MUTYH Mutations Do Not Cause HNPCC or Late Onset Familial Colorectal Cancer

Recently, carriers of biallelic mutations in the base excision repair gene MUTYH, have been demonstrated to have a predisposition for multiple adenomas and colorectal cancer. Still, many questions remain unanswered concerning MUTYH. We have addressed the following: Do biallelic MUTYH mutation carriers invariably demonstrate FAP, and may MUTYH be a gene causing HNPCC, HNPCC-like or dominantly inherited late onset colorectal cancer? We examined affecteds from our total series of HNPCC, HNPCC-like and dominantly inherited late onset colorectal cancer kindreds not demonstrated to have any MMR mutations. Bloodsamples from 96 patients were subjected to sequencing of exon 7 and exon 13 in the MUTYH gene. Two heterozygotes and one homozygote for the European founder mutations were found. The homozygous carrier did not meet criteria for FAP/AFAP. We conclude that MUTYH, when mutated, causes a rare recessively inherited disorder including colorectal- and duodenal cancers. It is not verified that heterozygous carriers of MUTYH mutations have an increased risk of cancer, and they do not explain the occurrence of familial colorectal cancer in the population

Current clinical criteria for Lynch syndrome are not sensitive enough to identify MSH6 mutation carriers

Background: Reported prevalence, penetrance and expression of deleterious mutations in the mismatch repair (MMR) genes, MLH1, MSH2, MSH6 and PMS2, may reflect differences in the clinical criteria used to select families for DNA testing. The authors have previously reported that clinical criteria are not sensitive enough to identify MMR mutation carriers among incident colorectal cancer cases. Objective: To describe the sensitivity of the criteria when applied to families with a demonstrated MMR mutation. Methods: Families with an aggregation of colorectal cancers were examined for deleterious MMR mutations according to the Mallorca guidelines. All families with a detected MMR mutation as of November 2009 were reclassified according to the Amsterdam and Bethesda criteria. Results: Sixty-nine different DNA variants were identified in a total of 129 families. The original Amsterdam clinical criteria were met by 38%, 12%, 78% and 25% of families with mutations in MSH2, MSH6, MLH1 and PMS2, respectively. Corresponding numbers for the revised Amsterdam criteria were 62%, 48%, 87% and 38%. Similarly, each of the four clinical Bethesda criteria had low sensitivity for identifying MSH6 or PMS2 mutations. Conclusion: Amsterdam criteria and each of the Bethesda criteria were inadequate for identifying MSH6 mutation-carrying kindreds. MSH6 mutations may be more common than currently assumed, and the penetrance/expression of MSH6 mutations, as derived from families meeting current clinical criteria, may be misleading. To increase detection rate of MMR mutation carriers, all cancers in the Lynch syndrome tumour spectrum should be subjected to immunohistochemical analysis and/or analysis for microsatellite instability

Particulate matter exposure during pregnancy is associated with birth weight, but not gestational age, 1962-1992: a cohort study

<p>Abstract</p> <p>Background</p> <p>Exposure to air pollutants is suggested to adversely affect fetal growth, but the evidence remains inconsistent in relation to specific outcomes and exposure windows.</p> <p>Methods</p> <p>Using birth records from the two major maternity hospitals in Newcastle upon Tyne in northern England between 1961 and 1992, we constructed a database of all births to mothers resident within the city. Weekly black smoke exposure levels from routine data recorded at 20 air pollution monitoring stations were obtained and individual exposures were estimated via a two-stage modeling strategy, incorporating temporally and spatially varying covariates. Regression analyses, including 88,679 births, assessed potential associations between exposure to black smoke and birth weight, gestational age and birth weight standardized for gestational age and sex.</p> <p>Results</p> <p>Significant associations were seen between black smoke and both standardized and unstandardized birth weight, but not for gestational age when adjusted for potential confounders. Not all associations were linear. For an increase in whole pregnancy black smoke exposure, from the 1^st(7.4 μg/m³) to the 25^th(17.2 μg/m³), 50^th(33.8 μg/m³), 75^th(108.3 μg/m³), and 90^th(180.8 μg/m³) percentiles, the adjusted estimated decreases in birth weight were 33 g (SE 1.05), 62 g (1.63), 98 g (2.26) and 109 g (2.44) respectively. A significant interaction was observed between socio-economic deprivation and black smoke on both standardized and unstandardized birth weight with increasing effects of black smoke in reducing birth weight seen with increasing socio-economic disadvantage.</p> <p>Conclusions</p> <p>The findings of this study progress the hypothesis that the association between black smoke and birth weight may be mediated through intrauterine growth restriction. The associations between black smoke and birth weight were of the same order of magnitude as those reported for passive smoking. These findings add to the growing evidence of the harmful effects of air pollution on birth outcomes.</p

