The ACE gene and Alzheimer's disease susceptibility

A recent study suggested that the insertion (I) allele in intron 16 of the angiotensin converting enzyme gene (ACE) is associated with Alzheimer's disease (AD) risk. In our series of 239 necropsy confirmed late onset AD cases and 342 elderly non-demented controls aged >73 years, we found significantly different ACE genotype distributions in the case and control groups (p=0.007). Homozygotes for both the I and D alleles were associated with a higher risk compared to DI heterozygotes. While the APOE epsilon4 allele was strongly associated with AD risk in our series, we found no evidence for an interaction between the APOE and ACE loci. In addition, no interactions were observed between ACE and gender or age at death of the AD cases. A meta-analysis of all published reports (12 case-control series in total) suggested that both the II and ID ACE genotypes are associated with increased AD risk (odds ratio (OR) for II v DD 1.36, 95% confidence interval (CI)=1.13-1.63, OR for DI v DD 1.33, 95% CI=1.14-1.53, p=0.0002).

Structural barriers and facilitators in HIV prevention: a review of international research

OBJECTIVES

This article provides an overview of a growing body of international research focusing on the structural and environmental factors that shape the spread of the HIV/AIDS epidemic, and create barriers and facilitators in relation to HIV-prevention programs. OVERVIEW OF STRUCTURAL-FACTORS LITERATURE: Most of the research on structural and environmental factors can be grouped into a small number of analytically distinct but interconnected categories: economic (under)development and poverty; mobility, including migration, seasonal work, and social disruption due to war and political instability; and gender inequalities. An additional focus in research on structural and environmental factors has been on the effects of particular governmental and intergovernmental policies in increasing or diminishing HIV vulnerability and transmission.

INTERVENTIONS

A smaller subset of the research on structural factors describes and/or evaluates specific interventions in detail. Approaches that have received significant attention include targeted interventions developed for heterosexual women, female commercial sex workers, male truck drivers, and men who have sex with men.

CONCLUSIONS

The structural and environmental factors literature offers important insights and reveals a number of productive intervention strategies that might be explored in both resource-rich and -poor settings. However, new methodologies are required to document and evaluate the effects of the structural interventions, which by their very nature involve large-scale elements that cannot be easily controlled by experimental or quasi-experimental research designs. Innovative, interdisciplinary approaches are needed that can move beyond the limited successes of traditional behavioral interventions and explicitly attempt to achieve broader social and structural change.

Bone marrow staging of patients with non-Hodgkin lymphoma by flow cytometry: correlation with morphology

BACKGROUND

Immunophenotypic analysis is an established tool in the diagnosis and classification of many hematolymphoid disorders; however, the role of flow cytometry (FC) in detecting bone marrow involvement during the staging of non-Hodgkin lymphoma (NHL) has yet to be defined.

METHODS

The authors retrospectively analyzed 157 staging and 70 restaging bone marrow biopsies on which morphologic and FC analyses were performed; these biopsies were taken from 195 consecutive patients. Bone marrow biopsies were blindly and independently reviewed and determined to be positive, negative, or suspicious for morphologic involvement by NHL, with disagreements settled by a third reviewer. A selected panel of monoclonal antibodies was used to determine whether bone marrow involvement was immunophenotypically positive (>5%), minimal (<5%), negative, or nondiagnostic.

RESULTS

FC and morphology agreed in 78% of cases (178 of 227: 129 both negative, 49 both positive) and were discrepant in 22% (49 of 227). Seven percent (16 of 227) were morphologically positive but showed no evidence of disease on FC, whereas 12% (27 of 227) were positive by FC but had no morphologic involvement. Of the 162 morphologically negative or suspicious bone marrows, 27 were shown to be involved by FC, resulting in a false-negative detection rate of 17%. Most of these (22 of 27, 81%) had minimal detectable disease. Seven percent of Stage I and 26% of Stage II NHL cases with negative staging bone marrow morphologically were found to be involved by FC.

