Age-specific incidence rates for breast cancer in carriers of BRCA1 mutations from Norway.

Incidence rates of breast cancer among women with a BRCA1 mutation vary according to their reproductive histories and country of residence. To measure cancer incidence, it is best to follow-up cohort of healthy women prospectively. We followed up a cohort of 675 women with a BRCA1 mutation who did not have breast or ovarian cancer before inclusion and who had a normal clinical examination and mammography at first visit. After a mean of 7.1 years, 98 incident cases of breast cancer were recorded in the cohort. Annual cancer incidence rates were calculated, and based on these, a penetrance curve was constructed. The average annual cancer risk for the Norwegian women from age 25 to 70 was 2.0%. Founder mutations had lower incidence rate (1.7%) than less frequent mutations (2.5%) (p = 0.03). The peak incidence (3.1% annual risk) was observed in women from age 50 to 59. The age-specific annual incidence rates and penetrance estimate were compared with published figures for women from North America and from Poland. The risk of breast cancer to age 70 was estimated to be 61% for women from Norway, compared with 55% for women from Poland and 69% for women from North America.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study.

OBJECTIVE: To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported. PATIENTS AND METHODS: Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation. RESULTS: In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant. CONCLUSIONS: The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Risk reducing mastectomy: outcomes in 10 European centres.

BACKGROUND: Increasingly women at high risk of breast cancer are opting for risk reducing surgery. The aim of this study was to assess the effectiveness of this approach in women at high risk in both carriers and non-carriers of BRCA1/2. METHODS: Data from 10 European centres that offer a genetic counselling and screening service to women at risk were obtained prospectively from 1995. Breast cancer risks were estimated from life tables and a control group of women at risk who did not undergo surgery. RESULTS: The combined centres have data on 550 women who have undergone risk reducing mastectomy with greater than 3334 women years of follow-up. Operations were carried out on women with lifetime risks of 25-80%, with an average expected incidence rate of 1% per year. No breast cancers have occurred in this cohort in the "at risk" unaffected breast, whereas >34 would have been expected. A high rate (2-3.6%) of occult disease was identified in the at risk breast at the time of surgery. INTERPRETATION: We conclude that risk reducing surgery is highly effective.

Screening for familial ovarian cancer: poor survival of BRCA1/2 related cancers.

AIM: To assess the effectiveness of annual ovarian cancer screening (transvaginal ultrasound and serum CA125 estimation) in reducing mortality from ovarian cancer in women at increased genetic risk. PATIENTS AND METHODS: A cohort of 3532 women at increased risk of ovarian cancer was screened at five European centres between January 1991 and March 2007. Survival from diagnosis of ovarian cancer was calculated using Kaplan-Meier analysis and compared for proven BRCA1/2 carriers with non-carriers and whether the cancer was detected at prevalence or post-prevalent scan. Screening was performed by annual transvaginal ultrasound and serum CA125 measurement. RESULTS: 64 epithelial ovarian malignancies (59 invasive and 5 borderline), developed in the cohort. 26 tumours were detected at prevalent round; there were 27 incident detected cancers and 11 interval. 65% of cancers were stage 3 or 4, however, stage and survival were little different for prevalent versus post-prevalent cancers. Five year and 10 year survival in 49 BRCA1/2 mutation carriers was 58.6% (95% CI 50.9% to 66.3%) and 36% (95% CI 27% to 45%), which was significantly worse than for 15 non-BRCA carriers (91.8%, 95% CI 84% to 99.6%, both 5 and 10 year survival p = 0.015). However, when borderline tumours were excluded, the difference in survival between carriers and non-carriers was no longer significant. CONCLUSION: Annual surveillance, by transvaginal ultrasound scanning and serum CA125 measurement, in women at increased familial risk of ovarian cancer is ineffective in detecting tumours at a sufficiently early stage to influence substantially survival in BRCA1/2 carriers.

The Norwegian founder mutations in BRCA1: high penetrance confirmed in an incident cancer series and differences observed in the risk of ovarian cancer.

