Numerical Chromosomal Alterations Research Articles

Recommendations, evaluation and validation of a semi-automated, fluorescent-based scoring protocol for micronucleus testing in human cells

Micronucleus (MN) induction is an established cytogenetic end point for evaluating structural and numerical chromosomal alterations in genotoxicity testing. A semi-automated scoring protocol for the assessment of MN preparations from human cell lines and a 3D skin cell model has been developed and validated. Following exposure to a range of test agents, slides were stained with 4'-6-diamidino-2-phenylindole (DAPI) and scanned by use of the MicroNuc module of metafer 4, after the development of a modified classifier for selecting MN in binucleate cells. A common difficulty observed with automated systems is an artefactual output of high false positives, in the case of the metafer system this is mainly due to the loss of cytoplasmic boundaries during slide preparation. Slide quality is paramount to obtain accurate results. We show here that to avoid elevated artefactual-positive MN outputs, diffuse cell density and low-intensity nuclear staining are critical. Comparisons between visual (Giemsa stained) and automated (DAPI stained) MN frequencies and dose-response curves were highly correlated (R (2) = 0.70 for hydrogen peroxide, R (2) = 0.98 for menadione, R (2) = 0.99 for mitomycin C, R (2) = 0.89 for potassium bromate and R (2) = 0.68 for quantum dots), indicating the system is adequate to produce biologically relevant and reliable results. Metafer offers many advantages over conventional scoring including increased output and statistical power, and reduced scoring subjectivity, labour and costs. Further, the metafer system is easily adaptable for use with a range of different cells, both suspension and adherent human cell lines. Awareness of the points raised here reduces the automatic positive errors flagged and drastically reduces slide scoring time, making metafer an ideal candidate for genotoxic biomonitoring and population studies and regulatory genotoxic testing.

Histiocytic Sarcoma of the Bile Duct

An 80-year-old man was admitted with anorexia, a high fever and general icterus. Laboratory examinations revealed remarkable inflammation and elevation of liver/biliary enzymes. Computed tomography (CT) showed a high-density lesion in the bile duct, and endoscopic retrograde cholangiopancreatography (ERCP) disclosed an oval filling defect mimicking choledocholithiasis. Plastic stents were inserted to treat the acute cholangitis; however, the patient's symptoms recurred. An erythematous hypervascular mass obtained with a balloon catheter contained numerous pleomorphic histiocytic cells with eosinophilic cytoplasm, remarkable anisonucleosis and occasional mitoses. A diagnosis of histiocytic sarcoma (HS) was made based on the results of intensive immunohistochemistry. Monoclonal rearrangement of the IGH and TCRG genes, IGH split and IGH/BCL2 fusion was negative, although polysomy 8, 14, and 18 was detected. The patient was treated conservatively and died of the disease 20 months after the initial diagnosis. To the best of our knowledge, this is the first case of bile duct HS. This case, which involved numerical alterations of chromosomes, presented with CT and ERCP findings similar to those of choledocholithiasis.

Les altérations génétiques dans le neuroblastome et leur apport pour la prise en charge thérapeutique

Neuroblastoma, the most frequent solid extracranial tumor of childhood, is characterized by a wide variability of its clinical course. The most important clinical prognostic markers are stage and age at diagnosis, but these markers are insufficient to predict outcome reliably and to determine treatment intensity. Recent evidence indicates that neuroblastoma can be considered as a “genetic disease”, firstly by the recent observation that certain alleles of specific genes significantly increase the relative risk to develop neuroblastoma, and the discovery of mutations in genes such as ALK or PHOX2B in rare familial cases. On the other hand, a large number of recurrent genetic somatic alterations have been described in neuroblastoma. Recent technological advances, such as array-CGH (comparative genomic hybridisation), now enable the analysis of these markers in a single step and allow the definition of genomic profiles associated with typical clinical features. Numerical chromosome alterations are observed more frequently in tumors of younger children with localised disease and a good prognosis, whereas segmental chromosome alterations are found more frequently in tumors of older children with advanced stages of disease and a poorer outcome. Future therapeutic stratification schemes can make use of the tumor genomic profile by proposing less intense treatment for infants with a neuroblastoma harboring a favorable tumor genomic profile, while intensifying treatment in case of a defavorable tumor genomic profile. Such approaches require standardisation of the molecular techniques and the interpretation of results for application in international trials.

