Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 324
Filter
1.
medRxiv ; 2020 Sep 02.
Article in English | MEDLINE | ID: mdl-32909007

ABSTRACT

The recent outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has led to a worldwide pandemic. One week after initial symptoms develop, a subset of patients progresses to severe disease, with high mortality and limited treatment options. To design novel interventions aimed at preventing spread of the virus and reducing progression to severe disease, detailed knowledge of the cell types and regulating factors driving cellular entry is urgently needed. Here we assess the expression patterns in genes required for COVID-19 entry into cells and replication, and their regulation by genetic, epigenetic and environmental factors, throughout the respiratory tract using samples collected from the upper (nasal) and lower airways (bronchi). Matched samples from the upper and lower airways show a clear increased expression of these genes in the nose compared to the bronchi and parenchyma. Cellular deconvolution indicates a clear association of these genes with the proportion of secretory epithelial cells. Smoking status was found to increase the majority of COVID-19 related genes including ACE2 and TMPRSS2 but only in the lower airways, which was associated with a significant increase in the predicted proportion of goblet cells in bronchial samples of current smokers. Both acute and second hand smoke were found to increase ACE2 expression in the bronchus. Inhaled corticosteroids decrease ACE2 expression in the lower airways. No significant effect of genetics on ACE2 expression was observed, but a strong association of DNA- methylation with ACE2 and TMPRSS2- mRNA expression was identified in the bronchus.

2.
Mol Oncol ; 10(5): 645-51, 2016 05.
Article in English | MEDLINE | ID: mdl-26797050

ABSTRACT

Comprehensive Cancer Centres (CCCs) serve as critical drivers for improving cancer survival. In Europe, we have developed an Excellence Designation System (EDS) consisting of criteria to assess "excellence" of CCCs in translational research (bench to bedside and back), with the expectation that many European CCCs will aspire to this status.


Subject(s)
Cancer Care Facilities , Neoplasms/therapy , Quality of Health Care , Translational Research, Biomedical , Cancer Care Facilities/standards , Europe , Humans , Quality of Health Care/standards , Translational Research, Biomedical/methods , Translational Research, Biomedical/standards
3.
Br J Cancer ; 102(8): 1294-9, 2010 Apr 13.
Article in English | MEDLINE | ID: mdl-20332777

ABSTRACT

BACKGROUND: A synonymous single nucleotide polymorphism (SNP) rs172378 (A>G, Gly->Gly) in the complement component C1QA has been proposed to be associated with distant breast cancer metastasis. We previously reported overexpression of this gene to be significantly associated with better prognosis in oestrogen-receptor-negative tumours. The purpose of this study was to investigate the association of rs172378 with expression of C1QA and breast cancer survival. METHODS: We analysed the gene expression pattern of rs172378 in normal and tumour tissue samples, and further explored its involvement in relation to mortality in 2270 women with breast cancer participating in Studies of Epidemiology and Risk factors in Cancer Heredity, a population-based case-control study. RESULTS: We found that although rs172378 showed differential allelic expression significantly different between normal (preferentially expressing the G allele) and tumour tissue samples (preferentially expressing the A allele), there was no significant difference in survival by rs172378 genotype (per allele hazard ratio (HR) 1.02, 95% CI: 0.88-1.19, P=0.78 for all-cause mortality; HR 1.03, 95% CI: 0.87-1.22, P=0.72 for breast-cancer-specific mortality). CONCLUSION: Our study results show that rs172378 is linked to a cis-regulatory element affecting gene expression and that allelic preferential expression is altered in tumour samples, but do not support an association between genetic variation in C1QA and breast cancer survival.


