Skewed X chromosome inactivation and early-onset breast cancer

BACKGROUND

Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early-onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study.

METHODS

We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme HpaII. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as > 90% of the signal from one allele in the HpaII digested sample.

RESULTS

There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre-menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR = 1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR = 0.9, 95% CI 0.4 to 2.0.

CONCLUSIONS

While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.

Prospective risk of cancer in CDKN2A germline mutation carriers

BACKGROUND

The CDKN2A gene is the major known high-risk melanoma susceptibility gene. Susceptibility to other cancers has also been suggested. However, most studies examining the risks of other cancers classified individuals according to the family's CDKN2A mutation rather than determining individual mutation status. For non-population-based studies, risks could also be biased because of cancer occurrence prior to family ascertainment.

METHODS

We examined the risk of non-melanoma cancer in 117 mutation-positive and 136 mutation-negative members from 15 families that had at least two first degree relatives with melanoma and CDKN2A mutations restricting the analysis to the period after the families were ascertained (that is, the prospective period) and using individual mutation data. The families have been followed prospectively for 4-26 years starting in the 1970s.

RESULTS

Overall, there was no significant association for mutation-negative subjects (Obs/Exp = 0.3, 95% confidence interval (CI) 0.0 to 1.2) although this group had only two observed cancers. In contrast, mutation-positive subjects had a significantly increased risk for all cancers combined (Obs/Exp = 12/5.5 = 2.2, 95% CI 1.1 to 3.8) primarily because of digestive system tumours, particularly pancreatic cancer. No other organ systems or individual tumour sites showed significantly increased risks.

CONCLUSIONS

Differences in CDKN2A-non-melanoma cancer associations across studies may result from variation in genetic backgrounds, insufficient follow up, misclassification of mutation carriers, or the presence of other genetic and/or environmental risk factors in both CDKN2A mutation carriers and non-carriers. Larger sample sizes, prospective follow up, and individual mutation data will be required to understand these differences.

XPD gene polymorphism and host characteristics in the association with cutaneous malignant melanoma risk

We recently reported an association between low DNA repair capacity, measured through the host-cell reactivation assay, and melanoma risk in subjects with dysplastic naevi or low tanning ability. We investigated the genetic basis for these findings by analysing the Asp312Asn and Lys751Gln polymorphisms of the XPD (ERCC2) DNA repair gene in the same subjects. Similar to our previous report, no significant association between XPD polymorphisms and melanoma risk was found in 176 melanoma cases and 177 controls (odds ratio (OR)=1.5, 95% confidence interval (CI)=0.9–2.5 for 312Asn; OR=1.3, 95% CI=0.8–2.1 for 751Gln, adjusted for age, gender, dysplastic naevi and pigmentation characteristics). However, XPD variants were associated with increased risk in older (>50 years) subjects (OR=3.4, 95% CI=1.6–7.3 for 312Asn; OR=2.3, 95% CI=1.1–4.9 for 751Gln). The 751Gln allele was associated with elevated melanoma risk among subjects without dysplastic naevi (OR=2.6, 95% CI=1.1–6.4). Subjects with low tanning ability and XPD variants exhibited a nonsignificant increase of melanoma risk (OR=2.3, 95% CI=0.7–7.0 for 312Asn; OR=3.0, 95% CI=1.0–8.8 for 751Gln). DNA repair capacity was slightly decreased in subjects carrying 751Gln alleles. XPD variants may modify melanoma risk in subjects with specific host characteristics, such as older age, lack of dysplastic naevi or low tanning ability.

Population attributes affecting the prevalence of BRCA mutation carriers in epithelial ovarian cancer cases in israel

OBJECTIVE

The objective was to evaluate the prevalence of BRCA1/2 mutations in selected categories of ovarian cancer patients in Israel.

METHODS

Blood samples and specimens of ovarian tumors were obtained in the course of a national case control study of women with ovarian cancer in Israel. Eight hundred ninety-six patients with epithelial ovarian cancer, 40 cases with nonepithelial ovarian cancer, and 68 with primary peritoneal cancer were tested for the BRCA mutations. Analysis of the three common BRCA mutations in Israel (185delAG, 5382insC in BRCA1, and 6174delT in BRCA2) was done using a multiplex polymerase chain reaction assay. A multivariate logistic regression model was used to assess the association of mutation carrier status and other factors (age, origin, family history, and clinical variables).

RESULTS

Of the 779 invasive epithelial ovarian cancer cases, 29.4% were mutation carriers. The prevalence of the mutations was higher among women below age 60 and in more advanced cases. The prevalence was low in mucinous tumors. There was almost a twofold excess of mutations among women with positive family history (45.7%), but still 26.5% of the family history negative cases were carriers. As expected, we found a higher rate of mutation carriers among the Ashkenazi group (34.2%) and 55% among Ashkenazi women with positive family history. No subjects born in North Africa were mutation positive.

CONCLUSION

BRCA mutations are strongly associated with ovarian cancer and they are present in variable rates in distinct age, ethnic, and histopathologic categories.

Frequency of BRCA mutations in primary peritoneal carcinoma in Israeli Jewish women

OBJECTIVE

The aim of the present study was to compare demographic and clinical characteristics of primary peritoneal carcinoma (PPC) to ovarian carcinoma (OvC) with regard to BRCA mutation frequencies.

METHODS

Incident cases of histologically confirmed cancer of the ovary or peritoneum diagnosed in Israeli Jewish women between March 1, 1994, and June 30, 1999, were identified within the framework of an ongoing nationwide epidemiological study of these neoplasms in Israel. The present study comprises 609 (81.5% of 747) Jewish women with epithelial stage III-IV OvC and 68 (77.3% of 88) Jewish women with PPC who were genetically tested for the BRCA mutations. Data from each patient were collected by the aid of a prestructured questionnaire and medical records. Blood samples or tumor tissue was tested for the 185delAG and 5382insC mutations in BRCA1 and the 6174delT mutations in BRCA2.

RESULTS

A carrier rate of 28% of any BRCA 1/2 mutation was observed among the PPC group and of 30% among the invasive stage III-IV OvC. No differences were found between PPC and OvC neither in the overall distribution of BRCA1/2 mutation carrier rates nor according to type of mutation, age, ethnic origin, and histologic subtype. Among women with a positive family history, a higher rate of mutation carriers was observed in the PPC group compared to the OvC group (72.7 vs 43.8%, respectively, P = 0.07).

