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Douglas Easton

Publications and source records attributed to Douglas Easton.

16 recordsLinked to original sources
PubMed2007

Basal-like grade III invasive ductal carcinoma of the breast: patterns of metastasis and long-term survival.

INTRODUCTION: Cytokeratin (CK) 14, one of several markers expressed in normal myoepithelial/basal cells, is also expressed in a proportion of breast carcinomas. Previous studies have suggested that expression of such 'basal' markers predicts different biological behaviour, with more frequent lung and brain metastases and poorer prognosis than other carcinomas. METHODS: We performed CK14 immunohistochemistry on 443 grade III invasive ductal carcinomas with extended clinical follow-up (mean 116 months), and we correlated CK14 immunopositivity (basal-like phenotype) with clinicopathological criteria. RESULTS: Eighty-eight of 443 (20%) tumours showed CK14 expression. CK14-positive tumours were more likely to be oestrogen receptor-negative (p < 0.0001) and axillary node-negative (p = 0.001) than were CK14-negative cases. CK14-positive cases developed less bone and liver metastases (hazard ratio [HR] 0.49, p = 0.01, and HR 0.53, p = 0.035, respectively) but more frequent brain metastases (HR 1.92, p = 0.051). In patients without metastatic disease, disease-free survival in CK14-positive cases was significantly better than in CK14-negative cases (HR 0.65, p = 0.005). In patients with metastatic disease, however, CK14 positivity was associated with a poorer prognosis (HR 1.84, p = 0.001). The overall survival in CK14-positive and -negative patients was similar at 5 years (60% and 59%, respectively), but the long-term survival was better in CK14-positive patients (HR 0.69, p = 0.02). CONCLUSION: These results demonstrate that basal-like tumours differ in their biological behaviour from other tumours, with a distinct pattern of metastatic spread. Compared to other grade III tumours, basal-like tumours appear to have a relatively good long-term survival but survival after metastases is poor.

Adult↗
PubMed2006

Late toxicity is not increased in BRCA1/BRCA2 mutation carriers undergoing breast radiotherapy in the United Kingdom.

PURPOSE: To undertake the first substantial clinical study of breast radiotherapy toxicity in BRCA1 and BRCA2 mutation carriers in the United Kingdom. EXPERIMENTAL DESIGN: Acute and late radiation effects were evaluated in a retrospective study of 55 BRCA1 and BRCA2 mutation carriers treated with radiotherapy for breast cancer at four centers between 1983 and 2002. Individual matching with controls who had sporadic breast cancer was undertaken for age at diagnosis, time since completion of radiation, and treatment variables. Detailed assessments were undertaken by one examiner. Median follow-up was 6.75 years for carriers and 7.75 years for controls. Rates of late events (rib fractures, lung fibrosis, necrosis of soft tissue/bone, and pericarditis) as well as LENT-SOMA scores and clinical photography scores of breast size, shape, and skin telangiectasia were the primary end points. RESULTS: No increase in clinically significant late toxicity was seen in the mutation carriers. CONCLUSIONS: These data add substantial weight to the evidence that the outcomes in the treated breast from radiotherapy in women with BRCA1 or BRCA2 mutations are comparable with those in women with sporadic breast cancer.

Adult↗
PubMed2006

Acute chemotherapy-related toxicity is not increased in BRCA1 and BRCA2 mutation carriers treated for breast cancer in the United Kingdom.

