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Fiona Lalloo

Publications and source records attributed to Fiona Lalloo.

13 recordsLinked to original sources
PubMed2007

Functional characterization of GATA3 mutations causing the hypoparathyroidism-deafness-renal (HDR) dysplasia syndrome: insight into mechanisms of DNA binding by the GATA3 transcription factor.

The hypoparathyroidism-deafness-renal (HDR) dysplasia syndrome is an autosomal dominant disorder caused by mutations of the dual zinc finger transcription factor, GATA3. We investigated 21 HDR probands and 14 patients with isolated hypoparathyroidism for GATA3 abnormalities. Thirteen different heterozygous germline mutations were identified in patients with HDR. These consisted of three nonsense mutations, six frameshifting deletions, two frameshifting insertions, one missense (Leu348Arg) mutation and one acceptor splice site mutation. The splice site mutation was demonstrated to cause a pre-mRNA processing abnormality leading to the use of an alternative acceptor site 8 bp downstream of the normal site, resulting in a frameshift and prematurely terminated protein. Electrophoretic mobility shift assays (EMSAs) revealed three classes of GATA3 mutations: those that lead to a loss of DNA binding which represent over 90% of all mutations, and involved a loss of the carboxy-terminal zinc finger; those that resulted in a reduced DNA-binding affinity; and those (e.g. Leu348Arg) that did not alter DNA binding or the affinity but likely altered the conformational change that occurs during binding in the DNA major groove as predicted by a three-dimensional modeling. These results elucidate further the molecular mechanisms underlying the altered functions of mutants of this zinc finger transcription factor and their role in causing this developmental anomaly. No mutations were identified in patients with isolated hypoparathyroidism, thereby indicating that GATA3 abnormalities are more likely to result in two or more of the phenotypic features of the HDR syndrome and not in one, such as isolated hypoparathyroidism.

Abnormalities, Multiple↗
PubMed2007

Familial colorectal cancer referral to regional genetics department--a single centre experience.

Evaluation of familial colorectal cancer referral can assist in the planning of future cancer surveillance. The aim of the study is to assess colorectal cancer referral pattern to our regional genetics service. Hospital computer records and/or department referral books were used to identify cases referred to the regional genetic service during a 10-year period (1992-2001 inclusive). All files were reviewed along with associated demographic data, risk assessments, referral details, results from mutation testing and screening recommendations. In terms of result, a total of 1100 family files were reviewed (Familial Adenomatous Polyposis families were in a separate register). The number of referrals showed a 10-fold increase over the 10 years. 171 (15.6%) of families met the Amsterdam criteria II were classified as high-risk, 589 (53.5%) families were classified as moderate-risk and 337 (31.0%) as average or low risk. 22.9% families were referred with inaccurate cancer history. Sixty-one families have been identified with mismatch repair mutations. 56.8% of referred individuals were recommended to have regular colonoscopy ranging from 18 monthly to 5 yearly depending on their risks. In conclusion, there has been a 10-fold increase in individuals with suspected hereditary bowel cancer referred to the North West Regional Genetics Service in the last ten years. Genetic assessment may reduce the number of low-risk individuals and those who were found not to be mutation carriers from having unnecessary colonoscopic screening. Thus genetic risk assessment should precede the initiation of regular endoscopic screening.

Adult↗
PubMed2006

BRCA1, BRCA2 and TP53 mutations in very early-onset breast cancer with associated risks to relatives.

Pathological mutations in BRCA1, BRCA2 and TP53 are associated with an increased risk of breast cancer. This study evaluated mutation frequency of these genes in early-onset breast cancer patients, and correlated this with family history and determined relative risks to family members. Patients with breast adenocarcinoma diagnosed 30 years were ascertained between 1980 and 1997. Family history was established and mutation screening of BRCA1, BRCA2 and TP53 genes was performed. Estimates of penetrance and relative risk were undertaken. DNA was obtained from 100/139 women. 17/36 familial cases had a BRCA1, BRCA2 or TP53 mutation. Of 64 non-familial cases, one BRCA2, two BRCA1 and two TP53 mutations were detected. Penetrance estimates (by age 70) for breast cancer were 84% for BRCA1 mutations and 91% for BRCA2 mutations and for ovarian cancer, 60% and 26%, respectively. Relative risks associated with mutations were consistent with previous studies. BRCA1 and BRCA2 mutations in patients with breast cancer 30 years are predicted strongly by family history. The majority of families with ovarian cancer were due to mutations in BRCA1/2 whereas these mutations only accounted for 30-50% of the excess breast cancers.

