Consistent Chromosomal Aberrations Research Articles

Oral lichen planus patients exhibit consistent chromosomal numerical aberrations: A follow-up analysis.

Oral lichen planus (OLP) carries an increased risk for malignant transformation with aneuploid cells (ACs) being found in brush samples of a quarter of patients with OLP. Patients with OLP were followed and repeated brush samples were simultaneously analyzed for morphology and fluorescent in situ hybridization (FISH) using centromeric probes for chromosomes 2 and 8. Three patients with a high proportion of ACs developed oral cancer. Fifteen patients had ≥1% ACs (13 in affected sites and 2 in nonaffected sites), whereas only 2 of the 15 patients with <1% ACs in the first sample had ≥1% ACs in the second sample. A strong positive correlation between the results of the initial and repeated samples was found. High proportion of ACs in brush samples from patients with OLP may imply an impending malignant transformation. As FISH analysis is consistent over time, it can be used to identify a subgroup of patients who would require close follow-up. © 2015 Wiley Periodicals, Inc. Head Neck 38: E741-E746, 2016.

Translocation (2;13) and other chromosome abnormalities in intraosseous schwannoma of the mandible

Intraosseous schwannoma is rare, and most commonly occurs in the mandible. Benign classic schwannomas commonly carry normal karyotypes admixed with aberrant near-diploid karyotypes with a few simple clonal chromosome changes, mainly numerical. No consistent chromosomal aberrations have been observed so far. It is unclear whether the chromosomal abnormalities are affected by the anatomic site of the tumor; however, we know of no cytogenetic reports on schwannoma in the oral area. This novel report of cytogenetic analysis of intraosseous schwannoma represents the fifth report on a new balanced translocation in schwannoma in general. We identified clonal t(2;13) in an intraosseous schwannoma of the mandible. The significance of t(2;13) in diagnosis or prognosis is not yet clear, and should be further examined by karyotyping of more schwannoma cases.

No genomic aberrations in Langerhans cell histiocytosis as assessed by diverse molecular technologies

The etiology of Langerhans cell histiocytosis (LCH), a disease characterized by uncontrolled proliferation of Langerhans cells, is unknown. Although some believe that LCH is reactive, others support a neoplastic origin. We tested the hypothesis that LCH is neoplastic by investigating potential consistent chromosomal aberrations in LCH cells. We used multiparameter DNA flow cytometry to analyze the DNA ploidy LCH cells in 20 cases, performed karyotype analysis in 31 cases, array-based comparative genomic hybridization (arrayCGH) and single nucleotide polymorphism (SNP) arrays with DNA from flow-sorted CD1a-positive and CD1a-negative cells in 19 cases. Ploidy analysis revealed diploid DNA content in all cases. The karyotype of all patients analyzed was normal, excluding the presence of balanced translocations. ArrayCGH and SNP arrays did not show genome abnormalities. Despite positive TP53 protein immunohistochemical staining, sequencing of exon 5 to 8 of p53 gene showed no alterations in 7 cases. This study strongly suggests that gross chromosomal abnormalities do not cause LCH. Although we cannot exclude cryptic point mutations in as yet unidentified genes, this study of 72 LCH cases shows that LCH may be the result of restricted oligoclonal stimulation rather than unlimited neoplastic proliferation. (c) 2008 Wiley-Liss, Inc.

The CM cell line derived from liver metastasis of malignant human insulinoma is not a valid beta cell model for in vitro studies

The CM cell line is derived from the ascitic fluid of a patient with liver metastasis of a malignant insulinoma. Insulin levels potentially derived from the insulinoma were detected only once in vivo in the subject with the malignant pancreatic tumor and hypoglycemia. After multiple unsuccessful attempts to detect insulin in the culture medium, insulin levels were again detected only once in vitro. In our repeated experiments, we extensively exposed early-passages of the CM cell line to 0.91 mM glucose and acutely to increasingly higher glucose concentrations (2.75, 5.5, 11, and 22 mM) and did not detect any insulin secretion as well as any significant insulin cell content. The electronic microscopic examinations of several vials containing early-passages of the CM cell lines showed a polyclonal nature of the cells mostly resembling fibroblasts. The karyotype detected severe and consistent chromosomal aberrations of the CM cell line, including the chromosome 11 tetraploidy and the genetic material translocation in three out of four chromosomes 11 at the insulin gene locus 11p15.1. These data, unfortunately, exclude the possibility of considering the CM cell line as a valid beta cell model in vitro.