Gender and ploidy in cancer survival

BackgroundFemales carry a better prognosis than men for many cancer types. We hypothesized that chromosomal changes, in particular numerical alterations of the sex chromosomes or the presence of near-triploidy may contribute to these gender differences.MethodsTo characterize the influence of gender a literature search was performed for survival data of 27 tumor types. All entities were categorized by the strength of evidence for differences in survival between females and males. To test our hypothesis the Mitelman database of chromosomal alterations was evaluated for the major tumor types occurring in both women and men. Numerical gonosome alterations were documented and mean chromosome numbers were converted into histograms to provide insight into the ploidy level of 37 cancer types.ResultsIn general, a survival advantage of women could be shown for most, but not all cancer types. In addition, 36.859 karyograms were analyzed. Numerical gonosome alterations were more frequent in males than females indicating a potential link with gender differences in survival. Neartriploidy was a common phenomenon in many cancer types suggesting that it represents a metastable condition of the cancer genome. It was not related to gender differences in survival. However, the extent of triploidy and aneuploidy was associated with poor prognosis in carcinomas. There was no single case in the Mitelman database with normal chromosome number (n = 46) that did not carry at least one structural or numerical aberration.ConclusionsOur study highlights the importance of chromosomal changes in tumor formation and progression. In addition, it suggests potential associations with gender specific differences in survival.Electronic supplementary materialThe online version of this article (doi:10.1007/s13402-011-0013-0) contains supplementary material, which is available to authorized users.

Evidence of Long Latency Periods Prior to Development of Mantle Cell Lymphoma

AbstractAbstract 323Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma characterized by treatment failures and short survival. At presentation, MCL is often widely disseminated. Occasionally, early lymphoma can be seen as in situ lesions involving the mantle zones of secondary follicles. The primary genetic lesion involved in the pathogenesis of the disease is the t(11;14)(q13;q32)/(IGH/CCND1) which leads to the overexpression of cyclin D1, a cell cycle regulatory protein that is not normally expressed in B-cells. However, MCL frequently has numerous additional chromosomal alterations making it one of the most genetically unstable lymphomas. Thus, while the IGH/CCND1 rearrangement is the critical initiating event, it appears that additional alterations are necessary to develop MCL. However, little is known about the latency period required to accumulate sufficient lesions to develop MCL. Recently, it has been appreciated that the initiating chromosomal events in other B-cell malignancies may precede the development of overt disease by many years. In particular, the defining chromosomal events in childhood ALL may be found in the heel sticks of children at birth, even if leukemia does not develop until a number of years later. We recently reported a unique case of mantle cell lymphoma arising simultaneously in the donor and recipient 12 years following allogeneic bone marrow transplantation for chronic myelogenous leukemia(J. Clin. Oncol., in press). This suggested that MCL may exhibit long latency periods prior to the development of frank lymphoma. In order to determine whether in situ MCL may be identified in patients with MCL, we identified 7 patients who were diagnosed with mantle cell lymphoma and who had previous pathological material available that contained lymphoid tissue and that was unrelated to the subsequent MCL. Remarkably, all 7 specimens showed evidence of in situ mantle cell lymphoma, as judged by cyclin D1 over-expression localized to lymphoid cells. Pathological specimens ranged from 2.1–15.5 years prior to the diagnosis of MCL. In all 7 specimens, cyclin D1 positive collections of lymphocytes were identified, 5 with distinct homing to mantle zones, one with follicular colonization and mantle homing, and 1 with a diffuse distribution. FISH studies were undertaken to identify cyclin D1 chromosomal translocations, and evidence of chromosomal translocations could be identified in 2/3 cases evaluated whereas no signals were seen in adjacent uninvolved lymphoid tissue. Taken together, the data presented strongly suggest that a long latency period following the initiating IGH/CCND1 translocation may occur in MCL with patients harboring in situ lesions for years prior to the development of clinical disease. These findings shed interesting new light on the natural history of MCL.Pre-lymphoma locationPattern of in situ MCLLatency (yrs)Lymphoma locationCCND1 FISH in pre-lymphoma specimenObturator node from radical prostatectomyCyclinD1+ focal colonized follicles, scattered cells in mantles7.4Sigmoid colon biopsyNDDuodenal serosal lymph node (perforated benign gastric ulcer)Diffuse scattered CyclinD1+ cells2.1Sigmoid colon biopsyNDRight neck subcutaneous lymph node (neurofibroma excision)CyclinD1+ cells in follicular mantles3.2Bone marrow biopsyNDPeriesophageal lymph nodes from esophagectomySeveral CyclinD1+ colonized primary follicles8.0Right cervical lymph nodeNDAxillary lymph node from mastectomyCyclinD1+ cells in follicular mantles15.5Mesenteric lymph node<5% positive signalsMesenteric lymph node dissection for colon cancerCyclinD1+ cells in follicular mantles10.6Base of tongue lesionPositiveCervical lymph node involved with T cell lymphomaCyclinD1+ cells in follicular mantles3.1Right axillary lymph nodePositive Disclosures:No relevant conflicts of interest to declare.

