A single BRCA2 mutation in male and female breast cancer families from Iceland with varied cancer phenotypes.

The BRCA2 gene on chromosome 13 has been shown to be associated with familial male and female breast cancer. Here we describe a study on BRCA2 in 21 Icelandic families, including 9 with male breast cancer. We have previously reported linkage to the BRCA2 region in an Icelandic male breast cancer family and subsequently found a strong indication of linkage to BRCA2 and the same BRCA2 haplotype in breast cancer cases from 15 additional families, indicating a common origin. We describe a five base-pair deletion in exon 9 of BRCA2 in an affected male from the male breast cancer family. The same mutation occurs in all the families with the shared BRCA2 haplotype indicating a founder effect. Among mutation carriers there are 12 males with breast cancer, which accounts for 40% of all males diagnosed with breast cancer in Iceland over the past 40 years. Three of them have no family history of breast cancer indicating that this mutation may have variable penetrance. The same BRCA2 mutation appears to be associated with different cancer phenotypes in this population including male and female breast cancer, prostate cancer, pancreas cancer and ovarian cancer.

The complete BRCA2 gene and mutations in chromosome 13q-linked kindreds.

Breast carcinoma is the most common malignancy among women in developed countries. Because family history remains the strongest single predictor of breast cancer risk, attention has focused on the role of highly penetrant, dominantly inherited genes in cancer-prone kindreds (1). BRCA1 was localized to chromosome 17 through analysis of a set of high-risk kindreds (2), and then identified four years later by a positional cloning strategy (3). BRCA2 was mapped to chromosomal 13q at about the same time (4). Just fifteen months later, Wooster et al. (5) reported a partial BRCA2 sequence and six mutations predicted to cause truncation of the BRCA2 protein. While these findings provide strong evidence that the identified gene corresponds to BRCA2, only two thirds of the coding sequence and 8 out of 27 exons were isolated and screened; consequently, several questions remained unanswered regarding the nature of BRCA2 and the frequency of mutations in 13q-linked families. We have now determined the complete coding sequence and exonic structure of BRCA2 (GenBank accession #U43746), and examined its pattern of expression. Here, we provide sequences for a set of PCR primers sufficient to screen the entire coding sequence of BRCA2 using genomic DNA. We also report a mutational analysis of BRCA2 in families selected on the basis of linkage analysis and/or the presence of one or more cases of male breast cancer. Together with the specific mutations described previously, our data provide preliminary insight into the BRCA2 mutation profile.

Breast and ovarian cancer risks to carriers of the BRCA1 5382insC and 185delAG and BRCA2 6174delT mutations: a combined analysis of 22 population based studies.

A recent report estimated the breast cancer risks in carriers of the three Ashkenazi founder mutations to be higher than previously published estimates derived from population based studies. In an attempt to confirm this, the breast and ovarian cancer risks associated with the three Ashkenazi founder mutations were estimated using families included in a previous meta-analysis of populatrion based studies. The estimated breast cancer risks for each of the founder BRCA1 and BRCA2 mutations were similar to the corresponding estimates based on all BRCA1 or BRCA2 mutations in the meta-analysis. These estimates appear to be consistent with the observed prevalence of the mutations in the Ashkenazi Jewish population.

Somatic p53 mutations in human breast carcinomas in an Icelandic population: a prognostic factor.

Mutations in the p53 gene are among the most common genetic changes in human carcinomas. They have been found in many tumor types including colon, lung, and breast. We have used constant denaturant gel electrophoresis in order to screen samples from 109 breast carcinomas for mutations in four conserved regions, exons 5, 7, and 8, of the p53 gene. Samples were also analyzed for allelic loss of the p53 gene and of markers more distal on chromosome 17 p. Mutations were confirmed by DNA sequencing. Mutations were found in 18 of the 109 samples (16.5%). Loss of heterozygosity at 17p was detected in the majority of informative mutated cases. All cases were also screened for germ line mutations, but none were found. The results obtained were analyzed with respect to clinical parameters and prognosis. There was a significant association between p53 mutation and low content of estrogen receptor protein in the tumors (P = 0.01). An association with poor prognosis was strongly indicated by mortality rates that were 37.5% among the patients with p53 mutation and 9.4% for the control group (mean follow up, 32 months). P53 mutation was found to be the strongest negative factor against survival in a covariate survival analysis (P = 0.001).

p53 abnormalities and genomic instability in primary human breast carcinomas.

