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M A Hermsen

Publications and source records attributed to M A Hermsen.

At least 19 recordsLinked to original sources
PubMed2001

Cytogenetic characteristics of oral squamous cell carcinomas in Fanconi anemia.

Fanconi anemia (FA) is an autosomal recessive syndrome with a marked predisposition to malignancies, in particular acute myeloid leukemia and squamous cell carcinoma of the oral cavity. We examined oral squamous cell carcinoma tissue from two FA patients (FA-A and FA-C) by comparative genomic hybridization. Both tumors, which were negative for human papilloma as well as Epstein-Barr viral sequences, showed multiple alterations with a high proportion of whole-arm chromosomal gains and losses. This combination of features as well as the sites involved in chromosomal breakage are very similar to what is typically observed in non-FA oral tumors. These results suggest that the process leading to early occurrence of oral cancer in FA patients follows a similar pathway as in non-FA cancer patients, which would support a caretaker function for FA genes in the protection against oral carcinogenesis. Since FA patients are uniquely hypersensitive to DNA cross-linking agents, while oral cancer in the general population is thought to be environmentally induced, these results also suggest that environmental DNA cross-linkers may be causally involved in oral carcinogenesis.

Adult↗
PubMed2001

Comparative genomic hybridization of microdissected familial ovarian carcinoma: two deleted regions on chromosome 15q not previously identified in sporadic ovarian carcinoma.

The vast majority of familial ovarian cancers harbor a germline mutation in either the breast cancer gene BRCA1 or BRCA2 tumor suppressor genes. However, mutations of these genes in sporadic ovarian cancer are rare. This suggests that in contrast to hereditary disease, BRCA1 and BRCA2 are not commonly involved in sporadic ovarian cancer and may indicate that there are two distinct pathways for the development of ovarian cancer. To characterize further differences between hereditary and sporadic cancers, the comparative genomic hybridization technique was employed to analyze changes in copy number of genetic material in a panel of 36 microdissected hereditary ovarian cancers. Gains at 8q23-qter (18 of 36, 5 cases with high-level amplifications), 3q26.3-qter (18 of 36, 2 cases with high-level amplifications), 11q22 (11 of 36) and 2q31-32 (8 of 36) were most frequent. Losses most frequently occurred (in decreasing order of frequency) on 8p21-pter (23 of 36), 16q22-pter (19 of 36), 22q13 (19 of 36), 9q31-33 (16 of 36), 12q24 (16 of 36), 15q11-15 (16 of 36), 17p12-13 (14 of 36), Xp21-22 (14 of 36), 20q13 (13 of 36), 15q24-25 (12 of 36), and 18q21 (12 of 36). Comparison with the literature revealed that the majority of these genetic alterations are also common in sporadic ovarian cancer. Deletions of 15q11-15, 15q24-25, 8p21-ter, 22q13, 12q24 and gains at 11q22, 13q22, and 17q23-25, however, appear to be specific to hereditary ovarian cancer. Aberrations at 15q11-15 and 15q24-25 have not yet been described in familial ovarian cancer. In these regions, important tumor suppressor genes, including the hRAD51 gene, are located. These and other yet unknown suppressor genes may be involved in a specific carcinogenic pathway for familial ovarian cancer and may explain the distinct clinical presentation and behavior of familial ovarian cancer.

BRCA2 Protein↗
PubMed2001

Distinct chromosomal aberrations in Epstein-Barr virus-carrying gastric carcinomas tested by comparative genomic hybridization.