Molecular pathogenesis and targeted therapies for NOTCH1-induced T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic tumor resulting from the malignant transformation of immature T-cell progenitors. Originally associated with a dismal prognosis, the outcome of T-ALL patients has improved remarkably over the last two decades as a result of the introduction of intensified chemotherapy protocols. However, these treatments are associated with significant acute and long-term toxicities, and the treatment of patients presenting with primary resistant disease or those relapsing after a transient response remains challenging. T-ALL is a genetically heterogeneous disease in which numerous chromosomal and genetic alterations cooperate to promote the aberrant proliferation and survival of leukemic lymphoblasts. However, the identification of activating mutations in the NOTCH1 gene in over 50% of T-ALL cases has come to define aberrant NOTCH signaling as a central player in this disease. Therefore, the NOTCH pathway represents an important potential therapeutic target. In this review, we will update our current understanding of the molecular basis of T-ALL, with a particular focus on the role of the NOTCH1 oncogene and the development of anti-NOTCH1 targeted therapies for the treatment of this disease.

Accumulation of Segmental Alterations Determines Progression in Neuroblastoma

Neuroblastoma is characterized by two distinct types of genetic profiles, consisting of either numerical or segmental chromosome alterations. The latter are associated with a higher risk of relapse, even when occurring together with numerical alterations. We explored the role of segmental alterations in tumor progression and the possibility of evolution from indolent to aggressive genomic types. Array-based comparative genomic hybridization data of 394 neuroblastoma samples were analyzed and linked to clinical data. Integration of ploidy and genomic data indicated that pseudotriploid tumors with mixed numerical and segmental profiles may be derived from pseudotriploid tumors with numerical alterations only. This was confirmed by the analysis of paired samples, at diagnosis and at relapse, as in tumors with a purely numerical profile at diagnosis additional segmental alterations at relapse were frequently observed. New segmental alterations at relapse were also seen in patients with segmental alterations at diagnosis. This was not linked to secondary effects of cytotoxic treatments since it occurred even in patients treated with surgery alone. A higher number of chromosome breakpoints were correlated with advanced age at diagnosis, advanced stage of disease, with a higher risk of relapse, and a poorer outcome. These data provide further evidence of the role of segmental alterations, suggesting that tumor progression is linked to the accumulation of segmental alterations in neuroblastoma. This possibility of genomic evolution should be taken into account in treatment strategies of low- and intermediate-risk neuroblastoma and should warrant biologic reinvestigation at the time of relapse.

HPV-Mediated Genome Instability: At the Roots of Cervical Carcinogenesis

Human papillomaviruses are small DNA viruses that cause hyperproliferative lesions of the mucosa and skin. Some HPV types, collectively known as high-risk types, are etiologically associated to cervical cancer and other anogenital malignancies. Infection by these HPV types has been associated to genomic instability, a hallmark of most human malignancies. High-risk HPV types express two oncoproteins, E6 and E7, which target specific cellular factors to promote cell proliferation. Furthermore, these proteins induce structural and numerical chromosome alterations and modulate cellular response to DNA damage. These observations are discussed in the context of cervical carcinogenesis.

