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1.
Screening for 185delAG in the Ashkenazim.   总被引:1,自引:1,他引:0  
A study was initiated to assess interest, educational effectiveness, and implications of genetic testing for the common BRCA1 mutation, 185delAG, in the Ashkenazim. Of 333 individuals who attended group sessions, 309 (92%) participated in the study. Participants were categorized as having negative family history (67%), positive family history (defined, by a relaxed criterion, as one first-degree relative or two second-degree relatives with breast [premenopausal] or ovarian cancer) (22%), positive personal history (7%), and both positive personal history and positive family history (4%). Group education was effective, as shown by the improvement in participant scores from pre- to posteducation tests. For the 289 individuals (94%) who requested testing, the major reasons included concern for their own risk, concern for the risk of their children, and desire to learn about surveillance options. The most common reason given by participants who declined testing was concern about health insurance. Six participants found to be heterozygous for the 185delAG mutation received results and were offered genetic counseling. Participants had consented for additional testing without receiving results and were screened for the 6174delT mutation in BRCA2, and seven were found to be positive. All identified carriers reported at least one first- or second-degree relative with a history of breast or ovarian cancer, although they did not all meet our study criteria for positive family history. Given these outcomes, we conclude that screening for breast and ovarian cancer susceptibility is most appropriate for individuals with a positive personal or positive family cancer history. We propose a guideline for future studies designed to identify individuals who may benefit from genetic testing for inherited breast and ovarian cancer.  相似文献   

2.
The frequency of genomic rearrangements in BRCA1 was assessed in 42 American families with breast and ovarian cancer who were seeking genetic testing and who were subsequently found to be negative for BRCA1 and BRCA2 coding-region mutations. An affected individual from each family was tested by PCR for the exon 13 duplication (Puget et al. 1999a) and by Southern blot analysis for novel genomic rearrangements. The exon 13 duplication was detected in one family, and four families had other genomic rearrangements. A total of 5 (11. 9%) of the 42 families with breast/ovarian cancer who did not have BRCA1 and BRCA2 coding-region mutations had mutations in BRCA1 that were missed by conformation-sensitive gel electrophoresis or sequencing. Four of five families with BRCA1 genomic rearrangements included at least one individual with both breast and ovarian cancer; therefore, 4 (30.8%) of 13 families with a case of multiple primary breast and ovarian cancer had a genomic rearrangement in BRCA1. Families with genomic rearrangements had prior probabilities of having a BRCA1 mutation, ranging from 33% to 97% (mean 70%) (Couch et al. 1997). In contrast, in families without rearrangements, prior probabilities of having a BRCA1 mutation ranged from 7% to 92% (mean 37%). Thus, the prior probability of detecting a BRCA1 mutation may be a useful predictor when considering the use of Southern blot analysis for families with breast/ovarian cancer who do not have detectable coding-region mutations.  相似文献   

3.
BRCA1/BRCA2 germline mutations are associated with an increased breast/ovarian cancer risk. Offspring gender ratios may be skewed against male births in BRCA1 mutation carriers. In addition, the lack of viable homozygous BRCA1/BRCA2-mutation carriers implies that recurrent miscarriages may be associated with homozygous fetuses. Jewish Israeli high-risk women who were tested for being carriers of the predominant BRCA1/BRCA2 mutations in Jewish high-risk families were analyzed for the sex of offspring and the rate of spontaneous miscarriages. Overall, 817 women participated: 393 BRCA1/BRCA2-mutation carriers (229 with breast/ovarian cancer) and 424 high-risk noncarriers (208 with breast/ovarian cancer). No differences between the male-to-female offspring ratios of all study groups were noted. Among mutation carriers, the offspring male-to-female ratio was 0.97 (444 : 460), and among mutation carriers with cancer it was 0.92 (262 : 284). Similarly, no offspring gender skewing was noted among high-risk noncarriers, regardless of health status. The rates of three or more spontaneous miscarriages among participants with at least one live birth were 4.37% (15/343) among mutation carriers and 3% (12/401) among high-risk women (P = not significant). In conclusion, the offspring gender ratio is similar in high-risk Jewish families and in the general population. The issue of the rate of recurrent miscarriages in high-risk Jewish women is unresolved.  相似文献   