Adenocarcinoma↗
PubMed2006

Parity and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

INTRODUCTION: Increasing parity and age at first full-term pregnancy are established risk factors for breast cancer in the general population. However, their effects among BRCA1 and BRCA2 mutation carriers is still under debate. We used retrospective data on BRCA1 and BRCA2 mutation carriers from the UK to assess the effects of parity-related variables on breast cancer risk. METHODS: The data set included 457 mutation carriers who developed breast cancer (cases) and 332 healthy mutation carriers (controls), ascertained through families seen in genetic clinics. Hazard ratios were estimated by using a weighted cohort approach. RESULTS: Parous BRCA1 and BRCA2 mutation carriers were at a significantly lower risk of developing breast cancer (hazard ratio 0.54, 95% confidence interval 0.37 to 0.81; p = 0.002). The protective effect was observed only among carriers who were older than 40 years. Increasing age at first live birth was associated with an increased breast cancer risk among BRCA2 mutation carriers (p trend = 0.002) but not BRCA1 carriers. However, the analysis by age at first live birth was based on small numbers. CONCLUSION: The results suggest that the relative risks of breast cancer associated with parity among BRCA1 and BRCA2 mutation carriers may be similar to those in the general population and that reproductive history may be used to improve risk prediction in carriers.

Adult↗
PubMed2005

Prediction of BRCA1 status in patients with breast cancer using estrogen receptor and basal phenotype.

PURPOSE: To investigate the proportion of breast cancers arising in patients with germ line BRCA1 and BRCA2 mutations expressing basal markers and developing predictive tests for identification of high-risk patients. EXPERIMENTAL DESIGN: Histopathologic material from 182 tumors in BRCA1 mutation carriers, 63 BRCA2 carriers, and 109 controls, collected as part of the international Breast Cancer Linkage Consortium were immunohistochemically stained for CK14, CK5/6, CK17, epidermal growth factor receptor (EGFR), and osteonectin. RESULTS: All five basal markers were commoner in BRCA1 tumors than in control tumors (CK14: 61% versus 12%; CK5/6: 58% versus 7%; CK17: 53% versus 10%; osteonectin: 43% versus 19%; EGFR: 67% versus 21%; P < 0.0001 in each case). In a multivariate analysis, CK14, CK5/6, and estrogen receptor (ER) remained significant predictors of BRCA1 carrier status. In contrast, the frequency of basal markers in BRCA2 tumors did not differ significant from controls. CONCLUSION: The use of cytokeratin staining in combination with ER and morphology provides a more accurate predictor of BRCA1 mutation status than previously available, that may be useful in selecting patients for BRCA1 mutation testing. The high percentage of BRCA1 cases positive for EGFR suggests that specific anti-tyrosine kinase therapy may be of potential benefit in these patients.

Biomarkers, Tumor↗
PubMed2004

BRCA1/2 predictive testing: a study of uptake in two centres.

Differences in reported uptake of genetic testing for mutations in BRCA1 and BRCA2 can largely be accounted for by different methodologies and by studying research vs nonresearch families. In our joint study of 75 nonresearch families from two UK centres in which at least 3 years had elapsed since the initial proband had been informed of the availability of testing, only 45 and 34% of eligible individuals from Manchester and London, respectively, had come forward for counselling. Final uptake rates using a non-proactive approach were 53 and 29% for women and 11-12% for men, but the figure among those attending clinic was 73 and 62%, respectively. Unlike previous studies, we did not find that uptake had stabilised after a year with 25% of those being tested more than 2 years after the family was informed, and several delaying a considerable time between genetics appointments. We believe that the particularly low uptake even of counselling in men may need to be addressed by improving family communication or providing information sheets for family members to disseminate.

Female↗
PubMed2003

Prediction of pathogenic mutations in patients with early-onset breast cancer by family history.

We aimed to assess frequency and penetrance of BRCA1, BRCA2,and TP53 mutations in women diagnosed with breast cancer aged 30 years or younger, and then correlate this frequency with family history. 17 of 36 familial cases had a BRCA1, BRCA2, or TP53 mutation, compared with three of 63 non-familial cases. The calculated population frequency of TP53 mutations was one in 5000, substantially greater than previous estimates. This finding underlines the importance of accurate elucidation of a family history from young women diagnosed with breast cancer. Establishment of family history could help with development of patient-specific management and tumour surveillance protocols.

Adult↗
PubMed2003

Genetic analysis of mitochondrial complex II subunits SDHD, SDHB and SDHC in paraganglioma and phaeochromocytoma susceptibility.