Identification en pratique clinique des carcinomes basal-like du sein : des carcinomes « triple zéro/BRCA1-like »

Basal-like carcinomas represent 10 to 15% of invasive breast carcinomas and have been identified from gene expression studies. Morphologically, these tumors are undifferentiated histopronostic grade 3 carcinomas, identified in clinical practice according to their immunophenotype “triple zero” (estrogen, progesterone and ERBB2 negative) associated with the high molecular weight cytokeratins 5/6/14 and/or EGFR expression. At the molecular level, these tumors harbour nearly 100% P53 mutations, a high rate of PTEN mutations with an AKT pathway’s activation and numerous chromosomal alterations such as gains and losses. They share a high degree of similarity at the morphological, phenotypical and molecular level with BRCA1 tumors that justify the proposal of a different name such as “triple zero/BRCA1 like” carcinomas for sporadic basal-like carcinomas. Indeed, the current “basal-like” name could suggest a myoepithelial cellular origin of such lesions. Furthermore, tumors with such a basal-like immunophenotype constitute a heterogeneous group of tumors encompassing good prognosis tumors such as adenoid cystic and juvenile secretory carcinomas. There is an urgent need for more specific therapies for basal-like/triple zero/BRCA1-like tumors. Therapeutic progresses rely on a better understanding of the molecular alterations that occur in these tumors and the BRCA1 tumors. Indeed, recent clinical trials with PARP inhibitors for basal-like/BRCA1 like tumors should improve the prognosis of these patients and are a direct benefit of a better understanding of the molecular biology of these tumors.

Chromosome 17 Aberration of Oral Squamous Cell Carcinoma in Malaysia

In most tumours including Oral squamous cell carcinoma (SCC), acquisition of genetic instability is an essential step during carcinogenesis that involves generalized increased rate of errors during DNA replication, and defective repair of DNA. The genomic change results in numerical and structural chromosomal alterations, particularly in chromosomes 3, 9, 11 and 17. Chromosome 17 abnormality was chosen in my study because it shown strong correlation with neoplastic development and progression. In my study, twenty Oral SCC archival blocks were selected retrospectively from two referred Malaysian oral cancer centres. Histopathological findings were prior diagnosed by experienced Oral Pathologist, then Fluorescent in-situ Hybridization (FISH) technique was conducted subsequently by using specific probe of chromosome 17 in these oral SCC cases. In this study, the numerical aberration of chromosome 17 by FISH method in oral SCC in apparently normal tissues was evaluated. In this study, normal control cases showed 67.8±11% cells of disomic signals in their nuclei, whereas the numerical aberration of chromosome 17 is frequent demonstrated in oral SCC (17/20, 85%) cases. In hence, FISH can be used as a possible prognostic marker for the degree of genomic instability and aneuploidy in excised specimens of oral SCC containing invasive cancer in Malaysia.

Valoración de una reacción en cadena de la polimerasa cuantitativa y fluorescente (QF-PCR) para el diagnóstico rápido de aneuploidías

Introduction Quantitative fluorescence polymerase chain reaction (QF-PCR) identifies in less than 24 h the most common chromosomal anomalies looked for in conventional prenatal karyotyping: numerical alterations of chromosomes 13, 18, 21, X and Y. Several polymorphic markers are used in QF-PCR for each chromosome, allowing a high reliability of results, speed, low cost and automation. Nevertheless, QF-PCR can not detect structural abnormalities, low-level mosaicism or marker chromosomes. Objective To develop and evaluate a fast, reliable and feasible method for detecting aneuploidies of chromosomes 13, 18, 21, X and Y, in the samples received for prenatal karyotyping in a cytogenetics department. Materials and methods In addition to the 465 amniotic fluids received during last year, stored DNA samples in which a disease was detected in the previous two years were assayed (corresponding to the study of around 1,000 prenatal samples). DNA extraction is automated. The STR polymorphic markers used, with high heterozygosity, are accepted internationally (Association for Clinical Cytogenetics. QF-PCR for the diagnosis of aneuploidy best practice guidelines (2007). Available at http://www.cytogenetics.org.uk/prof_standards/professional_standards.htm). The test has the same PCR amplification conditions for all four multiplex mixtures used. In each of them All the necessary components were included in each of them, except the sample, which was added at the time of the assay. Each amplified mixture is analyzed into the ABI3130 Genetic Analyzer, Applied Biosystems. Fragments analysis is achieved following the published recommendations. Results The results of all the tested samples, normal or pathological, matched the outcome of the conventional karyotype. In total the QF-PCR assay detected: 12 trisomy 21; 5 trisomy 18; 3 women 45,X ; 2 trisomy 47,XXY ; 2 trisomy 13 ; 2 Triple XXX ; 2 men XYY; and 2 triploid pregnancies. In each of these cases the proposed QF-PCR was diagnostic. A partial monosomy of chromosome 18 could not be detected, but a partial trisomy of chromosome 18 was identified. Conclusions The evaluated QF-PCR is a useful tool for the rapid diagnosis of aneuploidies (24 h). It is extremely valuable when the amniocyte cultures fail to grow, or suffer microbiological contamination. It serves to reduce maternal anxiety until the conventional karyotype is reported, and to take quick decisions when ultrasound anomalies are found in the second trimester of pregnancy.