Abnormalities in the p53 tumor suppressor gene have been shown to affect cell cycle control and lead to genetic instability in cell lines of murine and human origin. We have examined genetic instability in 183 primary human breast carcinomas with and without p53 abnormalities. Mutation analysis was performed by constant denaturant gel electrophoresis and DNA sequencing, and abnormal protein expression was examined by immunohistochemical staining methods. Genetic instability was studied by detection of gene amplification, allelic loss, karyotype analysis, and fluorescent in situ hybridization. We found a significant association between p53 abnormalities and genetic instability detected by these methods.

Screening for germ line TP53 mutations in breast cancer patients.

The constant denaturant gel electrophoresis technique was used to screen for TP53 germ line mutations in 237 women with breast carcinoma (167 unselected patients, 30 patients with at least one first-degree relative with breast cancer, and 40 women diagnosed with breast cancer before age 35). A germ line mutation at codon 181 was noted in one of the unselected patients and a codon 245 mutation in one of the early-onset patients. Both had a family history of breast cancer and other malignancies suggestive of Li-Fraumeni syndrome. The codon 245 mutation was also present in this patient's affected mother.

BRCA2 and p53 mutations in primary breast cancer in relation to genetic instability.

The products of the BRCA breast cancer susceptibility genes have been implicated in cell cycle control and DNA repair. It has been suggested that mutations in the p53 gene are a necessary step in tumorigenesis in BRCA tumors. We tested samples from 402 breast cancer patients for germ-line BRCA2 and p53 mutations in tumors. p53 mutations are more frequent in BRCA2 mutation carriers than they are in controls. Tumors with mutations in either gene had multiple chromosomal abnormalities, as shown by cytogenetic analysis.

Consortium study on 1280 breast carcinomas: allelic loss on chromosome 17 targets subregions associated with family history and clinical parameters.

The pattern of loss of heterozygosity (LOH) on chromosome 17 in human breast cancer is complicated and shows many different regions of loss. In an attempt to narrow down the relevant regions of LOH on chromosome 17, we have studied the deletion pattern and its association with clinical parameters in 1280 breast carcinoma-venous blood lymphocyte pairs. In total, 42 different chromosome 17 loci were investigated, and between 25 and 625 cases were analyzed at each locus. The frequency of LOH observed on the p arm was much higher than that observed on the q arm. The opposite effect was observed in 52 ovarian cancer cases investigated, with less LOH on 17p than on 17q. Patterns of loss consistent with interstitial and terminal deletions, as well as loss of either the p or q arm or monosomy 17 were observed. To determine whether loss at particular loci may be associated with biological features of breast tumors, clinical data including age of onset, family history of breast cancer, tumor histopathology, tumor size, estrogen receptor (ER) status, and occurrence of lymph node or distant metastases were collected for each case. Overall, large-sized, ER-negative, lymph node-positive ductal tumors showed the highest frequencies of LOH, with ER-negative and ductal tumors showing LOH for markers along the majority of the chromosome. Eight regions of chromosome 17 appear to be associated with human breast cancer, two on 17p and six on 17q. These regions were not necessarily in the areas exhibiting the highest frequencies of LOH but were defined by interstitial and terminal deletions in multiple independent cases. Seven of these regions showed statistically significant differences in LOH associated with clinical parameters. These data strongly suggest that loci on chromosome 17 may determine aspects of tumor presentation and disease behavior in human breast cancer and pinpoint candidate tumor suppressor gene loci.