CONCLUSIONS

The similar frequency distribution of BRCA1/2 mutations in PPC and OvC observed in the present study indicates that these mutations may predispose to PPC as well and that this neoplasm is part of the hereditary breast-ovarian cancer syndrome.

Effect of BRCA mutations on the length of survival in epithelial ovarian tumors

PURPOSE

To study the role of BRCA mutations in ovarian cancer survival.

PATIENTS AND METHODS

Blood samples and specimens of ovarian tumors (whenever blood samples were not available) at the time of the primary surgery were obtained in the course of a nationwide case-control study of women with ovarian cancer in Israel. The three common BRCA mutations in Israel (185delAG, 5382insC, and 6174delT) were analyzed with a multiplex polymerase chain reaction to amplify the exons containing the three mutations using fluor-labeled primers in a single reaction. Because each mutation is a small insertion or deletion, they can be detected as length polymorphisms. Patients were followed for up to 5 years (range, 20 to 64 months). Statistical analysis was performed using the Kaplan-Meier method and the log-rank test. Stepwise Cox regression analysis was used for determination of independent prognostic factors.

RESULTS

This report is based on 896 blood or tumor specimens analyzed for the presence of the BRCA mutations. Of these, 234 women (26.1%) were found to be positive. A significant difference in survival pattern was found between BRCA1/BRCA2 carriers and noncarriers among the women with invasive ovarian cancer (median survival, 53.4 months v. 37.8 months; 3-year survival, 65.8% v. 51.9%, respectively). These differences were independent of age at diagnosis or stage of the disease.

CONCLUSION

Our data indicate that the survival of patients with ovarian cancer is affected by BRCA germline mutation, at least in the early years after diagnosis.

A single nucleotide polymorphism in the 5' untranslated region of RAD51 and risk of cancer among BRCA1/2 mutation carriers

RAD51 colocalizes with both BRCA1 and BRCA2, and genetic variants in RAD51 would be candidate BRCA1/2 modifiers. We searched for RAD51 polymorphisms by sequencing 20 individuals. We compared the polymorphism allele frequencies between female BRCA1/2 mutation carriers with and without breast or ovarian cancer and between population-based ovarian cancer cases with BRCA1/2 mutations to cases and controls without mutations. We discovered two single nucleotide polymorphisms (SNPs) at positions 135 g-->c and 172 g-->t of the 5' untranslated region. In an initial group of BRCA1/2 mutation carriers, 14 (21%) of 67 breast cancer cases carried a "c" allele at RAD51:135 g-->c, whereas 8 (7%) of 119 women without breast cancer carried this allele. In a second set of 466 mutation carriers from three centers, the association of RAD51:135 g-->c with breast cancer risk was not confirmed. Analyses restricted to the 216 BRCA2 mutation carriers, however, showed a statistically significant association of the 135 "c" allele with the risk of breast cancer (adjusted odds ratio, 3.2; 95% confidence limit, 1.4-40). BRCA1/2 mutation carriers with ovarian cancer were only about one half as likely to carry the RAD51:135 g-->c SNP. Analysis of the RAD51:135 g-->c SNP in 738 subjects from an Israeli ovarian cancer case-control study was consistent with a lower risk of ovarian cancer among BRCA1/2 mutation carriers with the "c" allele. We have identified a RAD51 5' untranslated region SNP that may be associated with an increased risk of breast cancer and a lower risk of ovarian cancer among BRCA2 mutation carriers. The biochemical basis of this risk modifier is currently unknown.

A common founder for the V126D CDKN2A mutation in seven North American melanoma-prone families

One of the most common melanoma-related CDKN2A mutations reported in North America is the V126D mutation. We examined nine markers surrounding CDKN2A in three American and four Canadian families carrying the V126D mutation. All seven families had a haplotype consistent with a common ancestor/founder for this mutation. In addition, the mutation appears to have originated 34-52 generations ago (1-LOD-unit support interval 13-98 generations).

Parity, oral contraceptives, and the risk of ovarian cancer among carriers and noncarriers of a BRCA1 or BRCA2 mutation

BACKGROUND

Multiparity and the use of oral contraceptives reduce the risk of ovarian cancer, but their effects on this risk in women with a BRCA1 or BRCA2 mutation are unclear.

METHODS

We conducted a population-based case-control study of ovarian cancer among Jewish women in Israel. Women were tested for the two founder mutations in BRCA1 and the one founder mutation in BRCA2 that are known to be common among Jews. We estimated the effects of parity and oral-contraceptive use on the risk of ovarian cancer in carriers and noncarriers in separate analyses that included all control women, who did not have ovarian cancer.

RESULTS

Of 751 controls who underwent mutation analysis, 13 (1.7 percent) had a BRCA1 or BRCA2 mutation, whereas 244 of 840 women with ovarian cancer (29.0 percent) had a BRCA1 or BRCA2 mutation. Overall, each additional birth and each additional year of use of oral contraceptives were found to lower the risk of ovarian cancer, as expected. Additional births were protective in separate analyses of carriers and noncarriers, but oral-contraceptive use appeared to reduce the risk only in noncarriers; among carriers, the reduction in the odds of ovarian cancer was 12 percent per birth (95 percent confidence interval, 2.3 to 21 percent) and 0.2 percent per year of oral-contraceptive use (-4.9 to 5.0 percent).

CONCLUSIONS

The risk of ovarian cancer among carriers of a BRCA1 or BRCA2 mutation decreases with each birth but not with increased duration of use of oral contraceptives. These data suggest that it is premature to use oral contraceptives for the chemoprevention of ovarian cancer in carriers of such mutations.

Patients with double primary tumors in the breast and ovary- clinical characteristics and BRCA1-2 mutations status

OBJECTIVE

The aim of this study was to define the prevalence, clinical characteristics, and BRCA1-2 mutation carrier status of ovarian cancer (OvC) patients with a previous primary malignancy in the breast (PPMBr).

