1,720,972 research outputs found
Genetic pattern, histological structure, and cellular phenotype in early and advanced gastric cancers: evidence for structure-related genetic subsets and for loss of glandular structure during progression of some tumors
No full textLoss of heterozygosity at 18q21 region in gastric cancer involves a number of cancer-related genes and correlates with stage and histology, but lacks independent prognostic value
No full textSeveral studies support a role of 18q21 LOH, involving the DCC locus, in colorectal cancer progression; however, its contribution to the natural history of gastric cancer is less clear. Recently, a number of cancer-related genes have been mapped in the 18q21 region, either centromeric or telomeric to DCC. This study searched for 18q21 LOH in 161 gastric cancers representative of all tumour stages and main histological types. To this purpose, seven highly polymorphic markers were used flanking the 18q21 band and spanning the entire region. Thirty-four out of 147 (23.1%) informative cases showed LOH. In 27 of 34 cases (79%), LOH involved all the informative loci. The remaining seven cases showed LOH at more telomeric sites and retained heterozygosity at more centromeric markers, mostly those proximal to the DCC gene. A strong correlation between 18q21 LOH and level of gastric wall invasion, lymph node metastases, or stage was found in cohesive (glandular+solid) and mixed tumours, but not in diffuse cancers. Cox univariate and multivariate analysis showed that invasion level, lymph node metastases, distant metastases, TNM stage, and histology were effective predictors of survival, whereas 18q21 LOH did not show predictive power. The simultaneous deletion of a variety of cancer-related genes with different and even opposite roles might explain why, apparently, 18q21 LOH does not per se contribute significantly to the natural history of gastric cancer, despite strong correlation with stage
Loss of heterozygosity at 18q21 region in gastric cancer involves a number of cancer-related genes and correlates with stage and histology, but lacks independent prognostic value
No full textSeveral studies support a role of 18q21 LOH, involving the DCC locus, in colorectal cancer progression; however, its contribution to the natural history of gastric cancer is less clear. Recently, a number of cancer-related genes have been mapped in the 18q21 region, either centromeric or telomeric to DCC. This study searched for 18q21 LOH in 161 gastric cancers representative of all tumour stages and main histological types. To this purpose, seven highly polymorphic markers were used flanking the 18q21 band and spanning the entire region. Thirty-four out of 147 (23.1%) informative cases showed LOH. In 27 of 34 cases (79%), LOH involved all the informative loci. The remaining seven cases showed LOH at more telomeric sites and retained heterozygosity at more centromeric markers, mostly those proximal to the DCC gene. A strong correlation between 18q21 LOH and level of gastric wall invasion, lymph node metastases, or stage was found in cohesive (glandular+solid) and mixed tumours, but not in diffuse cancers. Cox univariate and multivariate analysis showed that invasion level, lymph node metastases, distant metastases, TNM stage, and histology were effective predictors of survival, whereas 18q21 LOH did not show predictive power. The simultaneous deletion of a variety of cancer-related genes with different and even opposite roles might explain why, apparently, 18q21 LOH does not per se contribute significantly to the natural history of gastric cancer, despite strong correlation with stage
Clustering patterns of human papillomavirus genotypes in multiple infections
No full textAbstract: Many human papillomavirus (HPV) infections are sustained by multiple viral genotypes whose effect on the risk of cervical intraepithelial neoplasia (CIN) is unknown.
The study investigated whether specific HPV types or species may affect the likelihood of multiple infections and have a clustered distribution in a consecutive series of 681 women with a histological diagnosis of CIN.
HPV typing was performed by the SPF(10)-LIPA assay; associations were evaluated by loglinear analysis of multiple contingency tables after stratification by age and CIN grade. HPV prevalence was 99.4% with a 72.1 % rate of coinfection. The risk of coinfection was higher for types 6, 11, 16, 18, 31, 33, 51, 52, 56. Significant interactions were found for species A7-A9-A10, A6-A9 and A7-A10. Coinfection by types 31-35-56, 16-51-52, 16-18 and 51-52 was more frequent than expected. Interactions between viral species and HPV 16-18 were maintained among CIN1, whereas interactions of 16-51-52 and 31-51-56 were significant only in CIN >= 2. Interactions between species and types were lost among women younger than 32 years.