Subject(s)
Breast Neoplasms/genetics , Breast Neoplasms/mortality , Complement C1q/genetics , Polymorphism, Single Nucleotide , Adult , Aged , Case-Control Studies , Female , Gene Frequency , Genome-Wide Association Study , Humans , Middle Aged , Prognosis
4.
Br J Cancer ; 101(1): 98-105, 2009 Jul 07.
Article in English | MEDLINE | ID: mdl-19491893

ABSTRACT

BACKGROUND: Bladder cancer is the second most common cancer of the urinary system. Early diagnosis of this tumour and estimation of risk of future progression after initial transuretherial resection have a significant impact on prognosis. Although there are several molecular markers for the diagnosis and prognosis for this tumour, their accuracy is not ideal. Previous reports have shown that UHRF1 (ubiquitin-like with PHD and ring-finger domains 1) is essential for cellular proliferation. In this study, we examined whether UHRF1 can be a novel molecular marker of bladder cancer. METHODS: We performed real-time TaqMan quantitative reverse transcription-PCR and immunohistochemistry to examine expression levels of UHRF1 in bladder and kidney cancers. RESULTS: Significant overexpression of UHRF1 was observed in bladder cancer. The overexpression was correlated with the stage and grade of the cancer. Although UHRF1 expression in muscle-invasive cancer was greater than in non-invasive (pTa) or superficially invasive (pT1) cancers, UHRF1 could still be detected by immunohistochemistry in these early-stage cancers. Overexpression of UHRF1 in bladder cancer was associated with increased risk of progression after transurethral resection. High expression of UHRF1 in kidney cancer was also observed. But the increased levels of UHRF1 in kidney cancer were less significant compared with those in bladder cancer. CONCLUSION: Our result indicates that an immunohistochemistry-based UHRF1 detection in urine sediment or surgical specimens can be a sensitive and cancer-specific diagnostic and/or prognosis method, and may greatly improve the current diagnosis based on cytology.


Subject(s)
Biomarkers, Tumor/biosynthesis , CCAAT-Enhancer-Binding Proteins/biosynthesis , Urinary Bladder Neoplasms/metabolism , Biomarkers, Tumor/genetics , CCAAT-Enhancer-Binding Proteins/genetics , Female , Humans , Immunohistochemistry , Kidney Neoplasms/genetics , Kidney Neoplasms/metabolism , Male , Neoplasm Staging , Prognosis , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Ubiquitin-Protein Ligases , Urinary Bladder Neoplasms/diagnosis , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/pathology
5.
Br J Cancer ; 100(6): 993-1001, 2009 Mar 24.
Article in English | MEDLINE | ID: mdl-19240718

ABSTRACT

Low-moderate risk alleles that are relatively common in the population may explain a significant proportion of the excess familial risk of ovarian cancer (OC) not attributed to highly penetrant genes. In this study, we evaluated the risks of OC associated with common germline variants in five oncogenes (BRAF, ERBB2, KRAS, NMI and PIK3CA) known to be involved in OC development. Thirty-four tagging SNPs in these genes were genotyped in approximately 1800 invasive OC cases and 3000 controls from population-based studies in Denmark, the United Kingdom and the United States. We found no evidence of disease association for SNPs in BRAF, KRAS, ERBB2 and PIK3CA when OC was considered as a single disease phenotype; but after stratification by histological subtype, we found borderline evidence of association for SNPs in KRAS and BRAF with mucinous OC and in ERBB2 and PIK3CA with endometrioid OC. For NMI, we identified a SNP (rs11683487) that was associated with a decreased risk of OC (unadjusted P(dominant)=0.004). We then genotyped rs11683487 in another 1097 cases and 1792 controls from an additional three case-control studies from the United States. The combined odds ratio was 0.89 (95% confidence interval (CI): 0.80-0.99) and remained statistically significant (P(dominant)=0.032). We also identified two haplotypes in ERBB2 associated with an increased OC risk (P(global)=0.034) and a haplotype in BRAF that had a protective effect (P(global)=0.005). In conclusion, these data provide borderline evidence of association for common allelic variation in the NMI with risk of epithelial OC.