CONCLUSIONS

Neither morphologic examination of bone marrow biopsy specimens nor FC alone is adequate to detect all cases of NHL with bone marrow involvement. FC is most sensitive for detecting minimal bone marrow lymphoma, whereas morphology will detect most cases in which involvement is >5%. Cases of early stage NHL with morphologically negative bone marrow could potentially be restaged as Stage IV on the basis of FC results. The clinical importance of minimal bone marrow involvement by NHL needs further evaluation.

The chaperoning activity of hsp110. Identification of functional domains by use of targeted deletions

hsp110 is one of major heat shock proteins of eukaryotic cells and is a diverged relative of the hsp70 family. It has been previously shown that hsp110 maintains heat-denatured luciferase in a soluble, folding competent state and also confers cellular heat resistance in vivo. In the present study the functional domains of hsp110 that are responsible for its chaperoning activity are identified by targeted deletion mutagenesis using the DnaK structure as the model. The chaperoning activity of mutants is assessed based on their ability to solubilize heat-denatured luciferase as well as to refold luciferase in the presence of rabbit reticulocyte lysate. It is shown that these functions require only an internal region of hsp110 that includes the predicted peptide binding domain and two immediately adjacent C-terminal domains. It is also shown that although hsp110 binds ATP, binding can be blocked by its C-terminal region.

Interim analysis of the incidence of breast cancer in the Royal Marsden Hospital tamoxifen randomised chemoprevention trial

BACKGROUND

Tamoxifen, a drug with antioestrogenic effects, is predicted to prevent the occurrence of breast cancer. We have undertaken a trial of tamoxifen in healthy women who are at increased risk of breast cancer because of family history. We report a planned interim analysis.

METHODS

Between October, 1986, and April, 1996, we accrued 2494 healthy women aged between 30 and 70 with a family history of breast cancer. They have been randomised (double blind) to receive tamoxifen 20 mg per day orally or placebo for up to 8 years. Follow-up included clinical assessment, annual mammography, and assessment of toxicity and compliance. The primary endpoint was the occurrence of breast cancer, which was analysed on an intention-to-treat basis with a survival curve.

FINDINGS

With a median follow-up of 70 months, 2471 women (tamoxifen 1238, placebo 1233) were suitable for analysis. The groups were evenly matched at baseline, and compliance was good. The overall frequency of breast cancer is the same for women on tamoxifen or placebo (tamoxifen 34, placebo 36, relative risk 1.06 [95% CI 0.7-1.7], p=0.8). Participants who were already on hormone-replacement therapy when they entered the study had an increased risk of breast cancer compared with non-users. Those participants who started such therapy while on trial had a significantly reduced risk. The safety profile of tamoxifen was as expected.

INTERPRETATION

We have been unable to show any effect of tamoxifen on breast-cancer incidence in healthy women, contrary to the report from the NSABP-P1 study showing a 45% reduction in healthy women given tamoxifen versus placebo. Differences in the study populations for the two trials may underlie these conflicting findings: eligibility in our trial was based predominantly on a strong family history of breast cancer whereas in the NSABP trial was mostly based on non-genetic risk factors. The importance of oestrogen promotion may vary between such populations.

Haplotype and phenotype analysis of nine recurrent BRCA2 mutations in 111 families: results of an international study

Several BRCA2 mutations are found to occur in geographically diverse breast and ovarian cancer families. To investigate both mutation origin and mutation-specific phenotypes due to BRCA2, we constructed a haplotype of 10 polymorphic short tandem-repeat (STR) markers flanking the BRCA2 locus, in a set of 111 breast or breast/ovarian cancer families selected for having one of nine recurrent BRCA2 mutations. Six of the individual mutations are estimated to have arisen 400-2,000 years ago. In particular, the 6174delT mutation, found in approximately 1% of individuals of Ashkenazi Jewish ancestry, was estimated to have arisen 29 generations ago (1-LOD support interval 22-38). This is substantially more recent than the estimated age of the BRCA1 185delAG mutation (46 generations), derived from our analogous study of BRCA1 mutations. In general, there was no evidence of multiple origins of identical BRCA2 mutations. Our study data were consistent with the previous report of a higher incidence of ovarian cancer in families with mutations in a 3.3-kb region of exon 11 (the ovarian cancer cluster region [OCCR]) (P=.10); but that higher incidence was not statistically significant. There was significant evidence that age at diagnosis of breast cancer varied by mutation (P<.001), although only 8% of the variance in age at diagnosis could be explained by the specific mutation, and there was no evidence of family-specific effects. When the age at diagnosis of the breast cancer cases was examined by OCCR, cases associated with mutations in the OCCR had a significantly older mean age at diagnosis than was seen in those outside this region (48 years vs. 42 years; P=.0005).