Significant clustering of HPV types and species occurs among women with CIN. This has implications for the assessment of the oncogenic potential and the prevention of HPV infections. (C) 2009 Elsevier B.V. All rights reserved
Time trends of human papillomavirus type distribution in Italian women with cervical intraepithelial neoplasia (CIN)
No full textOBJECTIVE: It is assumed that the circulation of HPV types in a population is stable over time although there are limited historical data to support this view. The existence of possible cohort effects in the circulation of HPV types has major implications for vaccination strategies and risk assessment in HPV-infected women. We analysed archival biopsy samples of cervical intraepithelial neoplasia (CIN) to study the distribution of HPV types in Northern Italy over the years 1985-2007.
METHODS: DNA from formalin-fixed paraffin-embedded cervical biopsies from the years 1985-87 (67 samples) and 1995-97 (92 samples) was HPV-typed by the SPF-(10) Lipa assay. Cases were compared with 159 control biopsies from the years 2005-07 matched by patient age and CIN grade. Quantitative PCR was used to compare titres of HPV sequences in DNA extracted from biopsies of the three periods. Type-specific PCR was used to confirm HPV51 and 52 typing by SPF-(10) Lipa.
RESULTS: HPV51, 52, 53, 56, 58, and 66 were markedly under-represented or undetectable in samples from past periods whereas they represented 5.7-30.8% of present infections. Frequency of multiple HPV infections and high-risk infections (p=0.0001) also increased in recent years. The main changes occurred over the last decade. Infections by HPV16, 18, were three times more frequent 20 years ago than today (p=0.012). Loss of amplifiable HPV sequences over prolonged storage was not observed. Type-specific PCR confirmed all HPV51 and 52 infections.
CONCLUSIONS: Secular trends in the distribution of HPV types among women with CIN may occur in specific populations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Time trends of human papillomavirus type distribution in Italian women with cervical intraepithelial neoplasia (CIN)
No full textExfoliated cells of the oral mucosa for HPV typing by SPF10 in head and neck cancer.
No full textHPV infection in the superficial cells of the oral mucosa could reflect the presence of HPV in head and neck cancer cells. Due mostly to the use of heterogeneous analytical methods, discordant data exist in the literature regarding the agreement between the presence of HPV in non-neoplastic oral mucosa and in tumour tissue from the same patient. The presence of HPV DNA and viral types were compared in paired cytological and biopsy samples from 56 patients with head and neck neoplastic and preneoplastic lesions using the highly sensitive SPF10 LiPA Extra assay, which has been validated recently for formalin-fixed paraffin-embedded tissue using paired cervical cytology and biopsy samples. Kappa statistics were used to measure the inter-rater agreement. The overall agreement with respect to HPV infection was 96.43% (kappa=0.8367). For 76.79% of subjects (kappa=0.6937), the same number of HPV types was detected in cytological and biopsy specimens. The overall positive typing agreement was 90.90%, comprising 130 out of 143 individual HPV type analyses. The agreement shown was good for HPV 18, 44, 45, 54 and 66 (kappa=0.6585-0. 7321), excellent for HPV 6, 16, 40, and 54 (kappa=0.8108-0.8679), and absolute for HPV 11, 31, 33, 35, 39, 51, 52, 53, 59, 74, and 69-71 (kappa=1.0000). The high sensitivity of the SPF10 LiPA and its excellent performance both for recognising HPV infection and for identifying the viral types present in tumour tissue and in oral exfoliated cells make it a useful method for the assessment of HPV infection in patients with head and neck cancer. The excellent agreement for HPV infection and genotyping in paired samples suggests that oral exfoliated cells can be used for HPV detection in the head and neck region
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