Subject(s)
Genetic Predisposition to Disease , Oncogenes , Ovarian Neoplasms/genetics , Polymorphism, Single Nucleotide , Adult , Aged , Class I Phosphatidylinositol 3-Kinases , Female , Genes, erbB-2 , Genotype , Haplotypes , Humans , Intracellular Signaling Peptides and Proteins/genetics , Middle Aged , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins p21(ras) , ras Proteins/genetics
6.
Br J Cancer ; 95(12): 1689-95, 2006 Dec 18.
Article in English | MEDLINE | ID: mdl-17117180

ABSTRACT

ERBB2 is frequently amplified in breast tumours as part of a wide region of amplification on chromosome 17q21. This amplicon contains many candidate genes for breast cancer susceptibility. We used a genetic association study design to determine if common genetic variation (frequency>or=5%) in a 400-kb region surrounding ERBB2 and containing the PPARBP, CRK7, NEUROD2, PPP1R1B, STARD3, TCAP, PNMT, CAB2, ERBB2, C17ORF37, GRB7 and ZNFN1A3 genes, was associated with breast cancer risk. Sixteen tagging single-nucleotide polymorphisms (tSNPs) selected within blocks of linkage disequilibrium from the HapMap database, one HapMap singleton SNP, and six additional SNPs randomly selected from dbSNP were genotyped using Taqman in a large study set of British women (2275 cases, 2280 controls). We observed no association between any of the genotypes or associated haplotypes and disease risk. In order to simulate unidentified SNPs, we performed the leave-one-out cross-validation procedure on the HapMap data; over 90% of the common genetic variation was well represented by tagging polymorphisms. We are therefore likely to have tagged any common variants present in our population. In summary, we found no association between common genetic variation in the 17q21 ERBB2 amplicon and breast cancer risk in British women.


Subject(s)
Breast Neoplasms/genetics , Chromosomes, Human, Pair 17/genetics , Gene Amplification , Genetic Predisposition to Disease , Haplotypes/genetics , Receptor, ErbB-2/genetics , Adult , Aged , Aged, 80 and over , Case-Control Studies , Female , Genomics , Humans , Middle Aged , Polymorphism, Single Nucleotide , Receptor, ErbB-2/metabolism
7.
Br J Cancer ; 95(4): 525-31, 2006 Aug 21.
Article in English | MEDLINE | ID: mdl-16868544

ABSTRACT

The aim of the study is to examine the association between multilocus genotypes across 10 genes encoding proteins in the antioxidant defence system and breast cancer. The 10 genes are SOD1, SOD2, GPX1, GPX4, GSR, CAT, TXN, TXN2, TXNRD1 and TXNRD2. In all, 2271 cases and 2280 controls were used to examine gene-gene interactions between 52 single nucleotide polymorphisms (SNPs) that are hypothesised to tag all common variants in the 10 genes. The statistical analysis is based on three methods: unconditional logistic regression, multifactor dimensionality reduction and hierarchical cluster analysis. We examined all two- and three-way combinations with unconditional logistic regression and multifactor dimensionality reduction, and used a global approach with all SNPs in the hierarchical cluster analysis. Single-locus studies of an association of genetic variants in the antioxidant defence genes and breast cancer have been contradictory and inconclusive. It is the first time, to our knowledge, the association between multilocus genotypes across genes coding for antioxidant defence enzymes and breast cancer is investigated. We found no evidence of an association with breast cancer with our multilocus approach. The search for two-way interactions gave experiment-wise significance levels of P=0.24 (TXN [t2715c] and TXNRD2 [g23524a]) and P=0.58 (GSR [c39396t] and TXNRD2 [a442g]), for the unconditional logistic regression and multifactor dimensionality reduction, respectively. The experiment-wise significance levels for the three-way interactions were P=0.94 (GPX4 [t2572c], TXN [t2715c] and TXNRD2 [g23524a]) and P=0.29 (GSR [c39396t], TXN [t2715c] and TXNRD2 [a442g]) for the unconditional logistic regression and multifactor dimensionality reduction, respectively. In the hierarchical cluster analysis neither the average across four rounds with replacement of missing values at random (P=0.12) nor a fifth round with more balanced proportion of missing values between cases and controls (P=0.17) was significant.


