The <Emphasis Type="Italic">CHEK2</Emphasis> 1100delC mutation is not present in Korean patients with breast cancer cases tested for <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation

The germline CHEK2 1100delC mutation is a low penetrance breast cancer susceptibility allele, frequently observed in patient with family history of breast cancer and/or young age and the frequency varied according to race or ethnicity. In this study, we evaluated the significance of CHEK2 1100delC in predisposition to breast cancer by assessing its frequency in a material of 493 Korean breast cancer patients who had been screened for BRCA1 and BRCA2 mutations (42 patients had deleterious mutation of BRCA1/2). Mutation detection of CHEK2 1100delC was based upon analysis of primer extension products generated for previously amplified genomic DNA using a chip based MALDI-TOP mass spectrometry platform. After overall measurement automatically, assays which had bad peaks were checked again manually. None of the 493 Korean patients with breast cancer who were candidate for BRCA1 and BRCA2 test carried the 1100delC mutation observed in Caucasians with limited frequency. In the previous studies, we observed higher or comparable prevalence of BRCA1 and BRCA2 mutations in Korean patients with breast cancer compared to Caucasian breast cancer population. In the present study, we evaluated the role of a CHEK2 1100delC as a susceptibility mutation of breast cancer in the Korean population. However, our results suggest that this mutation is absent or may be very infrequent in Korean patients with breast cancer who have high risk of BRCA1 and BRCA2 mutation, making its screening irrelevant from the practical point view.     

Predicting <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> gene mutation carriers: comparison of LAMBDA,BRCAPRO, Myriad II,and modified Couch models

Context Models have been developed to predict the probability that a person carries a detectable germline mutation in the BRCA1 or BRCA2 genes. Their relative performance in a clinical setting is unclear. Objective To compare the performance characteristics of four BRCA1/BRCA2 gene mutation prediction models: LAMBDA, based on a checklist and scores developed from data on Ashkenazi Jewish (AJ) women; BRCAPRO, a Bayesian computer program; modified Couch tables based on regression analyses; and Myriad II tables collated by Myriad Genetics Laboratories. Design and setting Family cancer history data were analyzed from 200 probands from the Mayo Clinic Familial Cancer Program, in a multispecialty tertiary care group practice. All probands had clinical testing for BRCA1 and BRCA2 mutations conducted in a single laboratory. Main outcomes measures For each model, performance was assessed by the area under the receiver operator characteristic curve (ROC) and by tests of accuracy and dispersion. Cases “missed” by one or more models (model predicted less than 10% probability of mutation when a mutation was actually found) were compared across models. Results All models gave similar areas under the ROC curve of 0.71 to 0.76. All models except LAMBDA substantially under-predicted the numbers of carriers. All models were too dispersed. Conclusions In terms of ranking, all prediction models performed reasonably well with similar performance characteristics. Model predictions were widely discrepant for some families. Review of cancer family histories by an experienced clinician continues to be vital to ensure that critical elements are not missed and that the most appropriate risk prediction figures are provided.     

Large <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> genomic rearrangements in Danish high risk breast-ovarian cancer families

BRCA1 and BRCA2 germ-line mutations predispose to breast and ovarian cancer. Large genomic rearrangements of BRCA1 account for 0–36% of all disease causing mutations in various populations, while large genomic rearrangements in BRCA2 are more rare. We examined 642 East Danish breast and/or ovarian cancer patients in whom a deleterious mutation in BRCA1 and BRCA2 was not detected by sequencing using the multiplex ligation-dependent probe amplification (MLPA) assay. We identified 15 patients with 7 different genomic rearrangements, including a BRCA1 exon 5–7 deletion with a novel breakpoint, a BRCA1 exon 13 duplication, a BRCA1 exon 17–19 deletion, a BRCA1 exon 3–16 deletion, and a BRCA2 exon 20 deletion with a novel breakpoint as well as two novel BRCA1 exon 17–18 and BRCA1 exon 19 deletions. The large rearrangements in BRCA1 and BRCA2 accounted for 9.2% (15/163) of all BRCA1 and BRCA2 mutations in East Denmark. Nine patients had the exon 3–16 deletion in BRCA1. By SNP analysis we find that the patients share a 5 Mb fragment of chromosome 17, including BRCA1, indicating that the exon 3–16 deletion represents a Danish founder mutation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Heterozygote <Emphasis Type="Italic">BRCA1</Emphasis> status and skewed chromosome X inactivation