BACKGROUND & AIMS: Approximately 10% of gastric adenocarcinomas carry the human pathogenic Epstein-Barr virus (EBV). The role of EBV in the pathogenesis of these carcinomas remains to be established. METHODS: To obtain a comprehensive overview of chromosomal aberrations in EBV-carrying and EBV-negative gastric carcinomas we performed comparative genomic hybridization (CGH) on 44 gastric carcinomas, 10 EBV-positive, and 34 EBV-negative. Additionally, DNA flow cytometry was done. RESULTS: Loss of chromosome 4p (P < 0.001) and of 11p (P < 0.02) was exclusively restricted to EBV-carrying gastric carcinomas. In addition, loss of 18q (P < 0.02) was significantly more frequent in EBV-carrying gastric carcinomas. The latter involves loci, which have already been linked to gastric carcinogenesis such as the DCC and SMAD4 gene. In contrast, the losses on chromosome 4 and 11 do not yet harbor a gene related to gastric carcinogenesis. No significant correlation was found between DNA-ploidy and the EBV-status. A number of chromosomal aberrations were found at comparable frequencies in both groups, i.e., losses of chromosome 17, 12q, and loss of 1p. Interestingly, gains of 13q (10/34) and 3q (5/34) and loss of 1q (5/34) were solely observed in EBV-negative gastric carcinomas. CONCLUSIONS: These data indicate that EBV-carrying and EBV-negative gastric carcinomas have different pathogenetic pathways in which EBV might play a crucial role.

Adenocarcinoma↗
PubMed2001

Clonally related but phenotypically divergent human cancer cell lines derived from a single follicular thyroid cancer recurrence (TT2609).

Starting from different regional samples taken from a heterogeneous follicular thyroid cancer recurrence in a male patient, a series of cell cultures was initiated. Three stable cancer cell lines were successfully established (TT2609-A02, TT2609-B02, and TT2609-C02) and kept in continuous culture for more than 3 years. The lines are each characterized by a unique set of biological parameters such as morphology, ploidy state, cell proliferation rate, ultrastructure, thyroid marker expression, p53 expression, karyogram, agar clonogenic capacity and tumorigenicity as xenografts in nude mice. These characterization studies point to a marked heterogeneity at the level of the clinical tumor recurrence. Karyotype analysis of the cell lines showed a pattern of aberrations indicating that the lines are clonally related and that the A02 and C02 lines are subsequently derived from the more "original" tumor cell type B02 after a tetraploidization event. It is concluded that the obtained cell lines represent an in vitro/in vivo model for human follicular thyroid cancer. The availability of a series of cell lines for human follicular thyroid cancer, mimicking the biological heterogeneity observed in patient tumors, enables both detailed fundamental investigation of thyroid cancer cell biology and the experimental exploration of new treatment approaches.

Animals↗
PubMed2001

Moral problems in palliative care journals.

With the growth of palliative care services, interest in moral issues also seems to be growing. However, we need to know which moral issues are specific to palliative care. The first step in answering this is to consider the moral concerns raised and discussed by the palliative care community itself. This article presents a bibliographical analysis of moral problems, first by selecting the problems identified as moral problems in the leading palliative care journals, and then by classifying these into different types.

Bibliometrics↗
PubMed2000

Helicobacter pylori-related and -non-related gastric cancers do not differ with respect to chromosomal aberrations.

Gastric carcinogenesis is strongly associated with Helicobacter pylori infection, but the underlying genetic mechanisms are largely unknown. The aim of this study was to correlate chromosomal aberrations in gastric cancer to H. pylori status and its different strains, as well as to histological type and other clinico-pathological variables. DNA from 46 gastric cancers (male/female 35/11, age 27-85 years) was extracted from formaldehyde-fixed, paraffin-embedded material and tested for chromosomal gains and losses by comparative genomic hybridization (CGH). Chromosomal aberrations with frequencies of 20% or higher were considered to be non-random changes associated with gastric cancer. The mean number of chromosomal events per tumour was 9.7 (range 0-27), with a mean of 3.2 gains (range 0-16) and 6.5 losses (range 0-15). Gains were most frequently found at chromosomes 8q and 13q (24% and 26%, respectively). Losses were predominantly found on chromosome arms 2q, 9p, 12q, 14q, 15q, 16p, 16q, 17p, 17q, 19p, 19q, and 22q (22%, 30%, 43%, 22%, 33%, 50%, 28%, 50%, 39%, 33%, 39%, and 37%, respectively). Common regions of overlap narrowed down to 2q11-14, 8q23, 9p21, 12q24, 13q21-22, 14q24 and 15q11-15. The mean number of gains was higher in tumours with metastases than in localized tumours (4.1 vs. 1.9, p=0.04). Tumours with a loss at 17p showed a higher number of losses than tumours without a 17p loss (9. 5 vs. 4.7 on average, p<0.001). Neither H. pylori status (+, n=25; -, n=21) nor H. pylori strain was correlated to the total number of events or to any specific chromosomal aberration, nor were there differences between intestinal (n=30) and diffuse (n=15) cancers or any other clinico-pathological variable tested. In conclusion, a complex of chromosomal aberrations is involved in gastric cancer, but their pattern does not depend on H. pylori status or strain, nor on the histological type of the tumour. The exact biological meaning of these aberrations in carcinogenesis needs further clarification.