Subject(s)
Breast Neoplasms/genetics , Oxidative Stress/genetics , Polymorphism, Single Nucleotide , Adult , Aged , Carcinoma, Ductal, Breast , Carcinoma, Lobular/genetics , Case-Control Studies , Epistasis, Genetic , Female , Humans , Middle Aged , Reactive Oxygen Species/metabolism , Risk Factors
8.
Br J Cancer ; 95(2): 233-8, 2006 Jul 17.
Article in English | MEDLINE | ID: mdl-16786042

ABSTRACT

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition affecting around one in 3000 live births. The manifestations of this condition are extremely variable, even within families, and genetic counselling is consequently difficult with regard to prognosis. Individuals with NF1 are acknowledged to be at increased risk of malignancy. Several studies have previously attempted to quantify this risk, but have involved relatively small study populations. We present prospective data from 448 individuals with NF1 with a total of 5705 years of patient follow-up. These data have been collected via the UK NF1 association for patients. Demographic information on the affected individuals was cross-referenced with UK cancer registry data by the UK Office of National Statistics. The overall risk of cancer was 2.7 times higher in this cohort of NF1 patients than in the general population (95% confidence interval (CI) 1.9-3.7). The cumulative risk of a malignancy by age 50 years was 20% (95% CI 14-29%); beyond this age, the risk of cancer was not significantly elevated (P=0.27). The most frequent types of cancer were connective tissue (14% risk by age 70, 95% CI 7.8-24%) and brain tumours (7.9, 95% CI 3.9-16%). There was no statistically significant excess of cancers at other sites (P=0.22).


Subject(s)
Neoplasms/epidemiology , Neoplasms/genetics , Neurofibromatosis 1/epidemiology , Neurofibromatosis 1/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cohort Studies , Comorbidity , Female , Follow-Up Studies , Humans , Incidence , Infant , Male , Middle Aged , Prospective Studies , Risk Assessment , United Kingdom/epidemiology
9.
Br J Cancer ; 94(12): 1921-6, 2006 Jun 19.
Article in English | MEDLINE | ID: mdl-16685266

ABSTRACT

A substantial proportion of the familial risk of breast cancer may be attributable to genetic variants each contributing a small effect. pRb controls the cell cycle and polymorphisms within it are candidates for such low penetrance susceptibility alleles, since the gene has been implicated in several human tumours, particularly breast cancer. The purpose of this study was to determine whether common variants in the RB1 gene are associated with breast cancer risk. We assessed 15 tagging single-nucleotide polymorphisms (SNPs) using a case-control study design (n< or = 4474 cases and n < or = 4560 controls). A difference in genotype frequencies was found between cases and controls for rs2854344 in intron 17 (P-trend = 0.007) and rs198580 in intron 19 (P-trend = 0.018). Carrying the minor allele of these SNPs appears to confer a protective effect on breast cancer risk (odd ratio (OR) = 0.86 (0.76-0.96) for rs2854344 and OR = 0.80 (0.66-0.96) for rs198580). However, after adjusting for multiple testing these associations were borderline with an adjusted P-trend = 0.068 for the most significant SNP (rs2854344). The RB1 gene is not known to contain any coding SNPs with allele frequencies > or = 5% but several intronic variants are in perfect linkage disequilibrium with the associated SNPs. Replication studies are needed to confirm the associations with breast cancer.


Subject(s)
Breast Neoplasms/genetics , Polymorphism, Single Nucleotide/genetics , Retinoblastoma Protein/genetics , Aged , Case-Control Studies , Female , Gene Frequency , Genetic Predisposition to Disease , Haplotypes , Humans , Linkage Disequilibrium/genetics , Middle Aged , Polymerase Chain Reaction , Risk Factors , United Kingdom
10.
J Clin Endocrinol Metab ; 90(6): 3454-7, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15741265

ABSTRACT

The effect of mutations at codon 804 in the RET protooncogene is disputed. Some studies have suggested that the V804L mutation causes the low penetrance multiple endocrine neoplasia type 2 syndrome, with late onset and relatively indolent course, whereas others have reported that V804L and V804M have an aggressive potential. In this paper, we report three apparently unrelated medullary thyroid carcinoma cases homozygous for these mutations. To clarify the phenotypic heterogeneity associated with these mutations, we compare the clinical data and age of diagnosis among these three homozygous patients, six other heterozygous cases from the same populations, and other homozygous and heterozygous subjects reported previously. The data are consistent with a model in which codon 804 mutations have low penetrance, the developing of medullary thyroid carcinoma being associated with a second germline or somatic mutation. The activity and (in the case of somatic mutations) timing of these other genetic alterations in the RET gene may explain the wide clinical variability associated with germline mutations at codon 804.


