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E J Speel

Publications and source records attributed to E J Speel.

At least 19 recordsLinked to original sources
PubMed2001

Genetic evidence for early divergence of small functioning and nonfunctioning endocrine pancreatic tumors: gain of 9Q34 is an early event in insulinomas.

The malignant potential among endocrine pancreatic tumors (EPTs) varies greatly and can frequently not be predicted using histopathological parameters. Thus, molecular markers that can predict the biological behavior of EPTs are required. In a previous comparative genomic hybridization study, we observed marked genetic differences between the various EPT subtypes and a correlation between losses of 3p and 6 and gains of 14q and Xq and metastatic disease. To search for genetic alterations that play a role during early tumor development, we have studied 38 small (< or =2 cm) EPTs, including 24 insulinomas and 10 nonfunctioning EPTs. Small EPTs are usually classified as clinically benign tumors in the absence of histological signs of malignancy. Using comparative genomic hybridization, we identified chromosomal aberrations in 27 EPTs (mean, 4.1). Interestingly, the number of gains differed strongly between nonfunctioning and functioning EPTs (3.4 versus 1.5, respectively; P = 0.0526), as did the number of aberrations in the benign (n = 30) and malignant (n = 8) tumors (3 versus 8.4, respectively; P = 0.0022). In the insulinomas, 9q gain (common region of involvement: 9q34) was most common (50%) and in nonfunctioning EPTs, gain of 4p was most common (40%). Most frequent losses in insulinomas involved 1p (20.8%), 1q, 4q, 11q, Xq, and Y (all 16.7%) and in nonfunctioning EPTs, 6q. Losses of 3pq and 6q and gains of 17pq and 20q proved to be strongly associated with malignant behavior in all of the small EPTs (P < or = 0.0219). Our results demonstrate marked genetic differences between small functioning and nonfunctioning EPTs, indicating that these subtypes evolve along different genetic pathways. In addition, our study endorses the importance of chromosomes 3 and 6q losses to discriminate EPTs with a malignant behavior from benign ones.

Adolescent↗
PubMed2001

Quantitative real-time PCR does not show selective targeting of p14(ARF) but concomitant inactivation of both p16(INK4A) and p14(ARF) in 105 human primary gliomas.

In many human cancers, the INK4A locus is frequently mutated by homozygous deletions. By alternative splicing this locus encodes two non-related tumor suppressor genes, p16(INK4A) and p14(ARF) (p19(ARF) in mice), which regulate cell cycle and cell survival in the retinoblastoma protein (pRb) and p53 pathways, respectively. In mice, the role of p16(INK4A) as the critical tumor suppressor gene at the INK4A locus was challenged when it was found that p19(ARF) only knock-out mice developed tumors, including gliomas. We have analysed the genetic status of the INK4A locus in 105 primary gliomas using both microsatellite mapping (MSM) and quantitative real-time PCR (QRT-PCR). Comparison of the results of the two methods revealed agreement in 67% of the tumors examined. In discordant cases, fluorescence in situ hybridization (FISH) analysis was always found to support QRT-PCR classification. Direct assessment of p14(ARF) exon 1beta, p16(INK4A) exon 1alpha and exon 2 by QRT-PCR revealed 43 (41%) homozygous and eight (7%) hemizygous deletions at the INK4A locus. In 49 (47%) gliomas, both alleles were retained. In addition, QRT-PCR, but not MSM, detected hyperploidy in five (5%) tumors. Deletion of p14(ARF) was always associated with co-deletion of p16(INK4A) and increased in frequency upon progression from low to high grade gliomas. Shorter survival was associated with homozygous deletions of INK4A in the subgroup of glioblastoma patients older than 50 years of age (P=0.025, Anova test single factor, alpha=0.05).

Chromosome Mapping↗
PubMed2001

Genomic imbalances in the progression of endocrine pancreatic tumors.