A high frequency of skewed X-chromosome inactivation has been reported in peripheral blood lymphocytes from early onset breast cancer or invasive ovarian cancer patients. Recent findings have shown that breast and ovarian carcinoma cells from BRCA1 mutation carrier women lack the hallmarks of inactive X chromatin structure. These observations suggested that loss of functional BRCA1 in female cells may perturb the process of X inactivation and have lead us to the hypothesis that analysis of skewing could be used as a predictive test for BRCA1 germline mutation in lymphocytes from breast cancer patients. In the present study, we have compared the X inactivation pattern in lymphoblastoid cell lines from 38 females carrying heterozygous BRCA1 mutation to 41 controls. X inactivation analysis was assessed on the polymorphic CAG repeat within the human androgen receptor gene. Our observations rule out an effect of a monoallelic BRCA1 germline mutation on the choice of inactivated chromosome X and therefore the possibility of using analysis of Xi skewing as a predictive test for BRCA1 germline mutation carrier status.     

High Incidence of 4153delA <Emphasis Type="Italic">BRCA1</Emphasis> Gene Mutations in Lithuanian Breast- and Breast-ovarian Cancer Families

Summary BRCA1 and BRCA2 gene mutations confer a high lifetime risk to breast and ovarian cancers. We have screened cancer patients from 13 families with at least three breast and/or ovarian cancers from Lithuania for 5382insC, C61G and 4153delA BRCA1 gene mutations. One of three mutations was found in 9 of the 13 studied families (69%). 4153delA was the most frequently detected and accounted for 56% of all identified mutation. 5382insC and C61G accounted for 33% and 11% of found mutations, respectively. Significantly higher, than in other populations, incidence of 4153delA indicates that this may be founder BRCA1 mutation characteristic for Lithuanians. Our analysis shows that testing of 4153delA, 5382insC, C61G BRCA1 mutations should be extremely effective and inexpensive tool in testing Lithuanian population aimed to identify individuals with high risk of breast and ovarian cancers.     

A high frequency of germline <Emphasis Type="Italic">BRCA1/2</Emphasis> mutations in western Sweden detected with complementary screening techniques

Dominant inheritance is presumed in 6–10% of breast and ovarian cancers. Mutations in BRCA1 and BRCA2 genes are the most commonly identified causative genes in such families. The frequency of mutation carriers with breast/ovarian cancer depends on the population studied, and display considerable variation that coincides with ethnic and geographical diversity. Mutation analyses were performed in 143 families registered at the Cancer Genetic Counseling Clinic of western Sweden. In a thorough mutation screening procedure, the entire BRCA1 and BRCA2 genes were analyzed using a combination of complementary mutation detection techniques. Mutations in either BRCA1 or BRCA2 were detected in 36% (52 out of 143) of all screened families. All families were clinically evaluated regarding age at diagnosis, type of cancer and number of cancer cases in the family. Among high-risk families, the mutation detection rate was 39% (46 out of 117). The detection rate observed among families with cases of ovarian cancer (42 out of 62, 68%), was substantially higher than in families with only breast cancer (10 out of 81, 12%). Age at ovarian cancer did not seem to have an effect on the detection rate. The analyses revealed 11 frameshift mutations, 4 nonsense mutations and 2 large deletions. Notably, the BRCA1 c.3171ins5 mutation accounted for 34 of 52 (65%) identified mutations. Seven mutations are novel: BRCA1c.409_410del; c.1912T>G; c.2228_2229del; c.3029delA; c.3433delA, a large deletion covering exons 1–3 of BRCA1and one BRCA2 mutation; BRCA2c.6287_6290del. We have shown that the founder mutation BRCA1 c.3171ins5 has a great influence on western Swedish breast/ovarian cancer families along with a high number of mutations unique for the region. In order to achieve a high mutation detection rate we suggest a combination of several detection techniques.     