Subject(s)
Codon/genetics , Multiple Endocrine Neoplasia Type 2a/genetics , Mutation, Missense , Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Thyroid Neoplasms/genetics , Adult , Aged , Amino Acid Substitution , Base Sequence , Child , Female , Humans , Male , Middle Aged , Proto-Oncogene Proteins c-ret
11.
Br J Cancer ; 92(5): 967-70, 2005 Mar 14.
Article in English | MEDLINE | ID: mdl-15726104

ABSTRACT

We typed 247 cases of nasopharyngeal carcinoma (NPC), a disease predominantly of the southern Chinese, and 274 controls from the Chao Shan region of China's Guangdong province for HLA A and B. Besides confirming the established associations with A2, A33, B46 and B58 (positive associations) and A11 (negative association), the results demonstrated a number of rarer alleles with strong negative association with NPC. Our data, combined with those from the previous studies in Southern Chinese, displayed the protective effects for A31 (odds ratio (OR)=0.0; 95% confidence interval (CI)=0-0.11), B13 (OR=0.50; 95% CI=0.35-0.69), B27 (OR=0.49; 95% CI=0.25-0.92), B39 (OR=0.18; 95% CI=0.06-0.48) and B55 (OR=0.32; 95% CI=0.14-0.68), the ORs comparing individuals with or without each allele. Other ethnic groups do not display such large HLA-associated variation in NPC risk. We show that a linked NPC gene with dominant mode of action could not generate such large protective effects. The results provide strong supporting evidence for the existence of a southern Chinese specific, recessive NPC gene closely linked to the HLA region as a major determinant of the Chinese risk for the disease.


Subject(s)
HLA-A Antigens/genetics , HLA-B Antigens/genetics , Major Histocompatibility Complex/genetics , Nasopharyngeal Neoplasms/genetics , China , Confidence Intervals , DNA/genetics , DNA/isolation & purification , DNA Primers , Genes, Recessive , Histocompatibility Testing , Odds Ratio , Reference Values
12.
Article in English | MEDLINE | ID: mdl-16869736

ABSTRACT

The known breast cancer predisposing genes account for only about 20% of inherited susceptibility. Epidemiological analyses suggest that much of the remaining 80% is explained by the combined effect of many individually weak genetic variants, rather than by further rare, highly penetrant mutations. In the near term, identification of variants may indicate new pathways or mechanisms in breast cancer development. The polygenic model implies a wide distribution of risk in the population. In the longer term, it may be possible to construct individual risk profiles to guide public health interventions. The search for genetic variants has so far proved difficult. A key unanswered question is the "genetic architecture" of predisposition-that is, strong or weak alleles, common or rare. We describe a genome-wide scan designed to provide a first-pass answer to this question.


Subject(s)
Breast Neoplasms/genetics , Models, Genetic , Multifactorial Inheritance , Alleles , Female , Genetic Predisposition to Disease , Genomics , Humans , Mutation , Oncogenes , Risk Factors
13.
Br J Cancer ; 91(11): 1911-5, 2004 Nov 29.
Article in English | MEDLINE | ID: mdl-15545966

ABSTRACT

Women with mutations of the genes BRCA1 or BRCA2 are at increased risk of ovarian cancer. Oral contraceptives protect against ovarian cancer in general, but it is not known whether they protect against the disease in carriers of these mutations. We obtained self-reported lifetime histories of oral contraceptive use from 451 women who carried mutations of BRCA1 or BRCA2. We used conditional logistic regression to estimate the odds ratios associated with oral contraceptive use, comparing the histories of 147 women with ovarian cancer (cases) to those of 304 women without ovarian cancer (controls) who were matched to cases on year of birth, country of residence and gene (BRCA1 vs BRCA2). Reference ages for controls had to exceed the ages at diagnosis of their matched cases. After adjusting for parity, the odds-ratio for ovarian cancer associated with use of oral contraceptives for at least 1 year was 0.85 (95 percent confidence interval, 0.53-1.36). The risk decreased by 5% (1-9%) with each year of use (P for trend=0.01). Use for 6 or more years was associated with an odds-ratio of 0.62 (0.35-1.09). These data support the hypothesis that long-term oral contraceptive use reduces the risk of ovarian cancer among women who carry mutations of BRCA1 or BRCA2.