4.
Three founder mutations in the cancer-associated genes BRCA1 and BRCA2 occur frequently enough among Ashkenazi Jews to warrant consideration of genetic testing outside the setting of high-risk families with multiple cases of breast or ovarian cancer. We estimated the prevalence of these founder mutations in BRCA1 and BRCA2 in the general population of Ashkenazi Jews according to age at testing, personal cancer history, and family cancer history. We compared the results of anonymous genetic testing of blood samples obtained in a survey of >5,000 Jewish participants from the Washington, DC, area with personal and family cancer histories obtained from questionnaires completed by the participants. In all subgroups defined by age and cancer history, fewer mutations were found in this community sample than in clinical series studied to date. For example, 11 (10%) of 109 Jewish women who had been given a diagnosis of breast cancer in their forties carried one of the mutations. The most important predictor of mutation status was a previous diagnosis of breast or ovarian cancer. In men and in women never given a diagnosis of cancer, family history of breast cancer before age 50 years was the strongest predictor. As interest in genetic testing for BRCA1 and BRCA2 in the Jewish community broadens, community-based estimates such as these help guide those seeking and those offering such testing. Even with accurate estimates of the likelihood of carrying a mutation and the likelihood of developing cancer if a mutation is detected, the most vexing clinical problems remain.  相似文献   

5.
BRCA1 and BRCA2 mutation carriers have an increased risk of developing breast and/or ovarian cancer. Technical advances in genetic testing have increased the need for genetic counseling services; therefore, we have developed a counseling program for these individuals. The purpose of this study is to characterize this population, assess level of interest in genetic testing, and evaluate our program over a 5-year period. Our Familial Cancer Genetic Counseling Program was established in November, 1994. Information was collected prospectively, with comprehensive evaluation including complete pedigree, risk assessment, and counseling by a genetic counselor, geneticist, and oncologist. Data were collected on risk level, and subsequent recommendations for screening and/or genetic testing. There were 824 contacts recorded from November, 1994, through August, 1999. To date, 162 families have undergone comprehensive genetic evaluation and counseling. 90 (56%) were seen for a concerning family history and 72 (44%) were seen due to a personal history of malignancy. The majority of families had a significant level of risk with 126 (78%) families having two and 70 (43%) families having three affected first-degree relatives. Of the 162 families who received full counseling, 125 (77%) met criteria to recommend BRCA1/BRCA2 genetic testing. At this time, 30 of the 162 (18%) have had genetic testing. A brief phone contact or clinic visit is useful to screen individuals so that counseling can be directed toward truly high-risk families. In our program, the majority of families counseled were eligible for BRCA1/BRCA2 testing, but only 18% have elected to proceed at this time.  相似文献   

6.
Genetic heterogeneity in hereditary breast cancer: role of BRCA1 and BRCA2.   总被引:7,自引:4,他引:3  
The common hereditary forms of breast cancer have been largely attributed to the inheritance of mutations in the BRCA1 or BRCA2 genes. However, it is not yet clear what proportion of hereditary breast cancer is explained by BRCA1 and BRCA2 or by some other unidentified susceptibility gene(s). We describe the proportion of hereditary breast cancer explained by BRCA1 or BRCA2 in a sample of North American hereditary breast cancers and assess the evidence for additional susceptibility genes that may confer hereditary breast or ovarian cancer risk. Twenty-three families were identified through two high-risk breast cancer research programs. Genetic analysis was undertaken to establish linkage between the breast or ovarian cancer cases and markers on chromosomes 17q (BRCA1) and 13q (BRCA2). Mutation analysis in the BRCA1 and BRCA2 genes was also undertaken in all families. The pattern of hereditary cancer in 14 (61%) of the 23 families studied was attributed to BRCA1 by a combination of linkage and mutation analyses. No families were attributed to BRCA2. Five families (22%) provided evidence against linkage to both BRCA1 and BRCA2. No BRCA1 or BRCA2 mutations were detected in these five families. The BRCA1 or BRCA2 status of four families (17%) could not be determined. BRCA1 and BRCA2 probably explain the majority of hereditary breast cancer that exists in the North American population. However, one or more additional genes may yet be found that explain some proportion of hereditary breast cancer.  相似文献   