BRCA2 mutation in Icelandic prostate cancer patients.

Molecular genetic analysis of prostate cancer has gained considerable attention in recent years. The hope is to find genetic markers that can help to determine which patients are likely to develop a progressive or lethal disease and would therefore benefit from early treatment. The BRCA2 gene on chromosome 13 has been associated with familial male and female breast cancer. A founder mutation in this gene has been detected in the Icelandic population. This is a 5-bp deletion that leads to an early termination and truncated protein. Clustering of prostate cancers in some of the Icelandic BRCA2 families implies that mutation carriers are at increased risk of developing cancer of the prostate. The aim of the study was to investigate this mutation in Icelandic prostate cancer patients related to BRCA2 positive breast cancer probands and to estimate the prevalence of this mutation in unselected prostate cancer patients. To examine the potential role of this mutation in prostate cancer we analyzed prostate cancer cases from 16 BRCA2 families and all available samples from individuals diagnosed with prostate cancer in Iceland over a period of 1 year. The risk ratio of prostate cancer was 4.6 (1.9-8.8) in first-degree relatives and 2.5 (1.2-4.6) in second-degree relatives of the 16 BRCA2 positive breast cancer probands. Of 26 prostate cancer cases found in these families 12 were analyzed, and 8 of these (66.7%) had the BRCA2 mutation. All of these patients developed an advanced disease, and all have died of prostate cancer (median survival 22.5 months). Among unselected cases 3.1% (2/65) had the mutation and developed an advanced disease as well. This specific mutation in the BRCA2 gene is found in a subset of Icelandic prostate cancer cases and appears to be a marker for poor prognosis.

Genetic changes in breast carcinomas in an Icelandic population.

We have examined breast tumour samples from 109 unselected breast cancer patients for genetic changes on chromosomes 13 and 17. We have looked for allelic losses, firstly, at the retinoblastoma locus, RB1, on chromosome 13q, and secondly, on both arms of chromosome 17. We have also studied the same samples for amplification of the erbB2 oncogene. We searched for mutations in four well conserved areas of the p53 gene using constant denaturant gradient electrophoresis (CDGE). Allelic loss or rearrangement was detected in a large proportion of the tumours, affecting 37-51% of cases with different probes. The areas most frequently affected were 17p13.1 and 17p13.3. Point mutations and small deletions in the p53 gene on 17p13.1 were detected in 16% of the tumours. The data on genetic changes were then analyzed for three different correlations: 1) co-operation between different lesions, 2) association with family history of breast cancer, 3) correlation with clinical factors and prognosis. There was association between losses at the retinoblastoma locus and losses on 17p and 17q. We also found an association between p53 mutations and amplification of the erbB2 oncogene. Relatives of patients having deletions at the retinoblastoma locus and/or sites on chromosome 17 in the tumours have a significantly increased relative risk of developing breast cancer. No such correlation is found for p53 mutations or erbB2 amplification. No p53 germline mutations were detected. P53 mutations do, however, appear to be a strong indication of poor prognosis in this population.

TP53 mutations and abnormal p53 protein staining in breast carcinomas related to prognosis.

Abnormalities in the TP53 tumour suppressor gene were evaluated in 106 unselected breast carcinomas and compared to clinical outcome of the disease. Tumours were screened for p53 abnormalities using immunohistochemical staining and polymerase chain reaction-constant denaturant gel electrophoresis (PCR-CDGE) analysis, followed by PCR and direct sequencing. Allelic loss at the TP53 locus was determined with polymorphic markers by comparing normal and tumour DNA. For approximately half of the patients, abnormal p53 protein expression in serum was determined by an ELISA assay. p53 abnormalities, detected as mutations and/or nuclear staining, were found in 37.6 (38/101) of cases. Nuclear staining for p53 protein could be identified in 33.7% of the tumours. Mutations in exons 5-8 were detected in 18.9% of the tumours, and an association was found between mutations and nuclear staining. Allelic loss in the TP53 region on 17p was more frequent in tumours showing changes in the TP53 gene (72.7%) compared to tumours with no mutation (45.8%). Serum levels of p53 antibodies showed no association with either TP53 mutations or nuclear staining. Women with TP53 mutations in their tumours had an elevated risk of dying during the study period (RR (relative risk) = 3.4, P = 0.014). The effects of p53 positive staining were similar (RR = 3.2, P = 0.013). Considering all abnormalities, mutation and/or staining, the relative risk of dying from breast cancer was 3.5 (P = 0.008).