We aimed to describe the penetrances of the four Norwegian founder mutations in BRCA1 (816delGT, 1135insA, 1675delA and 3347delAG) with regard to breast and ovarian cancers in families ascertained through cancer family clinics or a consecutive series of women with breast or ovarian cancer. We have extended the families as far as possible and tested all family members that asked for genetic testing. Penetrance is based upon counting the mutation carriers. The series contains sufficient numbers of mutation carriers to minimise variation in the estimates due to a limited sample set. The penetrances for all four mutations were high, both with respect to breast and ovarian cancers. This is in accordance with other reports from cancer family clinics, but contrasts with reports from population-based series of mutation carriers. Risks of first cancer (breast or ovarian), breast cancer, and ovarian cancer at age 50 years were 43, 30 and 17%, respectively. Corresponding risks at age 70 years were 84, 58 and 58%. Risks for breast cancer before age 30 years and for ovarian cancer before 35 years were low. Penetrances with regard to ovarian cancer were different for the four mutations. The risk of ovarian cancer was doubled in carriers of the 1675delA mutation when compared with the 816delGT mutation (24 versus 12% at age 50 years, P=0.004). The mutations analysed are high penetrance alleles. No differences in penetrance between the series ascertained through the cancer family clinic or the series of consecutive cancer patients was observed. There are discrepancies between our findings and the low penetrances reported for other mutations in other populations. This may be due to methodological differences, but may reflect differences between mutations and/or modifying factors in different populations.

Genetic epidemiology of BRCA1 mutations in Norway.

Familial breast-ovarian cancer has been demonstrated to be frequent but unevenly distributed in Norway. This was assumed to be caused by the reduced population size created by the medieval Bubonic plagues 25 generations ago, and by the following rapid expansion. We have previously reported that four mutations account for 68% of the BRCA1 mutation carriers. Subsequent analysis has resulted in a total of 100 separate families carrying one of these founder mutations. The four mutations occurred on one specific BRCA1 haplotype each. The 1675delA, 816delGT and 3347delAG families originated from the South-West coast of Norway with a few families in the north, while the traceable ancestors of the 1135insA families clustered along the historical inland road from the South-East to mid-Norway. The carriers of each of the four mutations today are descendants of one or a few individuals surviving the plagues. We may identify the majority of BRCA1 mutation carriers in Norway by screening for local founder mutations.

The BRCA1 syndrome and other inherited breast or breast-ovarian cancers in a Norwegian prospective series.

Inherited breast cancer is a heterogenous group of diseases. We examined this heterogeneity in a prospective series of inherited breast and ovarian cancers, previously demonstrated to include 84% of inherited cancers. Ninety-two tumours (65 breast and 27 ovarian) in 82 patients from 70 kindreds were prospectively diagnosed. Fifteen of the breast cancers were in situ, 50 were infiltrating. 40 (49%) of the 82 women carried a BRCA1 mutation, whereas no mutation in BRCA2 was found. Approximately, two-thirds of the BRCA1 mutation carriers had one of the four most frequent Norwegian founder mutations. Ninety-five per cent of the epithelial ovarian cancers occurred in BRCA1 mutation carrying women versus 38% of infiltrating breast cancers and 7% of carcinoma in situ of the breast. The BRCA1 syndrome was phenotypically distinct with invasive, high grade, oestrogen receptor-negative breast cancers and epithelial ovarian cancers. Non-BRCA1/2 inherited breast cancers included carcinoma in situ and lobular carcinoma and were frequently bilateral. Non-BRCA1/2 inherited breast cancer is not associated with epithelial ovarian cancer and in breast cancers has distinct biological characteristics, indicating that the different subgroups of inherited breast cancer may need different healthcare services.

[Hereditary breast cancer in Norway]. / Arvelig brystkreft i Norge.

Women at risk for inherited breast cancer have been evaluated in two collaborating Norwegian cancer genetics centres and offered follow-up in the out-patient clinics of all major Norwegian hospitals for the last 11 years. The families were identified on the basis of clinical criteria. The breast cancer genes BRCA1 and BRCA2 were identified in 1994-95. Even though several hundred different mutations in these genes have been described, a significant proportion of Norwegian families with breast cancer appears to have a few frequent mutations. This most probably is a result of the changes in the population structure of Norway as the population went through a genetic bottleneck during the Black Death, which was followed by rapid population expansion. Mutation analysis has now been put in use to identify Norwegian breast cancer families. Such analysis should be offered to all Norwegian patients with breast or ovarian cancers regardless of age of onset or positive family history. For the time being, analysis should be restricted to the detection of the demonstrated frequent mutations in BRCA1.