PURPOSE: To evaluate acute toxicity induced by chemotherapy for breast cancer in a retrospective study of 62 BRCA1/2 mutation carriers matched 1:1 with women who had treatment for sporadic disease in the United Kingdom between 1983 and 2003. EXPERIMENTAL DESIGN: All participants were interviewed by one of two researchers using standardized questionnaires, and their medical records were reviewed by one research nurse. The two main regimens received were cyclophosphamide, methotrexate, and fluorouracil and fluorouracil, epirubicin, and cyclophosphamide. The proportion of cases and controls receiving anthracycline-based treatment was equivalent, but fewer BRCA1 cases received this treatment than did BRCA2 mutation carriers. Toxicity was documented using the Eastern Cooperative Oncology Group Common Toxicity Criteria for hematologic, infective, and gastrointestinal toxicities. No increase in toxicity was seen in BRCA1/2 mutation carriers. RESULTS: The only significant difference was that neutropenia was less evident in BRCA2 mutation carriers than in either BRCA1 mutation carriers or controls. As a result, there was no requirement for dose reduction among BRCA2 mutation carriers, in contrast to 10 of 39 BRCA1 carriers and 16 of 62 controls (P = 0.02). CONCLUSIONS: This result has implications for therapy and indicates that women with mutations in BRCA1 and BRCA2 may be given the same doses of chemotherapy as noncarriers.

Adult↗
PubMed2006

Evaluation of BRCA1 and BRCA2 mutation prevalence, risk prediction models and a multistep testing approach in French-Canadian families with high risk of breast and ovarian cancer.

BACKGROUND AND OBJECTIVE: In clinical settings with fixed resources allocated to predictive genetic testing for high-risk cancer predisposition genes, optimal strategies for mutation screening programmes are critically important. These depend on the mutation spectrum found in the population under consideration and the frequency of mutations detected as a function of the personal and family history of cancer, which are both affected by the presence of founder mutations and demographic characteristics of the underlying population. The results of multistep genetic testing for mutations in BRCA1 or BRCA2 in a large series of families with breast cancer in the French-Canadian population of Quebec, Canada are reported. METHODS: A total of 256 high-risk families were ascertained from regional familial cancer clinics throughout the province of Quebec. Initially, families were tested for a panel of specific mutations known to occur in this population. Families in which no mutation was identified were then comprehensively tested. Three algorithms to predict the presence of mutations were evaluated, including the prevalence tables provided by Myriad Genetics Laboratories, the Manchester Scoring System and a logistic regression approach based on the data from this study. RESULTS: 8 of the 15 distinct mutations found in 62 BRCA1/BRCA2-positive families had never been previously reported in this population, whereas 82% carried 1 of the 4 mutations currently observed in > or =2 families. In the subset of 191 families in which at least 1 affected individual was tested, 29% carried a mutation. Of these 27 BRCA1-positive and 29 BRCA2-positive families, 48 (86%) were found to harbour a mutation detected by the initial test. Among the remaining 143 inconclusive families, all 8 families found to have a mutation after complete sequencing had Manchester Scores > or =18. The logistic regression and Manchester Scores provided equal predictive power, and both were significantly better than the Myriad Genetics Laboratories prevalence tables (p<0.001). A threshold of Manchester Score > or =18 provided an overall sensitivity of 86% and a specificity of 82%, with a positive predictive value of 66% in this population. CONCLUSION: In this population, a testing strategy with an initial test using a panel of reported recurrent mutations, followed by full sequencing in families with Manchester Scores > or =18, represents an efficient test in terms of overall cost and sensitivity.

Adolescent↗
PubMed2006

BRCA1/BRCA2 mutation status and analysis of cancer family history in participants of the Royal Marsden Hospital tamoxifen chemoprevention trial.

We have analysed the pedigrees of all 70 women who developed cancer in the Royal Marsden Hospital (RMH) tamoxifen chemoprevention trial, using the Claus model, to assess breast cancer susceptibility heterozygote risk (HR) and screened the entire coding regions of BRCA1 and 2 genes in 62 of these cases. We found a reduced incidence of breast cancers developing on tamoxifen in women who have a lower HR, but not in women with higher HR. There were too few BRCA1/2 mutations (4 cases) to be able to determine the efficacy of tamoxifen by BRCA status. Immunohistochemical analysis showed a significantly lower frequency of median ER (p=0.03) in the cancers developing in tamoxifen-treated patients. These results suggest that tamoxifen is less likely to be effective at reducing breast cancers which are ER negative and also in some individuals at higher HR.