METHODS

The study population comprised 1240 consecutive Jewish Israeli women with pathologically confirmed epithelial OvC diagnosed between March 1, 1994, and December 31, 1997. Demographic and clinical data were obtained from medical files and from a detailed questionnaire taken through a nationwide epidemiological case-control study on OvC. Blood samples and tumor tissues were collected for analysis of the three predominant germline BRCA1-2 Jewish founder mutations (185delAG, 5382insC, and 6174delT).

RESULTS

Fifty nine (4.7%) patients with OvC had a PPMBr. The median age at diagnosis of OvC was 60 years. The mean interval between the two diagnoses was 104 months (range 0-363 months). In the majority of the patients (n = 53), the diagnosis of breast cancer (BrC) preceded the OvC by more than 1 year. The ovarian tumors were diagnosed in 47% of the cases following investigation of patients' symptoms. In 41%, diagnosis was made as a consequence of check-up exams performed during the routine follow-up of BrC survivors. Patients with PPMBr were more likely to present with FIGO ovarian stage III-IV, compared to women with solitary OvC (73% vs 60. 3%, P < 0.05), and less likely to have borderline tumors (3.4% vs 17. 9%, P = 0.007). Family history of OvC/BrC was recorded in 26% of this group of patients compared to 10.5% among patients with solitary OvC (P = 0.003). Patients with PPMBr had an exceptionally high prevalence of BRCA1-2 mutations (57%), irrespective of family history.

CONCLUSIONS

Patients with PPMBr present with more advanced disease and invasive-type epithelial ovarian tumors when compared to cases associated with solitary OvC. The rate of BRCA1-2 mutations in Jewish women with OvC who had PPMBr is at least twice as high as in Jewish women with OvC as the solitary disease.

Psychosocial factors predicting BRCA1/BRCA2 testing decisions in members of hereditary breast and ovarian cancer families

Although BRCA1/2 testing has increasingly entered clinical practice, much is to be learned about the most effective ways to provide counseling to persons potentially interested in receiving test results. The purpose of this study was to identify factors affecting genetic testing decisions in a cohort of hereditary breast and ovarian cancer (HBOC) families presented with the choice to undergo testing. Relatives in these families are known to carry BRCA1 or BRCA2 mutations. Sociodemographics, personality traits, and family functioning were self-assessed using validated psychometric instruments at baseline. Among 172 individuals who participated in pretest education and counseling, 135 (78%) chose to undergo genetic testing and 37 (22%) chose not to be tested. Individuals who chose to undergo genetic testing were more likely to be older (> or =40 years), to have lower levels of optimism, and to report higher levels of cohesiveness in their families. A better understanding of factors that influence interest in predictive testing may help to inform the counseling that occurs prior to genetic testing.

Genotype-phenotype relationships in U.S. melanoma-prone families with CDKN2A and CDK4 mutations

BACKGROUND

Two genes have been implicated in the development of cutaneous malignant melanoma (CMM). CDK4 (the gene encoding cyclin-dependent kinase 4, an oncogene) has exhibited germline mutations found in only three melanoma-prone families to date. CDKN2A is a tumor suppressor gene that encodes p16 (which inhibits activity of the cyclin D1-CDK4 complex) with germline mutations detected in 10%-25% of melanoma-prone families, some of whom are also prone to pancreatic cancer.

METHODS

We compared 104 CMM patients from 17 CDKN2A families and 12 CMM case subjects from two CDK4 families. We used nonparametric statistics to test for differences in median age at first CMM diagnosis, numbers of CMMs, and numbers of nevi. The three recurrent mutations were haplotyped. All P values were two-sided.

RESULTS

The median age at CMM diagnosis (P =.70) and the median numbers of CMMs (P =.73) did not differ between CMM case subjects from CDKN2A versus CDK4 families. Assessment of CMM case subjects from CDKN2A families with and without pancreatic cancer revealed no statistically significant differences in median age at diagnosis (P =.80) or in tumor number (P =.24). There was, however, a statistically significant difference in age-adjusted median numbers of nevi (P =.004), and CMM case subjects from CDKN2A families without pancreatic cancer had greater numbers of nevi. Recurrent CDKN2A mutations were a change from valine to aspartic acid at codon 126 (n = 3) and from glycine to tryptophan at codon 101 (n = 3). Six CDKN2A families had pancreatic cancer. Both CDK4 families carried a mutation resulting in an arginine-to-cysteine substitution at codon 24. Analyses of recurrent CDKN2A and CDK4 mutations suggested common haplotypes.

CONCLUSIONS

The recurrent CDKN2A mutations were observed in families with and without pancreatic cancer, which suggests that other factors may be involved in the development of pancreatic cancer. Despite hypothetical differences in the mechanisms of action between CDKN2A and CDK4, clinical factors were indistinguishable between CMM case subjects from CDKN2A versus CDK4 families.

Automated detection of prevalent mutations in BRCA1 and BRCA2 genes, using a fluorogenic PCR allelic discrimination assay

Mutations in the genes BRCA1 and BRCA2 account for 5%-10% of familial early onset breast cancer. Identification of these mutations allows molecular diagnosis for breast cancer susceptibility. A high through-put automated PCR allelic discrimination assay (ADA) was developed to detect the prevalent mutations in these genes. Two allele specific oligonucleotides (ASO) are directly used in the PCR reaction, in both of which the fluorescent reporter and quencher dyes are attached to the 5' and 3' ends, respectively. During PCR, fluorescence is generated after cleavage of the annealed ASO by the 5' nuclease activity of Taq polymerase. The wild-type BRCA sequence is distinguished from the mutant sequence by the differential fluorescence emission of two different reporter dyes. The sensitivity of ADA is at the level of a single cell following a nested PCR. Eighty-six patient samples can be analyzed for each mutation in 15-min post-PCR without the need for radioactivity, gel electrophoresis, or membrane blotting/hybridization.

