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Biomedical subjects

A Ardern-Jones

Publications and source records attributed to A Ardern-Jones.

At least 19 recordsLinked to original sources

Increased level of chromosomal damage after irradiation of lymphocytes from BRCA1 mutation carriers.

Deleterious mutations in the BRCA1 gene predispose women to an increased risk of breast and ovarian cancer. Many functional studies have suggested that BRCA1 has a role in DNA damage repair and failure in the DNA damage response pathway often leads to the accumulation of chromosomal aberrations. Here, we have compared normal lymphocytes with those heterozygous for a BRCA1 mutation. Short-term cultures were irradiated (8Gy) using a high dose rate and subsequently metaphases were analysed by 24-colour chromosome painting (M-FISH). We scored the chromosomal rearrangements in the metaphases from five BRCA1 mutation carriers and from five noncarrier control samples 6 days after irradiation. A significantly higher level of chromosomal damage was detected in the lymphocytes heterozygous for BRCA1 mutations compared with normal controls; the average number of aberrations per mitosis was 3.48 compared with 1.62 in controls (P=0.0001). This provides new evidence that heterozygous mutation carriers have a different response to DNA damage compared with noncarriers and that BRCA1 has a role in DNA damage surveillance. Our finding has implications for treatment and screening of BRCA1 mutation carriers using modalities that involve irradiation.

Chromosome Aberrations↗

Men's decision-making about predictive BRCA1/2 testing: the role of family.

Men who have a family history of breast and/or ovarian cancer may be offered a predictive genetic test to determine whether or not they carry the family specific BRCA1/2 mutation. Male carriers may be at increased risk of breast and prostate cancers. Relatively little is known about at-risk men's decision-making about BRCA1/2 testing. This qualitative study explores the influences on male patients' genetic test decisions. Twenty-nine in-depth interviews were undertaken with both carrier and noncarrier men and immediate family members (17 male patients, 8 female partners, and 4 adult children). These explored family members' experiences of cancer and genetic testing, decision-making about testing, family support, communication of test results within the family, risk perception and risk management. Implicit influences on men's testing decisions such as familial obligations are examined. The extent to which other family members--partners and adult children--were involved in testing decisions is also described. It is demonstrated that mothers of potential mutation carriers not only perceive themselves as having a right to be involved in making this decision, but also were perceived by their male partners as having a legitimate role to play in decision-making. There was evidence that (adult) children were excluded from the decision-making, and some expressed resentment about this. The implications of these findings for the practice of genetic counseling are discussed.

Attitude↗

Association between hormonal genetic polymorphisms and early-onset prostate cancer.

We investigated the association between seven polymorphisms in four candidate genes involved in vitamin D and androgen metabolism with early-onset prostate cancer (CaP) risk. The polymorphisms were genotyped in 288 UK males who were diagnosed with CaP at the age of 55 y or younger and up to 700 population-based controls. An additional 50 cases (not selected for age) and 76 controls were also genotyped. Short (< or =22 repeats) AR (CAG)(n) repeats were associated with a significantly reduced risk of early onset CaP (OR 0.68, 95% CI 0.50-0.91) compared with men with long (> 22) repeats. Men homozygous for the leucine variant of SRD5A2 p.89V > L were also found to be at a significantly increased risk of CaP compared with men who were homozygous for the valine allele (OR 1.84, 95% CI 1.15-2.98). No associations were found with the AR (GGC)(n), CYP17 Msp A1 I, VDR Taq I, SRD5A2 (TA)(n) and p.49A >T polymorphisms and CaP risk. These findings suggest that common polymorphisms in the AR and SRD5A2 genes may be associated with early-onset CaP in British men.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

Too much, too soon? Patients and health professionals' views concerning the impact of genetic testing at the time of breast cancer diagnosis in women under the age of 40.

Recent research suggests that women who develop breast cancer between the ages of 30-34 may have specific tumour characteristics: Those with high grade, oestrogen receptor negative, human epidermal growth factor receptor 2 (HER-2) negative tumours have between a 10% and 27% chance of being a BRCA1 gene carrier. Carriers of BRCA1 and BRCA2 mutations have an increased risk of contralateral breast cancer and cancer of the ovary. Furthermore, recent research indicates that prophylactic mastectomy and/or oophorectomy offer a significant risk reduction in the development of breast/ovarian cancer. In the near future, women in the UK may be offered the choice of a genetic test close to the time of diagnosis. This timing not only provides additional dimensions to treatment decisions, but has psycho-social and familial implications as well. This exploratory study investigates, first, whether or not women diagnosed with breast cancer under the age of 40 would want to be offered information about genetic testing close to the time of their diagnosis. Then secondly, it explores whether the health care professionals treating them support this idea. Third, it highlights the reasons for the women and the health professionals perspectives and concerns. We held focus groups of 13 women who had their only, or first, breast cancer under the age of 40 and who were subsequently identified as BRCA1 or BRCA2 mutation carriers, asking them how they felt about this timing. We also interviewed 17 health care professionals involved in various aspect of breast cancer care and cancer genetics. The majority of former breast cancer women and professionals believed that there was already emotional overload in coping with the cancer diagnosis and decisions regarding existing cancer treatment options and that offering genetic testing would add too much additional stress. Some members of both groups, however, thought that offering genetic testing around the time of breast cancer diagnosis would be more important if the results could alter treatment decisions.