Breast Neoplasms↗
PubMed2006

Genetic and histopathologic evaluation of BRCA1 and BRCA2 DNA sequence variants of unknown clinical significance.

Classification of rare missense variants as neutral or disease causing is a challenge and has important implications for genetic counseling. A multifactorial likelihood model for classification of unclassified variants in BRCA1 and BRCA2 has previously been developed, which uses data on co-occurrence of the unclassified variant with pathogenic mutations in the same gene, cosegregation of the unclassified variant with affected status, and Grantham analysis of the fit between the missense substitution and the evolutionary range of variation observed at its position in the protein. We have further developed this model to take into account relevant features of BRCA1- and BRCA2-associated tumors, such as the characteristic histopathology and immunochemical profiles associated with pathogenic mutations in BRCA1, and the fact that approximately 80% of tumors from BRCA1 and BRCA2 carriers undergo inactivation of the wild-type allele by loss of heterozygosity. We examined 10 BRCA1 and 15 BRCA2 unclassified variants identified in Australian, multiple-case breast cancer families. By a combination of genetic, in silico, and histopathologic analyses, we were able to classify one BRCA1 variant as pathogenic and six BRCA1 and seven BRCA2 variants as neutral. Five of these neutral variants were also found in at least 1 of 180 healthy controls, suggesting that screening a large number of appropriate controls might be a useful adjunct to other methods for evaluation of unclassified variants.

Alleles↗
PubMed2006

Associations among mammographic density, circulating sex hormones, and polymorphisms in sex hormone metabolism genes in postmenopausal women.

Mammographic density and serum sex hormone levels are important risk factors for breast cancer, but their associations with one another are unclear. We studied these phenotypes, together with single nucleotide polymorphisms (SNP) in genes related to sex hormone metabolism, in a cross-sectional study of 1,413 postmenopausal women from the European Prospective Investigation into Cancer and Nutrition-Norfolk. All women were >1 year postmenopausal and had not taken hormone replacement therapy for >3 months before sampling. Serum levels of 7 sex hormones [estradiol, testosterone, sex hormone-binding globulin (SHBG), androstenedione, 17-OH-progesterone, estrone, and estrone sulfate] and 15 SNPs in the CYP17, CYP19, EDH17B2, SHBG, COMT, and CYP1B1 genes were studied. Mammograms nearest in time to the blood sampling were identified through the national breast screening program and visually assessed by three radiologists using the Boyd six-category and Wolfe four-category scales. We found a weak positive association between mammographic density and SHBG levels (P = 0.09) but no association with any other hormones. None of the SNPs, including those shown previously to be associated with estradiol or SHBG, showed significant associations with density. We conclude that mammographic density is largely independent of postmenopausal steroid hormone levels, indicating that these risk factors have, to a large extent, an independent etiology and suggesting that they may be independent predictors of breast cancer risk.

Aged↗
PubMed2004

CHEK2 variant I157T may be associated with increased breast cancer risk.

Cell cycle checkpoint kinase 2 (CHEK2) is a transducer of cellular responses to DNA damage. The CHEK2 1100delC has previously been shown to be a low-penetrance breast cancer susceptibility allele. We have evaluated the role of another CHEK2 variant, I157T in the FHA domain of the gene, for association with breast cancer. I157T was found at a significantly higher frequency in the population-based series of breast cancer patients (77/1035, 7.4%, odds ratio [OR] = 1.43, 95% confidence interval [CI] = 1.06-1.95, p = 0.021) than among population controls (100/1885, 5.3%). The frequency in the familial breast cancer patients was not elevated (28/507, 5.5%, OR = 1.04, 95% CI = 0.68-1.61). The I157T protein, that undermines cellular responses to ionizing radiation and shows deficiency in substrate recognition in vivo, was expressed at normal level in tumor tissues as well as in cultured cells. The I157T protein was stable and it dimerized with the wild-type CHEK2 co-expressed in human cells. These functional properties of the I157T protein suggest that this variant may have negative effect on the pool of normal CHEK2 protein in heterozygous carrier cells by formation of heterodimers with wild-type CHEK2. The I157T variant may be associated with breast cancer risk, but the risk is lower than for 1100delC.

