Showing papers by "Chris J.L.M. Meijer published in 1996"

The Incidence of Micrometastases in Neck Dissection Specimens Obtained From Elective Neck Dissections

Abstract: Although modern imaging techniques become more accurate for the assessment of lymph node metastases in the neck as criteria and technology evolve, micrometastases remain occult with any technique. Even the routine histopathological examination of neck dissection specimens is unable to detect all micrometastases. Because knowledge on the incidence of micrometastases in the clinically N0 neck might be of importance for decision making regarding elective treatment, a retrospective study on 96 elective neck dissections was conducted. Meticulous histopathological examination of the neck dissection specimens yielded 3092 lymph nodes of which 67 (2.2%) were tumor-positive. Twenty-six of these 67 lymph node metastases were micrometastases. Of the 36 tumor-positive neck dissection specimens, 21 contained micrometastases. In 9 tumor-positive specimens only micrometastases were found. This high incidence of micrometastases has important implications for the diagnostic work-up, the treatment, and histopathological examination of the N0 neck.

Human papillomavirus—the most significant risk determinant of cervical intraepithelial neoplasia

Abstract: Sexual behavior has been consistently identified as a major risk factor for cervical cancer. Population-based studies have demonstrated that risk related to sexual activity is mediated by human papillomavirus (HPV) infection. We conducted a case-control study of 199 cases with low-grade squamous intraepithelial lesions or high-grade squamous intraepithelial lesions as defined by cytology and 1000 control women selected from an ongoing prospective cohort study in Copenhagen, Denmark. Furthermore, 131 women with equivocal smears (atypical squamous cells of undetermined significance) were examined as a separate borderline case group. At enrollment, all women had a personal interview and a gynecological examination including cervical swabs for HPV testing and a Pap smear. HPV testing was performed using a combination of general primer 5/6-mediated and type-specific polymerase-chain-reaction-based methods. Cervical HPV infection was by far the most significant risk factor for cervical squamous intraepithelial lesions. The relationship with HPV was observed for all grades, while strength of association was greater for more severe lesions. The importance of the previously identified epidemiological risk factors for cervical neoplasia was also demonstrated. However, most of the effect of these factors could be explained by taking HPV infection into account, except for schooling and smoking. Non-use of barrier contraceptives and smoking were the only significant risk factors in HPV-positive women. In HPV-negative women, a residual effect existed for different measures of sexual activity, and use of oral contraceptives and smoking constituted significant risk determinants Overall, 66% of cases could be attributed to HPV; however, if the results were restricted to histologically confirmed high-grade lesions, the proportion of cases that could be attributed to HPV infection increased to 80%.

Prevalence of mucosotropic human papillomaviruses in squamous‐cell carcinomas of the head and neck

Abstract: The prevalence of mucosotropic human papillomavirus (HPV) DNA in 63 squamous-cell carcinomas (SCC) from different anatomic sites in the head and neck was determined by general primer-mediated polymerase chain reaction (GP-PCR). HPV DNA was detected in 20.6% of SCC. Additional type-specific PCR for HPV 6, 11, 16, 18, 31 and 33 demonstrated the presence of HPV 16 alone in these carcinomas. HPV 16 was also detected in normal epithelium from the resection margins of the majority of HPV-positive SCC. HPV status did not correlate with tumour site, whether primary or recurrent, TNM stage, metastases, degree of differentiation, smoking or alcohol history, fate or survival.

Transition of human papillomavirus type 16 and 18 transfected human foreskin keratinocytes towards immortality: activation of telomerase and allele losses at 3p, 10p, 11q and/or 18q.