Subject(s)
Contraceptives, Oral/therapeutic use , Genes, BRCA1 , Genes, BRCA2 , Germ-Line Mutation/genetics , Ovarian Neoplasms/genetics , Adult , Case-Control Studies , Female , Heterozygote , Humans , Middle Aged , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/prevention & control , Neoplasms, Glandular and Epithelial/genetics , Neoplasms, Glandular and Epithelial/prevention & control , Ovarian Neoplasms/prevention & control , Risk Factors
14.
Cancer Epidemiol Biomarkers Prev ; 12(8): 809-12, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12917215

ABSTRACT

A substantial proportion of the familial risk of breast cancer may be attributable to genetic variants each contributing a small effect. Polymorphisms in DNA repair genes are good candidates for such low penetrance breast cancer susceptibility alleles. Checkpoint kinase 2 (CHEK2) is a kinase in which the yeast counterpart regulates a cell cycle checkpoint and causes cells to arrest proliferation after DNA damage. A rare, protein truncating mutation in the CHEK2 gene has recently been shown to confer a modest risk of breast cancer. The aim of this study was to determine whether common polymorphic variants in CHEK2 are associated with an increase in breast cancer risk. We assessed two variants in CHEK2 using a case control study design (n = 1786 cases and 1828 controls). No differences in genotype frequencies were found between cases and control for either the IVS1 + 38insa or the a1013g polymorphisms (P = 0.3 and 0.2 respectively), and no genotype-specific risk was significantly different from unity. The haplotype frequency distribution in cases and controls were also similar (P = 0.3). We conclude that the CHEK2 polymorphisms IVS + 1a and a1013g do not confer an increased risk of breast cancer. It is also unlikely that other, as yet unidentified, common polymorphisms that affect risk are present in the gene in the British population.


Subject(s)
Breast Neoplasms/genetics , Polymorphism, Genetic , Protein Kinases/genetics , Protein Serine-Threonine Kinases , Checkpoint Kinase 2 , Female , Humans , Risk Factors
15.
Br J Cancer ; 87(10): 1162-5, 2002 Nov 04.
Article in English | MEDLINE | ID: mdl-12402157

ABSTRACT

In this study we screened the histone acetyltransferases CBP and PCAF for mutations in human epithelial cancer cell lines and primary tumours. We identified two CBP truncations (both in cell lines), seven PCAF missense variants and four CBP intronic microdeletions. These data suggest that neither gene is commonly inactivated in human epithelial cancers.


Subject(s)
Acetyltransferases/genetics , Mutation , Neoplasms, Glandular and Epithelial/genetics , Nuclear Proteins/genetics , Saccharomyces cerevisiae Proteins/genetics , Trans-Activators/genetics , Blotting, Western , CREB-Binding Protein , Cell Cycle Proteins/genetics , Exons , Histone Acetyltransferases , Humans , Introns , Transcription Factors , Tumor Cells, Cultured , p300-CBP Transcription Factors
16.
Vopr Onkol ; 48(1): 24-8, 2002.
Article in Russian | MEDLINE | ID: mdl-12101561

ABSTRACT

The proportion of BRCA1/2 genes varies widely among populations. We investigated 52 cases of breast cancer: 24 cases of familial breast cancer, 22--early-onset (till 40 years) and 6--bilateral cancer. The frequency of carriers of mutations among familial cancer cases was 16%, among cases of disease till 40 years--9%. 538insC BRCA1 was the most common genetic mutation among hereditary cases of breast cancer.