Absence of the common <Emphasis Type="Italic">IGF1</Emphasis> 19 CA-repeat allele is more common among <Emphasis Type="Italic">BRCA1</Emphasis> mutation carriers than among non-carriers from <Emphasis Type="Italic">BRCA1</Emphasis> families

BRCA1 mutations predispose to early-onset breast cancer. We previously reported an association between absence of the common IGF1 19 CA-repeat allele (IGF1-19/-19) and being a BRCA1 mutation carrier in young women from breast cancer high-risk families. Others have reported a four-fold risk of premenopausal breast cancer in women with a family history and the IGF1-19/-19 genotype. The aim of this study was to investigate whether the IGF1-19/-19 genotype was associated with being a BRCA1 mutation carrier among women from BRCA1 families. DNA was available from 268 women with known BRCA1 status from the South Swedish Health Care Region. IGF1 genotyping was successfully performed with fragment analysis in 211 women from 96 families. The IGF1-19/-19 genotype was significantly more common among BRCA1 mutation carriers (14.2%) than among non-carriers (4.8%), OR 3.3 (95%CI 1.11-9.78, P = 0.03) adjusted for family clustering. We confirmed our previous finding of an association between the IGF1-19/-19 genotype and BRCA1 mutation status. Since the IGF1-19/-19 genotype in combination with OC use or multiparity confers an increased risk for early onset breast cancer in high-risk women and in women from the general population, future studies are needed to elucidate the importance of the IGF1-19/-19 genotype concerning the variability in breast cancer risk among BRCA1 mutation carriers.     

Prostate screening uptake in Australian <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> carriers

Men who carry mutations in BRCA1 or BRCA2 are at increased risk for prostate cancer. However the efficacy of prostate screening in this setting is uncertain and limited data exists on the uptake of prostate screening by mutation carriers. This study prospectively evaluated uptake of prostate cancer screening in a multi-institutional cohort of mutation carriers. Subjects were unaffected male BRCA1 and BRCA2 mutation carriers, aged 40–69 years, enrolled in the Kathleen Cuningham Consortium for Research into Familial Breast Cancer (kConFab) and who had completed a mailed, self-report follow-up questionnaire 3 yearly after study entry. Of the 75 male carriers in this study, only 26 (35%) had elected to receive their mutation result. Overall, 51 (68%) did not recall having received a recommendation to have prostate screening because of their family history, but 41 (55%) had undergone a prostate specific antigen (PSA) test and 32 (43%) a digital rectal examination (DRE) in the previous 3 years. Those who were aware of their mutation result were more likely to have received a recommendation for prostate screening (43 vs. 6%, p = 0.0001), and to have had a PSA test (77 vs. 43%, p = 0.005) and a DRE (69 vs. 29%, p = 0.001) in the previous 3 years. The majority of unaffected males enrolled in kConFab with a BRCA1/2 mutation have not sought out their mutation result. However, of those aware of their positive mutation status, most have undergone at least one round of prostate screening in the previous 3 years.     

Polymorphisms of the <Emphasis Type="Italic">BRCA2</Emphasis> and <Emphasis Type="Italic">RAD51</Emphasis> Genes in Breast Cancer

Summary We performed a case-control study (150 cases and 150 controls) to test the association between three polymorphisms in BRCA2 and RAD51 genes and breast cancer risk. Genotypes were determined in DNA from blood cells by PCR–RFLP. Cancer occurrence was strongly associated with the BRCA2 Met/1915Thr homozygous polymorphic variants, whereas heterozygous variant was associated with significant reduction in breast cancer risk. Gene-gene interaction between the BRCA2-Met1915Thr Thr/Thr and BRCA2-Met784Val Met/Met homozygous variants increased the risk. Therefore, the Met1915Thr polymorphism in the BRCA2 gene may be considered as an independent marker of breast cancer.     