Abstract: This study aimed at resolving cellular genetic alterations in the process of in vitro immortalization of human keratinocytes by human papillomavirus (HPV) types 16 and 18. Four cell lines of primary human foreskin keratinocytes transfected with HPV 16 and HPV 18, respectively, were analysed during the transition from the mortal to immortal state. All cell lines showed strong telomerase activity at the immortal state, whereas no or only weak telomerase activity was detected in mortal precursor cells. This was consistent with telomere stabilization or restoration only observed in immortal cells, HPV physical state and copy number appeared constant during immortalization and HPV E6/E7 transcripts were present throughout. Immortalization was associated with clonal allele losses at 3p combined with either 11q or 18q or at 10p, dependent on the cell line. Moreover, a correlation was evident between the onset of telomerase activity and allele loss at 3p or 10p. All immortalized cells retained the capability to differentiate after growth in the presence of physiological calcium and serum. Moreover, one of the immortal cell lines displayed terminal differentiation after organotypic culturing on collagen rafts. The data suggest that (a) several pathways exist for HPV mediated immortalization that may involve genes residing at 3p, 10p, 11q and/or 18q; (b) 3p and 10p may encode genes involved in telomerase regulation; and (c) immortalization in vitro can be correlated with a spectrum of morphological changes varying from mild to severe dysplasia.

A non-radioactive PCR enzyme-immunoassay enables a rapid identification of HPV 16 and 18 in cervical scrapes after GP5+/6+ PCR.

Abstract: In previous studies, general primer mediated PCR (GP5+/6+ PCR) was applied successfully to detect a broad spectrum of human papillomaviruses (HPV) in cervical scrapes. In order to facilitate PCR based HPV detection and typing, a colourimetric microtitre plate based hybridisation assay was developed. The method utilised one biotinylated primer (bio-GP6+) in the GP-PCR. Biotinylated PCR products were captured on streptavidin coated microtitre plates, denaturated and hybridised to digoxigenin (DIG) labelled HPV specific internal oligo probes. The DIG labelled hybrids were detected using an enzyme immunoassay (EIA). Since HPV 16 and 18 are the most common HPV types found in cervical carcinomas, this approach was initiated for these two types. Cross-hybridisation reactions were not detected when the specificity of this PCR-EIA for HPV 16 and 18 was tested on a panel of 20 different HPV genotypes. The sensitivity of the assay was found to be between 10 and 100 HPV 16 and 18 viral genomes in a background of 100 ng cellular DNA. This was similar to the detection limit of Southern blot analysis of PCR products with radioactively labelled oligonucleotides. A group of cytomorphologically normal (n = 89) and abnormal (n = 96) cervical scrapes were composed of HPV 16 and HPV 18 positive and HPV negative scrapes. All HPV 16 and 18 positive smears were detected by PCR-EIA. These results indicate that PCR-EIA has the potential for a rapid and sensitive HPV DNA test for day-to-day routine examination of cervical scrapes.

Analysis of IgG reactivity against Human Papillomavirus type-16 E7 in patients with cervical intraepithelial neoplasia indicates an association with clearance of viral infection: results of a prospective study.

Abstract: IgG reactivity against the immunodominant region aa6-35 of Human Papillomavirus (HPV) type-16 E7 was determined in a peptide-based ELISA in a cohort study of women with initial mild to moderate cervical dyskaryosis. On the basis of HPV DNA patterns, as determined by PCR in cervical smears prior to IgG testing, HPV-16-positive patients were grouped as having either a cleared, a fluctuating, or a persistent HPV-16 infection. In a cross-sectional study at the start of serological follow-up, positive IgG reactivities were found more often in the total group of HPV-16-positive patients (20.0%) than in patients consistently typed as HPV-negative over a period of at least 12 months prior to testing (3.1%, p < 0.04). The highest proportion of positive responders was found in patients with a cleared HPV-16 infection (29.4%). Also, IgG reactivities found in HPV-16 clearance patients were significantly higher than in patients with a persistent infection (p < 0.008). In a subsequent longitudinal study over a period of up to 27 months, consistently positive reactivities were observed in patients with cleared viral infections who showed seroreactivity in the cross-sectional study, while mostly negative reactivities were found in patients with viral persistence. HPV-16 E7-specific IgG subclass responses were determined in a selection of 19 CIN and 11 HPV-16-positive cervical carcinoma (CeCa) patients with positive E7-specific IgG responses. IgG2 was predominant in the CIN patients, suggesting the presence of IFNgamma (Th1) at the site of HPV infection. In the CeCa patients IgG1 and IgG2 were produced equally, possibly indicating a rise in Th2 cytokines. Our data suggest that HPV-16 E7 IgG reactivity in a subset of CIN patients with viral clearance may result from successful Th1 responses.