Adult↗

Communication about genetic testing in families of male BRCA1/2 carriers and non-carriers: patterns, priorities and problems.

This qualitative interview study explored the way in which information about predictive BRCA1/2 testing and its implications for children is disseminated within the families of at-risk men who undergo genetic testing. Twenty-nine in-depth interviews were carried out with family members [male patients (n = 17), their partners (n = 8) and adult children (n = 4)]. These explored the following themes: experiences of cancer and genetic testing, decision-making about testing and the communication of test results and genetic information within the immediate family. The interviews revealed that both male patients and their partners perceive themselves, rather than health professionals, as responsible for disclosing information about genetic testing and genetic risks to their children. Parents described three different communication strategies for the disclosure of genetic information to their children: complete openness, limited disclosure and total secrecy. The adoption of a particular communication strategy was justified in terms of children's rights to information vs their parental duties to protect their children from anxiety-provoking information. Some of the problems arising from the adoption of different disclosure patterns are identified and the implications for clinical practice are discussed.

Adult↗

ATM polymorphisms as risk factors for prostate cancer development.

The risk of prostate cancer is known to be elevated in carriers of germline mutations in BRCA2, and possibly also in carriers of BRCA1 and CHEK2 mutations. These genes are components of the ATM-dependent DNA damage signalling pathways. To evaluate the hypothesis that variants in ATM itself might be associated with prostate cancer risk, we genotyped five ATM variants in DNA from 637 prostate cancer patients and 445 controls with no family history of cancer. No significant differences in the frequency of the variant alleles at 5557G>A (D1853N), 5558A>T (D1853V), ivs38-8t>c and ivs38-15g>c were found between the cases and controls. The 3161G (P1054R) variant allele was, however, significantly associated with an increased risk of developing prostate cancer (any G vs CC OR 2.13, 95% CI 1.17-3.87, P=0.016). A lymphoblastoid cell line carrying both the 3161G and the 2572C (858L) variant in the homozygote state shows a cell cycle progression profile after exposure to ionising radiation that is significantly different to that seen in cell lines carrying a wild-type ATM gene. These results provide evidence that the presence of common variants in the ATM gene, may confer an altered cellular phenotype, and that the ATM 3161C>G variant might be associated with prostate cancer risk.

Adult↗

Accommodating risk: responses to BRCA1/2 genetic testing of women who have had cancer.

The relationship between risk awareness and anxiety has been the subject of extensive theoretical debate and empirical research. Previous studies of women with a family history of hereditary breast and ovarian cancer suggest that both healthy at-risk women and former cancer patients report increased anxiety upon learning about their increased risks of developing these diseases. Indeed, anxiety about genetic risks has been reported as influencing decisions about DNA-testing and risk-reducing surgery on healthy breasts and ovaries. This qualitative study of women who had been treated for breast/ovarian cancer investigated their perceptions of, and reactions to, their genetic risks of developing further cancers following genetic testing (BRCA1/2 mutation searching). In-depth interviews were undertaken with 30 women (10 mutation carriers, 8 awaiting a result and 12 who received an inconclusive test result). Whilst the majority of women in all three groups adopted a fatalistic approach with regard to their future health and did not regard their genetic risks as a threat to self, a few reported heightened anxiety on learning they were at increased risk of developing a second primary cancer. The data suggest that affected women understand their genetic risks of cancer within the context of their previous disease experiences. It is observed that women's responses to their genetic risk are influenced by the degree to which they have accommodated their risk status in their biography following their diagnosis and treatment of cancer.

Adaptation, Psychological↗

Apoptosis, ageing and cancer susceptibility.

We have previously shown that peripheral blood lymphocytes (PBL) from individuals carrying a germline TP53 mutation show a dramatically reduced apoptotic response to radiation. As part of a study of this phenomenon, we also investigated apoptotic response in a series of breast cancer patients lacking TP53 mutations and in a control group of individuals without cancer. There was a significant reduction in mean apoptotic response with increasing age in all groups. These findings are consistent with a number of studies in rodents, which have demonstrated a reduction in DNA damage-induced apoptosis with increasing age. In addition, after adjusting for age, breast cancer patients showed significantly reduced apoptotic responses compared with normal controls (P=0.002). The odds ratio for breast cancer in women with an apoptotic response of <35%, compared with women with a response of >49%, was 6.42 (95% CI 1.68-24.6). The data further support the hypothesis that a reduction in apoptotic response to DNA damage with increasing age may play a significant role in the age-related increase in cancer.