Endocrine pancreatic tumors (EPTs) are neoplasms with malignant potential. To explore the molecular basis of metastatic progression in human EPTs, we analyzed 17 paired specimens of primary EPTs and their metastases and 28 nonmetastatic EPTs using comparative genomic hybridization (CGH). Genomic alterations were detected in all of the matched primary/metastatic tumors and 19 (58%) nonmetastatic EPTs. The mean number of genomic changes was 17.3 in metastases, 12.5 in their primary tumors, and 4.5 in nonmetastatic EPTs. Statistical analysis of shared genomic changes in matched pairs of primary tumors and metastases showed a high probability (>95%) of a clonal relationship in 15 of the 17 cases. A closely related genetic pattern was also demonstrated on the basis of concordance analysis of the two groups. The most striking genomic changes which were enriched in metastases included gains of chromosomes 4 and 7 and losses of 21q. Other common regions of frequent losses (>40%) identified in metastases and/or their primary tumors involved 2p, 2q, 3p, 3q, 6q, 10p, and 11p, whereas frequently detected gains (>40%) in the paired tumors involved 5p, 5q, 12q, 14q, 17q, 18q, and 20q. These chromosomal aberrations were found in significantly fewer nonmetastatic EPTs. Some of these chromosomal loci may harbor genes contributing to the progression of EPT.

Adenoma, Islet Cell↗
PubMed2001

Deletion at 3p25.3-p23 is frequently encountered in endocrine pancreatic tumours and is associated with metastatic progression.

For several reasons, chromosome 3p is thought to be involved in the pathogenesis of sporadic endocrine pancreatic tumours (EPTs): von Hippel-Lindau's disease (VHL gene at 3p25.5) is associated with EPTs; 3p is frequently involved in solid human tumours; and comparative genomic hybridization has identified frequent losses at 3p in EPTs. This study investigated 99 benign and malignant tumours, including 20 metastases, from 82 patients, by microsatellite loss of heterozygosity (LOH) analysis and fluorescence in situ hybridization (FISH) in order to evaluate the importance of chromosome 3p deletions in the molecular pathogenesis and biological behaviour of EPTs, to elaborate a common region of deletion, and to narrow down putative tumour suppressor gene loci. Allelic losses of 3p were found in 58/99 (58.6%) of tumours in 45/82 (54.9%) patients; analysis of seven microsatellite markers (3p26-p21) revealed a common region of LOH at 3p25.3-p23. The LOH frequency was significantly higher in malignant than in benign neoplasms (70.2% versus 28.0%; p=0.001). In addition, a strong correlation was found between the loss of alleles on chromosome 3p and clinically metastatic disease (LOH of 73.7% in metastasizing versus 41.5% in non-metastasizing tumours; p=0.008). EPTs from these patients showed a tendency towards losing large parts or the entire short arm of chromosome 3 with tumour progression. Furthermore, FISH analysis revealed complete loss of chromosome 3 in ten out of 37 EPTs (27%). These results indicate that a putative tumour suppressor gene at 3p25.3-p23 may play a role in the oncogenesis of sporadic EPTs and that losses of larger centromeric regions are associated with metastatic progression.

Adult↗
PubMed2001

Gains of 12q13-14 and overexpression of mdm2 are frequent findings in intimal sarcomas of the pulmonary artery.

The characterization of clinical, histopathological, immunohistochemical, and genetic features of intimal sarcomas arising in the pulmonary artery is presented in this study. Four resected lungs, one endarterectomy specimen and three biopsies from eight patients (four males and four females; median age 41 years) suffering from intimal sarcomas of the pulmonary artery using conventional stains, immunohistochemistry, and comparative genomic hybridization (CGH) were analyzed. The predominant clinical presentation was dyspnea (all eight patients) and febrile pulmonary disease (six of eight). Signs of embolic lung disease were present in all patients. One patient died postoperatively, six patients died of disease 8-35 months after presentation, and one patient was alive 6 months after surgery. Histopathological examination of the submitted material showed spindle cell, partially myxoid and pleomorphic sarcomas. Metastases were histologically confirmed in three patients (lung, pleura, and skull). Immunohistochemically, vimentin was strongly expressed in all tumors. Focal positivity was observed for alpha smooth muscle actin, CD117, CD68, p53, and bcl2. No reaction could be obtained for endothelial markers. The proliferation index Ki-67 was between 5% and 80%. Six examined tumors were positive for mdm2. In the CGH analysis, gains and amplifications in the 12q13-14 region were found in six of eight tumors (75%). Other, less consistent alterations, were losses on 3p, 3q, 4q, 9p, 11q, 13q, Xp, and Xq, gains on 7p, 17p, and 17q, and amplifications on 4q, 5p, 6p, and 11q. Intimal sarcomas of the pulmonary artery are tumors with an unfavorable prognosis and poorly differentiated morphology. A majority of tumors show a consistent genetic alteration (gains and amplifications in the 12q13-14 region) and overexpression of mdm2, implicating the mdm2/p53 pathway as a possible mechanism in the tumor pathogenesis.