Distinctive adhesion pathways are involved in epitheliotropic processes at different sites

Abstract: Intraepithelial migration of lymphoid cells (epitheliotropism) is a biological process that can be observed under various physiological and pathological conditions. Recently, epitheliotropism was proposed to be a multi-step process, involving interactions of lymphoid cells with both epithelial basement membrane (EBM) and epithelial cells. In the present study we analysed by immunohistochemistry the adhesion mechanisms that are potentially involved in epitheliotropism of lymphoid cells in various disorders, such as tonsillar hyperplasia, coeliac disease, malignant lymphomas of mucosa-associated lymphoid tissue (MALTomas), and mycosis fungoides (MF). The combinations of adhesion molecules expressed on the participating lymphoid and epithelial cells varied among these disorders. These findings suggest that the adhesion pathways utilized in epitheliotropism may be associated with the nature of the lymphoid cell (reactive or neoplastic/B or T) and/or the site of the epithelium involved. In some cases the specificity of the process was determined by the adhesion mechanism involved in the lymphocyte-EBM interaction, as in the case of alpha 3 beta 1 integrin/laminin-5 in MF, and in others by the adhesion mechanisms involved in the interaction between lymphoid and epithelial cells, such as alpha 4 integrin/VCAM-1 in tonsillar hyperplasia and alpha E beta 7/E-cadherin in coeliac disease.

Distribution of laminin variants and their integrin receptors in human secondary lymphoid tissue. Colocalization suggests that the alpha 6 beta 4-integrin is a receptor for laminin-5 in lymphoid follicles.

Abstract: Laminins are a family of multifunctional basement membrane glycoproteins. Over the last years, many laminin isoforms have been characterized, which were shown to be composed of distinct combinations of variant α β and γ chains. Some of these isoforms show remark-able tissue specificity, which suggests functional involvement in local processes. In this study the previously described mAb 4C7. which recognize epithelial basement membranes as well as endothelial basement membranes in lymphoid follicles, was identified as an anti-laminin-5 antibody. Using a set of mAbs against various variant laminin chains we established that specifically the γ2 chain of laminin-5 was confined to the endothelial basement membranes of vessels in lymphoid follicles, whereas other variant laminin chains were also expressed elsewhere in the lymphoid tissue. Additionally. the expression of the known integrin receptors of laminin-5 was also examined. The α6β4 integrin-receptor for laminin was found to be colocalized with the lamini...

Extracellular matrix and β1 integrin expression in nodal and extranodal T-cell lymphomas

Abstract: Since non-Hodgkin's lymphoma (NHL) cells interact with surrounding structures similarly to their normal counterparts, micro-environmental changes and the aberrant expression of adhesion molecules are considered to be of importance in lymphomagenesis. In this immunohistochemical study, the composition of several extracellular matrix (ECM) components and the expression of their beta 1 integrin receptors were examined in nodal and extranodal T-cell NHLs. Except for the T-lymphoblastic NHLs, almost all T-NHLs displayed abundant deposition of matrix and considerable expression of the alpha 4 and beta 1 integrin chains. This is in contrast to B-cell NHLs, which show ECM patterns comparable to those in reactive lymphoid tissue or, in cases of high-grade malignancy, active matrix degradation and very low expression or absence of beta 1 integrins, as previously described. This difference is probably based on distinct cytokine production in B- and T-cell malignancies. As in B-NHL, nodal and extranodal T-NHLs of the same morphological subtype exhibit identical ECM patterns, which suggests that malignant lymphoid cells of both B and T origin create at least part of their own specific micro-environment.

HPV-16-Positive Anal and Penile Carcinomas in a Young Man - Anogenital 'Field Effect' in the Immunosuppressed Male?

Abstract: This report presents the unusual occurrence of metachronous perianal and penile carcinomas in a young, immunosuppressed man. Both anogenital cancers were HPV-6-DNA-positive by the polymerase chain reaction. DNA in situ hybridization analysis of the penile carcinoma revealed HPV-16 in most neoplastic cells. HPV-16 appears to have played a central role in both anogenital cancers in this patient, suggesting that, like in immunologically susceptible women, a carcinogenic ‘field effect’ may exist in the anogenital area of the immunosuppressed male