Adult↗

Association between leptin receptor gene polymorphisms and early-onset prostate cancer.

OBJECTIVE: To report a case-control study examining the relationship between polymorphisms in the leptin receptor (OBR) gene and the development of young-onset prostate cancer, because epidemiological studies report that prostate cancer risk is associated with animal fat intake, and thus we investigated if this association occurs via this genetic mechanism. PATIENTS, SUBJECTS AND METHODS: The Lys109Arg (OBR1) and Gln223Arg (OBR2) polymorphisms in the coding region of OBR were studied in blood DNA from 271 patients with prostate cancer aged < 56 years at diagnosis and 277 geographically matched control subjects. Cases were collected through the Cancer Research UK/British Prostate Group Familial Prostate Cancer Study. Blood DNA was genotyped using the polymerase chain reaction and a restriction enzyme digest. RESULTS: There was no statistically significant association between the OBR genotype and prostate cancer risk; men homozygous for 109Arg genotype had a slightly increased risk for prostate cancer, with a relative risk (95% confidence interval) of 1.36 (0.65-2.85), and those homozygous for the 223Arg allele had some reduction in prostate cancer risk, at 0.82 (0.58-1.26), but neither was statistically significant. CONCLUSION: This case-control study showed no significant association between leptin receptor gene polymorphisms and the risk of young-onset prostate cancer, suggesting that genetic variations in OBR are unlikely to have a major role in the development of early-onset prostate cancer in the UK.

Adult↗

Balancing autonomy and responsibility: the ethics of generating and disclosing genetic information.

Using data obtained during a retrospective interview study of 30 women who had undergone genetic testing-BRCA1/2 mutation searching-this paper describes how women, previously diagnosed with breast/ovarian cancer, perceive their role in generating genetic information about themselves and their families. It observes that when describing their motivations for undergoing DNA testing and their experiences of disclosing genetic information within the family these women provide care based ethical justifications for their actions. Finally, it argues that generating genetic information and disclosing this information to kin raise different types of ethical issues. The implications of these findings for ethical debates about informed choice in the context of genetic testing are discussed.

Adult↗

HPC2/ELAC2 polymorphisms and prostate cancer risk: analysis by age of onset of disease.

The candidate prostate cancer susceptibility gene HPC2/ELAC2 has two common coding polymorphisms: (Ser-->Leu 217) and (Ala-->Thr 541). The Thr541 variant in the HPC2/ELAC2 gene has previously been reported to be at an increased frequency in prostate cancer cases. To evaluate this hypothesis we genotyped 432 prostate cancer patients (including 262 patients diagnosed 55 years (OR=1.27, 95% CI 0.59-2.74). We conclude that any association between the Thr541 variant and prostate cancer is likely to be weak.

Adult↗

Association between the GCG polymorphism of the selenium dependent GPX1 gene and the risk of young onset prostate cancer.

Epidemiological studies have suggested an association between low selenium levels and the development of prostate cancer. Human cellular glutathione peroxidase I (hGPX1) is a selenium-dependent enzyme that protects against oxidative damage and its peroxidase activity is a plausible mechanism for cancer prevention by selenium. The GPX1 gene has a GCG repeat polymorphism in exon 1, coding for a polyalanine tract of five to seven alanine residues. To test if the GPX1 GCG repeat polymorphism associates with the risk of young-onset prostate cancer we conducted a case-control study. The GPX1Ala genotypes were determined for 267 prostate cancer cases and 260 control individuals using polymerase chain reaction (PCR) amplification with fluorescently labelled primers and an ABI 377 automated genotyper. Associations between specific genotypes and the risk of prostate cancer were examined by logistic regression. We found no significant association between the GPX1 genotypes and prostate cancer. There was however an increased frequency of the GPX1Ala6/Ala6 genotype in the prostate cancer cases compared to controls (OR: 1.67; 95% CI: 0.97-2.87). The result of this study suggests that the GPX1 genotype is unlikely to be associated with the risk of developing prostate cancer.

Adult↗

Genetic testing for women previously diagnosed with breast/ovarian cancer: examining the impact of BRCA1 and BRCA2 mutation searching.