7.
As part of a multicenter study supported by the German Mildred Scheel foundation we have established an interdisciplinary counseling setting for members of breast and/or ovarian cancer families. We offer simultaneous counseling by a team consisting of a geneticist, a gynecologist and a psycho-oncologist. Here we describe our counseling protocol and our first short-term experience with this interdisciplinary approach. Preliminary data on patient perceptions and behaviors in the context of DNA testing are reported. Overall, our counseling approach was perceived as beneficial both by the counselors and the consultants. A marked overestimation of the risk to develop breast and/or ovarian cancer was noted in the group of unaffected individuals from medium to low risk breast cancer families in contrast to an appropriate risk perception in members from high risk families. All participants shared many of the same expectations about genetic testing and counseling and appeared to base their decision-making about testing on the risk classification given by the genetic counselor. The reported participation in gynecological cancer prevention programs was high in all families at risk, but was less sufficient in unaffected as compared to affected persons. Although current data on BRCA1/BRCA2 mutation analyses render testing in medium to low risk individuals questionable, our findings emphasize the importance of genetic counseling and education in all risk categories of breast and/or ovarian cancer families.  相似文献   

8.
Genetic epidemiological evidence suggests that mutations in BRCA1 may be responsible for approximately one half of early onset familial breast cancer and the majority of familial breast/ovarian cancer. The recent cloning of BRCA1 allows for the direct detection of mutations, but the feasibility of presymptomatic screening for cancer susceptibility is unknown. We analyzed genomic DNA from one affected individual from each of 24 families with at least three cases of ovarian or breast cancer, using SSCP assays. Variant SSCP bands were subcloned and sequenced. Allele-specific oligonucleotide hybridization was used to verify sequence changes and to screen DNA from control individuals. Six frameshift and two missense mutations were detected in 10 different families. A frameshift mutation was detected in a male proband affected with both breast and prostate cancer. A 40-bp deletion was detected in a patient who developed intra-abdominal carcinomatosis 1 year after prophylactic oophorectomy. Mutations were detected throughout the gene, and only one was detected in more than a single family. These results provide further evidence that inherited breast and ovarian cancer can occur as a consequence of a wide array of BRCA1 mutations. These results suggests that development of a screening test for BRCA1 mutations will be technically challenging. The finding of a mutation in a family with male breast cancer, not previously thought to be related to BRCA1, also illustrates the potential difficulties of genetic counseling for individuals known to carry mutations.  相似文献   

9.
We have undertaken a hospital-based study, to identify possible BRCA1 and BRCA2 founder mutations in the Polish population. The study group consisted of 66 Polish families with cancer who have at least three related females affected with breast or ovarian cancer and who had cancer diagnosed, in at least one of the three affected females, at age <50 years. A total of 26 families had both breast and ovarian cancers, 4 families had ovarian cancers only, and 36 families had breast cancers only. Genomic DNA was prepared from the peripheral blood leukocytes of at least one affected woman from each family. The entire coding region of BRCA1 and BRCA2 was screened for the presence of germline mutations, by use of SSCP followed by direct sequencing of observed variants. Mutations were found in 35 (53%) of the 66 families studied. All but one of the mutations were detected within the BRCA1 gene. BRCA1 abnormalities were identified in all four families with ovarian cancer only, in 67% of 27 families with both breast and ovarian cancer, and in 34% of 35 families with breast cancer only. The single family with a BRCA2 mutation had the breast-ovarian cancer syndrome. Seven distinct mutations were identified; five of these occurred in two or more families. In total, recurrent mutations were found in 33 (94%) of the 35 families with detected mutations. Three BRCA1 abnormalities-5382insC, C61G, and 4153delA-accounted for 51%, 20%, and 11% of the identified mutations, respectively.  相似文献   