Interrelationship between TP53gene deletion, protein expression and chromosome 17 aneusomy in gastric adenocarcinoma

BackgroundThis study evaluates the existence of numerical alterations of chromosome 17 and TP53 gene deletion in gastric adenocarcinoma. The p53 protein expression was also evaluated, as well as, possible associations with clinicopathological characteristics.MethodsDual-color fluorescence in situ hybridization and immunostaining were performed in twenty gastric cancer samples of individuals from Northern Brazil.ResultsDeletion of TP53 was found in all samples. TP53 was inactivated mainly by single allelic deletion, varying to 7–39% of cells/case. Aneusomy of chromosome 17 was observed in 85% of cases. Chromosome 17 monosomy and gain were both observed in about half of cases. Cells with gain of chromosome 17 frequently presented TP53 deletion. The frequency of cells with two chr17 and one TP53 signals observed was higher in diffuse than in intestinal-type GC. Immunoreactivity of p53 was found only in intestinal-type samples. The frequency of cells with two chr17 and two TP53 signals found was higher in samples with positive p53 expression than in negative cases in intestinal-type GC.ConclusionWe suggest that TP53 deletion and chromosome 17 aneusomy is a common event in GC and other TP53 alterations, as mutation, may be implicated in the distinct carcinogenesis process of diffuse and intestinal types.

Gene and chromosomal alterations in sporadic breast cancer: correlation with histopathological features and implications for genesis and progression

A number of gene and chromosome alterations have been identified in sporadic breast carcinomas, and their clinical implications have been investigated. Changes in proto-oncogenes and tumor-suppressor genes, e.g., HER2, p53, and E-cadherin, and various numerical and structural chromosome alterations are strongly correlated with histological type and grade in breast carcinomas. The amount of information on these alterations has been dramatically increased by the introduction of high-throughput molecular cytogenetic approaches. In the near future, breast cancers will be classified into specific groups according to their profile of gene and chromosome alterations, allowing more effective personalized therapies targeting the associated molecular pathways.

Pathogenesis of adrenocortical cancer

The study of the clonality of adrenocortical tumours (ACTs) has shown that adrenocortical cancers (ACCs) are of monoclonal origin. Numerous chromosomal alterations have been observed in ACCs, and they are much more frequent than in adrenocortical adenomas. Progress in the genetics of familial syndromes associated with ACTs helped to identify significant somatic molecular alterations in sporadic adult ACCs. Somatic mutations of the tumour suppressor gene TP53 are observed in a third of ACCs. Interestingly, allelic losses (LOH) at the TP53 locus (17p13) are very frequent, observed in more than 85% of ACCs. The insulin-like growth factor II (IGF-II) locus (11p15) is imprinted. IGF-II is over-expressed in 90% of ACCs. Transcriptome studies have identified an IGF-II cluster of genes significantly over-expressed in ACCs. Transcriptome analysis suggests also that the Wnt/beta-catenin signalling pathway is activated in ACT. About a third of ACCs harbours somatic activating mutations of the beta-catenin gene. This recent progress in the molecular genetics of ACC has led to the development of new molecular markers for the diagnosis of malignancy; these might also help to identify prognostic markers of ACC and may ultimately lead to novel therapeutic approaches.