Histopathologic features of ovaries at increased risk for carcinoma. A case-control analysis

In this study, the pathogenesis of ovarian carcinoma was investigated by performing a masked histopathologic comparison of benign ovaries removed from 61 women predicted to be at increased risk for developing carcinoma (cases) with ovaries removed from 121 women without known predisposing conditions (controls). The cases included 26 women who had a unilateral invasive carcinoma and 35 women undergoing prophylactic oophorectomy for a family history of ovarian cancer. As predicted by previously developed models, epithelial inclusion cysts were identified more frequently with advancing age in both cases and controls. However, the mean and maximum number of cysts per slide in a woman were not increased among cases. Surface epithelial "atypia," a designation based on a composite impression of multiple features, was found in 13% of cases compared with 3% of controls (relative risk 7.1; 95% confidence interval, 1.9 to 26.1), but this result was based on small numbers. None of the other histologic features examined was found more often in cases following age-adjustment. Reexamination of sections with well-preserved surface epithelium or inclusion cysts under oil immersion demonstrated several differences in the detection of specific features between cases and controls and increased detection of "atypia" among cases, but none of these findings reached statistical significance. It is concluded that there may be subtle differences in the surface epithelium of ovaries predisposed to developing cancer as compared with controls, but these changes are difficult to identify reliably with light microscopy. Future etiologic studies should attempt to optimize specific handling and include molecular studies and epidemiologic analyses.

The prevalence of common BRCA1 and BRCA2 mutations among Ashkenazi Jews

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

Survival after breast cancer in Ashkenazi Jewish BRCA1 and BRCA2 mutation carriers

BACKGROUND

Studies of survival following breast and ovarian cancers in BRCA1 and/or BRCA2 mutation carriers have yielded conflicting results. We undertook an analysis of a community-based study of Ashkenazi Jews to investigate the effect of three founder mutations in BRCA1 and BRCA2 on survival among patients with breast or ovarian cancer.

METHODS

We collected blood samples and questionnaire data from 5318 Ashkenazi Jewish volunteers. The blood samples were tested for 185delAG (two nucleotide deletion) and 5382insC (single nucleotide insertion) mutations in BRCA1 and the 6174delT (single nucleotide deletion) mutation in BRCA2. To estimate survival differences in the affected relatives according to their BRCA1 and/or BRCA2 mutation carrier status, we devised and applied a novel extension of the kin-cohort method.

RESULTS

Fifty mutation carriers reported that 58 of their first-degree relatives had been diagnosed with breast cancer and 10 with ovarian cancer; 907 noncarriers reported 979 first-degree relatives with breast cancer and 116 with ovarian cancer. Kaplan-Meier estimates of median survival after breast cancer were 16 years (95% confidence interval [CI] = 11-40) in the relatives of carriers and 18 years (95% CI = 15-22) in the relatives of noncarriers, a difference that was not statistically significant (two-sided P = .87). There was also no difference in survival times among the 126 first-degree relatives with ovarian cancer. We found no survival difference between patients with breast or ovarian cancer who were inferred carriers of BRCA1 and/or BRCA2 mutations and noncarriers.

CONCLUSIONS

Carriers of BRCA1 and BRCA2 mutations appeared to have neither better nor worse survival prognosis.

Population-based study of risk of breast cancer in carriers of BRCA2 mutation

BACKGROUND

Estimates of an 80-90% risk of breast cancer for carriers of germline mutations in the BRCA1 and BRCA2 genes are based on studies of families at high risk of breast cancer. Risk estimates for a population are possible if the mutation status of a representative sample of that population can be assessed. In Iceland, one common founder BRCA2 mutation occurs in 0.6% of the population. Iceland has a population-based cancer registry and a large collection of pedigrees, and estimation of cancer risk in mutation carriers is therefore possible.

METHODS

We studied 575 breast-cancer patients, 541 women and 34 men unselected for family history of breast cancer. Data on cancer in first-degree relatives were available from the cancer registry. Risk of cancer was estimated by comparing the history of cancer in first-degree relatives of carriers and non-carriers.

FINDINGS

56 (10.4%) of the 541 women and 13 (38%) of the 34 men carried the 999del5 mutation. The estimated risk of breast cancer at age 50 for all female carriers of the 999del5 mutation was 17.0% (95% CI 9.1-25.9) and 37.2% (22.4-53.9) at age 70.

INTERPRETATION

The results of our population-based study show that the mean risk of breast cancer in carriers of mutation in BRCA2 is lower than previously suggested. Individual risk assessment will, however, have to take account of family history.

The kin-cohort study for estimating penetrance

A cross-sectional study may be more feasible than a cohort or case-control study for examining the effect of a genetic mutation on cancer penetrance outside of cancer families. The kin-cohort design uses volunteer probands selected from a population with a relatively high frequency of the mutations of interest. By considering the cancer risk in first-degree relatives of mutation-positive and -negative probands as a weighted average of the risk in carriers and noncarriers, with weights calculated assuming a known mode of inheritance, one can infer the penetrance of the mutations. The estimates of penetrance by age 70 years for three specific mutations in the BRCA1 and BRCA2 genes common among Ashkenazi Jews for the first occurrence of breast or ovary cancer is 63%. The kin-cohort design can be a useful tool for quickly estimating penetrance from volunteers in a setting in which the mutation prevalence is relatively high.

The APCI1307K allele and cancer risk in a community-based study of Ashkenazi Jews

Mutations in APC are classically associated with familial adenomatous polyposis (FAP), a highly penetrant autosomal dominant disorder characterized by multiple intestinal polyps and, without surgical intervention, the development of colorectal cancer (CRC). APC is a tumour-suppressor gene, and somatic loss occurs in tumours. The germline T-to-A transversion responsible for the APC I1307K allele converts the wild-type sequence to a homopolymer tract (A8) that is genetically unstable and prone to somatic mutation. The I1307K allele was found in 6.1% of unselected Ashkenazi Jews and higher proportions of Ashkenazim with family or personal histories of CRC (ref. 2). To evaluate the role of I1307K in cancer, we genotyped 5,081 Ashkenazi volunteers in a community survey. Risk of developing colorectal, breast and other cancers were compared between genotyped I1307K carriers and non-carriers and their first-degree relatives.

Multifactorial analysis of differences between sporadic breast cancers and cancers involving BRCA1 and BRCA2 mutations

BACKGROUND

We have previously demonstrated that breast cancers associated with inherited BRCA1 and BRCA2 gene mutations differ from each other in their histopathologic appearances and that each of these types differs from breast cancers in patients unselected for family history (i.e., sporadic cancers). We have now conducted a more detailed examination of cytologic and architectural features of these tumors.