Adult↗
PubMed2000

Intratumor heterogeneity of k-ras and p53 mutations among human colorectal adenomas containing early cancer.

The molecular pathways and the timing of genetic events during human colorectal carcinogenesis are still not fully understood. We have addressed the intratumor heterogeneity of the mutational status of the k-ras oncogene and of the p53 oncosuppressor gene during the adenoma-carcinoma sequence by investigating 26 human colorectal adenomas containing early cancer. An intratumor comparative analysis was obtained among the adenomatous and carcinomatous component pairs. Additionally, we have analyzed 17 adenomas having cancer in the near vicinity. The adenomatous components of the adenomas containing early cancer and the adenomas having cancer in the near vicinity had comparable frequencies for k-ras mutations (28 and 47%) but different for p53 mutations (52 and 7%, p-value = 0.01). Interestingly, the adenomatous and carcinomatous components of the adenomas containing early cancer were rarely heterogeneous for the k-ras mutational status (only in 13% of the cases) but were characterized by heterogeneity of the p53 status in 59% of the cases (p-value < 0.01). In addition, the mutations of p53 for the adenomatous components of the adenomas containing early cancer were statistically significantly associated with severe dysplasia (p-value = 0.01). Intratumor homogeneity of k-ras status during the human colorectal adenoma-carcinoma sequence suggests that the role of k-ras is more related to tumor initiation than to tumor progression. On the contrary, intratumor heterogeneity of p53 mutations indicates that the type of the p53 mutations may also be relevant for selection and expansion of new subclones leading to tumor progression.

Adenoma↗
PubMed1999

Analysis by comparative genomic hybridization of epithelial and spindle cell components in sarcomatoid carcinoma and carcinosarcoma: histogenetic aspects.

Sarcomatoid carcinomas and carcinosarcomas are histologically malignant biphasic neoplasms with an epithelial and a spindle cell component. Both a polyclonal and a monoclonal origin have been postulated for these tumours, but the latter has been favoured. For carcinosarcoma, the stem cell from which the epithelial and mesenchymal components are derived is expected to be more immature than the epithelial stem cell from which different components of sarcomatoid carcinoma originate, since in the latter, immunohistochemical or ultrastructural epithelial characteristics are still detectable. In the present study, comparative genomic hybridization was used to test the hypothesis that both tumour components in sarcomatoid carcinoma have more chromosomal aberrations in common than those in carcinosarcoma. From three sarcomatoid carcinomas originating from the urinary bladder and two carcinosarcomas from the pharynx, the epithelial and spindle cell components were microdissected and analysed for their respective chromosomal aberrations, using comparative genomic hybridization. High-level homology was seen in chromosomal aberrations between the different components in each tumour. This level of homology was even higher in the carcinosarcomas (65 and 91 per cent) than in both sarcomatoid carcinomas (21-51 per cent). The different phenotypic components of both sarcomatoid carcinoma and carcinosarcoma show a large overlap of chromosomal aberrations, strongly suggesting a monoclonal origin for all of these tumours. These findings do not support the hypothesis that the divergence between epithelial and spindle cell components occurs at an earlier stage in carcinosarcomas than in sarcomatoid carcinoma.

Carcinoma↗
PubMed1999

Evidence for an ependymoma tumour suppressor gene in chromosome region 22pter-22q11.2.

