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Biomedical subjects

H Sobol

Publications and source records attributed to H Sobol.

At least 19 recordsLinked to original sources
PubMed2001

Localization of a susceptibility gene for familial nonmedullary thyroid carcinoma to chromosome 2q21.

The familial form of nonmedullary thyroid carcinoma (NMTC) is a complex genetic disorder characterized by multifocal neoplasia and a higher degree of aggressiveness than its sporadic counterpart. In a large Tasmanian pedigree (Tas1) with recurrence of papillary thyroid carcinoma (PTC), the most common form of NMTC, an extensive genomewide scan revealed a common haplotype on chromosome 2q21 in seven of the eight patients with PTC. To verify the significance of the 2q21 locus, we performed linkage analysis in an independent sample set of 80 pedigrees, yielding a multipoint heterogeneity LOD score (HLOD) of 3.07 (alpha=0.42), nonparametric linkage (NPL) 3.19, (P=.001) at marker D2S2271. Stratification based on the presence of at least one case of the follicular variant of PTC, the phenotype observed in the Tas1 family, identified 17 such pedigrees, yielding a maximal HLOD score of 4.17 (alpha=0.80) and NPL=4.99 (P=.00002) at markers AFMa272zg9 and D2S2271, respectively. These results indicate the existence of a susceptibility locus for familial NMTC on chromosome 2q21.

Carcinoma, Papillary↗
PubMed2001

Tamoxifen and breast cancer risk in women harboring a BRCA1 germline mutation: computed efficacy, effectiveness and impact.

The management of breast cancer prone women remains a tough issue despite the release of institutional guidelines. Currently, only the anti-estrogen agent Tamoxifen and prophylactic surgery are claimed to decrease breast cancer incidence. However, efficacy of Tamoxifen, particularly in BRCA1 gene carriers, remains controversial and acceptability of prophylactic surgery is low. To evaluate the expected impact of Tamoxifen in preventing hereditary breast cancers, a modelling was made according to the efficacy of the treatment with respect to biological predictors of response: estrogen receptor (ER) and pS2 status of a series of 33 BRCA1-related breast cancers (BRCA1-BCs), and using data on BRCA1-BCs penetrance, as well as compliance and acceptability of the strategy. Although, 88% of BRCA1-BCs are ER negative in our series, 30% of cases are pS2 positive, implying a potential hormonal sensitivity of a proportion of these cancers. From our modelling, the expected impact of Tamoxifen in BRCA1 gene carriers is a reduction of breast cancer incidence of about 10% according to acceptability and compliance, close to that of 5% and of 13.5% for prophylactic mastectomy, according to acceptability rates from US and French surveys respectively. Since autonomy of choice is the root of western ethics, cancer prone women should be informed about the low but valuable expected reduction of incidence of breast cancer using Tamoxifen preventive therapy.

Antineoplastic Agents, Hormonal↗
PubMed2001

Diagnostic strategy for analytical scanning of BRCA1 gene by fluorescence-assisted mismatch analysis using large, bifluorescently labeled amplicons.

The aim of this study was to develop a protocol for reliable, sensitive, and cost-effective mutation scanning of the BRCA1 gene, based on a modification of fluorescence-assisted mismatch analysis. The main features of this method are: (a) robust PCR amplification and strandspecific labeling of 25 large amplicons using uniform conditions and universal fluorescent primers; and (b) sensitive characterization of the position of sequence changes. The diagnostic accuracy of this method was tested by scanning the large exon 11 in 12 DNA samples with reported mutations. In a blind test, specific patterns of fluorescence profiles were obtained, and all were attributed correctly, without sequencing, to each mutation or polymorphism. Seven breast/ovarian cancer families with high probability of BRCA1-related predisposition were screened. Three truncating mutations (of which one was novel and three were missense changes, including two novel ones) were detected. The three missense mutations affect the highly conserved BRCT domain. Scanning by FAMA appears to be free of biases for particular types of sequence changes-except for exon deletions/duplications, which cannot be detected by conventional PCR-based methods-and allows substantial savings in the number of sequencing reactions and in the time invested in their interpretation. Therefore, it lends itself to screening structurally complex loci in the diagnostic context and in other fields of genetic analysis.

Base Pair Mismatch↗
PubMed2000

Disclosure to the family of breast/ovarian cancer genetic test results: patient's willingness and associated factors.

Informed probands are key actors for disclosing genetic information to their relatives when a mutation has been identified in the family. The objectives were to study women's attitudes towards the family disclosure of positive breast cancer genetic testing results and to determine the predictive factors of the diffusion patterns observed. A national multi-center cross-sectional survey was carried out at five French cancer genetic clinics during a 1-year period. Self-administered questionnaires were completed after the consultation by 84.5% (398/471) of women attending breast cancer genetic clinics for the first time. Among the 383 respondents who had at least one living first-degree relative to inform, 8.6% would inform none, 33.2% would inform at least one of them, and 58.2% would inform all of them. The sibship would be the most frequently informed blood relatives, sisters in 86.9% and brothers in 79% compared with mother in 71.4%, children in 70.4%, and father in 64.9%. Women of the family would be more frequently informed than men (P < 0.05). After multivariate adjustment, age, the fact to be affected by cancer, the number of daughters, and the emotional disturbance due to cancer in a close relationship were the main determinants (P < 0.05) of the diffusion patterns observed. The first step of the relatives' attendance to genetic counseling and the proband's willingness to disclose breast cancer genetic tests results was high in this study and was clearly dependent on the women's personal and emotional characteristics.

