1,720,995 research outputs found
Genetics and clinicopathological findings in thyroid carcinomas associated with familial adenomatous polyposis.
No full textFirst description of the association of two rare diseases with familial adenomatous polyposis (FAP)
No full textMethods for routine diagnosis of genomic rearrangements: multiplex PCR-based methods and future perspectives
No full textGermline and somatic genomic rearrangement play a relevant role in the pathogenesis of genetic disorders, and their identification is a fundamental task in molecular diagnosis. However, screening for structural genomic abnormalities is often not included in routine mutational analyses and consequently the proportion of rearrangements playing a pathogenic role in several genetic disorders is likely to be underestimated. A wide range of molecular techniques for the detection of large genomic rearrangements has been developed: some methods have the power to screen the whole genome, others are designed to analyze one or few loci that are known to be involved in a specific disease; some may detect balanced rearrangements, while others only unbalanced rearrangements; some are suitable for detection of germline abnormalities, yet others also detect somatic abnormalities. This review provides a brief summary of principles, applications and limitations of the methods available for the screening of genomic rearrangements, focusing on multiplex PCR-based protocols that are currently employed in routine detection of extended germline genomic deletions or duplications. Future developments based on microarray platforms and high-throughput sequencing are also discussed
Balance between endoscopic and genetic information in the choice of ileorectal anastomosis for familial adenomatous polyposis
No full textBackground and objectives: The number of rectal polyps and the site of mutations in
the APC (Adenomatous polyposis coli) gene have been used to guide the surgical
management in patients with familial adenomatous polyposis (FAP). The aim of this
study is to assess the utility of the APC mutation screening compared to the degree of
the rectal polyposis in surgical decision making.
Methods: The post-surgical courses of 25 patients submitted to subtotal colectomy
with ileorectal anastomosis (IRA) were reviewed. Preservation of the rectum was
prospectively decided on the basis of well-defined endoscopic criteria. The number of
rectal polyps was assessed preoperatively and every 6–12 months. APC gene was
screened for mutations by heteroduplex analysis, single strand conformation
polymorphism, in vitro synthesized protein (IVSP), and DNA sequencing. Patients
negative for APC mutations were tested for MYH mutations.
Results: On the basis of preoperative polyp rectal count we categorized patients as
follows: Group I, 5 or fewer adenomas; Group II, 6–9 adenomas; Group III, 10 or
more adenomas. After a follow-up ranging from 12 to 225 months we have observed a
significant difference of recurrent rectal adenomas between Groups I–II versus III. No
difference was detected among patients of Group I and II. The mean number of
adenomas/year/patient was 0.67, 1.62, and 9.29 for Group I, II, and III, respectively.
Carpeting polyposis of the rectal stump developed in three patients with APC mutation
at codon 1309 and two of them needed later proctectomy. Diffuse rectal polyposis was
observed in one patient with mutation at exon 9 who had 10 small polyps at time of
surgery. Mutation at the 50-end of APC (codons 144–232), mutation of MYH and
unknown APC or MYH mutation were correlated with a low number of polyps both at
presentation and follow-up. No IRA patients developed rectal cancer.
Conclusions: In our experience fewer than 10 rectal polyps at presentation can predict
a favorable outcome after IRA. Identification of specific germ-line APC or MYH
mutation can address the choice of surgical treatment
C-myc and c-H-ras-1 mRNA levels in colon carcinomas and adenomas: in situ RNA:RNA hybridization and Northern blot study.
No full textMolecular studies of pulmonary carcinoids
No full textThirtyeight pulmonary carcinoids, 30 typicals (TPCs) and 8 atypical (APCs) were analyzed for membrane, cytoplasmic and/or nuclear immunohistochemical expression of Menin, -catenin, E-cadherin and p53 proteins using a Tissue Microarrays technique combined with mutational analysis. Statistical data were done by the Spearman’s Rho correlation and the SPSS (version 15.0) program was used for statistical analysis. Staining for cytoplasmic Menin was observed in 19/30 TPCs and 7/8 APCs. Membrane β-catenin expression was detected in 11/30 TPCs and 3/8 APCs, cytoplasmic expression in 8/30 TPCs and 4/8 APCs. Nuclear p53 staining was observed in only 2/38 PCs. Moreover, 24/30 TPCs and 8/8 APCs displayed membrane expression of E-cadherin. Cytoplasmic expression of Menin resulted positively associated with the cytoplasmic expression of β-catenin (P = 0.008), whereas β-catenin membrane staining showed positive correlations with cytoplasmic β-catenin (P = 0.022) and E-cadherin (P = 0.040) expressions. The DHPLC and direct sequencing of MEN1 (entire coding sequence), TP53 (exons 5-8) and CTNNB1 (exon 3) genes allowed to characterize several nucleotide variants. MEN1 gene variants were identified in 9/30 TPCs and in 5/8 APCs and included a frameshift mutation, 4 missense variants and 4 synonymous variants. Moreover, we found a novel intronic variant that is not predicted to have any effect on splicing. PCs with MEN1 variants presented an average higher level of cytoplasmic Menin stained cells compared with cases without MEN1 variants (P = 0.023). Analysis of TP53 allowed to identify 3 variants, one of which is associated with a high nuclear expression of p53. Mutational study of the CTNNB1 gene resulted negative and no nucleotide variants were detected. In conclusion, the study support a role of Menin and of theβ-catenin-Ecadherin complex in PCs, while the role of p53 results more limited
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
Multiplex PCR analysis and genotype-phenotype correlations of frequent APC mutations.