Nonrandom de novo chromosome aberrations in human lymphocytes and amniotic cells.

The incidences and types of chromosome aberrations in single cells of individuals with a normal chromosome constitution were studied in two cell types, viz. lymphocytes and amniotic cells. A total of 17, 545 lymphocytes and 17, 262 amniotic cells were analyzed from 2, 554 consecutive individuals. The total incidence of numerical and structural aberrations was 2.0% and 1.6% in lymphocytes and amniotic cells, respectively. Two particular translocation types-t (7:14) (p 14–15; q 11–12) and t (7;14) (q 36: q 12)-were present in the lymphocytes of 1/145 individuals (1/1, 595 metaphases), whereas none of the amniotic cell metaphases displayed such a translocation. Otherwise, no apparent differences were found between the two cell types as regards incidences and types of numerical and structural aberrations. None of the structural aberrations found in lymphocytes and amniotic cells were identical to any of the consistent chromosome aberrations characteristics of malignant cells. The fact that the breakpoints in structural chromosome aberrations in isolated somatic cells seem to be basically different from these characteristic of neoplastic cells supports the conclusion that the cancer-associated aberrations are produced by mechanisms that actively favor the formation of such aberrations.

Distinctive Cytogenetic Profile in Benign Metastasizing Leiomyoma: Pathogenetic Implications

"Benign metastasizing leiomyoma" is the terminology used to describe a controversial entity characterized by a proliferation of bland-appearing smooth muscle in lung or abdominopelvic lymph nodes. In this report, we describe 5 cases of pulmonary-based smooth muscle tumors that are clinically and histologically consistent with this entity, and in which we identified consistent chromosomal aberrations (19q and 22q terminal deletion in all cases). This cytogenetic profile is found in approximately 3% of uterine leiomyoma, but has not been described in other types of benign or malignant neoplasia. These findings suggest that the nodular pulmonary smooth muscle proliferations termed "benign metastasizing leiomyoma," are a genetically distinct entity, which likely originate from a biologically distinctive subset of uterine leiomyoma.

Cytogenetic features of ependymoblastomas

Ependymoblastomas are very rare and highly malignant embryonal tumours of the central nervous system with distinctive multilayered rosettes being the main histopathological feature. They are a diagnostically challenging subtype of embryonal tumours, whose genetic features are unknown. Primary ependymoblastomas from four children (one boy, three girls; mean age 24.8 months, range 4-41 months) were investigated by comparative genomic hybridisation (CGH), to our knowledge constituting the only cohort of this entity studied by cytogenetic means. DNA copy number changes were found in each case, consisting mainly of gains of chromosome 2 as well as losses of chromosomes 6q and 13q (75% each). The tumours showed between one and five aberrations with a mean of 3.25 DNA copy number changes per case, with gains being less frequent than losses (1.25 gains vs 2 losses per case). The youngest patient showed the least imbalances (one), whereas the oldest child presented with the most aberrations (five). Clinical follow-up data were available for three of the four patients. All three had died of their disease after a post-operative survival of 9 months (range 6-14 months). Our CGH data suggest that ependymoblastomas show distinct and fairly consistent chromosomal aberrations.