Ependymomas are glial tumours of the brain and spinal cord. The most frequent genetic change in sporadic ependymoma is monosomy 22, suggesting the presence of an ependymoma tumour suppressor gene on that chromosome. Clustering of ependymomas has been reported to occur in some families. From an earlier study in a family in which four cousins developed an ependymoma, we concluded that an ependymoma-susceptibility gene, which is not the NF2 gene in 22q12, might be located on chromosome 22. To localize that gene, we performed a segregation analysis with chromosome 22 markers in this family. This analysis revealed that the susceptibility gene may be located proximal to marker D22S941 in 22pter-22q11.2. Comparative genomic hybridization showed that monosomy 22 was the sole detectable genetic aberration in the tumour of one of the patients. Loss of heterozygosity studies in that tumour revealed that, in accordance to Knudson's two-hit theory of tumorigenesis, the lost chromosome 22 originated from the parent presumed to have contributed the wild-type allele of the susceptibility gene. Thus, our segregation and tumour studies collectively indicate that an ependymoma tumour suppressor gene may be present in region 22pter-22q11.2.

Central Nervous System Neoplasms↗
PubMed1999

Comparative genomic hybridisation.

Comparative genomic hybridisation (CGH) is a technique that permits the detection of chromosomal copy number changes without the need for cell culturing. It provides a global overview of chromosomal gains and losses throughout the whole genome of a tumour. Tumour DNA is labelled with a green fluorochrome, which is subsequently mixed (1:1) with red labelled normal DNA and hybridised to normal human metaphase preparations. The green and red labelled DNA fragments compete for hybridisation to their locus of origin on the chromosomes. The green to red fluorescence ratio measured along the chromosomal axis represents loss or gain of genetic material in the tumour at that specific locus. In addition to a fluorescence microscope, the technique requires a computer with dedicated image analysis software to perform the analysis. This review aims to provide a detailed discussion of the CGH technique, and to provide a protocol with an emphasis on crucial steps.

Chromosome Aberrations↗
PubMed1998

Non-random allelic losses at 3p, 11p and 13q during HPV-mediated immortalization and concomitant loss of terminal differentiation of human keratinocytes.

To obtain a comprehensive overview of chromosomal alterations that may underlie human papillomavirus (HPV)-mediated immortalization, 4 foreskin keratinocyte cell lines generated by transfection with either HPV 16 (cell lines FK16A and FK16B) or HPV 18 (FK18A and FK18B) were subjected to chromosomal analysis using comparative genomic hybridization (CGH). Three cell lines were analyzed both in the mortal state during their extended lifespan and in the subsequent immortal state. From cell line FK18A, only immortal cells were tested. Chromosomal imbalances increased in number through the process of immortalization. Subsequent loss of heterozygosity (LOH) analysis, using a panel of 21 microsatellite markers selected on the basis of CGH losses, revealed no clonal LOHs in cells at the mortal stage. However, in the immortal descendants 67% of underrepresentations detected by CGH were expressed as clonal LOH at the respective loci. Clonal LOHs at 3p, 11p and 13q were detected in 2 cell lines each and were thus considered non-random. Immortal cells of 1 cell line (FK18B) revealed LOH at all 3 loci. Moreover, all immortal cell lines displaying allelic losses at one or more of these loci shared a severely dysplastic phenotype after organotypic culturing, as shown previously. Therefore, loss-of-function mutations of genes at these loci, eventually in combination, are potentially involved in the process of HPV-mediated immortalization that is attended by a loss of terminal differentiation. Since chromosomal changes at these loci are also found in HPV-associated carcinomas in vivo, the HPV-transfected cell lines seem to provide a valuable model system for studying HPV-mediated carcinogenesis.

Alleles↗
PubMed1998

Genetic analysis of 53 lymph node-negative breast carcinomas by CGH and relation to clinical, pathological, morphometric, and DNA cytometric prognostic factors.