Subject(s)
Breast Neoplasms/genetics , Genes, BRCA1 , Genes, BRCA2 , Mutation , Adult , Age of Onset , Female , Humans , Pedigree
17.
Br J Cancer ; 86(1): 76-83, 2002 Jan 07.
Article in English | MEDLINE | ID: mdl-11857015

ABSTRACT

In computing the probability that a woman is a BRCA1 or BRCA2 carrier for genetic counselling purposes, it is important to allow for the fact that other breast cancer susceptibility genes may exist. We used data from both a population based series of breast cancer cases and high risk families in the UK, with information on BRCA1 and BRCA2 mutation status, to investigate the genetic models that can best explain familial breast cancer outside BRCA1 and BRCA2 families. We also evaluated the evidence for risk modifiers in BRCA1 and BRCA2 carriers. We estimated the simultaneous effects of BRCA1, BRCA2, a third hypothetical gene 'BRCA3', and a polygenic effect using segregation analysis. The hypergeometric polygenic model was used to approximate polygenic inheritance and the effect of risk modifiers. BRCA1 and BRCA2 could not explain all the observed familial clustering. The best fitting model for the residual familial breast cancer was the polygenic, although a model with a single recessive allele produced a similar fit. There was also significant evidence for a modifying effect of other genes on the risks of breast cancer in BRCA1 and BRCA2 mutation carriers. Under this model, the frequency of BRCA1 was estimated to be 0.051% (95% CI: 0.021-0.125%) and of BRCA2 0.068% (95% CI: 0.033-0.141%). The breast cancer risk by age 70 years, based on the average incidence over all modifiers was estimated to be 35.3% for BRCA1 and 50.3% for BRCA2. The corresponding ovarian cancer risks were 25.9% for BRCA1 and 9.1% for BRCA2. The findings suggest that several common, low penetrance genes with multiplicative effects on risk may account for the residual non-BRCA1/2 familial aggregation of breast cancer. The modifying effect may explain the previously reported differences between population based estimates for BRCA1/2 penetrance and estimates based on high-risk families.


Subject(s)
Breast Neoplasms/genetics , Models, Genetic , Adult , Aged , Female , Genes, BRCA1 , Genes, BRCA2 , Humans , Middle Aged , Mutation
18.
Hum Mol Genet ; 10(26): 3001-7, 2001 Dec 15.
Article in English | MEDLINE | ID: mdl-11751682

ABSTRACT

Cancer cells have aberrant patterns of DNA methylation including hypermethylation of gene promoter CpG islands and global demethylation of the genome. Genes that cause familial cancer, as well as other genes, can be silenced by promoter hypermethylation in sporadic tumors, but the methylation of these genes in tumors from kindreds with inherited cancer syndromes has not been well characterized. Here, we examine CpG island methylation of 10 genes (hMLH1, BRCA1, APC, LKB1, CDH1, p16(INK4a), p14(ARF), MGMT, GSTP1 and RARbeta2) and 5-methylcytosine DNA content, in inherited (n = 342) and non-inherited (n = 215) breast and colorectal cancers. Our results show that singly retained alleles of germline mutated genes are never hypermethylated in inherited tumors. However, this epigenetic change is a frequent second "hit", associated with the wild-type copy of these genes in inherited tumors where both alleles are retained. Global hypomethylation was similar between sporadic and hereditary cases, but distinct differences existed in patterns of methylation at non-familial genes. This study demonstrates that hereditary cancers "mimic" the DNA methylation patterns present in the sporadic tumors.


Subject(s)
Breast Neoplasms/genetics , Colonic Neoplasms/genetics , DNA Methylation , Neoplastic Syndromes, Hereditary/genetics , Oncogenes , Breast Neoplasms/metabolism , Colonic Neoplasms/metabolism , CpG Islands , Genes, Tumor Suppressor , Genetic Predisposition to Disease , Humans , Mutation , Neoplastic Syndromes, Hereditary/physiopathology , Promoter Regions, Genetic
19.
J Clin Endocrinol Metab ; 86(12): 5658-71, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11739416