Loss of heterozygosity at selective sites on chromosomes 13 and 17 in human breast carcinoma.

Four chromosomal regions were tested for loss of constitutional heterozygosity in primary tumours from 85 Icelandic breast cancer patients. Loss of heterozygosity and other types of gene rearrangements were observed in 37% of informative cases at the retinoblastoma locus, RB1, on chromosome 13q. Allele losses on chromosome 17 were tested with two polymorphic probes on 17p and two on 17q. Loss of heterozygosity or other types of genetic rearrangement were detected in 43.5% of cases on 17p near the p53 gene and 40.5% on 17q. In our study abnormalities at the RB1 locus and on chromosome 17 frequently occurred together, indicating that the coincident inactivation of more than one tumour suppressor gene may, in some cases, play a part in tumour formation. No significant correlation was found between these losses and clinico-histological parameters. Family history of breast cancer was found to be more common among patients with RB1 deletions and this trend was strengthened in cases where there were deletions at both the RB1 locus and on chromosome 17.

[Disability in Iceland 1996: size and characteristics.].

OBJECTIVE: To determine the size and main medical and social characteristics of the group of individuals receiving disability benefits in Iceland and compare those with figures from the other Nordic countries. MATERIAL AND METHODS: The study includes all those receiving disability benefits on the 1st of December 1996 as ascertained by the disability register at the State Social Security Institute of Iceland. RESULTS: On the prevalence day 8714 individuals were receiving disability benefits. Of those there were 7315 individuals who had disability assessed as being more than 75% (4.2% of the total population between 16 and 66 years of age); women: 4286 (58.6%), men: 3029 (41.4%). Disability was assessed as being 50% or 65% for 1399 individuals (0.7% of the total population between 16 and 66 years of age); women: 914 (65.3%), men: 485 (34.7%). Of those receiving disability benefits there is thus a significant excess of women (p<0.0001). Individuals with >75% disability are in excess in the capital region as compared with other areas (p<0.001 for men, p=0.03 for women). When different age groups within the population are compared there is a steady increase with age of the ratio of individuals with >75% disability. Disability is most commonly associated with mental disorders or diseases of the musculoskeletal system. CONCLUSION: The percentage of the total population receiving disability benefits in Iceland, is similar to that in Denmark but considerably lower than in Finland, Norway and Sweden. When different age groups are compared it emerges that there are more individuals below 30 years of age receiving disability benefits in Iceland than in the other Nordic countries. In the older age groups this ratio is reversed and gets more marked with increasing age. The following main explanations for this difference are suggested: the level of allowance and organization of the social security system is different in Iceland compared with the other Nordic countries; the Icelandic unemployment level is lower and work participation higher, especially in the upper age groups in Iceland.

The cerebrospinal fluid in myasthenia gravis.

We examined the number of leucocytes and the concentration of total protein, albumin and IgG in the cerebrospinal fluid (CSF) from 46 patients with myasthenia gravis (MG) and 50 controls. Mean leucocyte number in the MG patients was 1634 cells/ml (controls 1244), mean total protein 0.38 g/l (controls 0.32), mean IgG 0.034 g/l (controls 0.025) and mean albumin 0.199 g/l (controls 0.176). No evidence of intrathecal IgG synthesis was demonstrated. The CSF was normal in most cases. When pathological changes occurred they were slight and could be attributed to associated diseases or to iatrogenic blood contamination of the CSF. We demonstrated that an artificial blood contamination of the CSF, although macroscopically undetectable, increased the CSF albumin concentration and the CSF albumin/serum albumin ratio considerably.