Within the subgroup of lymph node-negative breast cancers, there is a need for accurate prognostic indicators to select high-risk patients. Comparative genomic hybridization (CGH) provides an opportunity to screen the whole genome for chromosomal aberrations which may be associated with poor clinical outcome. The results of CGH analysis of 53 lymph node-negative breast carcinomas are presented and correlated with a set of clinico-pathological and cytometric features with strong prognostic value. The most frequent chromosomal gains were, in descending order of frequency, 8q, 1q, Xq, 5q, 4q, and 3q. Recurring losses were observed at chromosomal arms 19p, 1p, 17p, 22q, 4q, and 8p. There was not a single, unique combination of chromosomal aberrations, but gains of 1q and 8q were frequently observed simultaneously (15/53 cases). DNA aneuploid tumours harboured more gains than DNA diploid tumours, but there was no correlation between the total number of events per tumour detected by CGH and any of the prognostic features. Of the many chromosomal aberrations found, only gains of chromosome 8q were strongly correlated with high values of mean nuclear area. A clearer picture was obtained when comparing only those cases which, according to their cytometric and morphometric features, had either the worst or the best prognosis. Gains occurred mainly in the 'poor prognostic features' group, in particular at 8q, 11q13, 17q, and 20q. It is hypothesized that these gains could be late, progression-related events and may be associated with aggressive clinical behaviour. These four chromosomal regions may therefore be of potential prognostic value. Correlation with real follow-up data will enable us better to identify those patients who have a high risk of recurrence within the subgroup of lymph node-negative breast cancer patients.

Adult↗
PubMed1998

Progression from colorectal adenoma to carcinoma is associated with non-random chromosomal gains as detected by comparative genomic hybridisation.

AIMS: Chromosomal gains and losses were surveyed by comparative genomic hybridisation (CGH) in a series of colorectal adenomas and carcinomas, in search of high risk genomic changes involved in colorectal carcinogenesis. METHODS: Nine colorectal adenomas and 14 carcinomas were analysed by CGH, and DNA ploidy was assessed with both flow and image cytometry. RESULTS: In the nine adenomas analysed, an average of 6.6 (range 1 to 11) chromosomal aberrations were identified. In the 14 carcinomas an average of 11.9 (range 5 to 17) events were found per tumour. In the adenomas the number of gains and losses was in balance (3.6 v 3.0) while in carcinomas gains occurred more often than losses (8.2 v 3.7). Frequent gains involved 13q, 7p, 8q, and 20q, whereas losses most often occurred at 18q, 4q, and 8p. Gains of 13q, 8q, and 20q, and loss of 18q occurred more often in carcinomas than in adenomas (p = 0.005, p = 0.05, p = 0.05, and p = 0.02, respectively). Aneuploid tumours showed more gains than losses (mean 9.3 v 4.9, p = 0.02), in contrast to diploid tumours where gains and losses were nearly balanced (mean 3.1 v 4.1, p = 0.5). CONCLUSIONS: The most striking difference between chromosomal aberrations in colorectal adenomas and carcinomas, as detected by CGH, is an increased number of chromosomal gains that show a nonrandom distribution. Gains of 13q and also of 20q and 8q seem especially to be involved in the progression of adenomas to carcinomas, possibly owing to low level overexpression of oncogenes at these loci.

Adenoma↗
PubMed1997

Cytoplasmic localization of a functionally active Fanconi anemia group A-green fluorescent protein chimera in human 293 cells.

Hypersensitivity to cross-linking agents and predisposition to malignancy are characteristic of the genetically heterogeneous inherited bone marrow failure syndrome, Fanconi anemia (FA). The protein encoded by the recently cloned FA complementation group A gene, FAA, has been expected to localize in the nucleus as based on the presence of sequences homologous to a bipartite nuclear localization signal (NLS) and a leucine repeat motif. In contrast to this expectation, we show here that a functionally active FAA-green fluorescent protein (GFP) hybrid resides in the cytoplasmic compartment of human kidney 293 cells. In accordance with this finding, disruption of the putative NLS by site-directed mutagenesis failed to affect both subcellular localization and the capacity to complement hypersensitivity to the cross-linking agent mitomycin C in FA-A lymphoblasts. Furthermore, the N-terminal part of FAA with the putative NLS at amino acid position 18 to 35 showed no nuclear translocation activity when fused to GFP, while the first 115 N-terminal amino acids appeared to be indispensable for the complementing activity in FA-A cells. Similarly, mutagenesis studies of the putative leucine repeat showed that, even though this region of the protein is important for complementing activity, this activity does not depend on an intact leucine zipper motif. Finally, fusion of the NLS motif derived from the SV40 large T antigen to FAA could not direct the hybrid protein into the nucleus of 293 cells, suggesting that FAA is somehow maintained in the cytoplasm via currently unknown mechanisms. Thus, like the first identified FA protein, FAC, FAA seems to exert its function in the cytoplasmic compartment suggesting FA proteins to be active in a yet to be elucidated cytoplasmic pathway that governs hematopoiesis and protects against genomic instability.