Identification of a Novel Homozygous Deletion Region at 6q23.1 in Medulloblastomas Using High-Resolution Array Comparative Genomic Hybridization Analysis

The aim of this study is to comprehensively characterize genome copy number aberrations in medulloblastomas using high-resolution array comparative genomic hybridization. High-density genomic arrays containing 1,803 BAC clones were used to define recurrent chromosomal regions of gains or losses throughout the whole genome of medulloblastoma. A series of 3 medulloblastoma cell lines and 16 primary tumors were investigated. The detected consistent chromosomal aberrations included gains of 1q21.3-q23.1 (36.8%), 1q32.1 (47.4%), 2p23.1-p25.3 (52.6%), 7 (57.9%), 9q34.13-q34.3 (47.4%), 17p11.2-q25.3 (89.5%), and 20q13.31-q13.33 (42.1%), as well as losses of 3q26.1 (57.9%), 4q31.23-q32.3 (42.1%), 6q23.1-25.3 (57.9%), 8p22-23.3 (79%), 10q24.32-26.2 (57.9%), and 16q23.2-q24.3 (63.2%). One of the most notable aberrations was a homozygous deletion on chromosome 6q23 in the cell line DAOY, and single copy loss on 30.3% primary tumors. Further analyses defined a 0.887 Mbp minimal region of homozygous deletion at 6q23.1 flanked by markers SHGC-14149 (6q22.33) and SHGC-110551 (6q23.1). Quantitative reverse transcription-PCR analysis showed complete loss of expression of two genes located at 6q23.1, AK091351 (hypothetical protein FLJ34032) and KIAA1913, in the cell line DAOY. mRNA levels of these genes was reduced in cell lines D283 and D384, and in 50% and 70% of primary tumors, respectively. Current array comparative genomic hybridization analysis generates a comprehensive pattern of chromosomal aberrations in medulloblastomas. This information will lead to a better understanding of medulloblastoma tumorigenesis. The delineated regions of gains or losses will indicate locations of medulloblastoma-associated genes. A 0.887 Mbp homozygous deletion region was newly identified at 6q23.1. Frequent detection of reduced expression of AK091351 and KIAA1913 genes implicates them as suppressors of medulloblastoma tumorigenesis.

SynMuv verité—Myb comes into focus: Figure 1.

Over the past 25 years, tremendous progress has been made in the identification of the genetic alterations that cause cancer. The discovery of oncogenes and tumorsuppressor genes relied largely on studies of animal retroviruses, consistent chromosomal aberrations in human cancers, transfection of human tumor DNA into rodent cells, DNA tumor viruses, and rare familial cancer syndromes (Bishop 1995). A major challenge has been to understand the function of the protein products of these genes in both normal and malignant cells. In many cases studies of developmental genetics in model organisms have provided key insights that have illuminated the pathways that go awry in human cancer. In particular, the awesome power of beast genetics in the nematode and fruit fly has benefited from the speed and rela

PIK3CA as an oncogene in cervical cancer.

Amplification of chromosome arm 3q is the most consistent aberration in cervical cancer, and is implicated in the progression of dysplastic uterine cervical cells into invasive cancer. The present study employed the 'positional candidate gene' strategy to determine the contribution of PIK3CA, which is located in 3q26.3, in cervical tumorigenesis. PIK3CA is known to be involved in the PI 3-kinase/AKT signaling pathway, which plays an important role in regulating cell growth and apoptosis. The results of comparative genomic hybridization show that the 3q26.3 amplification was the most consistent chromosomal aberration in primary tissues of cervical carcinoma, and a positive correlation between an increased copy number of PIK3CA (detected by competitive PCR) and 3q26.3 amplification was found in tumor tissues and in cervical cancer cell lines. In cervical cancer cell lines harboring amplified PIK3CA, the expression of gene product (p110alpha) of PIK3CA was increased, and was subsequently associated with high kinase activity. In addition, transformation phenotypes in these lines, including increased cell growth and decreased apoptosis, were found to be significantly affected by the treatment of specific PI 3-kinase inhibitor, suggesting that increased expression of PIK3CA in cervical cancer may result in promoting cell proliferation and reducing apoptosis. These evidences support that PIK3CA is an oncogene in cervical cancer and PIK3CA amplification may be linked to cervical tumorigenesis. Oncogene (2000).