Oncogene Mutations in Colorectal Polyps Identified in the Norwegian Colorectal Cancer Prevention (NORCCAP) Screening Study

Data are limited on oncogene mutation frequencies in polyps from principally asymptomatic participants of population-based colorectal cancer screening studies. In this study, DNA from 204 polyps, 5 mm or larger, were collected from 176 participants of the NORCCAP screening study and analyzed for mutations in KRAS, BRAF , and PIK3CA including the rarely studied KRAS exons 3 and 4 mutations. KRAS mutations were identified in 23.0% of the lesions and were significantly associated with tubulovillous adenomas and large size. A significantly higher frequency of KRAS mutations in females was associated with mutations in codon 12. The KRAS exon 3 and 4 mutations constituted 23.4% of the KRAS positive lesions, which is a larger proportion compared to previous observations in colorectal cancer. BRAF mutations were identified in 11.3% and were associated with serrated polyps. None of the individuals were diagnosed with de novo or recurrent colorectal cancer during the follow-up time (median 11.2 years). Revealing differences in mutation-spectra according to gender and stages in tumorigenesis might be important for optimal use of oncogenes as therapeutic targets and biomarkers

Establishment and Characterization of Paired Primary Cultures of Human Pancreatic Cancer Cells and Stellate Cells Derived from the Same Tumor

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an extremely poor prognosis, and its treatment remains a challenge. As the existing in vitro experimental models offer only a limited resemblance to human PDAC, there is a strong need for additional research tools to better understand PDAC tumor biology, particularly the impact of the tumor stroma. Here, we report for the first time the establishment and characterization of human PDAC-derived paired primary monolayer cultures of (epithelial) cancer cells (PCCs) and mesenchymal stellate cells (PSCs) derived from the same tumor by the outgrowth method. Characterization of cell morphology, cytostructural, and functional profiles and proteomics-based secretome analysis were performed. All PCCs harbored KRAS and TP53 mutations, and expressed cytokeratin 19, ki-67, and p53, while the expression of EpCAM and vimentin was variable. All PSCs expressed α-smooth muscle actin (α-SMA) and vimentin. PCCs showed a significantly higher growth rate and proliferation than PSCs. Secretome analysis confirmed the distinct nature of PCCs as compared to PSCs and allowed identification of potential molecular regulators of PSC-conditioned medium (PSC-CM)-induced migration of PCCs. Paired primary cultures of PCCs and PSCs derived from the same tumor specimen represent a novel experimental model for basic research in PDAC tumor biology

Human Polyomavirus Type 1 (BK Virus) Agnoprotein Is Abundantly Expressed but Immunologically Ignored▿

Impaired BK virus (BKV)-specific immunity is a key risk factor of polyomavirus-associated nephropathy. We hypothesized that BKV agnoprotein might constitute an important immune target, as it is highly expressed after infection in vitro. We demonstrate abundant expression of BKV agnoprotein in vivo by immunostaining of kidney transplant (KT) biopsy specimens. Antibody responses to the recombinant affinity-purified BKV agnoprotein, large tumor (LT), and VP1 antigens in 146 sera from 38 KT patients and in 19 sera from 16 healthy donors (HD) were compared by enzyme immunoassay. In HD, low titers of anti-agnoprotein immunoglobulin G (IgG) were found in 15% of sera, compared to 41% for anti-LT antigen and 63% for anti-VP1. No anti-BKV IgM was detectable. In KT patients, anti-agnoprotein IgG and IgM were found in 8% and 3.6% of sera, compared to 63% and 18% for anti-LT IgG and IgM and 80% and 41% for anti-VP1 IgG and IgM, respectively. Anti-LT antigen and anti-VP1, but not anti-agnoprotein, activities increased during and after BKV viremia in KT patients. To investigate specific cellular immune responses, we compared levels of gamma interferon production in peripheral blood mononuclear cells (PBMC) of 10 HD and 30 KT patients by enzyme-linked immunospot assay. In HD, the median numbers of gamma interferon spot-forming units per million PBMC for the agnoprotein, LT antigen, and VP1 peptides were 1, 23, and 25, respectively, whereas the responses in KT patients were 2, 24, and 99, respectively. We conclude that BKV agnoprotein, though abundantly expressed in vivo, is poorly recognized immunologically

抽象設計論による教育の数理的形式化

博士（学術）神戸大