Adult↗
PubMed2000

Major improvement in the efficacy of BRCA1 mutation screening using morphoclinical features of breast cancer.

A family history of breast and/or ovarian cancer is the main criterion used in screening BRCA1 gene carriers. However, ascertaining a patient's family history is a difficult task, which significantly restricts the use of this parameter in clinical practice. Alternative individual criteria that can be used to identity BRCA1 gene carriers would, therefore, be of great value. In this context, it was recently established that BRCA1-associated breast cancers (BRCA1-BCs) show a specific morphoclinical pattern. In multivariate analyses, the two most discriminant morphoclinical parameters available for establishing the BRCA1 status, in addition to an early age at onset, are estrogen receptor negativity (ER-) and poor tumor differentiation (TD3). Here we tested the efficacy of these two morphological parameters as BRCA1 mutation indicators and investigated their economic impact, in a population-based survey on a series of women who developed invasive breast cancer by the age of 35 years, regardless of their family history. A high rate of 28.6% of BRCA1 mutations was found to have occurred in the group of tumors with both ER- and TD3 versus only 3.6% in tumors with other profiles (P = 0.007; odds ratio, 10.8). When the sole criterion used was early onset by the age of 35 years, the mutation rate was found to be 8.6%. The resulting cost of testing only women with ER- and TD3 tumors worked out at 30% that of testing the whole population of women with cancer by the age of 35 years, and the sensitivity was found to be of 66%. Lastly, the family history of ER- and TD3 cases with a BRCA1 mutation was investigated retrospectively, and none of these cases was found to have a particularly extensive family history of breast and/or ovarian cancer. The use of these morphological features of BRCA1-BCs that are currently typed in clinical practice, therefore, provides a helpful and cost-effective tool for those making decisions about genetic screening. This strategy makes it possible to identify gene carriers who would be overlooked using current criteria.

Adult↗
PubMed2000

Physicians' attitudes towards mammography and prophylactic surgery for hereditary breast/ovarian cancer risk and subsequently published guidelines.

After a BRCA mutation has been identified in the context of hereditary breast/ovarian cancer (HBOC), mammographic screening and prophylactic surgery are two of the main options available to those responsible for the clinical management of healthy women. The aim of this study was to describe the attitudes of specialists towards the clinical management of women with an HBOC risk: this information was collected prior to the publication of the recent French guidelines. A random national sample of 1169 French surgeons, gynaecologists and obstetricians was surveyed using a mailed questionnaire, to which 700 of these physicians (60%) responded. When dealing with a BRCA mutated woman, 88.6% of the respondents said they would recommend mammographic screening, but only 27.1% would recommend that it should be carried out annually from the age of 30 years onwards, as recommended in the French guidelines; 10.9% would find it acceptable to propose prophylactic mastectomy from the age of 30 years, and 22.9% would find it acceptable to propose prophylactic oophorectomy from the age of 35 years. The specialists who agreed with recommending breast/ovarian cancer genetic testing also had more positive attitudes towards prophylactic mastectomy (adj OR = 3.4, 95% CI = 1.4-8.2), as did those who had previously recommended prophylactic mastectomy when gene testing was not yet available (adj OR = 2.06, 95% CI = 1.23-3.44). The respondents' attitudes towards prophylactic oophorectomy and mastectomy were significantly associated (adj OR = 3.9; 95% CI = 2.3-6.5). Previous recommendation of prophylactic mastectomy was associated (P < 0.01) with a higher level of knowledge of breast/ovarian cancer genetics and with medical practice in this field. French physicians' attitudes towards mammographic screening and prophylactic surgery were not in complete agreement with the subsequently published French guidelines, the impact of which has now to be considered. Constantly evolving knowledge about the efficacy of preventive intervention will give practitioners new elements to integrate into their counselling.

Attitude of Health Personnel↗
PubMed2000

Translocation and coamplification of loci from chromosome arms 8p and 11q in the MDA-MB-175 mammary carcinoma cell line.

Rearrangement and coamplification of the 8p12 and 11q13 chromosomal regions occurs in a significant proportion of breast cancers. It usually involves a complex hybrid structure in which the FGFR1 and CCND1 genes are amplified. We report here a different type of 8p12-11q13 rearrangement in the MDA-MB-175 mammary carcinoma cell line. This amplification contains the NRG1/HGL (from 8p12-21) and DOC4 (from 11q13) genes, encoding respectively a ligand for ERBB receptors and a stress-induced protein which is a mammalian ortholog of Drosophila Tenm/Odz. It has been shown previously (Wang et al, Oncogene 18: 5718-5721, 1999) that these two genes are rearranged and fused by a translocation event. This type of event was not found in 30 tumors tested that showed coamplification of the 8p12 and 11q13 regions.

Breast Neoplasms↗