Creutzfeldt-Jakob disease (CJD) after blood product transfusion from a donor with CJD

We report a second case of an association between an albumin transfusion and Creutzfeldt-Jakob disease. On balance, we believe our case represents a chance and not a causal relation.

A systematic review and meta-analysis of family history and risk of ovarian cancer

OBJECTIVE

To estimate the relative risk and lifetime risk of ovarian cancer in women with various categories of family history.

DESIGN

A meta-analysis of all published case-control and cohort studies.

METHODS

Pooled relative risk estimates were calculated for the case control studies, using the Mantel-Haenzel method. These estimates were combined with the relative risks from the cohort studies. The pooled estimates of relative risk were used to estimate lifetime risks of ovarian cancer from age 15 up to age 75, for various categories of family history.

MAIN OUTCOME MEASURES

Relative risks and lifetime risks of developing ovarian cancer were calculated for the categories of women with 1. an affected first degree relative; 2. an affected mother; 3. an affected sister; and 4. women with more than one affected relative.

RESULTS

The relative risk to first degree relatives is 3.1 (95% CI 2.6-3.7). There is some evidence that this relative risk declines with age. The relative risk to mothers of cases 1.1 (95% CI 0.8-1.6) was lower than the relative risks to sisters: 3.8 (95% CI 2.9-5.1), and daughters: 6.0 (95% CI 3.0-11.9); the explanation of this difference is unclear.

CONCLUSIONS

Women with a family history of ovarian cancer have a substantially higher risk of developing ovarian cancer compared with women without such a history. However the risk is small for most categories of family history, except for the small number of individuals who have more than one affected relative.

Linkage analysis of chromosome 1q markers in 136 prostate cancer families. The Cancer Research Campaign/British Prostate Group U.K. Familial Prostate Cancer Study Collaborators

Prostate cancer shows evidence of familial aggregation, particularly at young ages at diagnosis, but the inherited basis of familial prostate cancer is poorly understood. Smith et al. recently found evidence of linkage to markers on 1q, at a locus designated "HPC1," in 91 families with multiple cases of early-onset prostate cancer. Using both parametric and nonparametric methods, we attempted to confirm this finding, in 60 affected related pairs and in 76 families with three or more cases of prostate cancer, but we found no significant evidence of linkage. The estimated proportion of linked families, under a standard autosomal dominant model, was 4%, with an upper 95% confidence limit of 31%. We conclude that the HPC1 locus is responsible for only a minority of familial prostate cancer cases and that it is likely to be most important in families with at least four cases of the disease.

Contribution of BRCA1 mutations to ovarian cancer

BACKGROUND

Inherited mutations in the BRCA1 gene confer a high risk of breast and ovarian cancer in some families. To determine the contribution of BRCA1 mutations to ovarian cancer in the general population, we analyzed DNA samples from a consecutive series of women with ovarian cancer seen at one center.

METHODS

We studied 374 women who received a diagnosis of epithelial ovarian cancer before the age of 70 years and were treated at the Royal Marsden Hospital between July 1993 and September 1995. Genomic DNA was analyzed by multiplex heteroduplex analysis. Variants were further identified by sequencing.

RESULTS

Probable germ-line BRCA1 mutations were identified in 13 of the 374 women (3 percent; 95 percent confidence interval, 2 to 6 percent). Six of the variants have not been described previously. Of the 13 mutations, 12 are predicted to result in a truncated protein product. An additional variant results in an in-frame deletion just outside the putative zinc-finger domain. Nine of the 12 women with truncating mutations had family histories of breast or ovarian cancer or both.