Higher occurrence of childhood cancer in families with germline mutations in <Emphasis Type="Italic">BRCA2</Emphasis>, MMR and <Emphasis Type="Italic">CDKN2A</Emphasis> genes

The contribution of hereditary factors for development of childhood tumors is limited to some few known syndromes associated with predominance of tumors in childhood. Occurrence of childhood tumors in hereditary cancer syndromes such as BRCA1/2 associated breast and ovarian cancer, DNA-mismatch repair (MMR) genes associated hereditary non polyposis colorectal cancer and CDKN2A associated familial malignant melanoma are very little studied. Herein we report the prevalence of childhood tumors (diagnosed ≤18 years of age) in families identified with mutation in the BRCA1/2, MMR and CDKN2A genes. Using pedigrees at the Regional Oncogenetic Clinic at Lund University Hospital, the prevalence of childhood cancer was estimated in families with mutations in the BRCA1 (n = 98), BRCA2 (n = 43) MMR (MLH1, MSH2 MSH6) (n = 31) and CDKN2A (n = 15) genes in comparison with population based control families (n = 854). Compared with the control group, a significantly higher prevalence of childhood cancer was found in families with mutations in BRCA2 (9.3% vs. 0.8% P = 0.001), MMR genes (19.4% vs. 0.8% P < 0.001) and CDKN2A (20.0% vs. 0.8% P < 0.001), but not in families with BRCA1 mutations (1.0% vs. 0.8% P = 0.6). Further analyses showed an increased risk for childhood tumors in families with mutations in BRCA2 (OR 12.4; 95% CI 3.5–44.1), MMR genes (OR 29.0; 95% CI 9.1–92.6), and CDKN2A (OR 30.2; 95% CI 7.0–131.1). This study suggests that the risk for childhood tumors is increased in families with germline mutations in the BRCA2, MMR and CDKN2A genes.     

Breast cancer screening in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation carriers after risk reducing salpingo-oophorectomy

Breast cancer screening is offered to BRCA1 and BRCA2 mutation carriers from the age of 25 years because of their increased risk of breast cancer. As ovarian cancer screening is not effective, risk-reducing salpingho-oophorectomy (RRSO) is offered after child bearing age. RRSO before menopause reduces the breast cancer risk as well as breast density. It can be questioned whether after premenopausal RRSO, the intensive breast cancer screening program needs modification. We evaluated the effectiveness of breast cancer screening by clinical breast examination (CBE), mammography, and MRI in a population of 88 BRCA1 and 51 BRCA2 mutation carriers who had RRSO before the age of 52. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each screening modality. During 422 women years, 14 breast cancers were diagnosed; 2 prevalent, 10 screen detected and 2 interval breast cancers (12 in BRCA1 and 2 in BRCA2 mutation carriers). Sensitivity, specificity, PPV, and NPV for the combined screening were 85.7%, 97.6%, 30.0%, and 99.8%, respectively. No tumors were found with CBE, MRI had a sensitivity of 60.0% and mammography of 55.6%. Off all the tumors, 60% were node positive. Effectiveness of CBE and mammography was comparable to earlier findings. MRI screening seemed less effective than earlier findings. After RRSO, the breast cancer risk in BRCA1 and BRCA2 mutation carriers is still high enough to justify intensive breast cancer screening with MRI and mammography.     

<Emphasis Type="BoldItalic">BAP1</Emphasis> and Breast Cancer Risk

BAP1 whose protein interacts with BRCA1 was analysed in a series of 47 French familial breast cancer cases negatively tested for BRCA1/2 mutations. The lack of detection of deleterious mutations suggests that BAP1 is not a high risk breast cancer predisposing gene. However, a common identified variant, rs123602, may be tested in sporadic cases as candidate for moderate risk.     

<Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> germline mutation analysis in the Indonesian population

Specific mutations in BRCA1 and BRCA2 genes have been identified in specific populations and ethnic groups. However, little is known about the contribution of BRCA1 and BRCA2 mutations to breast cancers in the Indonesian population. One hundred-twenty moderate to high risk breast cancer patients were tested using PCR-DGGE, and any aberrant band was sequenced. Multiplex ligation-dependent probe amplification (MLPA) was performed on all samples to detect large deletions in the two genes. Twenty-three different mutations were detected in 30 individuals, ten were deleterious mutations and 20 were "unclassified variants" with uncertain clinical consequences. Three of seven (c.2784_2875insT, p.Leu1415X and del exon 13-15) and two of four (p.Glu2183X and p.Gln2894X) deleterious mutations that were found in BRCA1 and BRCA2 respectively, are novel. Several novel, pathogenic BRCA1 and BRCA2 germline mutations are found in early onset Indonesian breast cancer patients, these may therefore be specific for the Indonesian population.     

Mutation analysis of <Emphasis Type="Italic">PALB2</Emphasis> in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis>-negative breast and/or ovarian cancer families from Eastern Ontario,Canada

Background

PALB2 has emerged as a breast cancer susceptibility gene. Mutations in PALB2 have been identified in almost all breast cancer populations studied to date, but the rarity of these mutations and lack of information regarding their penetrance makes genetic counseling for these families challenging. We studied BRCA1/2 -negative breast and/or ovarian cancer families to a) assess the contribution of PALB2 mutations in this series and b) identify clinical, pathological and family history characteristics that might make PALB2 screening more efficient.

Methods

The coding region of the PALB2 gene was analyzed in 175 probands with family histories of breast and/or ovarian cancer ascertained from a single Canadian institution in Eastern Ontario.

Results

We identified 2 probands with PALB2 mutations that are known or strongly considered to be pathogenic and 3 probands with missense mutations that are possibly pathogenic. One of the identified truncating mutations [c.3113G > A (p.Gly1000_Trp1038del – major product)], has been previously described while the other four mutations [c.3507_3508delTC (p.H1170Ffs*19), c.1846G > C (p.D616H), c.3418 T > G (p.W1140G), c.3287A > G (p.N1096S)] have not been previously reported. Loss of heterozygosity was detected in two breast tumors from one c.3507_3508delTC mutation carrier but not in other available tumors from that family or in tumors from carriers of other mutations.

Conclusions

PALB2 mutation screening identifies a small, but significant number of mutations in BRCA1/2 -negative breast and/or ovarian cancer families. We show that mutations are more likely to be found in families with three or more breast cancers as well as other BRCA2-related cancers. In our cohort, both clearly pathogenic mutations were identified in premenopausal breast cancer cases (2/77, 2.6%). Testing should be preferentially offered to affected women from such families.     

Variation in breast cancer risk in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation carriers

Genetic testing for BRCA1 and BRCA2 (BRCA1/2) mutations can provide important information for women who are concerned about their breast and ovarian cancer risks and need to make relevant prevention and medical management decisions. However, lifetime risks of breast cancer in individual BRCA1/2 mutation carriers have been confusing to apply in clinical decision-making. Published risk estimates vary significantly and are very dependent on the characteristics of the population under study. Recently, Begg and colleagues estimated cancer risks in a population-based study of BRCA1/2 mutation carriers. Here, we discuss the clinical decision-making implications of this research in the context of risk factors that may influence risk estimates in BRCA1/2 mutation carriers.     

Selected Aspects of Molecular Diagnostics of Constitutional Alterations in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> Genes Associated with Increased Risk of Breast Cancer in the Polish Population

Objectives

This study was undertaken to determine: 1) Type and prevalence of founder mutations BRCA1 and BRCA2 genes in Polish families with strong aggregation of breast and/or ovarian cancer. 2) Risk of breast and/or ovarian cancer depending on type of BRCA1 gene mutation. 3) Prevalence of BRCA1 mutation and of other alleles presumably linked with predisposition to breast cancer in unselected Polish patients with breast cancer. 4) Risk of breast cancer in patients with 5972C/T polymorphism that alters the BRCA2 protein structure.