METHODS

Specimens of tumor tissue (5-microm-thick sections) were examined independently by two pathologists, who were unaware of the case or control subject status, for the presence of cell mitosis, lymphocytic infiltration, continuous pushing margins, and solid sheets of cancer cells; cell nuclei, cell nucleoli, cell necrosis, and cell borders were also evaluated. The resulting data were combined with previously available information on tumor type and tumor grade and further evaluated by multifactorial analysis. All statistical tests are two-sided.

RESULTS

Cancers associated with BRCA1 mutations exhibited higher mitotic counts (P = .001), a greater proportion of the tumor with a continuous pushing margin (P<.0001), and more lymphocytic infiltration (P = .002) than sporadic (i.e., control) cancers. Cancers associated with BRCA2 mutations exhibited a higher score for tubule formation (fewer tubules) (P = .0002), a higher proportion of the tumor perimeter with a continuous pushing margin (P<.0001), and a lower mitotic count (P = .003) than control cancers.

CONCLUSIONS

Our study has identified key features of the histologic phenotypes of breast cancers in carriers of mutant BRCA1 and BRCA2 genes. This information may improve the classification of breast cancers in individuals with a family history of the disease and may ultimately aid in the clinical management of patients.

BRCA1 in special populations

A restricted number of mutant BRCA1 alleles are present at high frequency in the Ashkenazi Jewish population: 185delAG and 5382insC and, perhaps, 188del11. These mutations have provided a means to re-estimate the penetrance function of an abnormal BRCA1 allele to be in the range of 50-60% for breast cancer, and 8-16% for ovarian cancer. Moreover, there was an increased rate of prostate, but not colorectal, cancers in BRCA1 carriers. Further studies in the Ashkenazi population may provide one approach to identifying the environmental or genetic cofactors that modify the impact of an abnormal BRCA1 gene.

The risk of cancer associated with specific mutations of BRCA1 and BRCA2 among Ashkenazi Jews

BACKGROUND

Carriers of germ-line mutations in BRCA1 and BRCA2 from families at high risk for cancer have been estimated to have an 85 percent risk of breast cancer. Since the combined frequency of BRCA1 and BRCA2 mutations exceeds 2 percent among Ashkenazi Jews, we were able to estimate the risk of cancer in a large group of Jewish men and women from the Washington, D.C., area.

METHODS

We collected blood samples from 5318 Jewish subjects who had filled out epidemiologic questionnaires. Carriers of the 185delAG and 5382insC mutations in BRCA1 and the 6174delT mutation in BRCA2 were identified with assays based on the polymerase chain reaction. We estimated the risks of breast and other cancers by comparing the cancer histories of relatives of carriers of the mutations and noncarriers.

RESULTS

One hundred twenty carriers of a BRCA1 or BRCA2 mutation were identified. By the age of 70, the estimated risk of breast cancer among carriers was 56 percent (95 percent confidence interval, 40 to 73 percent); of ovarian cancer, 16 percent (95 percent confidence interval, 6 to 28 percent); and of prostate cancer, 16 percent (95 percent confidence interval, 4 to 30 percent). There were no significant differences in the risk of breast cancer between carriers of BRCA1 mutations and carriers of BRCA2 mutations, and the incidence of colon cancer among the relatives of carriers was not elevated.

CONCLUSIONS

Over 2 percent of Ashkenazi Jews carry mutations in BRCA1 or BRCA2 that confer increased risks of breast, ovarian, and prostate cancer. The risks of breast cancer may be overestimated, but they fall well below previous estimates based on subjects from high-risk families.

The carrier frequency of the BRCA2 6174delT mutation among Ashkenazi Jewish individuals is approximately 1%

Certain germline mutations in either BRCA1 or BRCA2 confer a lifetime risk of developing breast cancer that may approach 90%. The BRCA1 185delAG mutation was found in 20% and the BRCA2 6174delT mutation in 8% of Ashkenazi Jewish women with early-onset breast cancer. The 185delAG mutation was observed in 0.9% of 858 Ashkenazi Jews unselected for a personal or family history of cancer. Assuming comparable age-specific penetrances, a carrier frequency of 0.3% was estimated for the 6174delT BRCA2 mutation. To test this hypothesis, we performed a population survey of 1,255 Jewish individuals. In two independent groups, a prevalence of approximately 1% (C.I. 0.6-1.5) was observed for the 6174delT mutation. The relative risk of developing breast cancer by age 42 was estimated to be 9.3 (C.I. 2.5-22.5) for 6174delT, compared to 31 (C.I. 11-77) for 185delAG. Analysis of 107 Ashkenazi Jewish women with breast cancer and a family history of breast or ovarian cancer confirmed a four-fold greater prevalence for the BRCA1 185delAG mutation compared to the BRCA2 6174delT mutation. Our findings suggest a difference in cumulative life-time penetrance for the two mutations. Genetic counseling for the one in 50 Ashkenazi Jewish individuals harbouring specific germline mutations in BRCA1 or BRCA2 must be tailored to reflect the different risks associated with the two mutations.

Increased risk of pancreatic cancer in melanoma-prone kindreds with p16INK4 mutations

BACKGROUND

A gene on chromosome 9p, p16INK4, has been implicated in the pathogenesis of cutaneous malignant melanoma in 19 melanoma-prone families. In 10 of these kindreds mutations that impaired the function of the p16INK4 protein (p16M alleles) cosegregated with the disease. By contrast, in the other nine kindreds the mutation did not alter the function of p16INK4 (p16W alleles). We looked for differences in clinical and genetic epidemiologic features in these two groups of families.

METHODS

We compared the median ages at diagnosis of melanoma, number of melanomas, thickness of the tumors, and number of nevi in the kindreds. We estimated prospectively the risks of melanoma or other cancers in families followed for 6 to 18 years and the risks of other cancers since 1925 (the entire period) by comparing the number of cancer cases observed with the number expected.

RESULTS

The risk of invasive melanoma was increased by a factor of 75 in kindreds with p16M alleles and a factor of 38 in kindreds with p16W alleles. Although this difference was not significant (P = 0.14), there was a striking difference in the risk of other tumors. In kindreds with p16M alleles, the risk of pancreatic cancer was increased by a factor of 13 in the prospective period (2 cases observed, 0.15 expected; standardized incidence ratio, 13.1; 95 percent confidence interval, 1.5 to 47.4) and by a factor of 22 in the entire period (7 cases observed, 0.32 expected; standardized incidence ratio, 21.8; 95 percent confidence interval, 8.7 to 44.8). In contrast, we found no cases of pancreatic cancer in kindred with p16W alleles.

