Reproductive decision-making in young female carriers of a BRCA mutation.

STUDY QUESTION: How do young women, who were identified as carrying a BRCA gene mutation before they had children, approach reproductive decision-making and what are their attitudes towards reproductive genetic testing? SUMMARY ANSWER: Reproductive decision-making within the context of cancer risk is complex and influenced by personal experiences of cancer. Younger women were not concerned with reproductive decision-making at the time of their genetic test; however, the impact on subsequent reproductive decision-making was considerable and left them with unanticipated dilemmas, such as having children who would be at risk of inheriting cancer predisposition, timing risk-reducing surgery and changing perceptions of responsibility. WHAT IS KNOWN ALREADY: Individuals carrying gene mutations predisposing to hereditary breast/ovarian cancer have concerns about passing on the gene mutation to children. STUDY DESIGN, SIZE, DURATION: Qualitative methodology and thematic analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data were collected through semi-structured interviews with 25 women aged 18-45 who had received a positive result for a BRCA1 or BRCA2 gene mutation while childless. MAIN RESULTS AND THE ROLE OF CHANCE: Analysis revealed four central themes: (i) the impact of cancer on reproductive decision-making; (ii) motivation for genetic testing; (iii) risk management and timing of planning children; and (iv) optimism for future medical advancements. LIMITATIONS, REASONS FOR CAUTION: This study explores the views of female BRCA carriers. Further research should explore the views of couples, men, and include samples with greater ethnic and social diversity. WIDER IMPLICATIONS OF THE FINDINGS: This evidence highlights the need for reproductive decision-making to be addressed at the time of pretest genetic counselling. More information should be provided on reproductive options as well as counselling/support to guide women's reproductive decision-making and prenatal testing options at the time they undertake genetic testing. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by Cancer Research UK (Number C1226 A7920) and NIHR support to the Biomedical Research Centre at The Institute of Cancer Research and RMH. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Communicating genetics research results to families: problems arising when the patient participant is deceased.

OBJECTIVES: This study explores communication within families of clinically significant genetics research results, after the death of the patient participant. BRCA2 mutations were found in several men after their death from prostate cancer. Spouses were given the results in a genetic counselling session and asked to inform relatives. METHODS: Cross-sectional, qualitative exploratory study. Interviews with 13 relatives, including informers and recipients of the information, were analysed using interpretative phenomenological analysis. RESULTS: Dissemination was hampered when communication channels between relatives were limited, because of family rifts or socially distant or problematic relationships. When informing other branches of the family, relatives approached individuals in the generation of the deceased man, regardless of their risk status, who were then responsible for informing younger relatives. Most people informed by a relative did not seek genetic counselling. The informing relative may not have sufficient authority for the information either to be taken seriously or to challenge individual constructions about the aetiology of cancer. This impeded information transmission to further at-risk relatives. Most participants knew of relatives who had not been told about their cancer risk. CONCLUSIONS: The implications of this limited efficiency of information transfer among relatives are discussed in the context of a potential role for genetics services in contacting at-risk relatives directly.

Disclosure of genetics research results after the death of the patient participant: a qualitative study of the impact on relatives.

When a gene mutation is identified in a research study following the death of the study participant, it is not clear whether such information should be made available to relatives. We report here an evaluation of the impact on relatives of being informed of study results that detected pathogenic BRCA2 mutations in a male relative, now deceased, who had early onset (under the age of 55) prostate cancer. The breast and ovarian cancer risk was unknown to the living relatives. Qualitative analysis of interviews with thirteen relatives indicated that those who had a higher risk perception, resulting from an awareness of cancer family history or experiential knowledge of cancer in their family, tended to adjust more easily to the results. All participants believed that genetics research results of clinical significance should be fed back to relatives. Those who were fully aware of the BRCA2 results and implications for themselves felt they had benefited from the information, irrespective of whether or not they had elected for genetic testing, because of the consequent availability of surveillance programs. Initial anxiety upon learning about the BRCA2 result was alleviated by genetic counselling. Factors influencing those who have not engaged with the information included scepticism related to the relative who attempted to inform them, young age and fear of cancer. Those who had not sought genetic counselling did not attempt further dissemination, and some were not undergoing regular screening. Implications for informed consent in genetics research programs, and the requirement for genetic counselling when research results are disclosed, are discussed.

A new member of the DP family, DP-3, with distinct protein products suggests a regulatory role for alternative splicing in the cell cycle transcription factor DRTF1/E2F.