Summary of the results

1. Among 66 families from several regions in Poland with a strong aggregation of breast/ovarian cancer, founder mutation of the BRCA1 gene were disclosed in 34 families and of the BRCA2 gene in on family. Altogether, seven different mutations were disclosed. Five mutations were found in at least two families in this group. The most frequent mutation was 5382insC (18 families), followed by C61G (7 families) and 4153delA (4 families). 2. Among 200 families representative for Poland with strong aggregation of breast/ovarian cancer, mutation of the BRCA1 gene were found in 122 families (61%) and of the BRCA2 gene in seven families (3,5%). 119 out of 122 mutations of the BRCA1 gene (97,5%) were repeatable. Three recurrent mutations of the BRCA1 gene (5382insC, C61G, 4153delA) characteristic for the Polish population were disclosed in 111 families representing 86% of all pathogenic sequences of this gene. 3. The risk of ovarian cancer in carriers of the three most frequent recurrent mutation of the BRCA1 gene in Poland is similar (OR 43.6 for 5382insC and 50 for 4153delA). The risk of breast cancer is significantly different for 4153delA (OR 1) and for other mutations (OR 10.9). 4. Among 2012 unselected breast cancers diagnosed in hospitals of nine Polish cities, mutations of the BRCA1 gene (5382insC, C61G, 4153delA) were disclosed in 2.9% patients. CHEK2 alternation (1100delC, IVS2+1G>A, I157T) was discovered in 8.1% and NBS1 mutation (657del5) in 0.8% of the patients. The changes were more frequent in the study than the control group. However, the risk of breast cancer was significantly higher for only three of them. Two changes, namely 5382insC and C61G of the BRCA1 gene revealed a high penetrance (OR 6.2 and 15.0, respectively), while I157T of the CHEK2 gene was associated with a low risk of breast cancer (OR 1.4). Mutations of the BRCA1, CHEK2 and NSB1 genes were significantly more frequent in patients with breast cancer diagnosed prior to 50 years of age. The mean age at diagnosis was 47.2 years for carriers of the BRCA1 mutation, 50.7 years for NBS1 and 54.2 for CHEK2. The mean age at diagnosis in the group of patients without any if the mutations described above was 56.1 years. When breast cancer patients with the diagnosis before and after 50 years of age were compared, the greatest difference in the frequency of mutation was revealed for the BRCA1 gene (5.5% vs 1.5%).BRCA1 mutations were significantly more frequent I familial aggregates of the tumor (10.8%), but were also present in sporadic cases (1.8%). For the CHEK2 and NBS1 genes, there was no correlation between frequency and family history of cancer in probands. 5. A higher frequency of heterozygous carriers of 5972C/T polymorphism of the BRCA2 gene was demonstrated for breast cancer prior to 50 years of age (OR 1.4). the risk of breast cancer prior to 50 years of age was particularly high in 5972T/T homozygote (OR 4.7). This polymorphism was associated with breast cancer notable for intraductal growth.

Conclusions

1. Efficient molecular diagnostics of genetic predisposition to breast/ovarian cancer in Poland could be based on relatively simple tests disclosing some of the most frequent recurrent mutations of the BRCA1 gene. 2. The risk of breast cancer seems to be only slightly higher in carriers of some BRCA1 gene mutations. This finding should be taken into account during work on prevention schemes for carriers of the BRCA1 mutations. 3. 5382insC and C61G mutations of the BRCA1 gene are linked with high risk of breast cancer. Changes in the CHEK2 and NBS1 genes appear to be linked with a higher risk of breast cancers, particularly at young age. However, penetrance in this case is low. All patients with breast cancer should be tested for BRCA1 gene mutations because the percentage of mutations is also high in patients older than 50 years of age or without familiar aggregation of breast/ovarian cancer. 4. Polymorphic changes in the BRCA2 gene sequence previously regarded as non-pathogenic may nevertheless predispose, homozygotes in particular, to breast cancer. Apparently, the recessive character of these changes is responsible for the negative family history in most cases. The use of DNA tests is the only way to disclose increased risk of breast cancer in carriers of the 5972T/T mutation.