CONCLUSIONS

The development of pancreatic cancer in kindreds prone to melanoma may require a p16M mutation. Genetic factors, such as the kind of mutation found in p16INK4, may explain the inconsistent occurrence of other cancers in these kindreds.

The carrier frequency of the BRCA1 185delAG mutation is approximately 1 percent in Ashkenazi Jewish individuals

Since BRCA1, the first major gene responsible for inherited breast cancer, was cloned, more than 50 unique mutations have been detected in the germline of individuals with breast and ovarian cancer. In high-risk pedigrees, female carriers of BRCA1 mutations have an 80-90% lifetime risk of breast cancer, and a 40-50% risk of ovarian cancer. However, the mutation stats of individuals unselected for breast or ovarian cancer has not been determined, and it is not known whether mutations in such individuals confer the same risk of cancer as in individuals from the high-risk families studied so far. Following the finding of a 185delAG frameshift mutation in several Ashkenazi Jewish breast/ovarian families, we have determined the frequency of this mutation in 858 Ashkenazim seeking genetic testing for conditions unrelated to cancer, and in 815 reference individuals not selected for ethnic origin. We observed the 185delAG mutation in 0.9% of Ashkenazim (95% confidence limit, 0.4-1.8%) and in none of the reference samples. Our results suggest that one in a hundred women of Ashkenazi descent may be at especially high risk of developing breast and/or ovarian cancer.

Detection of eight BRCA1 mutations in 10 breast/ovarian cancer families, including 1 family with male breast cancer

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

Anticipated uptake and impact of genetic testing in hereditary breast and ovarian cancer families

In anticipation of the identification of the BRCA1 gene, we studied the interest in and anticipated reaction to DNA testing for mutations in this gene in members of high-risk families. We surveyed 91 female and 49 male subjects using a structured interview by study nurses. All subjects were members of inherited breast-ovarian cancer families participating in a genetic linkage study at the National Cancer Institute. The main outcomes of the study were interest in genetic testing and anticipated impact of test results. Seventy nine % of subjects indicated that they would "definitely" want to be tested, and 16% would "probably" want to be tested for mutations in the BRCA1 gene. Subjects with a high self-perceived risk of having an altered BRCA1 gene were more likely to definitely want testing (P = 0.02), while estimated true genetic risk did not predict interest in the test. Females were significantly more likely to definitely want testing (P = 0.005) and had a significantly greater mean anticipated negative-impact score (2.3) compared to males (1.0) (P < 0.001). We found a high level of interest in genetic testing for BRCA1 among members of inherited breast-ovarian cancer families participating in a genetic linkage study. While utilization may fall below levels of interest reported in this and other preliminary surveys, given the potential for early detection and treatment of breast and ovarian cancer, interest in BRCA1 testing may translate into high rates of uptake. These results indicate that it will be critical to incorporate follow-up counseling and support into BRCA1 testing programs.

Germline p16 mutations in familial melanoma

The p16 gene is located in chromosome 9p21, a region that is linked to familial melanoma and homozygously deleted in many tumour cell lines. We describe eight p16 germline substitutions (one nonsense, one splice donor site and six missense) in 13/18 familial melanoma kindreds. Six of these mutations were identified in 33/36 melanoma cases in nine families, whereas two were detected in normal controls and are not disease-related. The melanoma-specific mutations were detected in 9p21-linked, but not in 1p36-linked, families, thereby confirming previous reports of genetic heterogeneity. Functional analyses of these mutations will confirm those causally related to the development of familial melanoma.

Localisation of the breast-ovarian cancer susceptibility gene (BRCA1) on 17q12-21 to an interval of < or = 1 cM

A breast-ovarian cancer susceptibility gene, BRCA1, which is responsible for disease in approximately 45% of breast cancer families and most families that contain breast and ovarian cancer, has been assigned by genetic linkage to 17q12-21. Here, we report the analysis of three marker-disease recombinants in families that contain breast and ovarian cancer, two of which strongly suggest a location for BRCA1 telomeric to D17S702, a microsatellite polymorphism, and a third which suggests a location centromeric to EDH17B, the gene encoding estradiol-17B dehydrogenase. If the interpretation of these recombinants is correct, the results localise BRCA1 to an interval of < or = 1 cM.

The risk of measles, mumps, and varicella among young adults: a serosurvey of US Navy and Marine Corps recruits

OBJECTIVES

To assess the risk of epidemic transmission and to guide immunization policy, the seroprevalence of antibody to measles, mumps, and varicella was determined in a group of young adults.

METHODS

A cross-sectional study of 1533 US Navy and Marine Corps recruits was conducted in June 1989. Antibody status was determined with commercially available enzyme-linked immunosorbent assays.

RESULTS

Direct sex and race adjustment to the 15- to 29-year-old US population resulted in seronegativity rates of 17.8% for measles, 12.3% for mumps, and 6.7% for varicella. Measles and mumps seronegativity rates were higher among Whites whereas varicella seronegativity was higher among non-Whites. Recruits enlisting from outside the 50 US states, especially those from island territories, were more likely to lack varicella antibody. The sensitivity of a positive history of vaccination or disease in predicting antibody status was less than 90% for all diseases.

CONCLUSIONS

These results suggest a continued potential for epidemics, especially of measles, and the need for mandatory immunization policies. Immigrants to the United States, especially those from island territories, may be a high-risk group that could benefit from varicella vaccination.

Interpreting a single antistreptolysin O test: a comparison of the "upper limit of normal" and likelihood ratio methods

Single serologic tests may occasionally influence clinicians in making diagnoses. The antistreptolysin O (ASO) test is a frequently used tool for detecting recent Streptococcus pyogenes infection and is helpful in the diagnosis of diseases like rheumatic fever. Using data from a 1989 prospective study of 600 healthy male military recruits, in which 43% experienced S. pyogenes upper respiratory tract infection (2-dilution rise in ASO), this report compared two methods of interpreting a single ASO titer. Using the "upper limit of normal" (80 percentile) method, recruits with an ASO titer of greater than 400 showed evidence of recent S. pyogenes infection. This method had a sensitivity and specificity of only 65.9 and 81.9% respectively. In contrast to the "yes-no" dichotomy of the "upper limit of normal" method, the likelihood ratio method statistics were ASO value specific, more consistent with clinical judgment, and better emphasized the caution clinicians must use in interpreting a single ASO test.