Integrating cell cycle progression with transcription provides an important level of control during proliferation. The cellular transcription factor DRTF1/E2F is implicated in this integration process by virtue of its physical interaction and control by key regulators of proliferation, such as retinoblastoma protein, cyclins and cyclin-dependent kinases and regulation of target genes required for cell cycle progression. Generic DRTF1/E2F DNA binding activity arises when a member of two distinct families of proteins, DP and E2F, interact as DP/E2F heterodimers. Here, we report the isolation and characterisation of a new member of the murine DP family, called DP-3 (also referred to as human DP-2). In contrast to previously characterised members of the DP and E2F families, processing of DP-3 RNA provides an important level of control by generating at least four distinct DP-3 proteins, of which three have been isolated, called alpha, beta and gamma. Processing events, which we show are both tissue- and cell-restricted, can occur either in the 5' region of DP-3 RNA and determine whether translation begins at one or two potential intiating codons, or within the coding sequence, producing variations in internal domains of the DP-3 proteins. The DP-3 proteins studied can co-operate with E2F-1 in DNA binding activity and trans activation of E2F site-dependent transcription. This analysis of DP-3, which has uncovered a hitherto unexpected and surprising level of complexity, documents a new member of the DP family and novel levels of control which may influence the activity DRTF1/E2F and hence cell cycle progression.

Molecular cloning, cDNA sequence, and chromosomal localization of the human phosphatidylinositol 3-kinase p110 alpha (PIK3CA) gene.

Phosphatidylinositol (PI) 3-kinase is a heterodimeric enzyme comprising a 110-kDa catalytic subunit and an 85-kDa regulatory subunit that binds to tyrosine phosphopeptide sites linked directly or indirectly to receptors serving diverse signal functions. Knowledge of the structure and function of PI 3-kinase was greatly advanced by the purification, cDNA cloning, and subsequent expression of the bovine enzyme. Here the cloning of the cDNA for the human p110 alpha subunit of PI 3-kinase (PIK3CA), encoding a protein 99% identical to the bovine p110, and of its gene in YAC is described. The chromosomal localization of the gene for PIK3CA is shown to be at 3q21-qter as determined using somatic cell hybrids. In situ hybridization performed using Alu-PCR from the YAC DNA located the gene in 3q26.3.

Molecular characterization of Xenopus laevis DP proteins.

It is widely believed that in mammalian cells the cellular transcription factor (DRTF1/E2F integrates cell-cycle events with the transcription apparatus by interacting with important regulators of the cell cycle, such as the retinoblastoma gene product (pRb) and related proteins, cyclins, and cyclin-dependent kinases. Here, we have defined DRTF1/E2F in Xenopus laevis that, like its mammalian counterpart, specifically binds to the E2F site, is regulated during development, and interacts with pRb and related proteins. We have isolated cDNAs that encode the functional homologue of mammalian DP-1, X1 DP-1, together with a close relative, X1 DP-2. X1 DP-1, which is highly conserved with murine DP-1, is a major DNA binding component of X1 DRTF1/E2F. Both DP-1 and DP-2 synergistically interact with members of the E2F family of proteins, E2F-1, E2F-2, and E2F-3, to generate DNA binding complexes that specifically recognize the E2F site and functionally interact with E2F-1 in E2F site-dependent transcriptional activation of cellular genes. DP-1 and DP-2 encode maternally stored transcripts that are expressed during early development. In the adult however, the expression of DP-1 and DP-2 is tissue restricted. This study therefore defines a new family of transcription factors, the DP proteins, members of which can interact combinatorially with E2F proteins to generate an array of DNA binding complexes that integrate cell-cycle progression with the transcription apparatus through the E2F binding site. The tissue-specific expression of DP family members suggests that the combination of DP/E2F heterodimers that constitute DRTF1/E2F is influenced by the phenotype of the cell.

Mapping of cosmid clones in Huntington's disease region of chromosome 4.

Huntington's disease (HD) is tightly linked to genetic markers in 4p16.3. We have used a regional somatic cell hybrid mapping panel to isolate and map 25 cosmids to the proximal portion of 4p16.3 and 17 cosmids to the distal portion. The latter were positioned by long-range restriction mapping relative to previously mapped markers. One cosmid, L6 (D4S166), spans the critical breakpoint in the mapping panel that distinguishes proximal and distal 4p16.3. Four of the cosmids mapped distal to D4S90, the previous terminal marker on 4p, and stretched to within 75 kb of the telomere. Several of the cosmids that mapped between L6 and D4S90 were clustered near a number of previously isolated clones in a region with many NotI sites. Cosmid E4 (D4S168) was localized immediately proximal to the one remaining gap in the long-range restriction map of distal 4p16.3. Although pulsed field gel mapping with E4 failed to link the two segments of the map, the intervening gap was excluded as a potential site for the HD gene by genetic analysis.

Physical maps of 4p16.3, the area expected to contain the Huntington disease mutation.

The gene for Huntington disease, a neurodegenerative disorder with autosomal dominant inheritance, has been localized to the terminal portion of the short arm of human chromosome 4 (4p16.3) by linkage analysis. Since eventual isolation of the gene requires the application of high-resolution genetic analysis coupled with long-range DNA mapping and cloning techniques, we have constructed a physical map of the chromosomal region 4p16.3 using more than 20 independently derived probes. We have grouped these markers into three clusters which have been ordered and oriented by genetic and somatic cell genetic mapping information. The mapped region extends from D4S10 (G8) toward the telomere and covers minimally 5 Mb.