BRCA1 1675delA and 1135insA account for one third of Norwegian familial breast-ovarian cancer and are associated with later disease onset than less frequent mutations.

A total of 845 women from breast-ovarian cancer kindreds were enrolled in a clinical follow-up program for early disease diagnosis; 35 women were prospectively identified with cancer. In order to estimate the role of genetic factors for cancer predisposition in this well-defined set of patients, considered as representative for familial breast-ovarian cancer in the Norwegian population, the BRCA1 gene was investigated for germline mutations. The entire coding region of BRCA1 was analysed using a protein truncation test, direct sequencing and a screen for known large genomic deletions and insertions. Twenty one (60%) of the 35 patients were identified as carriers of 11 distinct BRCA1 mutations. Two previously described founder mutations, 1675delA and 1135insA, were found to account for more than half (11/21) of all BRCA1 cases and for almost one third (11/35) of all breast and ovarian cancers. Supported by a previous population-based analysis of these founder mutations in ovarian cancer, our findings suggest that a significant proportion of women at risk for developing inherited breast and ovarian cancer can be identified. This is particularly obvious in certain geographic regions where these founder mutations are prevalent. Women carrying the two founder mutations had a significantly older age of disease onset as compared to women with other BRCA1 mutations. This observation indicates that BRCA mutation penetrance estimates from populations with strong founder effects may be biased. One reason why some deleterious mutations are allowed to prevail in a population may be coupled to penetrance and the fact that they seldom induce disease in women in child-bearing ages. Eleven out of 12 (92%) breast cancers in BRCA1 mutation carriers were estrogen receptor negative, versus 4 out of 9 (44%) in mutation negative patients (p = 0.03). Histopathological characteristics of the prospectively detected cancers indicated an unfavourable prognosis in mutation carriers.

Costs and benefits of diagnosing familial breast cancer.

Based on results from our surveillance program for women at risk for inherited breast cancer, we have calculated cost per year earned. Norwegian National Insurance Service reimbursement fees were used in the calculations. The calculated costs are based on empirical figures for expanding already established medical genetic departments and diagnostic outpatient clinics to undertake the work described. Cost per year earned was estimated at Euro 753 using our current practice of identifying the high-risk women through a traditional cancer family clinic. A strategy of identifying the high-risk families through genetic testing of all incident breast and ovarian cancers for founder mutations in BRCA1, will increase the cost to Euro 832. Costs related more to genetic counseling and clinical follow-up than to laboratory procedures. This potential economic limiting factor coincides with a shortage of personnel trained in genetic counseling. The number of relatives counseled to identify one healthy female mutation carrier (i.e. the uptake of genetic testing) is more important to cost-effectiveness than family size. Costs will vary depending upon the penetrance of the mutations detected and the prevalence of founder mutations in the population examined. Prevalences of BRCA1 founder mutations in some high incidence areas of Norway may be sufficiently high to consider population screening. Unlike mutation screening of cancer genes, founder mutation analysis will not identify DNA variants of uncertain clinical significance. Identification of high-risk families through founder mutation analysis of BRCA1 ensures that families with maximum risks are given first access to the limited resources of the high-risk clinics. This may be the greatest contribution to increased cost effectiveness of such a strategy. The assumptions underlying the calculations are discussed. The conclusion is that inherited breast cancer may be managed effectively for the cost of Euro 750-1,600 per year earned.

Efficacy of early diagnosis and treatment in women with a family history of breast cancer. European Familial Breast Cancer Collaborative Group.