Breast Neoplasms↗
PubMed2004

Mutations in the DLG3 gene cause nonsyndromic X-linked mental retardation.

We have identified truncating mutations in the human DLG3 (neuroendocrine dlg) gene in 4 of 329 families with moderate to severe X-linked mental retardation. DLG3 encodes synapse-associated protein 102 (SAP102), a member of the membrane-associated guanylate kinase protein family. Neuronal SAP102 is expressed during early brain development and is localized to the postsynaptic density of excitatory synapses. It is composed of three amino-terminal PDZ domains, an src homology domain, and a carboxyl-terminal guanylate kinase domain. The PDZ domains interact directly with the NR2 subunits of the NMDA glutamate receptor and with other proteins responsible for NMDA receptor localization, immobilization, and signaling. The mutations identified in this study all introduce premature stop codons within or before the third PDZ domain, and it is likely that this impairs the ability of SAP102 to interact with the NMDA receptor and/or other proteins involved in downstream NMDA receptor signaling pathways. NMDA receptors have been implicated in the induction of certain forms of synaptic plasticity, such as long-term potentiation and long-term depression, and these changes in synaptic efficacy have been proposed as neural mechanisms underlying memory and learning. The disruption of NMDA receptor targeting or signaling, as a result of the loss of SAP102, may lead to altered synaptic plasticity and may explain the intellectual impairment observed in individuals with DLG3 mutations.

Base Sequence↗
PubMed2004

Lifetime risks of common cancers among retinoblastoma survivors.

BACKGROUND: Compared with the general population, carriers of germline mutations in RB1 who survive retinoblastoma (i.e., hereditary retinoblastoma survivors) are at increased risk of early-onset second cancers, particularly sarcomas, brain tumors, and melanoma. However, their risks for the epithelial cancers that commonly occur after age 50 years are not known. METHODS: We used hospital records to identify British retinoblastoma survivors born between 1873 and 1950, a period when few British retinoblastoma patients received high-dose radiotherapy. Cancers and deaths were identified by linkage with national registration records. All statistical tests were two-sided. RESULTS: We could trace the cancer histories of 144 survivors of hereditary retinoblastoma. From age 25 to age 84, there were 58 subsequent cancers, for a cumulative cancer incidence of 68.8% (95% confidence interval [CI] = 48.0% to 87.4%) and a cumulative cancer mortality of 56.3% (95% CI = 40.5% to 73.3%). Only eight of the 58 cancers were of bone or soft tissue, in marked contrast to findings from contemporary studies of American patients treated with external beam radiotherapy, among whom most second tumors are sarcomas. Compared with the general population, hereditary retinoblastoma survivors had higher mortality from lung cancer (standardized mortality ratio [SMR] = 7.01, 95% CI = 3.83 to 11.76), bladder cancer (SMR = 26.31, 95% CI = 8.54 to 61.41), and all other epithelial cancers combined (SMR = 3.29, 95% CI = 1.64 to 5.89). The overall standardized mortality ratio for epithelial cancer was inversely proportional to the approximate square of age (exponent of age = -2.1, 95% CI = -3.6 to -0.7), declining from 11.32 (95% CI = 4.15 to 24.64) at age 25-44 to 2.83 (95% CI = 1.04 to 6.16) at age 65-84. CONCLUSIONS: Survivors of hereditary retinoblastoma who are not exposed to high-dose radiotherapy have a high lifetime risk of developing a late-onset epithelial cancer. Most of the excess cancer risks in hereditary retinoblastoma survivors might be preventable by limiting exposures to DNA damaging agents (radiotherapy, tobacco, and UV light).