10.
Abstract

In recent months, genetic testing for the breast and ovarian cancer genes, BRCA1 and BRCA2, has again hit the headlines in the UK press. Four women, all from families with a strong breast cancer pedigree, have asked the Human Fertility and Embryology Authority for permission to screen their embryos for BRCA1/2 mutations. Although this may be a dramatic example of parental responsibility, other studies have shown that women at risk of BRCA-related cancers frequently cite responsibility to others as an important influence on their testing and treatment decision making. In this paper, I explore the decision-making explanations that women at risk of BRCA-related breast and ovarian cancer provide when accounting for their decision to undergo genetic testing. In doing so, I treat women's accounts critically, and examine how and why the women verbalize their explanations in the manner that they do.  相似文献   

11.
Since the discovery of the BRCA1 and BRCA2 genes, there has been an increasing demand for breast cancer risk assessment programs. In an effort to understand and serve the population such programs target better, several studies have identified factors influencing high-risk women to pursue breast cancer risk assessment and genetic testing services; none, however, has focused on how the motivations and concerns of at-risk women may differ from their previously affected counterparts, who are typically the initial members of their families to undergo genetic testing. The majority of both previously affected and unaffected women felt that preventative surgery decisions, surveillance practices, the assessment of children's risks, and increased breast cancer anxiety were "more important" or "very important" issues regarding their thoughts about genetic testing. Significantly more affected women deemed family members' opinions "more" or "very important" (p < 0.01). Opinions concerning insurance and employment discrimination did not vary significantly between groups; however, a larger percentage of affected women felt this issue was of importance. Although all issues above should be addressed with women seeking cancer risk assessment and genetic testing, this research may help health care providers to gain a greater understanding of how the motivators and concerns of high-risk women can differ with personal cancer status so that referral, counseling, and education can be executed optimally.  相似文献   

12.
Dominant predisposition to early-onset breast cancer and/or ovarian cancer in many families is known to be the result of germ-line mutations in a gene on chromosome 17q, known as BRCA1. In this paper we use data from families with evidence of linkage to BRCA1 to estimate the age-specific risks of breast and ovarian cancer in BRCA1-mutation carriers and to examine the variation in risk between and within families. Under the assumption of no heterogeneity of risk between families, BRCA1 is estimated to confer a breast cancer risk of 54% by age 60 years (95% confidence interval [CI] 27%-71%) and an ovarian cancer risk of 30% by age 60 years (95% CI 8%-47%). Similar lifetime-risk estimates are obtained by examining the risks of contralateral breast cancer and of ovarian cancer, in breast cancer cases in linked families. However, there is significant evidence of heterogeneity of risk between families; a much better fit to the data is obtained by assuming two BRCA1 alleles, one conferring a breast cancer risk of 62% and an ovarian cancer risk of 11% by age 60 years, the other conferring a breast cancer risk of 39% and an ovarian cancer risk of 42%, with the first allele representing 71% of all mutations (95% CI 55%-87%). There is no evidence of clustering of breast and ovarian cancer cases within families.  相似文献   

13.
BRCA1/2 test decliners/deferrers have received almost no attention in the literature and this is the first study of this population in the United Kingdom. The aim of this multicenter study is to examine the attributes of a group of individuals offered predictive genetic testing for breast/ovarian cancer predisposition who did not wish to proceed with testing at the time of entry into this study. This forms part of a larger study involving 9 U.K. centers investigating the psychosocial impact of predictive genetic testing for BRCA1/2. Cancer worry and reasons for declining or deferring BRCA1/2 predictive genetic testing were evaluated by questionnaire following genetic counseling. A total of 34 individuals declined the offer of predictive genetic testing. Compared to the national cohort of test acceptors, test decliners are significantly younger. Female test decliners have lower levels of cancer worry than female test acceptors. Barriers to testing include apprehension about the result, traveling to the genetics clinic, and taking time away from work/family. Women are more likely than men to worry about receiving less screening if found not to be a carrier. The findings do not indicate that healthy BRCA1/2 test decliners are a more vulnerable group in terms of cancer worry. However, barriers to testing need to be discussed in genetic counseling.  相似文献   