Genomic Changes and HPV Type in Cervical Carcinoma

Abstract. To identify chromosomal regions that may include the loci of abnormally expressed cellular genes and may be specifically altered depending on the histological subtype of the tumor, we studied primary cervical carcinoma using CGH and HPV genotyping. Eighty‐seven percent of the primary tumors were positive for DNA of a “high‐risk” HPV type (e.g., 16 or 18). In the cervical carcinomas, without reference to histologic subtype, overrepresentation of chromosome 3q was the most consistent chromosomal aberration with underrepresentation of chromosome 3p also a frequent finding. Chromosome arms 1q, 5p, 20q, and Xq were overrepresented in many tumors and 3p loss and 5p, 8q, and 16q gain were only associated with squamous cell carcinoma in this series.

Genomic changes and HPV type in cervical carcinoma.

To identify chromosomal regions that may include the loci of abnormally expressed cellular genes and may be specifically altered depending on the histological subtype of the tumor, we studied primary cervical carcinoma using CGH and HPV genotyping. Eighty-seven percent of the primary tumors were positive for DNA of a "high-risk" HPV type (e.g., 16 or 18). In the cervical carcinomas, without reference to histologic subtype, overrepresentation of chromosome 3q was the most consistent chromosomal aberration with underrepresentation of chromosome 3p also a frequent finding. Chromosome arms 1q, 5p, 20q, and Xq were overrepresented in many tumors and 3p loss and 5p, 8q, and 16q gain were only associated with squamous cell carcinoma in this series.

Genetics of uterine leiomyomata

Leiomyomata represent the most common gynecologic tumors in women of reproductive age and are the primary indication for hysterectomy in the United States. Cytogenetic and genetic studies have in recent years advanced our understanding of the etiology of these tumors. Cytogenetic aberrations involving chromosomes 6, 7, 12, and 14 constitute the major chromosomal abnormalities seen in leiomyomata and have led to the discovery that disruptions or dysregulations of HMGIC and HMGIY contribute to the development of these tumors. Based on the finding of a variety of other consistent chromosomal aberrations detected in these tumors, other genes with fundamental roles in the pathobiology of uterine leiomyomata await identification. Genes Chromosomes Cancer 28:235-245, 2000.

Additional chromosome 1q aberrations and der(16)t(1;16), correlation to the phenotypic expression and clinical behavior of the Ewing family of tumors.

The cytogenetic hallmark of the Ewing family of tumors is t(11,22)(q24;q12) in its simple, complex or variant forms and/or its molecular equivalent EWS/FLI, EWS/ERG rearrangement. Additional secondary consistent chromosomal aberrations include the der(16)t(1;16) and frequently, other chromosome 1q abnormalities leading to 1q overdosage. We studied whether these secondary cytogenetic changes are correlated to clinical features and phenotypic expression which may have a prognostic impact. Successful cytogenetic evaluation was performed in eight patients with a Ewing family tumor. In four of these, in addition to the primary aberration, chromosome 1q overdosage (including two with der (16)t(1;16)) was noted. Out of these four patients, two had metastatic disease at the time of evaluation, while in the other four, disease was localized. Morphologically, the tumors with the additional 1q aberration, revealed the pPNET subtype more frequently than the typical Ewing. They also expressed a higher degree of neural differentiation by neural marker immunocytochemistry, in comparison to tumors without the 1q aberration. Determination of the prognostic significance of this finding requires a longer follow-up with a larger group of patients.