Actins↗
PubMed2001

Putative tumor suppressor loci at 6q22 and 6q23-q24 are involved in the malignant progression of sporadic endocrine pancreatic tumors.

Our previous comparative genomic hybridization study on sporadic endocrine pancreatic tumors (EPTs) revealed frequent losses on chromosomes 11q, 3p, and 6q. The aim of this study was to evaluate the importance of 6q losses in the oncogenesis of sporadic EPTs and to narrow down the smallest regions of allelic deletion. A multimodal approach combining polymerase chain reaction-based allelotyping, double-target fluorescence in situ hybridization, and comparative genomic hybridization was used in a collection of 109 sporadic EPTs from 93 patients. Nine polymorphic microsatellite markers (6q13 to 6q25-q27) were investigated, demonstrating a loss of heterozygosity (LOH) in 62.2% of the patients. A LOH was significantly more common in tumors >2 cm in diameter than below this threshold as well as in malignant than in benign tumors. We were able to narrow down the smallest regions of allelic deletion at 6q22.1 (D6S262) and 6q23-q24 (D6S310-UTRN) with LOH-frequencies of 50.0% and 41.2 to 56.3%, respectively. Several promising tumor suppressor candidates are located in these regions. Additional fluorescence in situ hybridization analysis on 46 EPTs using three locus-specific probes (6q21, 6q22, and 6q27) as well as a centromere 6-specific probe revealed complete loss of chromosome 6 especially in metastatic disease. We conclude that the two hot spots found on 6q may harbor putative tumor suppressor genes involved not only in the oncogenesis but maybe also in the malignant and metastatic progression of sporadic EPTs.

Adenoma, Islet Cell↗
PubMed2001

Differential loss of chromosome 11q in familial and sporadic parasympathetic paragangliomas detected by comparative genomic hybridization.

Parasympathetic paragangliomas (PGLs) represent neuroendocrine tumors arising from chief cells in branchiomeric and intravagal paraganglia, which share several histological features with their sympathetic counterpart sympathoadrenal paragangliomas. In recent years, genetic analyses of the familial form of PGL have attracted considerable interest. However, the majority of paragangliomas occurs sporadically and it remains to be determined whether the pathogenesis of sporadic paraganglioma resembles that of the familial form. Furthermore, data on comparative genetic aberrations are scarce. To provide fundamental cytogenetic data on sporadic and hereditary PGLs, we performed comparative genomic hybridization using directly fluorochrome-conjugated DNA extracted from 12 frozen and 4 paraffin-embedded tumors. The comparative genomic hybridization data were extended by loss of heterozygosity analysis of chromosome 11q. DNA copy number changes were found in 10 (63%) of 16 tumors. The most frequent chromosomal imbalance involved loss of chromosome 11. Six of seven familial tumors and two of nine sporadic tumors showed loss of 11q (86% versus 22%, P = 0.012). Deletions of 11p and 5p were found in two of nine sporadic tumors. We conclude that overall DNA copy number changes are infrequent in PGLs compared to sympathetic paragangliomas and that loss of chromosome 11 may be an important event in their tumorigenesis, particularly in familial paragangliomas.

Adult↗
PubMed2001

Spectral imaging of multi-color chromogenic dyes in pathological specimens.

We have investigated the use of spectral imaging for multi-color analysis of permanent cytochemical dyes and enzyme precipitates on cytopathological specimens. Spectral imaging is based on Fourier-transform spectroscopy and digital imaging. A pixel-by-pixel spectrum-based color classification is presented of single-, double-, and triple-color in situ hybridization for centromeric probes in T24 bladder cancer cells, and immunocytochemical staining of nuclear antigens Ki-67 and TP53 in paraffin-embedded cervical brush material (AgarCyto). The results demonstrate that spectral imaging unambiguously identifies three chromogenic dyes in a single bright-field microscopic specimen. Serial microscopic fields from the same specimen can be analyzed using a spectral reference library. We conclude that spectral imaging of multi-color chromogenic dyes is a reliable and robust method for pixel color recognition and classification. Our data further indicate that the use of spectral imaging (a) may increase the number of parameters studied simultaneously in pathological diagnosis, (b) may provide quantitative data (such as positive labeling indices) more accurately, and (c) may solve segmentation problems currently faced in automated screening of cell- and tissue specimens.