14.
We searched for criteria that could indicate breast cancer families with a high prior probability of being caused by the breast/ovarian cancer susceptibility locus BRCA1 on chromosome 17. To this end, we performed a linkage study with 59 consecutively collected Dutch breast cancer families, including 16 with at least one case of ovarian cancer. We used an intake cut-off of at least three first-degree relatives with breast and/or ovarian cancer at any age. Significant evidence for linkage was found only among the 13 breast cancer families with a mean age at diagnosis of less than 45 years. An unexpectedly low proportion of the breast-ovarian cancer families were estimated to be linked to BRCA1, which could be due to a founder effect in the Dutch population. Given the expected logistical problems in clinical management now that BRCA1 has been identified, we propose an interim period in which only families with a strong positive family history for early onset breast and/or ovarian cancer will be offered BRCA1 mutation testing. More recent work has indicated that RUL09 is probably due to BRCA2 (multipoint lod score of 1.17), while in families RUL47 and RUL49 a frameshift mutation in BRCA1 has been evidenced. Each of these two latter families contain an early-onset sporadic breast cancer patient, explaining their negative lod scores with 17q-markers.  相似文献   

15.
The aim of the study was to optimize the criteria for the BRCA1 and BRCA2 gene testing and to improve oncogenetic counseling in the Stockholm region. Screening for inherited breast cancer genes is laborious and a majority of tested samples turn out to be negative. The frequencies of mutations in the BRCA1 and BRCA2 genes differ across populations. Between 1997 and 2000, 160 families with breast and/or ovarian cancer were counseled and screened for mutations in the two genes. Twenty-five BRCA1 and two BRCA2 disease-causing mutations were found. Various factors associated with the probability of finding a BRCA1 mutation in the families were estimated. Age of onset in different generations and other malignancies were also studied. Families from our region in which both breast and ovarian cancer occur were likely to carry a BRCA1 mutation (34%). In breast-only cancer families, mutations were found only in those with very early onset. All breast- only cancer families with a mutation had at least one case of onset before 36 years of age and a young median age of onset (<43 years). Other malignancies than breast and ovarian cancers did not segregate in the BRCA1 families and surveillance for other malignancies is not needed, in general. Decreasing age of onset with successive generations was common and must be taken into account when surveillance options are considered.  相似文献   

16.
Women with mutations in the breast cancer genes BRCA1 or BRCA2 have an increased lifetime risk of developing breast, ovarian and other BRCA-associated cancers. However, the number of detected germline mutations in families with hereditary breast and ovarian cancer (HBOC) syndrome is lower than expected based upon genetic linkage data. Undetected deleterious mutations in the BRCA genes in some high-risk families are due to the presence of intragenic rearrangements such as deletions, duplications or insertions that span whole exons. This article reviews the molecular aspects of BRCA1 and BRCA2 rearrangements and their frequency among different populations. An overview of the techniques used to screen for large rearrangements in BRCA1 and BRCA2 is also presented. The detection of rearrangements in BRCA genes, especially BRCA1, offers a promising outlook for mutation screening in clinical practice, particularly in HBOC families that test negative for a germline mutation assessed by traditional methods.  相似文献   

17.
The discovery of deleterious mutations in the breast and ovarian cancer susceptibility genes, BRCA1 and BRCA2, has facilitated the identification of individuals at particularly high risk of these diseases. There is a wide variation between populations in the prevalence and related risks of various types of BRCA1/2 mutations, so estimates cannot be extrapolated to Canadians, especially not founder populations such as French- Canadians. Polymerase chain reaction (PCR)-based methods were used to detect the majority of these mutations. These approaches usually failed to detect large DNA rearrangements, which have been claimed to be involved in other populations in 5% to up to 36% of BRCA1-positive families. There is very little information about the contribution of this type of mutation in BRCA2-positive families. To investigate if our available mutation spectrum of BRCA1 and BRCA2 in high-risk French-Canadian breast/ovarian cancer families has been biased by PCR-based direct sequencing methods, we first used Southern blot analysis to test DNA samples from 61 affected/obligate carrier individuals from 58 families in which no BRCA1/2 deleterious mutation was found. Finally, 154 individuals from 135 BRCA1/2 nonconclusive families, including all those tested previously by Southern blot analysis, were tested with the new multiplex ligation probe amplification (MLPA) technique. These approaches failed to detect any rearrangement. Moreover, if the frequency of MLPA-detectable rearrangements in our cohort of 135 BRCA1/2 nonconclusive families was 2.2% or higher, we would have had a 95% or greater chance of observing at least one such rearrangement. As no rearrangements were identified, such large rearrangements must be quite rare in our population.  相似文献   