CONCLUSIONS

Assuming that our method has a sensitivity of 70 percent, mutations in BRCA1 occur in approximately 5 percent (95 percent confidence interval, 3 to 8 percent) of women in whom ovarian cancer is diagnosed before the age of 70 years.

Common BRCA1 variants and susceptibility to breast and ovarian cancer in the general population

Most multiple case families of young onset breast cancer and ovarian cancer are thought to be due to highly penetrant mutations in the predisposing genes BRCA1 and BRCA2. However, these mutations are uncommon in the population and they probably account for only a few percent of all breast cancer incidence. A much larger fraction of breast cancer might, in principle, be due to common variants which confer more modest individual risks. There are several common polymorphisms in the BRCA1 gene which generate amino acid substitutions. We have examined the frequency of four of these polymorphisms: Gln356Arg, Pro871Leu, Glu1038Gly and Ser1613Gly in large series of breast and ovarian cancer cases and matched controls. Due to strong linkage disequilibrium, these four sites generate only three haplotypes with a frequency > 1.3%. The most common haplotypes, defined by the alleles Gln356Pro871Glu1038Ser1613 and Gln356Leu871Gly1038Gly1613, have frequencies of 0.57 and 0.32 respectively, and these frequencies do not differ significantly between patient and control groups. Thus the most common polymorphisms of the BRCA1 gene do not make a significant contribution to breast or ovarian cancer risk. However, our data suggest that the Arg356 allele may have a different genotype distribution in breast cancer patients from that in controls (Arg356 homozygotes are more frequent in the control groups, P = 0.01), indicating that it may be protective against breast cancer. If this finding can be confirmed, it may provide an insight into the structural features of the BRCA1 protein that are important for its function.

Variation of risks of breast and ovarian cancer associated with different germline mutations of the BRCA2 gene

The breast cancer susceptibility gene BRCA2 on chromosome 13q12-13 has recently been identified. Germline mutations of BRCA2 are predicted to account for approximately 35% of families with multiple case, early onset female breast cancer, and they are also associated with an increased risk of male breast cancer, ovarian cancer, prostate cancer and pancreatic cancer. Germline mutations of a second cancer susceptibility gene BRCA1 (ref. 5), are associated with a strong predisposition to ovarian cancer as well as female breast cancer. Recent studies have suggested that the phenotype in BRCA1 families with respect to the ratio of breast to ovarian cancer varies with the location of the BRCA1 mutation. To determine whether germline mutations in BRCA2 are associated with a similar variation in phenotypic risk, we have analysed the distribution of mutations in 25 families with multiple cases of breast and/or ovarian cancer ascertained in the United Kingdom and Eire. These mutations all lead to premature truncation of BRCA2 as a result of frameshift deletions/insertions or nonsense mutations. Analysis of the mutation distribution along the length of the gene indicates a significant genotype-phenotype correlation. Truncating mutations in families with the highest risk of ovarian cancer relative to breast cancer are clustered in a region of approximately 3.3 kb in exon 11 (P = 0.0004). Published data on mutations in 45 other BRCA2-linked families provide support for this correlation.

Linkage of the gene for the triple A syndrome to chromosome 12q13 near the type II keratin gene cluster

The triple A or Allgrove's syndrome (MIM*231550) is an autosomal recessive disease characterized by the triad of adrenocorticotropic hormone (ACTH) resistant adrenal insufficiency, achalasia and alacrima. Since its first description by Allgrove et al. (1978) more than 70 cases from all over the world have been reported. The syndrome manifests itself during the first decade of life with severe hypoglycaemic episodes which can cause sudden death. The frequent association with neurological disorders presenting as a mixed pattern of upper and lower motor neuropathy, sensory impairment, autonomic neuropathy and mental retardation may result in a severely disabling disease. As an additional feature some patients have hyperkeratosis of their palms and soles. We have performed a systematic genome linkage scan in eight triple A families of which three were consanguineous [including the large highly inbred kindred described by Moore et al. (1991)]. We obtained conclusive evidence for linkage of the triple A syndrome locus to markers on chromosome 12q13 (D12S368, theta max = 0, Zmax = 10.81) with no indication of genetic heterogeneity. Haplotype and multipoint analyses suggest that the gene is located on a chromosomal segment flanked by the markers D12S1629 and D12S312 which are 6 cM apart. This region harbors the type II keratin gene cluster, and potential candidate genes include SCN8A and HOXC genes.