Tuberculosis infection among young adults entering the US Navy in 1990

BACKGROUND

From 1958 through 1969, more than 1.2 million US Navy recruits received tuberculin skin tests; 5.2 per 100 were tuberculin reactors. Subsequent analyses predicted a downward trend in the risk of tuberculosis infection in the United States. We sought to determine the current prevalence of tuberculin reactors by sex, race/ethnic group, and birthplace among young adult residents of the United States entering the US Navy.

METHODS

Recruits routinely receive a tuberculin skin test on entering US Navy recruit training in Great Lakes, Ill, Orlando, Fla, or San Diego, Calif. In January and February 1990, 2416 young men and women (mean age, 20.6 years) received tuberculin skin tests and completed questionnaires eliciting demographic and tuberculosis risk factor data. A tuberculin reactor was defined as a subject having 10 mm or greater induration to a skin test with 5 tuberculin units, purified protein derivative, administered intradermally by the Mantoux method.

RESULTS

Fifty-five of 2214 men (2.5 per 100; 95% confidence interval, 1.9 to 3.2 per 100) and five of 202 women (2.5 per 100; 95% confidence interval, 0.8 to 5.8 per 100) were tuberculin reactors. For men, the prevalence was greater in blacks (5.2 per 100), Hispanics (5.4 per 100), and Asian/Pacific Islanders (26.4 per 100) than in whites (0.8 per 100) and greater in foreign-born recruits (19.2 per 100) than in recruits born in the United States (1.6 per 100). Women had the same pattern of prevalence by race/ethnic group and birthplace.

CONCLUSIONS

The prevalence of tuberculosis reactors declined as predicted among young adults, especially the white US-born recruits, entering the US Navy. Although the prevalence also declined among nonwhites and the foreign-born recruits, a substantial proportion continue to enter adulthood with preexisting tuberculosis infection.

Genetic epidemiology of epithelial ovarian cancer

BACKGROUND

Aside from age, family history is the strongest predictor of ovarian cancer risk. Genetic components of risk for ovarian cancer have been evaluated by a number of designs, including case-control studies of family history and other risk factors, segregation and genetic linkage studies, and studies of biomarkers and tumor-specific cytogenetic abnormalities.

METHODS

Data were extracted from all available case-control studies that included family history. Cytogenetic, biomarker, segregation, analytic, and genetic linkage studies were reviewed.

RESULTS

Family history of ovarian cancer confers a 3.6-fold increased risk for this disease. Segregation studies of breast and ovarian cancer in five large families were consistent with dominant inheritance. Low levels of alpha-L-fucosidase confer mildly increased risk for ovarian cancer. Low galactose-1-phosphate uridyl transferase and type A blood group may increase risk for ovarian cancer. Cytogenetic and oncogene studies have identified regions that may be important in tumorigenesis and metastasis, but discriminating between early and late changes is difficult from these studies. Presence of a genetic susceptibility locus for breast and ovarian cancer has been confirmed on chromosome 17q21.

CONCLUSIONS

Family history is an important predictor of ovarian cancer risk. In rare families, a specific dominantly acting gene can be identified, but in the vast majority of familial ovarian cancers the underlying mechanism remains unclear. Specific studies are needed for women with a family history of ovarian cancer because evidence suggests modification of the effects of oral contraceptive use and reproductive patterns in this population of women.

Seroprevalence of hepatitis A, B, and C in a United States military recruit population

One thousand five hundred thirty-eight U.S. Navy and Marine Corps enlisted recruits were tested for hepatitis A, B, and C serologic markers. The recruit population (mean age, 19 years) was 91% male, 69% white, 17% black, 9% Hispanic, 2% Filipino, and 2% "other" racial/ethnic group. Anti-HAV was found in 129 (8.4%) recruits, anti-HBc in 35 (2.3%), HBsAg in 5 (0.3%), and anti-HCV in 4 (0.3%). For recruits born in the U.S., the prevalence of anti-HAV and anti-HBc was 5.5% and 1.3%, respectively; for the 7% of recruits born outside the U.S., the prevalence was 44.9% and 14.0%, respectively. By logistic regression analysis, seropositivity for hepatitis A and B was independently associated with age, nonwhite racial/ethnic groups, and birth outside of the U.S. This study indicates that there is a relatively low risk of hepatitis A, B, and C infection among Navy and Marine Corps recruits.

Efficacy of hepatitis B vaccination in primary school children from a village endemic for Schistosoma mansoni

To determine whether chronic Schistosoma mansoni infection interferes with hepatitis B virus (HBV) immunization, 308 schoolchildren aged 6-12 years with no evidence of prior HBV infection (156 with active schistosomiasis) were vaccinated with three 5-micrograms injections of recombinant DNA-derived HBV vaccine. The vaccine was given in the deltoid muscle at time 0 and 1 and 7 months later. All vaccinees were examined 1 and 3 years after vaccination for quantitative antibody to hepatitis B surface antigen (anti-HBs). Seroconversion was detected in 284 vaccinated children (92%), of whom 271 had a good (51-300 mIU/mL) or excellent (greater than 300 mIU/mL) anti-HBs response. Sixteen other children (5%) had evidence of natural HBV infection (antibody to hepatitis B core antigen). Of those with good or excellent response, 99% retained high antibody titers for 3 years. Response was not influenced by S. mansoni infection. Hepatomegaly and splenomegaly were associated with reduced vaccine response.

Oral erythromycin prophylaxis against Streptococcus pyogenes infection in penicillin-allergic military recruits: a randomized clinical trial

Historically, military recruits have required benzathine penicillin G to prevent epidemics of Streptococcus pyogenes. In this randomized clinical trial, low-dose oral erythromycin was evaluated as an alternative for prophylaxis against group A beta-hemolytic streptococci in penicillin-allergic recruits. US Marine Corps recruits (186) reporting penicillin allergy were randomly given either oral erythromycin (250 mg twice a day) or a vitamin (one tablet daily) for 60 days. Evidence of infection was defined as a two-dilution rise in anti-streptolysin O titer. The erythromycin group had a significantly lower risk of S. pyogenes infection than did the vitamin group (relative risk 0.44; 95% confidence interval, 0.22-0.89). There was no significant difference among the treatment groups in isolation of group A beta-hemolytic streptococci from throat cultures. Low-dose oral erythromycin appears as effective as benzanthine penicillin G in preventing S. pyogenes infection.