18.
Male breast cancer is a rare disorder, and little is known about the molecular mechanisms associated with the tumorigenic process. We genotyped 31 Jewish Israeli males with breast cancer for the predominant Jewish BRCA1 (185delAG, 5382InsC) and BRCA2 (6174delT) germline mutations: 11 individuals from high-risk families and 20 patients unselected for family history of cancer. Two patients of the high-risk group (18.2%) displayed germline mutations: one harbored the 185delAG BRCA1 mutation, and the other the 6174delT mutation in BRCA2. None of the unselected patients displayed any mutation. In 2 patients, complete mutation analysis of the BRCA2 gene did not reveal any disease-associated mutations. We conclude that the predominant Jewish germline mutations in BRCA1/BRCA2 contribute to male breast cancer in Israel, primarily in Ashkenazi individuals with a family history of cancer.  相似文献   

19.
We investigate the familial risks of cancers of the breast and ovary, using data pooled from three population-based case-control studies of ovarian cancer that were conducted in the United States. We base estimates of the frequency of mutations of BRCA1 (and possibly other genes) on the reported occurrence of breast cancer and ovarian cancer in the mothers and sisters of 922 women with incident ovarian cancer (cases) and in 922 women with no history of ovarian cancer (controls). Segregation analysis and goodness-of-fit testing of genetic models suggest that rare mutations (frequency .0014; 95% confidence interval .0002-.011) account for all the observed aggregation of breast cancer and ovarian cancer in these families. The estimated risk of breast cancer by age 80 years is 73.5% in mutation carriers and 6.8% in noncarriers. The corresponding estimates for ovarian cancer are 27.8% in carriers and 1.8% in noncarriers. For cancer risk in carriers, these estimates are lower than those obtained from families selected for high cancer prevalence. The estimated proportion of all U.S. cancer diagnoses, by age 80 years, that are due to germ-line BRCA1 mutations is 3.0% for breast cancer and 4.4% for ovarian cancer. Aggregation of breast cancer and ovarian cancer was less evident in the families of 169 cases with borderline ovarian cancers than in the families of cases with invasive cancers. Familial aggregation did not differ by the ethnicity of the probands, although the number of non-White and Hispanic cases (N = 99) was sparse.  相似文献   

20.
The recognition that the prevalence of three founder mutations in the BRCA1 and BRCA2 genes is over 2% in Ashkenazi Jews has resulted in numerous epidemiological research studies of this ethno-religious group. To determine the effects of incorporating research into clinical practice, a psychological impact study of women participating in an epidemiological study was conducted. Sixty women of Ashkenazi Jewish background who underwent genetic testing for founder mutations were assessed using mailed, self-administered questionnaires with validated measures of psychological outcome. Forty-three women elected to learn their results and 17 women declined to do so. Women who elected to learn their results were also assessed 7-10 days, 4 months, and 12 months after results disclosure. Women who chose to learn their results had significantly higher baseline breast cancer anxiety, compared to those who elected not to learn their results (z = -2.27; p = 0.023). Unaffected women who elected to learn their results showed a significant decrease in breast cancer anxiety 4 months (z = -2.37, p = 0.018) and 12 months (z = -3.06, p = 0.002) post-notification compared to baseline. Genetic testing for mutations common in Ashkenazi Jewish women with result disclosure does not lead to adverse psychological outcomes.  相似文献   

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