Analysis of the contribution of HLA genes to genetic predisposition in inflammatory bowel disease

Crohn disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases (IBDs) of unknown etiology. First-degree relatives of IBD patients have a 10-fold increase in risk of developing the same disease, and distinct associations between specific HLA types and both CD and UC have been reported. We have evaluated the contribution of genes at the HLA locus to susceptibility in IBD by linkage analysis of highly informative microsatellite polymorphisms in 43 families with multiple affected cases. No evidence for linkage of HLA to IBD was obtained under any of the four models tested. Analysis of HLA haplotype sharing in affected relatives indicated that the relative risk to a sibling conferred by the HLA locus was 1.11 in UC and 0.75 in CD, with upper (95%) confidence limits of 2.41 and 1.37, respectively. This suggests that other genetic or environmental factors are responsible for most of the familial aggregation in IBD.

The 170 kDa glucose regulated stress protein is a large HSP70-, HSP110-like protein of the endoplasmic reticulum

The existence of a family of unusually large and highly diverged hsp70-like proteins (the hsp110/SSE family) has recently been described. The 170 kDa glucose regulated stress protein (grp170) is a retained endoplasmic reticulum glycoprotein that may be involved in immunoglobulin folding and/or assembly. We describe here the cloning of the cDNA for grp170 and show that it, like hsp110, is a large and highly diverged hsp70-like polypeptide which shares specific features with hsp70 (the dnaK family) and the hsp110/SSE family, while also differing from both. Grp170 contains an ATP binding domain and binds ATP, it possesses a carboxyl terminal NDEL sequence, and its mRNA is anoxia inducible.

Haplotype and phenotype analysis of six recurrent BRCA1 mutations in 61 families: results of an international study

Several BRCA1 mutations have now been found to occur in geographically diverse breast and ovarian cancer families. To investigate mutation origin and mutation-specific phenotypes due to BRCA1, we constructed a haplotype of nine polymorphic markers within or immediately flanking the BRCA1 locus in a set of 61 breast/ovarian cancer families selected for having one of six recurrent BRCA1 mutations. Tests of both mutations and family-specific differences in age at diagnosis were not significant. A comparison of the six mutations in the relative proportions of cases of breast and ovarian cancer was suggestive of an effect (P = .069), with 57% of women presumed affected because of the 1294 del 40 BRCA1 mutation having ovarian cancer, compared with 14% of affected women with the splice-site mutation in intron 5 of BRCA1. For the BRCA1 mutations studied here, the individual mutations are estimated to have arisen 9-170 generations ago. In general, a high degree of haplotype conservation across the region was observed, with haplotype differences most often due to mutations in the short-tandem-repeat markers, although some likely instances of recombination also were observed. For several of the instances, there was evidence for multiple, independent, BRCA1 mutational events.

Germline mutations of the BRCA1 gene in breast and ovarian cancer families provide evidence for a genotype-phenotype correlation

Mutations in the BRCA1 gene, discovered in 1994, are associated with an 80-90% lifetime risk of breast cancer. We have analysed 60 families with a history of breast and/or ovarian cancer for germline mutations in BRCA1. Twenty-two different mutations were detected in 32 families (53%), of which 14 are previously unreported. We observed a significant correlation between the location of the mutation in the gene and the ratio of breast to ovarian cancer incidence within each family. Our data suggest a transition in risk such that mutations in the 3' third of the gene are associated with a lower proportion of ovarian cancer. Haplotype analysis supports previous data which suggest some BRCA1 mutation carriers have common ancestors; however, we have found at least two examples where recurrent mutations appear to have arisen independently.