Carcinoma, Transitional Cell↗
PubMed2000

Losses of chromosomes 1p and 3q are early genetic events in the development of sporadic pheochromocytomas.

Despite several loss of heterozygosity studies, a comprehensive genomic survey of pheochromocytomas is still lacking. To identify DNA copy number changes which might be important in tumor development and progression and which may have diagnostic utility, we evaluated genetic aberrations in 29 sporadic adrenal and extra-adrenal pheochromocytomas (19 clinically benign tumors and 10 malignant lesions). Comparative genomic hybridization was performed using directly fluorochrome-conjugated DNA extracted from frozen (16) and paraffin-embedded (13) tumor tissues. The most frequently observed changes were losses of chromosomes 1p11-p32 (86%), 3q (52%), 6q (34%), 3p, 17p (31% each), 11q (28%), and gains of chromosomes 9q (38%) and 17q (31%). No amplification was identified and no difference between adrenal and extra-adrenal tumors was detected. Progression to malignant tumors was strongly associated with deletions of chromosome 6q (60% versus 21% in clinically benign lesions, P = 0.0368) and 17p (50% versus 21%). Fluorescence in situ hybridization confirmed the comparative genomic hybridization data of chromosomes 1p, 3q, and 6q, and revealed aneuploidy in some tumors. Our results suggest that the development of pheochromocytomas is associated with specific genomic aberrations, such as losses of 1p, 3q, and 6q and gains of 9q and 17q. In particular, tumor suppressor genes on chromosomes 1p and 3q may be involved in early tumorigenesis, and deletions of chromosomes 6q and 17p in progression to malignancy.

Adult↗
PubMed2000

Genomic alterations in well-differentiated gastrointestinal and bronchial neuroendocrine tumors (carcinoids): marked differences indicating diversity in molecular pathogenesis.

Neuroendocrine tumors (carcinoids) are a heterogeneous group of neoplasms arising from the diffuse neuroendocrine system. Genetic changes underlying their tumorigenesis are primarily unknown. We used comparative genomic hybridization to screen 32 well-differentiated neuroendocrine tumors (21 gastrointestinal and 11 bronchial) and three associated metastases for genomic alterations. There were striking differences of genomic imbalances between the two subgroups of neuroendocrine tumors. Losses of chromosome 18q and 18p were shown in eight (38%) and seven (33%), respectively, out of 21 gastrointestinal tumors and in none of the 11 bronchial tumors. Conversely, deletions of 11q occurred in four of 11 (36%) bronchial tumors but only in one gastrointestinal tumor. These comparative genomic hybridization findings were confirmed by interphase cytogenetics. Our data indicate that neuroendocrine tumors of the two subgroups develop via different molecular pathways. Inactivation of one or several tumor suppressor genes on chromosome 18 may be important for the biological behavior of gastrointestinal tumors, whereas gene inactivation on 11q seems to be associated with tumor development of the bronchi.

Adult↗
PubMed1999

MEN1 gene mutation analysis of sporadic adrenocortical lesions.