No full textGermline mutations of the adenomatous polyposis coli (APC) gene tend to cluster in discrete regions. Some of these mutations occur frequently in familial adenomatous polyposis coli (FAP) patients, and strategies for genetic diagnosis of the disease should include simple methods for their detection. We studied a total of 48 FAP-affected or "at-risk" members from 31 unrelated FAP pedigrees. Unrelated patients were analyzed using heteroduplex analysis on agarose minigels (HAAM) and multiplex allele-specific PCR. This novel strategy readily and reliably detected the three frequently occurring APC deletions at codons 1061, 1068, and 1309, allowing identification of mutant alleles in nine unrelated patients. A targeted mutational analysis, based on HAAM and amplification refractory mutation system (ARMS), allowed the rapid identification of 11 additional subjects with germline deletions, among relatives of the patients in whom mutations had been detected by multiplex PCR and HAAM. The use of two independent PCR-based tests, employing distinct sets of primers, reduces the possibility that artifacts occurring during DNA amplification may interfere with the diagnostic evaluation. The analysis of genotype-phenotype correlations provided evidence for heterogeneity with regard to the extent of colonic and extracolonic manifestations of the disease in subjects bearing identical mutations. However, the consistent association of the deletion at codon 1309 with more severe colonic disease than that observed in patients with mutations at codons 1061 and 1068, supports a correlation between mutation site and penetrance of FAP
Genetic alterations of Wnt pathways in familial versus sporadic polyps
No full textIn previous work we supported the inclusion of germline ASE (allele specific expression) analysis and screening of polyposis genes in algorithms for genetic diagnosis of hereditary forms of colorectal cancer. In the present work we are analyzing gene expression in tissue samples from a series of patients with polyposis, familial and sporadic to gain insights into the role of somatic expression of APC and other components of canonical and non canonical Wnt pathways in colorectal polyposis.
Individuals with age ≥ 18 years were included and patients with inflammatory bowel disease were exluded.
Normal colonic mucosa were collected from donors with no family history of cancer as control. mRNA expression levels were investigated by qRT-PCR. The correlation among clinical and molecular features was evaluated.
We analyzed APC expression in 11 patients with FAP (familial adenomatous polyposis) with and without APC mutation, and 25 with sporadic adenomas (overall, 26 colon tumour tissues and 19 adjacent mucosa) and in normal colonic mucosa from 12 healthy controls. qRT-PCR showed a reduced APC expression in colon tumour tissues as compared to the adjacent mucosa. The differences in APC expression between colon tumour tissues and adiacent mucosa in familial and sporadic cases were statistically significant in the familial group. We also correlated APC expression with age. In patients the expression levels tend to decrease more rapidly with age. Instead in control group there is a constant APC expression trend in life. Correlation with sex showed that the APC reduced expression is more evident in men than in female. Intriguingly the APC expression in polyp-adjacent colonic mucosa was higher also compared to healthy controls colonic mucosa. Wnt pathway BCL9 and LEF1 downstream components and Wnt5a and Wnt3a ligands showed a reduced expression in adjacent colonic mucosa vs adenomas. Expression analysis of other Wnt components is in progress.
This study showed that the APC gene is less expressed in colon tumor tissue compared to the adjacent mucosa either in familial or in sporadic polyps, but it is more expressed in adjacent mucosa compared to the mucosa of healthy controls. The increased APC expression in adjacent mucosa could be due to a cross talk between tumor and surrounding colonic epithelium. BCL9, LEF1, Wnt5a and Wnt3a showed an opposite trend compared to APC, suggesting the involvement of noncanonical Wnt signalling in adenoma formation
- …