     

Contribution of the Defective <Emphasis Type="Italic">BRCA1</Emphasis>, <Emphasis Type="Italic">BRCA2</Emphasis> and <Emphasis Type="Italic">CHEK2</Emphasis> Genes to the Familial Aggregation of Breast Cancer: a Simulation Study Based on the Swedish Family-Cancer Database

The known breast cancer susceptibility genes only account for 20% to 25% of the excess familial risk of the disease [1]. The present study assessed the contribution of BRCA1/2 mutations and CHEK2 variants to the relative risk of breast cancer for women with affected mothers or sisters. The familial relative risks were estimated by Poisson regression based on the Swedish Family-Cancer Database. The Database was also used to calculate the distribution of life expectancy, the number of daughters per family and the age specific cumulative risk of female breast cancer. This information, together with the penetrances of BRCA1, BRCA2 and CHEK2 from the literature, was used to simulate the familial clustering of breast cancer under different scenarios. The excess risk explained by BRCA1, BRCA2 and CHEK2 decreased steeply with the age at diagnosis of the cancers. Around 40% of the familial risk for cases diagnosed before the age of 50 years was associated with BRCA1/2 mutations. In contrast, roughly 85% of the familial risk of breast cancer diagnosed before the age of 69 years remained unexplained. The contribution of CHEK2 to familial breast cancer was small.     

Prospective study of breast MRI in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation carriers: effect of mutation status on cancer incidence

Annual MRI screening is recommended as an adjunct to mammography for BRCA1 and BRCA2 mutation carriers. Prophylactic oophorectomy has been shown to decrease breast cancer risk in BRCA1/2 mutation carriers. Here, we aimed to examine the combined effects of MRI and oophorectomy. For this purpose, 93 BRCA1/2 mutation carriers were screened with yearly mammograms and yearly MRI scans. Study endpoints were defined as date of breast cancer diagnosis, date of prophylactic mastectomy, or date of most recent contact. Of 93 women, with a median age of 47, 80 (86%) had prophylactic oophorectomy. Fifty-one women (55%) had BRCA1 mutations. A total of 283 MRI scans were performed. Eleven breast cancers (9 invasive, 2 ductal carcinoma in situ) were detected in 93 women (12%) with a median follow-up of 3.2 years (incidence 40 per 1,000 person-years). Six cancers were first detected on MRI, three were first detected by mammogram, and two were “interval cancers.” All breast cancers occurred in BRCA1 mutation carriers (incidence 67 per 1,000 person-years). Apart from BRCA1 vs. BRCA2 mutation status, there were no other significant predictors of breast cancer incidence. Most invasive breast cancers were estrogen receptor negative (7 of 9) and lymph node negative (7 of 9). There have been no systemic recurrences with a median follow-up of 19 months after cancer diagnosis. Finally, it was concluded that all breast cancers occurred in BRCA1 mutation carriers, in most cases despite oophorectomy. These data suggest that surveillance and prevention strategies may have different outcomes in BRCA1 and BRCA2 mutation carriers.     

Genetic uptake in <Emphasis Type="BoldItalic">BRCA</Emphasis>-mutation families is related to emotional and behavioral communication characteristics of index patients

Introduction: Carriers of a hereditary mutation in BRCA are at high risk for breast and ovarian cancer. The first person from a family known to carry the mutation, the index person, has to share genetic information with relatives. This study is aimed at determining the number of relatives tested for a BRCA mutation, and the exploration of facilitating and debilitating factors in the transmission of genetic information from index patient to relatives. Methods: The study includes 50 female index patients, with a germline mutation in either BRCA1 or BRCA2. Results: The percentage of first- and second-degree relatives tested for the BRCA-mutation was 36%. Uptake levels for predictive BRCA-mutation testing could not be explained by demographic or counseling characteristics, nor by cancer-related history. In 14 families, fewer than 20% of first- and second-degree relatives were tested. These families were compared with the other families. In retrospect, the index patients of families with few BRCA-mutation tests more often asked for support in the communication with family members (62% vs. 27%). A psychosocial worker had been absent more often during counseling (39% vs. 9%). Emotional factors debilitating the information transmission were only reported by index patients from families with few BRCA-mutation tests (18% vs. 0%), who also informed their parents less often (21% vs. 67%) and did so less often personally (38% vs. 71%). Conclusion: Uptake of predictive BRCA-mutation testing by first- and second-degree relatives is low. Emotional and behavioral factors of index patients are related to this uptake.