To clarify the role of the MEN1 gene in the tumorigenesis of sporadic adrenocortical tumors, we performed a molecular study on 35 adrenocortical lesions including 6 hyperplasias, 19 adenomas and 10 carcinomas. Loss of heterozygosity (LOH) of the MEN1 gene was assessed by PCR using an intragenic (D11S4946) and 2 flanking microsatellite markers (D11S4936, PYGM) and/or fluorescence in situ hybridization (FISH) with a 40-kb cosmid probe containing the MEN1 gene. The complete coding sequence of the MEN1 gene was screened for mutations using non-radioactive, PCR-based single-strand conformation polymorphism (SSCP) analysis and MDE heteroduplex gel electrophoresis. PCR-LOH and FISH analyses performed in 29 tumors (PCR-LOH in 4, FISH in 17 and both in 8 tumors) revealed allelic deletion of the MEN1 locus in 8 (27.5%) and at 11q13 in 9 (31%) tumors. Furthermore, the frequency of LOH at 11q13 was significantly higher in adrenocortical carcinomas (60%) than in benign lesions (11%). Mutation analysis of tumor samples revealed 9 polymorphisms in 7 tumors (S145S, R171Q, R171Q together with L432L) but no mutations, with the exception of one adrenocortical adenoma. The latter tumor contained a somatic E109X stop codon mutation in exon 2 and a 5178-9G-->A splice mutation in intron 4, which was also detectable in various nontumorous tissues and blood indicative of a germ-line mutation. The patient, who had no clinical signs or family history of MEN1, later also developed a neuroendocrine carcinoma (atypical carcinoid) of the lung. Our findings indicate that inactivating mutations of the MEN1 tumor-suppressor gene appear not to play a prominent role in the development of sporadic hyperplastic or neoplastic lesions of the adrenal cortex and that the newly reported 5178-9G-->A splice mutation in intron 4 might cause a variant of the MEN1 phenotype.

Adrenal Cortex↗
PubMed1999

Robert Feulgen Prize Lecture 1999. Detection and amplification systems for sensitive, multiple-target DNA and RNA in situ hybridization: looking inside cells with a spectrum of colors.

In situ hybridization (ISH) is a powerful technique for localizing specific nucleic acid sequences (DNA, RNA) in microscopic preparations of tissues, cells, chromosomes, and linear DNA fibers. To date, a wide variety of research and diagnostic applications of ISH have been described, making the technique an integral part of studies concerning gene mapping, gene expression, RNA processing and transport, the three-dimensional organization of the nucleus, tumor genetics, microbial infections, and prenatal diagnosis. In this review, I first describe the ISH procedure in short and then focus on the currently available non-radioactive probe-labeling and cytochemical detection methodologies that are utilized to visualize one or multiple different nucleic acid targets in situ with different colors. Special emphasis is placed on the procedures applying fluorescence and brightfield microscopy, the simultaneous detection of nucleic acids and proteins by combined ISH and immunocytochemistry, and, in addition, on the recent progress that has been made with the introduction of signal amplification procedures to increase the detection sensitivity of ISH. Finally, a comparison of fluorescence, enzyme cytochemical, and colloidal gold silver probe detection systems will be presented, and possible future directions of in situ nucleic acid detection will be discussed.

Animals↗
PubMed1999

Analysis of genomic alterations in sporadic adrenocortical lesions. Gain of chromosome 17 is an early event in adrenocortical tumorigenesis.

Genetic changes underlying the tumorigenesis of sporadic adrenocortical tumors are poorly characterized. To search for characteristic genomic imbalances involved in adrenocortical tumors, we examined 41 adrenocortical lesions (12 carcinomas, 23 adenomas, and 6 hyperplasias) by comparative genomic hybridization. Our results show that genetic alterations are more frequent in malignant than in benign lesions and that they rarely occur in hyperplastic lesions. The most frequent DNA copy number changes in adrenocortical carcinomas included losses of 1p21-31, 2q, 3p, 3q, 6q, 9p, and 11q14-qter, as well as gains and amplifications of 5q12, 9q32-qter, 12q, and 20q. The genomic aberrations prevalently occurring in adrenocortical adenomas were gains of 17q, 17p, and 9q32-qter. Gains found in 2 of 6 adrenocortical hyperplastic lesions involved chromosome 17 or 17q only. These data indicate that oncogenes determining the early tumorigenesis of adrenocortical tumors may exist on chromosome 17 and that the number of genomic alterations is closely associated with tumor behavior in adrenocortical tumors.

Adolescent↗
PubMed1999

Mutations and allelic deletions of the MEN1 gene are associated with a subset of sporadic endocrine pancreatic and neuroendocrine tumors and not restricted to foregut neoplasms.