BACKGROUND: Surveillance programmes for women at increased genetic risk of breast cancer are being established worldwide but little is known of their efficacy in early detection of cancers and hence reduction in mortality. METHODS: Data were contributed from seven centres participating in the EU Demonstration Programme on Clinical Services for Familial Breast Cancer. All breast tumours (n = 161) detected prospectively, from the time of enrolment of women in a screening programme, were recorded. Analysis took account of age at diagnosis, whether tumours were screen-detected or not, their pathological stage and outcome by Kaplan-Meier survival plots. RESULTS: Mean age at diagnosis was 48.6 years. Overall, 75% of tumours were detected in the course of planned examinations. For women under age 50 at diagnosis, this figure was 68%. Eighteen percent were mammographically negative, (23% in patients under age 50). At first ("prevalence") round and at follow-up screening, 16% and 22% of tumours respectively were carcinoma in situ (CIS) while 27% and 22% respectively had evidence of nodal or distant spread (CaN+). Comparison of screen-detected and other tumours showed that the latter were more frequently mammogram-negative and CaN+. Overall five-year survival was 89% and five-year event-free survival 86%. Five-year event-free survival was 100% for CIS, 88% for invasive cancer without nodal or distant spread and 67% for CaN+. CONCLUSIONS: The majority of cancers arising in women at increased genetic risk of breast cancer can be detected by planned screening, even in those under age 50. Surveillance should include regular expert clinical examination and teaching of "breast awareness" as well as mammography. Attention to the logistics of screening programmes may improve still further the proportion of tumours that are screen-detected. The trend towards earlier pathological stage in tumours detected during follow-up rounds and the preliminary findings on survival analysis suggest that this approach will prove to be of long-term benefit for breast cancer families.

Growth of human lung adenocarcinoma in nude mice is influenced by various types of dietary fat and vitamin E.

Studies have shown effects of dietary lipids on carcinogenesis and tumour progression. Different mechanisms for the inhibitory effect of n-3 fatty acids (FA) have been proposed. The inhibition of the growth of subcutaneously transplanted A427 lung adenocarcinoma cells in athymic nude mice may occur due to an increased level of lipid peroxidation products and is the object of this study. The nude mice were fed diets supplemented with corn oil (CO), olive oil (OO) or K85, a mixture of ethyl esters of n-3 FAs, mainly eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). Tumours of the n-3 FA group showed reduced growth. Peroxidation products measured by the thiobarbituric acid reactive substances (TBARS) test showed higher levels in tumours from n-3 FA fed mice than in the other diet groups. The growth inhibitory effects and the elevated level of TBARS in the n-3 FA diet group were counteracted by vitamin E supplement in the diet. Cu/Zn-superoxide dismutase (SOD) activity in liver did not differ greatly among the diet groups. The Ki-67 labelling index (LI), indicating cell proliferation rate was significantly lower in the K85 diet group compared to the other diet groups.

A BRCA1 founder mutation, identified with haplotype analysis, allowing genotype/phenotype determination and predictive testing.

We searched for a founder mutation in a population from one geographic region of Norway with prevalent breast/ovarian cancer families. We sampled 33 breast/ovarian cancer families and determined haplotypes of four markers linked to the BRCA1 region. Of the affected 33 index women, 13 (39.4%) shared one haplotype. In five (15% of total), an identical mutation was indicated by an abnormal truncated protein test (PTT) of exon 11 and shown to represent a 1675delA mutation. In the other index women, PTT of exon 11 showed no abnormality. No other BRCA1 founder mutation of this prevalence is likely because no other haplotype was more frequent in affecteds than in controls. All families with the 1675delA mutation in this geographic region may be considered as part of one large kindred. This allows a genotype-phenotype correlation to be precisely determined and used in genetic counselling for predictive testing within this kindred. Identification of identical haplotypes between unrelated affected individuals may be used to estimate the extent of founder effects for any mapped disease, without knowledge of the specific founder mutation.

Nickel(II) induces alterations in EGF- and TGF-beta 1-mediated growth control during malignant transformation of human kidney epithelial cells.

We have previously described immortalization of normal human kidney epithelial cells by nickel(II) and the subsequent tumorigenic conversion by v-Ha-ras transfection. We report here that nickel(II) induces alterations in growth regulatory control. Normal human kidney epithelial cells (NHKE) were growth inhibited by transforming growth factor beta 1 (TGF-beta 1). This effect was abrogated in both the immortalized (IHKE) and transformed (THKE) cells. NHKE expressed approximately 4700 high-affinity binding sites/cell for TGF-beta 1. IHKE and THKE showed reduced binding of 47% and 44% relative to NHKE respectively. On the other hand, expression of epidermal growth factor (EGF) receptors was elevated in IHKE (260%) and THKE (236%) relative to NHKE, which expressed 1.5 x 10(5) receptors/cell. Preincubation of IHKE and THKE with TGF-beta 1 resulted in reduced EGF binding, whereas this binding was unaltered in NHKE. Exposure of human kidney epithelial cells to EGF led to tyrosine phosphorylation of the EGF receptor and other cellular proteins in the mol. wt range from 42 to > 300 kDa. The level of receptor phosphorylation induced by EGF reflected receptor expression. Tyrosine phosphorylated proteins appear to be identical in all three cell lines, and reach phosphorylation maxima independently of EGF receptor expression. These studies indicate that nickel carcinogenesis may involve changes in sets of genes important in normal growth regulation.