ABSTRACT

This is a consensus statement from an international group, mostly of clinical endocrinologists. MEN1 and MEN2 are hereditary cancer syndromes. The commonest tumors secrete PTH or gastrin in MEN1, and calcitonin or catecholamines in MEN2. Management strategies improved after the discoveries of their genes. MEN1 has no clear syndromic variants. Tumor monitoring in MEN1 carriers includes biochemical tests yearly and imaging tests less often. Neck surgery includes subtotal or total parathyroidectomy, parathyroid cryopreservation, and thymectomy. Proton pump inhibitors or somatostatin analogs are the main management for oversecretion of entero-pancreatic hormones, except insulin. The roles for surgery of most entero-pancreatic tumors present several controversies: exclusion of most operations on gastrinomas and indications for surgery on other tumors. Each MEN1 family probably has an inactivating MEN1 germline mutation. Testing for a germline MEN1 mutation gives useful information, but rarely mandates an intervention. The most distinctive MEN2 variants are MEN2A, MEN2B, and familial medullary thyroid cancer (MTC). They vary in aggressiveness of MTC and spectrum of disturbed organs. Mortality in MEN2 is greater from MTC than from pheochromocytoma. Thyroidectomy, during childhood if possible, is the goal in all MEN2 carriers to prevent or cure MTC. Each MEN2 index case probably has an activating germline RET mutation. RET testing has replaced calcitonin testing to diagnose the MEN2 carrier state. The specific RET codon mutation correlates with the MEN2 syndromic variant, the age of onset of MTC, and the aggressiveness of MTC; consequently, that mutation should guide major management decisions, such as whether and when to perform thyroidectomy.


Subject(s)
Multiple Endocrine Neoplasia Type 1/diagnosis , Multiple Endocrine Neoplasia Type 1/therapy , Multiple Endocrine Neoplasia Type 2a/diagnosis , Multiple Endocrine Neoplasia Type 2a/therapy , Humans , Practice Guidelines as Topic
20.
Carcinogenesis ; 22(11): 1797-800, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11698341

ABSTRACT

Several studies have investigated polymorphisms in CYP1A1 and breast cancer risk with inconsistent results. We have carried out a population based case-control study of the Thr461Asn and Ile462Val polymorphisms in CYP1A1 to clarify their importance in determining breast cancer susceptibility. A total of 1873 cases and 712 controls were genotyped for Thr461Asn and 1948 cases and 1355 controls were genotyped for Ile462Val. We have also investigated a putative interaction between smoking and CYP1A1 genotype and breast cancer risk using a case only study design. The genotype distribution of Thr461Asp in controls was close to that expected under Hardy-Weinberg equilibrium (HWE). We detected no significant differences in genotype frequencies between breast cancer cases and controls (P = 0.68). Compared with the Thr/Thr homozygotes there was no significant risk for either the Thr/Asp heterozygote [OR = 1.1 (95% CI 0.8-1.4)] or the Asp/Asp homozygote [OR = 0.4 (0.02-6.1)]. The genotype distribution of Ile462Val in controls was also close to that expected under HWE with no significant differences between breast cancer cases and the controls (P = 0.44). No significant risk was found for either the Ile/Val heterozygote [OR = 0.8 (0.6-1.1)] or the Val/Val homozygote [OR = 2.7 (0.3-24)] compared with the Ile/Ile homozygotes. Furthermore, subgroup analyses revealed no effect of age or menopausal status on genotypic risks, and we found no evidence for an interaction between genotype and smoking habit or alcohol consumption and susceptibility to breast cancer. We combined our data for the Ile462Val polymorphism with those from four other published studies, but even with >5000 subjects, none of the genotype-associated risks achieved statistical significance, and there was no consistent pattern to the risks associated with increasing Val allele dosage [Ile/Val OR = 0.9 (0.7-1.1), Val/Val OR = 2.3 (0.4-12), and Val carrier OR = 1.0 (0.9-1.1)].


Subject(s)
Breast Neoplasms/etiology , Cytochrome P-450 CYP1A1/genetics , Polymorphism, Genetic , Smoking/adverse effects , Aged , Breast Neoplasms/genetics , Case-Control Studies , DNA Primers/chemistry , Female , Gene Frequency , Genotype , Humans , Middle Aged , Neoplasm Staging , Polymerase Chain Reaction , Prospective Studies , Risk Factors , Sequence Analysis, DNA
SELECTION OF CITATIONS
SEARCH DETAIL