Endocrine pancreatic tumors (EPT) and neuroendocrine tumors (NET) occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). We analyzed the frequency of allelic deletions and mutations of the recently identified MEN1 gene in 53 sporadic tumors including 30 EPT and 23 NET (carcinoids) of different locations and types. Allelic deletion of the MEN1 locus was identified in 18/49 (36.7%) tumors (13/30, 43.3% in EPT and 5/19, 26.3% in NET) and mutations of the MEN1 gene were present in 8/52 (15.3%) tumors (4/30 (13.3%) EPT and 4/22 (18.1%) NET). The somatic mutations were clustered in the 5' region of the coding sequence and most frequently encompassed missense mutations. All tumors with mutations exhibited a loss of the other allele and a wild-type sequence of the MEN1 gene in nontumorous DNA. In one additional patient with a NET of the lung and no clinical signs or history of MEN1, a 5178-9G-->A splice donor site mutation in intron 4 was identified in both the tumor and blood DNA, indicating the presence of a thus far unknown MEN1 syndrome. In most tumor groups the frequency of allelic deletions at 11q13 was 2 to 3 times higher than the frequency of identified MEN1 gene mutations. Some tumor types, including rare forms of EPT and NET of the duodenum and small intestine, exhibited mutations more frequently than other types. Furthermore, somatic mutations were not restricted to foregut tumors but were also detectable in a midgut tumor (15.2% versus 16.6%). Our data indicate that somatic MEN1 gene mutations contribute to a subset of sporadic EPT and NET, including midgut tumors. Because the frequency of mutations varies significantly among the investigated tumor subgroups and allelic deletions are 2 to 3 times more frequently observed, factors other than MEN1 gene inactivation, including other tumor-suppressor genes on 11q13, may also be involved in the tumorigenesis of these neoplasms.

Adenoma, Islet Cell↗
PubMed1999

Mixed medullary-follicular thyroid carcinoma. Molecular evidence for a dual origin of tumor components.

Mixed medullary-follicular carcinomas (MMFCs) are tumors of the thyroid that display morphological and immunohistochemical features of both medullary and follicular neoplasms. The histogenetic origin and possible molecular mechanisms leading to MMFCs are still unclear. To address these questions, we have isolated the two histological components of 12 MMFCs by (laser-based) microdissection, analyzed them for mutations in the RET proto-oncogene and allelic losses of nine loci on six chromosomes, and studied the clonal composition of MMFCs in female patients. Our results provide strong evidence that the follicular and medullary components in MMFCs are not derived from a single progenitor cell, because the seven tumors amenable for analysis consistently exhibited a different pattern of mutations, allelic losses, and clonal composition. We also demonstrate that follicular structures in MMFCs are often oligo/polyclonal and more frequently exhibit hyperplastic than neoplastic histological features, indicating that at least a subset of MMFCs are composed of a medullary thyroid carcinoma containing hyperplastic follicles.

Adult↗
PubMed1999

Genetic differences in endocrine pancreatic tumor subtypes detected by comparative genomic hybridization.

The molecular pathogenesis as well as histogenesis of endocrine pancreatic tumors (EPTs) is not well understood, and the clinical behavior of EPTs is difficult to predict using current morphological criteria. Thus, more accurate markers of risk and better understanding of tumor initiation and progression are needed to allow a precise classification of EPTs. We have studied 44 benign and malignant EPTs by comparative genomic hybridization to correlate the overall number of genetic alterations with clinical and histopathological parameters and to identify chromosomal regions which might harbor genes involved in EPT pathogenesis and progression. Aberrations were found in 36 EPTs, and chromosomal losses (mean, 5.3) were slightly more frequent than gains (mean, 4. 6). The most frequent losses involved Y (45% of male EPTs), 6q (39%), 11q (36%), 3p, 3q, 11p (each 30%), 6p (27%), and 10q and Xq (each 25%), whereas most common gains included 7q (43%), 17q (41%), 5q and 14q (each 32%), 7p, 9q, 17p, 20q (each 27%), and 12q and Xp (each 25%). A correlation was found between the total number of genetic changes per tumor and both tumor size and disease stage. In particular, losses of 3p and 6 and gains of 14q and Xq were found to be associated with metastatic disease. Furthermore, characteristic patterns of genetic changes were found in the various EPT subtypes, eg, 6q loss in malignant insulinomas, indicating that these groups might evolve along genetically different pathways. The highlighted genetic aberrations, including the newly found involvement of 6q losses and sex chromosome alterations, should stimulate the further analysis of these chromosomal regions, which may lead to the discovery of novel genes important in the tumorigenesis and evolution of EPTs.

Chromosome Aberrations↗