age variation in bitter taste perception in relation to the tas2r38 taste receptor phenotype

n/

Beta catenin and cytokine pathway dysregulation in patients with manifestations of the "PTEN hamartoma tumor syndrome"

Background. The "PTEN hamartoma tumor syndrome" (PHTS) includes a group of syndromes caused by germline mutations within the tumor suppressor gene "phosphatase and tensin homolog deleted on chromosome ten" (PTEN), characterized by multiple polyps in the gastrointestinal tract and by a highly increased risk of developing malignant tumours in many tissues. The current work clarifies the molecular basis of PHTS in three unrelated Italian patients, and sheds light on molecular pathway disregulation constitutively associated to PTEN alteration. Methods. We performed a combination of RT-PCR, PCR, sequencing of the amplified fragments, Real Time PCR and western blot techniques. Results. Our data provide the first evidence of β-catenin accumulation in blood cells of patients with hereditary cancer syndrome caused by germ-line PTEN alteration. In addition, for the first time we show, in all PHTS patients analysed, alterations in the expression of TNFα, its receptors and IL-10. Importantly, the isoform of TNFRI that lacks the DEATH domain (TNFRSF1β) was found to be overexpressed. Conclusion. In light of our findings, we suggest that the PTEN pathway disregulation could determine, in non-neoplastic cells of PHTS patients, cell survival and pro-inflammatory stimulation, mediated by the expression of molecules such as β-catenin, TNFα and TNFα receptors, which could predispose these patients to the development of multiple cancers

HAMARTOMATOUS POLYPOSIS SYNDROMES:MOLECULAR MECHANISMS AND GENETIC TESTING.

Hamartomatous polyposis syndromes are a rare group of hereditary autosomal dominant disorders that comprise less than 1% of all hereditary colorectal cancers. However, these hamartomatous polyposis syndromes have a malignant potential for the development of colorectal cancer as well as extracolonic cancers. The hamartomatous polyposis syndromes include juvenile polyposis syndrome (JPS); PTEN hamartoma tumor syndrome, which includes Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome (BRRS), and Peutz-Jeghers syndrome (PJS). Due to the rarity of these conditions, a thorough understanding of their clinical presentation, including extraintestinal manifestations, and genetics is important. For pediatric gastroenterologists, understanding how to recognize and establish the appropriate diagnosis and cancer risk and following appropriate screening and surveillance guidelines is crucial for early detection to minimize the risk of carcinoma as children reach adulthood. Peutz-Jeghers syndrome (PJS) is an autosomal dominantly inherited syndrome characterized by mucocutanoeus pigmentation, multiple hamartomatous polyps in the gastrointestinal tract and an increased risk of cancer at a young age. Inactivating germ-line mutations in the tumor suppressor gene STK11/LKB1 have been detected in approximately 80% of patients. The aim of this work is to clarify the molecular basis of the disease in Italian PJS patients. We investigate the STK11/LKB1 gene mutations in a well-characterized series of 9 unrelated Italian PJS patients, by using a combination of PCR, RT-PCR, DNA sequencing, Southern blot analysis and real-time polymerase chain reaction techniques. We have characterized the specific STK11 mutation in 6 probands, and identified 2 truncating mutations (1 novel and 1 known mutation), one missense known mutation in the exon four, and two novel small in-frame deletions in the exon six. Finally, we have found an intra-exonic in-frame deletion encompassing exons 2 and 4: the possible mechanism leading to this genomic rearrangement is most likely an Alu-Alu homologous recombination. In our study point mutations, small scale deletions/insertions and exonic STK11 deletions account for about 67% of PJS; mutations in other STK11 related genes examined have not be found. Other gene inactivating methods, such as chromosomal rearrangements mediated by Alu-Alu homologous recombination, which cannot be detected by routinely molecular biology screening methods, might be responsible for PJS in mutations negative population subset. However, the existence of genetic heterogeneity cannot be excluded. The “PTEN hamartomatous tumor sindrome” (PHTS), include a group af syndromes that are caused by germline mutations of the tumor suppressor gene PTEN (phosphatase and tensin homolog deleted on chromosome ten). They belong to hamartomatous polyposis syndromes family, a rare and heterogeneous group of hereditary autosomal dominant disorders characterized by multiple polyps in the gastrointestinal tract and greatly increased risk of developing malignant tumours in multiple tissues. The PTEN tumor suppressor gene affects multiple cellular processes including cell growth, proliferation, and cell migration by antagonizing phosphatidylinositol 3-kinase (PI3K)/Akt phatway. we have first screened the PTEN coding region in three italian patients with clinical diagnosis of PHTS by using a combination of RT-PCR, direct sequencing of the amplified fragments and real-time polymerase chain reaction techniques. Afterwards, in periferal blood cells of these patients, we have defined the expression profile of other genes directly related to PI3K/Akt phatway, as cMYC, COX2, CCND1 and TNFa, or involved in colorectal cancer onset, as APC, DKC1 and hTERT. We have characterized the specific PTEN mutation in 1 subject, the c406C->T (C136R) mutation, a missence mutation of the catalytic domain just described in literature before. The others two patients showed a low level of PTEN mRNA expression, respectively of 0,3 and 0,4 fold change, related to a healthy controls. All three patients were characterized by an high level of COX2, TNFa and CCND1 genes expression and decrease expression of APC gene. Our data represent the first evidence of a PI3K/Akt phatway dysregulation in periferal blood cells of PHTS patients that probably determine a pro inflammation attivation. Knowledge of specific molecular phatways costitutively dysregulated in this syndrome could be helpful in optimizing molecular targeted therapy and preventative care