This study sought to investigate the impact of BRCA1 and BRCA2 mutation searching on women previously diagnosed with breast or ovarian cancer. In-depth interviews were undertaken with 30 women who had undergone a BRCA1 and BRCA2 mutation search within the clinical setting. The main reasons reported for undergoing mutation searching were: to provide genetic information for other family members, general altruism, curiosity about the aetiology of cancer, and to provide information to facilitate risk management decisions. In the main, the process of undergoing genetic testing was not experienced as anxiety provoking. The benefit of receiving a result confirming the presence of a genetic mutation was seen as an end to uncertainty, whereas the costs included difficulties in disclosing information to kin and potentially increased anxiety about one's own or others' cancer risks. Women receiving an inconclusive test result reported a range of emotional reactions. There was evidence that some women misunderstood the meaning of this result, interpreting it as definitive confirmation that a cancer-predisposing mutation was not present within the family. It is concluded that women with cancer who participate in BRCA1 and BRCA2 testing need to receive clear information about the meaning and implications of the different types of test results. Some recommendations for clinical practice are discussed.

Adult↗

A paradox: urgent BRCA genetic testing.

Diagnostic or predictive testing for germline mutations in cancer predisposition genes is inherently slow as result of both genetic counselling and mutation analysis. The overall time taken for mutation testing is not generally perceived as harmful to the individual and may be positively beneficial in order to permit full reflection on the implication of the genetic test results. However, we present three cases where we considered urgent genetic testing for the presence of mutations in th BRCA 1 and 2 genes to be necessary as the test result would have altered the subsequent clinical management of these individuals or their families.

Breast Neoplasms↗

Relationship between glutathione S-transferase M1, P1 and T1 polymorphisms and early onset prostate cancer.

There is evidence suggesting that polymorphic variations in the glutathione S-transferases (GSTs) are associated with cancer susceptibility. Inter-individual differences in cancer susceptibility may be mediated in part through polymorphic variability in the bioactivation and detoxification of carcinogens. The GSTs have been consistently implicated as cancer susceptibility genes in this context. The GST supergene family includes several loci with well characterized polymorphisms. Approximately 50% of the Caucasian population are homozygous for deletions in GSTM1 and approximately 20% are homozygous for deletions in GSTT1, resulting in conjugation deficiency of mutagenic electrophiles to glutathione. The GSTP1 gene has a polymorphism at codon 105 resulting in an Ile to Val substitution which consequently alters the enzymatic activity of the protein and this has been suggested as a putative high-risk genotype in various cancers. We investigated the relationship between GST polymorphisms and young onset prostate cancer in a case-control study. GSTM1, GSTT1 and GSTP1 genotypes were determined for 275 prostate cancer patients and for 280 geographically matched control subjects. We found no significant difference in the frequency of GSTM1 or GSTT1 null genotypes between cases and controls. GSTP1 genotype was, however, significantly associated with prostate cancer risk: the Ile/Ile homozygotes had the lowest risk and there was a trend in increasing the risk with the number of 105 Val alleles: Ile/Val odds ratio (OR)= 1.30 (95% FCI 0.99-1.69), Val/Val OR = 1.80 (95% FCI 1.11-2.91); Ptrend = 0.026. These results suggest that the GSTP1 polymorphism may be a risk factor for developing young onset prostate cancer. We also found that carrying more than one putative high-risk allele in the carcinogen metabolizing GST family was associated with an elevated risk for early onset prostate cancer (OR 2.48, 95% FCI 1.22-5.04, Ptrend = 0.017).

Adult↗

The frequency of germ-line mutations in the breast cancer predisposition genes BRCA1 and BRCA2 in familial prostate cancer. The Cancer Research Campaign/British Prostate Group United Kingdom Familial Prostate Cancer Study Collaborators.

Predisposition to prostate cancer has a genetic component, and there are reports of familial clustering of breast and prostate cancer. Two highly penetrant genes that predispose individuals to breast cancer (BRCA1 and BRCA2) are known to confer an increased risk of prostate cancer of about 3-fold and 7-fold, respectively, in breast cancer families. Blood DNA from affected individuals in 38 prostate cancer clusters was analyzed for germ-line mutations in BRCA1 and BRCA2 to assess the contribution of each of these genes to familial prostate cancer. Seventeen DNA samples were each from an affected individual in families with three or more cases of prostate cancer at any age; 20 samples were from one of affected sibling pairs where one was < or = 67 years at diagnosis. No germ-line mutations were found in BRCA1. Two germ-line mutations in BRCA2 were found, and both were seen in individuals whose age at diagnosis was very young (< or = 56 years) and who were members of an affected sibling pair. One is a 4-bp deletion at base 6710 (exon 11) in a man who had prostate cancer at 54 years, and the other is a 2-bp deletion at base 5531 (exon 11) in a man who had prostate cancer at 56 years. In both cases, the wild-type allele was lost in the patient's prostate tumor at the BRCA2 locus. However, intriguingly, in neither case did the affected brother also carry the mutation. Germ-line mutations in BRCA2 may therefore account for about 5% of prostate cancer in familial clusters.

Adult↗