Genomic instability in giant cell tumor of bone. A study of 52 cases using DNA ploidy, relocalization FISH, and array‐CGH analysis

Genetic instability in relation to clinical behavior was studied in 52 cases of giant cell tumor of bone (GCTB). Ploidy was determined in the mononuclear cell population by using native cell smears and image cytometry. A relocalization technique allowed fluorescent in situ hybridization (FISH) analysis of CD68-negative neoplastic cells for numerical changes of chromosomes X, 3, 4, 6, 11, and telomeric association on 11p. Genome-wide alterations were tested using array comparative genomic hybridization (array-CGH) on magnetically separated CD68-negative tumor cells. CTNNB1, TP53, and BCL2 protein expression was also analyzed in formol-paraffin sections to see if their pathways are involved in the development of chromosomal instability. CD68-positive histiocytes showed no significant numerical chromosome and telomeric alterations. Based on ploidy values and clinical outcome, we could distinguish five groups as follows: diploid nonrecurrent (n = 20), tetraploid nonrecurrent (n = 6), diploid recurrent (n = 5), tetraploid and/or aneuploid recurrent (n = 14), and malignant cases (n = 7). Random individual-cell aneusomy was significantly (P < 0.001) more frequent in the recurrent groups (36.01 +/- 11.94%) than in the benign nonrecurrent cases (10.65 +/- 3.66%). The diploid recurrent group showed significantly (P < 0.001) increased balanced aneusomy compared with the diploid nonrecurrent group and the tetraploid nonrecurrent group represented eusomic polysomy. Array-CGH and FISH showed clonal aberrations almost exclusively in the malignant group. None of the protein markers tested showed significant correlation with elevated aneuploidy/polysomy (P = 0.56). Our results show that ploidy determination combined with FISH analysis may help predicting recurrence potential of GCTB and suggest that chromosomal abnormalities superimposed on telomeric associations could be responsible for an aggressive clinical course.

Oncogenomic analysis of mycosis fungoides reveals major differences with Sézary syndrome

AbstractMycosis fungoides (MF), the most common cutaneous T-cell lymphoma, is a malignancy of mature, skin-homing T cells. Sézary syndrome (Sz) is often considered to represent a leukemic phase of MF. In this study, the pattern of numerical chromosomal alterations in MF tumor samples was defined using array-based comparative genomic hybridization (CGH); simultaneously, gene expression was analyzed using microarrays. Highly recurrent chromosomal alterations in MF include gain of 7q36, 7q21-7q22 and loss of 5q13 and 9p21. The pattern characteristic of MF differs markedly from chromosomal alterations observed in Sz. Integration of data from array-based CGH and gene-expression analysis yielded several candidate genes with potential relevance in the pathogenesis of MF. We confirmed that the FASTK and SKAP1 genes, residing in loci with recurrent gain, demonstrated increased expression. The RB1 and DLEU1 tumor suppressor genes showed diminished expression associated with loss. In addition, it was found that the presence of chromosomal alterations on 9p21, 8q24, and 1q21-1q22 was associated with poor prognosis in patients with MF. This study provides novel insight into genetic alterations underlying MF. Furthermore, our analysis uncovered genomic differences between MF and Sz, which suggest that the molecular pathogenesis and therefore therapeutic requirements of these cutaneous T-cell lymphomas may be distinct.

Hormone escape is associated with genomic instability in a human prostate cancer model

Lack of hormone dependency in prostate cancers is an irreversible event that occurs through generation of genomic instability induced by androgen deprivation. Indeed, the cytogenetic profile of hormone-dependent (HD) prostate cancer remains stable as long as it received a hormone supply, whereas the profile of hormone-independent (HID) variants acquired new and various alterations. This is demonstrated here using a HD xenografted model of a human prostate cancer, PAC120, transplanted for 11 years into male nude mice and 4 HID variants obtained by surgical castration. Cytogenetic analysis, done by karyotype, FISH, CGH and array-CGH, shows that PAC120 at early passage presents numerous chromosomal alterations. Very few additional alterations were found between the 5th and 47th passages, indicating the stability of the parental tumor. HID variants largely maintained the core of chromosomal alterations of PAC120 - losses at 6q, 7p, 12q, 15q and 17q sites. However, each HID variant displayed a number of new alterations, almost all being specific to each variant and very few shared by all. None of the HID had androgen receptor mutations. Our study indicates that hormone castration is responsible for genomic instability generating new cytogenetic abnormalities susceptible to alter the properties of cancer cell associated with tumor progression, such as increased cell survival and ability to metastasize.