Psychophysiologic response patterns in migraine before and after temperature biofeedback. Prediction of treatment outcome.

Psychophysiologic response patterns were studied in female migraine patients during headache-free periods (n = 16) and in controls (n = 8). Cardiovascular variables studied were heart rate (HR) and temporal artery pulse wave amplitudes (PWA). Phasic responses to 80-dB, 1000-Hz tones, each lasting 2 sec and sounded at irregular intervals, were studied within a habituation laboratory design. In addition, electromyographic (EMG) levels from the frontal muscles and hand temperature were measured. HR responses were less pronounced and PWA reduction more pronounced in migraine patients than in controls. There were no differences between migraine patients and controls in habituation pattern. Migraine patients showed lower hand temperature and higher EMG levels than controls. Migraine patients were treated with eight temperature biofeedback sessions and were evaluated clinically and psychophysiologically during and 2 months after treatment. Clinical follow-up evaluation was done 2 years after treatment. An average reduction in headache frequency of 66% was reported. A relationship between HR and PWA response pattern before treatment and treatment outcome was found. Migraine patient reporting most pronounced clinical improvement showed a "normalization" of the PWA response pattern after treatment.

[Neuropsychiatric manifestations in an unselected group of patients with systemic lupus erythematosus in Iceland.].

INTRODUCTION: There has been substantial difference in the reported frequency of neuropsychiatric manifestations in systemic lupus erythematosus (SLE). This difference can at least partly be explained by methodological difference, especially in case identification. MATERIAL AND METHODS: A retrospective study in a group of 65 unselected SLE patients was performed. The study consisted of two parts: 1) a neuropsychiatric evaluation which included a review of the patient's charts and a neurological interview, 2) a structured psychiatric interview, i.e. the Diagnostic Interview Schedule. RESULTS: In part one 37 patients or 57% had positive findings, while in part two the number was 32 pa nottients or 49%. Overall, 46 patients or 71% had experienced one or more neuropsychiatric manifestations. The most prevalent manifestations in part one were headache and psychoses, and in part two simple phobia, agarophobia, social phobia and generalized anxiety. Approximately 25% of the patients were treated solely outside hospitals. CONCLUSION: The unselected nature of this study gives a picture probably more representative of the true neuropsychiatric involvement in systemic lupus erythematosus than previous studies of selected patient populations.

Anxiety disorders: a result of long-term chronic fatigue--the psychiatric characteristics of the sufferers of Iceland disease.

OBJECTIVE: In order to clarify the lifetime likelihood of developing psychiatric disorder following the Akureyri disease, we have investigated 55 well documented cases of the Akureyri disease. MATERIALS AND METHODS: All participants were interviewed and diagnosed as to psychiatric disorders according to DSM-III. RESULTS: Of the 55 subjects included in this analysis 53 were women. The mean age of the participants was 67.7 years. The most common problem was agoraphobia with panic attacks 12.7% (P < 0.0001); agoraphobia without panic attacks 21.8% (P < 0.0001); social phobia 14.5% (P < 0.001); simple phobia 18.1% (P < 0.05); schizophrenia 3.6% (P < 0.01); and alcohol dependence 5.4% (P < 0.05). CONCLUSION: Prolonged chronic fatigue most commonly results in anxiety disorders. Following the infection, the more serious psychiatric disorders do not seem to play a major role in the long run.

Plasma exchange in myasthenia gravis: clinical effect.

Seventeen patients suffering from myasthenia gravis were treated with plasma exchange. Serious complications were not encountered. The effect usually appeared on the second or the third day of treatment. In 12 patients with a total of 31 plasma exchange courses, the treatment resulted in a shift in Osserman group. Six of these had long-standing remissions. Three patients responded moderately and two patients did not respond to plasma exchange.