Gene Expression Profiling of Celiac Biopsies and Peripheral Blood Monocytes Using Taqman Assays

Quantitative real-time PCR (qPCR) allows for highly sensitive, rapid, and reproducible quantification of mRNA: it has become an established technology for the quantification of gene expression with the 5' nuclease assay using TaqMan(®) probes. It is used for a broad range of applications, including quantification of gene expression, measuring RNA interference, biomarker discovery, pathogen detection, and drug target validation. When studying gene expression with qPCR, scientists usually investigate changes-increases or decreases-in the quantity of particular gene products or a set of gene products. Investigations typically evaluate gene response to biological conditions such as disease states, exposure to pathogens or chemical compounds, organ or tissue location, and cell cycle or differentiation status. Here we describe this technique applied to molecular profiling of candidate genes in celiac biopsies and peripheral blood monocytes. Using data obtained by gene expression experiments, a discriminant equation has been developed that allows the correct classification of Celiac Disease (CD) patients compared to healthy controls, CD patients on a Gluten Free Diet (GFD), and other disease controls

Implication of adenomatous polyposis coli and MUTYH mutations in familial colorectal polyposis.

PURPOSE: Familial adenomatous polyposis is an autosomal dominantly inherited syndrome characterized by hundreds or thousands of colorectal polyps and a high risk of colorectal cancer at a young age. Truncating germline mutations in the adenomatous polyposis coli gene are detected in approximately 80 percent of patients with classical familial adenomatous polyposis and in approximately 10 percent of the attenuated familial adenomatous polyposis patients. METHODS: We investigated the adenomatous polyposis coli and MUTYH genes mutations in a well-characterized series of 25 unrelated Italian patients with familial adenomatous polyposis. RESULTS: We characterized the specific adenomatous polyposis coli gene mutation in 10 probands, and identified eight truncating mutations (4 novel and 4 known mutations) and two splicing mutations. One of these, a novel missense mutation in exon 15, activates an exonic splicing enhancer control sequence. Moreover, 11 MUTYH gene mutations have been identified in 7 patients without a dominant family history of polyposis. CONCLUSIONS: This study enlarges the genotype-phenotype correlations of familial adenomatous polyposis and suggests that messenger alterations could be responsible for a subset of familial adenomatous polyposis cases without germ-line adenomatous polyposis coli or MUTYH gene mutations. It also confirms that genotype-phenotype correlations in MUTYH-associated polyposis are very complex

High Frequency of Haplotype HLA-DQ7 in Celiac Disease Patients from South Italy: Retrospective Evaluation of 5,535 Subjects at Risk of Celiac Disease

Celiac disease (CD) has a strong genetic component mainly due to HLA DQ2/DQ8 encoding genes. However, a minority of CD patients are DQ2/DQ8-negative. To address this issue, we retrospectively characterized HLA haplotypes in 5,535 subjects at risk of CD (either relatives of CD patients or subjects with CD-like symptoms) referred to our center during a 10-year period