Karyotypic characteristics of borderline malignant tumors of the ovary: Trisomy 12, trisomy 7, and r(1) as nonrandom features

Clonal karyotypic abnormalities were detected in five of 14 cytogenetically analyzed borderline malignant ovarian tumors of clinical stages I–II. One mucinous and one seropapillary tumor had trisomy 7 and r(1)(p36q42) as the sole chromsome abnormality, respectively. Trisomy 12 was found in the remaining three cases. It was the only change in one mucinous and one serous tumor, whereas the third, a seropopillary borderline tumor, had the karyotype 49,XX,+5,+8,+12. These findings, especially when collated with those of previous reports on ovarian borderline tumor cytogenetics, indicate that +12 is the most consistent chromosomal aberration in this group of neoplasms and that also +7 and r(1) are nonrandom features. From the karyotypic point of view, benign ovarian tumors and well-differentiated carcinomas are similar to borderline ovarian tumors, with the possible exception that the former have no tendency to form r(1). Highly malignant carcinomas, on the other hand, are typically much more complex. Chromosome-level changes therefore cannot account for the putative phenotypic passage through the most innocuous tumor stages as epithelial ovarian neoplasms go from benign to fully malignant.

Trisomy 1 and 8 occur frequently in hepatocellular carcinoma but not in liver cell adenoma and focal nodular hyperplasia. A fluorescence in situ hybridization study.

Conventional cytogenetic studies revealed gains and structural aberrations of chromosome 1 to be the most consistent chromosomal aberrations in hepatocellular carcinoma (HCC). We investigated touch preparations of eight HCC, five cholangiocellular carcinomas (CCC), five liver cell adenomas (LCA), four focal nodular hyperplasias (FNH) as well as nine specimens of normal liver tissue using fluorescence in situ hybridization (FISH) with centromere specific probes for chromosomes 1 and 8. Polysomies of chromosome 1, especially trisomy 1, were found in five of eight HCC and four of five CCC but in no normal liver tissue or benign tumour. Only three of seven cases of HCC revealed trisomy 8 whereas the five benign liver tumours and all normal liver tissues examined had disomy 8. Our results confirm conventional cytogenetic findings in terms of chromosome 1 aberrations in HCC although they are not specific for these types of malignant liver tumours. Since alpha-satellite probes were used in our study, only gains or losses including the centromeric regions of the chromosomes 1 and 8 could be detected. Nevertheless, our findings suggest that FISH may help in the differential diagnosis of malignant versus benign neoplasms of the liver.

Rapid Diagnosis of Acute Promyelocytic Leukemia by Immunohistochemical Localization of PML/RAR-α Protein

Acute promyelocytic leukemia (APL) is characterized by a consistent chromosomal aberration that fuses the retinoic acid receptor alpha (RAR alpha) gene with the novel gene PML, resulting in the expression of a PML/RAR-alpha fusion protein. Immunohistochemical examination of APL cells shows a unique abnormal distribution of anti-PML and anti-RAR alpha antibody labeling. The PML labeling pattern observed in normal cells consists of 5 to 10 discrete spherical nuclear bodies called PODs (for "PML oncogenic domains"), whereas that of APL consists of a smaller and far more numerous speckled pattern. We examined malignant cells from patients with a variety of hematopoietic cancers by immunohistochemistry (IH) and found this abnormal PML pattern expressed in cells from patients with t(15;17)-associated leukemia but not in patients with other neoplastic disorders. IH results agreed with reverse transcription polymerase chain reaction for PML/RAR-alpha in 31 of 32 patients with acute myelogenous leukemia, including 5 of 5 patients in whom the initial clinical diagnosis of APL was not supported by cytogenetics, molecular tests, or response to all-trans retinoic acid (RA). Cells from patients with APL were examined during the course of retinoid therapy and at the time of complete remission and relapse. Reorganization of the PML labeling into PODs with normal appearance was observed in cells from patients who received RA. IH showed primarily normal PML staining during clinical remission, although the APL-specific labeling pattern was again seen in cells taken from patients at the time of relapse. Thus, IH provides an independent assay for the presence and expression of the molecular rearrangement of APL. The relative ease and speed of detecting the APL-specific PML labeling pattern should make IH a useful diagnostic tool to guide specific therapy of APL, and establish a direct assay for PML/RAR-alpha protein expression and localization in individual patient cells.