Hyperendemic Streptococcus pyogenes infection despite prophylaxis with penicillin G benzathine

BACKGROUND

In closely confined populations, in which epidemics of Streptococcus pyogenes infection are common, penicillin G benzathine has long been used prophylactically to reduce morbidity from this pathogen. We report on our investigations of the effectiveness of penicillin G benzathine prophylaxis at a military recruit camp.

METHODS

We prospectively studied the rates of pharyngeal colonization and infection by S. pyogenes among 736 male U.S. Marine Corps recruits from January through March 1989. Throat swabs for culture, clinical data, and questionnaire data were obtained during six examinations at intervals of two weeks. Serum samples obtained before training, after training, and from acutely ill recruits were analyzed with use of an antistreptolysin O microtitration technique.

RESULTS

Although 93 percent of the recruits received prophylaxis with two intramuscular injections of 1.2 million units of penicillin G benzathine each (administered 30 to 39 days apart), 33 percent of the recruits were colonized by S. pyogenes, and 42 percent had infection (as defined by a two-dilution increase in the antistreptolysin O titer). Thirty-seven percent of 265 recruits who reported a sore throat and were infected with S. pyogenes did not seek medical attention. The recruits who were allergic to penicillin (7 percent of the total), who received no prophylaxis, were more likely to be colonized; an increased risk of colonization and infection among the nonallergic recruits was associated with the presence of a higher percentage of allergic recruits in the platoon. After the study was completed, all recruits who were allergic to penicillin were prescribed 250 mg of oral erythromycin twice daily (a total daily dose of 500 mg) for 60 days. Subsequently, the average weekly rate of clinically evident S. pyogenes pharyngitis fell by more than 75 percent.

CONCLUSIONS

If the prevention of S. pyogenes infection is to be effective in closely confined populations such as military recruits, prophylactic antibiotics must be administered to all members of the population. Exempting those who are allergic to penicillin may create a bacterial reservoir from which infection can be transmitted to nonallergic members of the population.

Improving colorectal cancer screening in a medical residents' primary care clinic

Colorectal cancer is a major cause of morbidity and mortality in the United States. Despite the availability of methods for early detection of this cancer, compliance with published screening guidelines is poor. We began a study using a pretest/posttest design to determine the effectiveness of several methods of improving colorectal cancer screening in an internal medicine residents' Veterans' Administration (VA) Primary Care Clinic. The interventions varied by day of the week and included (1) distributing self-administered Hemoccult II slide kits to patients at clinic registration; (2) conducting an education session for house staff on colorectal cancer screening; and (3) placing reminder cards on patients' medical records. Preintervention rates of compliance with age-related screening guidelines recorded in the medical record within the past year were digital rectal examination, 70%; one-time fecal occult blood test, 59%; three-day fecal occult blood test, 1%; and screening sigmoidoscopy (at any time in the past), 5%. No change in physician-performed examinations was seen in any group approximately six weeks after the interventions. However, systematic distribution of Hemoccult II kits resulted in a dramatic increase in screening through this method, to 56.8% (P less than .001). In this setting, physician education and reminders may be insufficient to improve colorectal cancer screening. We discuss possible explanations for this finding, including the high preintervention screening levels and the perception of an already overburdened system. Patient involvement in screening and mechanisms built into the clinic operation may be more successful.

An epidemic of respiratory complaints exacerbated by mass psychogenic illness in a military recruit population

The authors report an episode of mass psychogenic illness exacerbating respiratory symptoms in military recruits. The epidemic occurred over a 10- to 12-hour period in September 1988, in a group initially complaining of cough and pleuritic chest pain. More than 1,800 men were evacuated from their barracks because of a suspected toxic gaseous exposure. Approximately 1,000 recruits developed at least one new symptom, 375 were evacuated by ambulance to receive further medical evaluation, and at least eight were hospitalized. Air sample testing from the area was unremarkable, and there were few abnormal physical examination or laboratory findings. The epidemiologic investigation included a questionnaire administered 2 weeks after the epidemic to 1,000 of the recruits involved. A total of 55% of those who completed the questionnaire reported the onset of at least one new symptom after supper, with at least 25% reporting the new onset of cough, light-headedness, chest pain, shortness of breath, headache, sore throat, or dizziness. A total of 18% received further medical evaluation. The development of new symptoms and the receipt of further medical evaluation were associated with evidence of physical stress, mental stress, and awareness of rumors of odors, gases, and/or smoke. This epidemic was unique because of its size and its occurrence in an all-male population.

Sonographic studies of schoolchildren in a village endemic for Schistosoma mansoni

Parasitological, clinical, and sonographic examinations were performed on 309 school children in a village endemic for schistosomiasis mansoni. Data from the 255 denying treatment within the previous 2 years were analysed separately. On a single Kato examination 42% were uninfected; the remainder had light (26%), moderate (21%), or heavy (11%) infections with Schistosoma mansoni. Hepatomegaly (53%) and palpable spleens (35%) were common but clinical and parasitological findings often were unrelated. Abdominal sonography also demonstrated a high frequency of hepatomegaly (82%) and splenomegaly (49%). Sonographically determined liver span and spleen size correlated with the egg count. Sonographic lesions of periportal fibrosis of schistosomiasis mansoni with thickening of portal tracts and portal vein walls were frequently present and more common in infected than in uninfected children, and were correlated with the number of S. mansoni ova in the stool. Ultrasonographically detected periportal fibrosis was a reliable measurement of the prevalence and morbidity of schistosomiasis mansoni in this population, and provided very useful information, even when the parasitological and clinical findings were equivocal.

Predictors of rehabilitation outcome among patients with SCI

Because rehabilitation medicine has undergone major changes with respect to patient management and case mix since 1980, it is important to determine whether the factors predictive of rehabilitation outcomes also have changed over time.