Adult↗
PubMed2004

The genetic epidemiology of breast cancer genes.

Genetic susceptibility to breast cancer in women is conferred by a large number of genes, of which six have so far been identified. In the context of multiple-case families, BRCA1 and BRCA2 are the most important. Mutations in these genes confer high lifetime risks of breast cancer and ovarian cancer, and more moderate risks of prostate cancer and some other cancer types. Mutations in the CHEK2 and ATM genes, by contrast, cause much more modest (2-4 fold) risks of breast cancer. Genes so far identified explain approximately 20% of the familial aggregation of breast cancer. The remaining susceptibility genes have, so far, proved illusive, suggesting that they are numerous and confer moderate risks. A variety of techniques including genome-wide association studies, use of quantitative intermediate endpoints, and resequencing of genes may be required to identify them. The identification of such genes can provide a basis for targeted prevention of breast cancer.

Ataxia Telangiectasia↗
PubMed2002

Low-penetrance susceptibility to breast cancer due to CHEK2(*)1100delC in noncarriers of BRCA1 or BRCA2 mutations.

Mutations in BRCA1 and BRCA2 confer a high risk of breast and ovarian cancer, but account for only a small fraction of breast cancer susceptibility. To find additional genes conferring susceptibility to breast cancer, we analyzed CHEK2 (also known as CHK2), which encodes a cell-cycle checkpoint kinase that is implicated in DNA repair processes involving BRCA1 and p53 (refs 3,4,5). We show that CHEK2(*)1100delC, a truncating variant that abrogates the kinase activity, has a frequency of 1.1% in healthy individuals. However, this variant is present in 5.1% of individuals with breast cancer from 718 families that do not carry mutations in BRCA1 or BRCA2 (P = 0.00000003), including 13.5% of individuals from families with male breast cancer (P = 0.00015). We estimate that the CHEK2(*)1100delC variant results in an approximately twofold increase of breast cancer risk in women and a tenfold increase of risk in men. By contrast, the variant confers no increased cancer risk in carriers of BRCA1 or BRCA2 mutations. This suggests that the biological mechanisms underlying the elevated risk of breast cancer in CHEK2 mutation carriers are already subverted in carriers of BRCA1 or BRCA2 mutations, which is consistent with participation of the encoded proteins in the same pathway.

Breast Neoplasms↗
PubMed2002

Variation in BRCA1 cancer risks by mutation position.

Previous studies have reported variation in BRCA1 breast and ovarian cancer risks with mutation position, suggesting that mutations toward the 3' end of the gene are associated with lower ovarian cancer risks. We evaluated the evidence for genotype-phenotype correlations in 356 families with protein-truncating BRCA1 mutations. In contrast to previous reports, the ovarian:breast cancer ratio associated with mutations in a central region of the gene (nucleotides 2401-4190) was significantly higher than for other mutations [odds ratio, 1.70 (P = 0.017) compared with nucleotides 1-2400; odds ratio, 1.89 (P = 0.02) compared with nucleotides 4191-end]. The risks of breast and ovarian cancer conferred by mutations in different regions of the gene were estimated separately by conditional maximum likelihood. According to the best fitting model, the breast cancer risk associated with mutations in the central region was found to be significantly lower than for other mutations (relative risk, 0.71; 95% confidence interval, 0.58-0.86; P = 0.0002), whereas the ovarian cancer risk associated with mutations 3' to nucleotide 4191 was significantly reduced relative to the rest of the gene (relative risk, 0.81; 95% confidence interval, 0.66-1.00; P = 0.044). The cancer risks associated with missense mutations in the RING domain in exon 5 appear to be similar to those associated with protein-truncating mutations toward the 3' end of BRCA1, based on nine additional families.

Aged↗