BACKGROUND: Germline mutations in three subunits of mitochondrial complex II (SDHB, SDHC and SDHD) may be associated with susceptibility to phaeochromocytoma (PC) and/or head and neck paraganglioma (HNPGL). METHODS: To further define the role of SDH subunit mutations in these disorders, we analysed a series of 22 probands with PC and evidence of genetic susceptibility (seven with familial PC only, one with familial PC and HNPGL, 10 sporadic cases with multiple PC and four cases of isolated paediatric onset PC) for germline SDHB, SDHC and SDHD mutations. In addition, we analysed 34 cases of HNPGL (30 isolated cases with single tumours, three isolated cases with multiple tumours and one familial case with multiple tumours) for somatic and germline mutations in SDHB, SDHC and SDHD. RESULTS: We identified four germline mutations (three SDHB and one SDHD, three novel) in the 22 PC probands. Combining these results with our previous series, we have detected germline SDHB or SDHD mutations in 2/12 (17%) of familial PC only kindreds, 4/5 (80%) of familial PC and HNPGL cases, 1/10 of sporadic multiple PC cases and 2/4 (50%) of paediatric PCs. No somatic mutations were detected in the HNPGL tumours, but four cases with multiple HNPGL had the common P81L germline SDHD mutation. Intriguingly a silent SNP (c.204C > T) in SDHD was significantly more common in HNPGL cases (6/34) than in controls (1/100, P = 0.0011). Combining our results with those from two other large studies in which both SDHB and SDHD have been analysed, SDHB mutations were most commonly associated with phaeochromocytoma susceptibility and SDHD with the development of HNPGL (P = 0.025). However, germline SDHB and SDHD mutations demonstrate considerable phenotypic variability and genotype-phenotype correlations are complex. CONCLUSION: The significantly lower frequency (P = 0.028) of germline SDH subunit mutations in familial PC only cases compared to those with familial PC and HNPGL suggests that further PC susceptibility gene(s) remain to be identified.

Adolescent↗
PubMed2003

Do women understand the odds? Risk perceptions and recall of risk information in women with a family history of breast cancer.

OBJECTIVES: To describe and compare women's risk perceptions and recall of breast cancer risk information in a cohort of first-time attendees at a family history clinic. METHODS: We conducted a 1-year prospective study of 158 women aged 18-45 years with a confirmed lifetime risk of breast cancer of 1 in 6 or greater. Risk perception and recall were assessed using a self-report questionnaire, completed pre-counselling and 3, 6, 9 and 12 months post-counselling, and through interviews conducted at 3 and 12 months. RESULTS: The proportion of women with accurate personal risk perceptions based on 'gambling' odds ('1 chance in x') significantly improved after risk counselling from 12% pre-counselling to 67% 3 months post-counselling (p < 0.001), which was maintained for 1 year. This was the method of reporting perceived risk associated with the best level of risk accuracy and the women's preferred format for describing risk, but the concept of lifetime risk was understood by only 44% of women. Qualitative risk categories ('high', moderate' or 'low') correlated significantly with women's self-reported odds values, but each category comprised a wide range of women's perceived numeric risks. Describing risk as the 'likelihood of breast cancer' resulted in a broad and somewhat inaccurate reporting of risk, compared with numeric ratings made at the same time. There was an increase of up to 4-fold in the proportion of women who failed to recall their risk value over time, and women were unable to accurately put the breast cancer risk in context compared with other health threats. CONCLUSIONS: All methods of describing risk have limitations, but the results of the present study provide good support for women's accurate recall of numeric risk values and their preference for use of these 'gambling' odds. This may have been influenced by consistency of the use of this method both in risk communication and in personal summary letters. Descriptive risk formats reflected higher levels of perceived vulnerability to breast cancer, and genetic counsellors need to be aware of these different perceptions.

Adolescent↗
PubMed2002

Survival in prospectively ascertained familial breast cancer: analysis of a series stratified by tumour characteristics, BRCA mutations and oophorectomy.

Dedicated clinics have been established for the early diagnosis and treatment of women at risk for inherited breast cancer, but the effects of such interventions are currently unproven. This second report on prospectively diagnosed inherited breast cancer from the European collaborating centres supports the previous conclusions and adds information on genetic heterogeneity and the effect of oophorectomy. Of 249 patients, 20% had carcinoma in situ (CIS), 54% had infiltrating cancer without spread (CaN0) and 26% had cancer with spread (CaN+). Five-year survival was 100% for CIS, 94% for CaN0 and 72% for CaN+ (p = 0.007). Thirty-six patients had BRCA1 mutations, and 8 had BRCA2 mutations. Presence of BRCA1 mutation was associated with infiltrating cancer, high grade and lack of oestrogen receptor (p < 0.05 for all 3 characteristics). For BRCA1 mutation carriers, 5-year survival was 63% vs. 91% for noncarriers (p = 0.04). For CaN0 patients, mutation carriers had 75% 5-year disease-free survival vs. 96% for noncarriers (p = 0.01). Twenty-one of the mutation carriers had undergone prophylactic oophorectomy, prior to or within 6 months of diagnosis in 13 cases. All but 1 relapse occurred in the 15 who had kept their ovaries, (p < 0.01); no relapse occurred in those who had removed the ovaries within 6 months (p = 0.04) Contralateral cancer was more frequently observed in mutation noncarriers, but this finding did not reach statistical significance. Our findings support the concept that BRCA1 cancer is biologically different from other inherited breast cancers. While current screening protocols appear satisfactory for the majority of women at risk of familial breast cancer, this may not be the case for BRCA1 mutation carriers. The observed effect of oophorectomy was striking.

Adult↗