Unbalanced translocation, a major chromosome alteration causing loss of heterozygosity in human lung cancer

Loss of heterozygosity (LOH) is a major genetic event causing inactivation of tumor suppressor genes in human carcinogenesis. To elucidate chromosomal mechanisms causing LOH, 201 LOHs in 10 cases of human lung cancer, which were detected by a genome-wide single nucleotide polymorphism array analysis, were investigated for responsible chromosome alterations by integrating information on breakpoints for DNA copy number changes obtained by array-comparative genome hybridization and on numerical and structural chromosomal alterations obtained by spectral karyotyping. The majority (80%) of LOHs were partial chromosome LOHs caused by structural chromosomal alterations, while the remaining (20%) were whole chromosome LOHs caused by whole chromosome deletions. Unbalanced translocation was defined as the most frequent alteration, and it accounted for 30% of all LOHs. Three other structural alterations-interstitial deletion (19%), mitotic recombination (9%) and gene conversion (6%)-also contributed to the occurrence of LOH, while terminal deletion contributed to only a small subset (1%). Since unbalanced translocation is a common chromosomal alteration in lung cancer cells, the results in the present study strongly indicate that a considerable fraction of LOHs detected in lung cancer cells are caused by unbalanced translocation.

Effect of temporary nuclear arrest by Phosphodiesterase 3‐Inhibitor on morphological and functional aspects of in vitro matured mouse oocytes

The present study aimed to analyze detailed morphological and functional characteristics of mouse in vitro matured oocytes after a pre-maturation culture (PMC) by temporary nuclear arrest with the specific phosphodiesterase 3-inhibitor (PDE3-I) Cilostamide. In a first experiment the lowest effective dose of Cilostamide was determined. Cumulus-oocyte complexes (COCs), isolated from small antral follicles, were exposed to different concentrations of Cilostamide (ranging from 0 (control) to 10 microM) for 24 hr. Afterwards, oocytes were removed from PDE3-I-containing medium and underwent in vitro maturation (IVM) for 16-18 hr. A concentration of 1 microM Cilostamide was the lowest effective dose for maximum level of inhibition and reversibility of meiosis inhibition. This concentration was used in further experiments to evaluate oocyte quality following IVM in relation to different parameters: kinetics of meiotic progression, metaphase II (MII) spindle morphology, aneuploidy rate, fertilization, and embryonic developmental rates. The results were compared to nonarrested (in vitro control) and in vivo matured oocytes (in vivo control). Following withdrawal of the inhibitor, the progression of meiosis was more synchronous and accelerated in arrested when compared to nonarrested oocytes. A PMC resulted in a significant increase in the number of oocytes constituting a MII spindle of normal morphology. None of the oocytes exposed to PDE3-I showed numerical chromosome alterations. In addition, fertilization and embryonic developmental rates were higher in the PMC group compared to in vitro controls, but lower than in vivo controls. These results provide evidence that induced nuclear arrest by PDE3-I is a safe and reliable method to improve oocyte quality after IVM.

Common and Distinct Genomic Events in Sporadic Colorectal Cancer and Diverse Cancer Types

Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality, and elucidation of its underlying genetics has advanced diagnostic screening, early detection, and treatment. Because CRC genomes are characterized by numerous non-random chromosomal structural alterations, we sought to delimit regions of recurrent amplifications and deletions in a collection of 42 primary specimens and 37 tumor cell lines derived from chromosomal instability neoplasia and microsatellite instability neoplasia CRC subtypes and to compare the pattern of genomic aberrations in CRC with those in other cancers. Application of oligomer-based array-comparative genome hybridization and custom analytic tools identified 50 minimal common regions (MCRs) of copy number alterations, 28 amplifications, and 22 deletions. Fifteen were highly recurrent and focal (<12 genes) MCRs, five of them harboring known CRC genes including EGFR and MYC with the remaining 10 containing a total of 65 resident genes with established links to cancer. Furthermore, comparisons of these delimited genomic profiles revealed that 22 of the 50 CRC MCRs are also present in lung cancer, glioblastoma, and/or multiple myeloma. Among 22 shared MCRs, nine do not contain genes previously shown genetically altered in cancer, whereas the remaining 13 harbor 35 known cancer genes, of which only 14 have been linked to CRC pathogenesis. Together, these observations point to the existence of many yet-to-be discovered cancer genes driving CRC development, as well as other human cancers, and show the utility of high-resolution copy number analysis in the identification of genetic events common and specific to the development of various tumor types.