Inherited breast carcinoma--prospective findings in 1,194 women at risk.

According to preset criteria, 1,194 women at risk for inherited breast carcinoma were selected and subjected to examination. Six hundred and three women were examined once, 591 were followed for a mean of 1.8 years. Twenty infiltrating cancers (median age 49 years) and 16 precancers (median age 44 years) were found, demonstrating that breast carcinoma continued to occur in the selected families as expected under the hypothesis of dominant inheritance. At first round, 14 (1.2%) infiltrating carcinomas and a total of 22 (1.8%) cancers or precancers were found. Incidence rates of 0.58% pr. year for infiltrating cancers, and 1.04% pr. year for cancer or precancer were calculated. This confirms the tentative conclusions that were drawn in our previous report. These are the first prospective reports documenting how to delineate a high risk group for premenopausal breast cancer, and how to diagnose cancer at an early stage. All but two affected women had cancer without lymph node metastasis. Although a longer observation time is needed, we cautiously conclude that the results are in keeping with our aim of providing safety for those at risk. Clinical use of predictive genetic testing may be implemented within these families.

Effects of n-3 fatty acids during neoplastic progression and comparison of in vitro and in vivo sensitivity of two human tumour cell lines.

Several studies have shown that dietary lipid exerts an effect on carcinogenesis. We report here that progression to malignancy in vitro is associated with changes in the response to fatty acids (FAs). Tumorigenic (THKE) cells were more sensitive to the n-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than immortalised (IHKE) cells. The growth of THKE cells was inhibited 25% more than the growth of IHKE cells at 80 microM EPA (P < 0.01) and 35% more at 40 microM DHA (P < 0.001). Furthermore, the results indicate that there is a wide cell type variation in the response to FAs. We found that the in vitro inhibition by FAs correlated with the reduction in the growth rate of the tumour in nude mice fed K85 (55% EPA and 30% DHA). A significant difference in tumour latency was observed for the A427 cell tumour groups (10 days, P < 0.05). Tumours in the animals fed n-3 FA exhibited significantly higher levels of EPA and DHA; the level of arachidonic acid (ARA) was significantly lower in THKE tumours and the level of linoleic acid (LA) was significantly lower in A427 tumours than in controls fed corn oil. The higher sensitivity of the A427 cell line was not explained by higher uptake of EPA/DHA.

Nickel-induced alterations in human renal epithelial cells.

Cellular progression to malignancy appears to require a number of distinct steps in which genetic damage in key regulatory genes accumulates. Immortalization, or escape from senescence, is considered to be one of the first phenotypic changes. Ni2+ treatment of normal human kidney epithelial (NHKE) cells in vitro resulted in immortalization of the cells IHKE cells). The combined action of Ni2+ and v-Ha-ras oncogene fully transformed the cells to tumorigenicity in athymic nude mice. Sequence analysis of DNA from IHKE cells revealed point mutation in the p53 gene at codon 238 with T-->C transition. These findings suggest that Ni-induced mutation in the p53 gene can be involved in the immortalization of the NHKE cells. The results also show that changes in the responses to EGF and TGF beta and in the expression of their receptors occur during malignant progression in vitro.

Altered p53 gene structure and expression in human epithelial cells after exposure to nickel.

The carcinogenicity of certain nickel compounds is well known. We have previously shown that human kidney epithelial cells were immortalized by treatment with Ni(II) and in cooperation with the v-Ha-ras oncogene transformed the cells to acquire tumorigenicity in athymic nude mice. Immunocytochemistry and sequence analysis of DNA from the nickel-immortalized cells revealed abnormal p53 expression and a T----C transition mutation in codon 238. These data are consistent with the hypothesis that Ni(II)-induced mutation in the p53 gene can be involved in the escape from senescence of kidney epithelial cells.