Rapid diagnosis of acute promyelocytic leukemia by immunohistochemical localization of PML/RAR-alpha protein

Acute promyelocytic leukemia (APL) is characterized by a consistent chromosomal aberration that fuses the retinoic acid receptor alpha (RAR alpha) gene with the novel gene PML, resulting in the expression of a PML/RAR-alpha fusion protein. Immunohistochemical examination of APL cells shows a unique abnormal distribution of anti-PML and anti-RAR alpha antibody labeling. The PML labeling pattern observed in normal cells consists of 5 to 10 discrete spherical nuclear bodies called PODs (for “PML oncogenic domains”), whereas that of APL consists of a smaller and far more numerous speckled pattern. We examined malignant cells from patients with a variety of hematopoietic cancers by immunohistochemistry (IH) and found this abnormal PML pattern expressed in cells from patients with t(15;17)-associated leukemia but not in patients with other neoplastic disorders. IH results agreed with reverse transcription polymerase chain reaction for PML/RAR-alpha in 31 of 32 patients with acute myelogenous leukemia, including 5 of 5 patients in whom the initial clinical diagnosis of APL was not supported by cytogenetics, molecular tests, or response to all-trans retinoic acid (RA). Cells from patients with APL were examined during the course of retinoid therapy and at the time of complete remission and relapse. Reorganization of the PML labeling into PODs with normal appearance was observed in cells from patients who received RA. IH showed primarily normal PML staining during clinical remission, although the APL-specific labeling pattern was again seen in cells taken from patients at the time of relapse. Thus, IH provides an independent assay for the presence and expression of the molecular rearrangement of APL. The relative ease and speed of detecting the APL- specific PML labeling pattern should make IH a useful diagnostic tool to guide specific therapy of APL, and establish a direct assay for PML/RAR-alpha protein expression and localization in individual patient cells.

Consistent chromosomal aberration in cell lines transformed with Marek's disease herpesvirus: evidence of genomic DNA amplification.

A specific chromosomal aberration was observed in 14 of 15 avian lymphoblastoid cell lines transformed with Marek's disease herpesvirus. This aberration, designated dup(1p)(p22-p23), appeared as an extra G-positive band and interband on the short arm of one chromosome I homolog. Using fluorescent in situ hybridization, we identified amplified genomic DNA sequences in this region. This amplification involves sequences linked to an endogenous retrovirus locus and genes in the histone multigene family. This aberration was not observed in cells transformed by reticuloendotheliosis virus or by avian leukosis virus, nor has it been observed in untransformed chicken cells. The induction of the 1p+ chromosomal aberration may be an essential event in the transformation of lymphocytes by Marek's disease virus.

Diagnosis of Ewing's sarcoma and peripheral neuroectodermal tumour based on the detection of t(11;22) using fluorescence in situ hybridisation.

Fluorescence in situ hybridisation (FISH) has been used increasingly for gene mapping and ordering probes on interphase and metaphase preparations. The association of consistent chromosomal aberrations with certain malignancies allows the possibility of using interphase cytogenetics as a diagnostic tool. In small round cell tumours of children accurate diagnosis may be difficult using existing methods. We have therefore evaluated the diagnostic potential of this technique when applied to the characteristic t(11;22) found in Ewing's sarcoma and peripheral neuroectodermal tumour (ES and PNET). Interphase nuclei were prepared from normal human foreskin fibroblasts (HFF), two Ewing's sarcoma cell lines and several fresh tumour biopsies. DNA probes each side of the breakpoint at 22q12 were labelled with biotin and digoxygenin, hybridised to chromosomes in interphase and detected in different colours. Measurements between pairs of signals arising from each copy of chromosome 22 were taken and statistical analysis performed. There was a highly significant difference (P < 0.0001) between the two populations of measurements obtained (from nuclei with and without the t(11;22)). Studying four tumours and one further ES line (blind) it was found that median values from 30 nuclei could correctly identify which samples contained the t(11;22). This application of interphase cytogenetics contributes a reliable, accurate and conceptually simple diagnostic test for ES and PNET. It may now be applied to other tumours with characteristic translocations, amplifications or deletions when suitable probes are available. This approach is likely to become a routine in clinical diagnosis.