓系白血病及急性淋巴细胞白血病中的研究进展作一综述.     

Oncosuppressor proteins of fragile sites are reduced in cervical cancer

FHIT and WWOX are tumor suppressor genes that span the common fragile sites FRA3B and FRA16D, respectively. To analyze possible synergisms among these genes in cervical cancer progression, we considered 159 cervical intraepithelial neoplasias, and 58 invasive squamous cell carcinomas of the uterine cervix. All cases were previously selected as high risk HPV. FHIT and WWOX proteins were examined by immunohistochemistry and their expression was inversely correlated with precancerous vs. invasive lesions. Statistics among biological markers indicated an association between FHIT and WWOX. Protein expression of these two genes was also absent or reduced in cancer cell lines. Thus, WWOX may be considered as a novel important genetic marker in cervical cancer and the association between the altered expression of FHIT and WWOX may be a critical event in the progression of this neoplasia.     

Are fragile sites "hot-spots": a causative factor in tumor biology

Genomic integrity of the cancer cell is doubt-full because of fragility on chromosome. Fragile--sites are non-randomly distributed on human genome prone to form gaps or breaks at either pre/or metaphase chromosome arise when cells are exposed to a perturbation of DNA replication process. Cancer cells commonly show various form of "hot spots" including point mutation, chromosome copy number and translocation involving specific gene mutation but the genetic diversity of fragile sites are still not clear. The chromosomal fragile sites (rare & common fragile sites) make the cancer cells not only susceptible to genomic instability but also contribute the process of malignancy due to expansions of microsatellite CGG or AT rich minisatellite. Fragile sites have been implicated due to inter chromosomal amplification events by initiation breakage - fusion cycles. The mechanisms behind these changes give raise to new insight the cytogenetic manifestation of oncogenesis. Fragile sites loci are associated with activation of oncogenesis during cell--cycle analysis. However, these mutations at fragile sites loci might have play a causative or functional role in tumor biology. The topography organization and informatics complexity of the fragile sites remained unexplored due to lack of systematic approach towards molecular cloning of the fragile sites DNA sequences and specific models as not are under taken. The information regarding mode of inheritance of fragile sites are still lacking but the first degree relative specially young proband and maternal side having variable prevalence in different population could be uses as suitable marker for determining genetic predisposition to cancer. This comprehensive review of fragile sites in tumor biology probably helpful to explore to understand the molecular mechanism of carcinogenesis or tumorgenesis.