Base Sequence↗
PubMed1997

Relationship between the parameters cellular differentiation, doubling time and platinum accumulation and cisplatin sensitivity in a panel of head and neck cancer cell lines.

Patients with head and neck squamous cell carcinoma (HNSCC) treated with cisplatin show a large inter-individual variation in tumor response. Little is known about factors that contribute to this variation. The aim of our study was to correlate the sensitivity to cisplatin with a number of cellular parameters using a panel of 10 human HNSCC cell lines. A 7-fold variation in response after 72 hr of exposure to cisplatin as determined in a colorimetric proliferation assay was observed. The IC50 values did not correlate with the DNA index, the cellular doubling time or the expression of differentiation markers. Intracellular platinum (Pt) concentrations were measured by atomic absorption spectroscopy after exposing the cells to 10 microM cisplatin for 1-72 hr. The intracellular Pt levels increased up to 24 hr. One cell line, derived from the tumor of a patient previously treated with radiotherapy, accumulated much more Pt than the other cell lines. For these other cell lines, a significant positive correlation was found between Pt accumulation and sensitivity. In conclusion, cisplatin-induced growth inhibition in HNSCC in vitro is generally positively correlated with cellular Pt levels. However, the fact that occasionally cancer cells can survive despite high intracellular Pt levels indicates that additional parameters are needed to explain a response unequivocally.

Adult↗
PubMed1997

Assessment of chromosomal gains and losses in oral squamous cell carcinoma by comparative genomic hybridisation.

Cytogenetic studies have demonstrated that oral squamous cell carcinomas (OSCCs) are usually characterised by complex karyotypes with many marker chromosomes. We analysed the genetic changes of six OSCC cell cultures by comparative genomic hybridisation (CGH). The CGH technique provides information on chromosomal gains and losses of the whole tumour genome in a single experiment and can therefore identify regions that harbour putative tumour suppressor genes (in the case of loss of chromosomal material) or oncogenes (in the case of gain or amplification of chromosomal material). Recurrent losses were detected at chromosome arms Xp and 3p (four cases). Gains consistently occurred at chromosome arms 8q and 9q (four cases) and at 1q, 3q, 5p, 7p, and 9p (three cases). The same six tumour cultures have previously been analysed by classical karyotyping. An important discrepancy between the two techniques was the number of losses detected: 55 with karyotyping versus 26 with CGH. On the basis of the cytogenetic complexity of these tumours and on FISH experiments that confirmed the CGH results, we conclude that genetic changes, particularly losses, can be more reliably detected by CGH analysis.

Carcinoma, Squamous Cell↗
PubMed1996

Centromeric breakage as a major cause of cytogenetic abnormalities in oral squamous cell carcinoma.

Cytogenetic analysis of short-term explant tumor cultures derived from 11 human oral squamous cell carcinomas (nine from primary tumors and two from nude mouse xenograft cultures) revealed clonal chromosomal aberrations with multiple numerical and structural changes in all tumors. Recurrent breakpoints were located at chromosomal bands 1p13 (five tumors), 11q13 (four tumors), 3q27-29 (three tumors), and 12q13 (three tumors). Four tumors had a homogeneously staining region at band 11q13. Consistent chromosomal losses included 3p, 9p13-pter, and 18q22-qter, each occurring in eight tumors. Gain of material was observed for chromosome arms 3q, 5p, 7p, and 8q. As many as 134 of a total of 218 chromosomal breakpoints (61%) occurred in centromeric regions, often resulting in isochromosomes and unbalanced whole-arm translocations. Using fluorescence in situ hybridization with chromosome-specific centromeric alphoid repeat probes, two whole-arm translocations, der(Xq;11q) and a der(3q;11q), each from a different tumor, were shown to contain juxtaposed centromeric sequences of both participating chromosomes, strongly suggesting that the breakpoints were within the centromeres. We propose that centromeric breakage is an important mechanism for the generation of genetic imbalance in the development of oral squamous cell carcinoma.

Animals↗