Skeletal dysplasias caused by a disruption of skeletal patterning and endochondral ossification

Identification of a number of the genes that cause skeletal dysplasias has helped clinicians to provide accurate diagnoses, genetic counseling, and pre-natal diagnosis for this complex group of disorders. This review considers how some of the recent advances in human and murine genetics have led to an increased understanding of normal bone development and, in particular, the processes of skeletal patterning and endochondral ossification.

Heterocyclic amines, meat intake, and association with colon cancer in a population-based study

The authors examined the association between colon cancer and meat intake categorized by level of doneness, cooking method, and estimated levels of heterocyclic amines (HCAs), benzo[a]pyrene, and mutagenicity. Data were collected as part of a population-based, case-control study of colon cancer in North Carolina between 1996 and 2000 that included 701 African-American (274 cases, 427 controls) and 957 White (346 cases, 611 controls) participants. Odds ratios were calculated by using unconditional logistic regression, comparing the fifth to the first quintile levels of intake or exposure. Intake of red meat was positively associated with colon cancer (odds ratio (OR) = 2.0, 95% confidence interval (CI): 1.3, 3.2). Associations with meat intake by cooking method were strongest for pan-fried red meat (OR = 2.0, 95% CI: 1.4, 3.0). Associations with meat intake by doneness were strongest for well-/very well done red meat (OR = 1.7, 95% CI: 1.2, 2.5). The strongest association for individual HCAs was reported for 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) across all levels of exposure, with odds ratios of 1.8-2.0. Overall, sophisticated exposure measures were used to report modest, positive associations between red meat intake and colon cancer consistent with the hypothesis that HCAs may be among the etiologically relevant compounds in red meat.

Protective role of appendicectomy on onset and severity of ulcerative colitis and Crohn's disease

BACKGROUND AND AIMS

Recent studies on appendicectomy rates in ulcerative colitis and Crohn's disease have generally not addressed the effect of appendicectomy on disease characteristics. The aims of this study were to compare appendicectomy rates in Australian inflammatory bowel disease patients and matched controls, and to evaluate the effect of prior appendicectomy on disease characteristics.

METHODS

Patients were ascertained from the Brisbane Inflammatory Bowel Disease database. Controls matched for age and sex were randomly selected from the Australian Twin Registry. Disease characteristics included age at diagnosis, disease site, need for immunosuppression, and intestinal resection.

RESULTS

The study confirmed the significant negative association between appendicectomy and ulcerative colitis (odds ratio (OR) 0.23, 95% confidence interval (CI) 0.14-0.38; p<0.0001) and found a similar result for Crohn's disease once the bias of appendicectomy at diagnosis was addressed (OR 0.34, 95% CI 0.23-0.51; p<0.0001). Prior appendicectomy delayed age of presentation for both diseases and was statistically significant for Crohn's disease (p=0.02). In ulcerative colitis, patients with prior appendicectomy had clinically milder disease with reduced requirement for immunosuppression (OR 0.15, 95% CI 0.02-1.15; p=0.04) and proctocolectomy (p=0.02).

CONCLUSIONS

Compared with patients without prior appendicectomy, appendicectomy before diagnosis delays disease onset in ulcerative colitis and Crohn's disease and gives rise to a milder disease phenotype in ulcerative colitis.

Socioeconomic differences among Australian adults in consumption of fruit and vegetables and intakes of vitamins A, C and folate

OBJECTIVE

To determine whether socioeconomic groups differ in their food intakes for fruit and vegetables, their consumption of fruit and vegetables dense in vitamin A, folate and vitamin C, and their nutrient intakes of vitamin C, folate and vitamin A.

METHODS

The 1995 Australian National Nutrition Survey collected food intake data from 8883 adults aged 18-64 years using a 24-h dietary recall. Fruit and vegetables were measured as amount (g) consumed. Intakes of nutrients were estimated from the 24-h dietary recall data. Participants were categorized by whether or not they consumed fruit or vegetables high in vitamin A, folate and vitamin C. Gross annual household income was used to measure socioeconomic position.

RESULTS

Participants from low-income households consumed a smaller quantity of fruit and vegetables. They were also less likely to consume fruit and vegetables high in vitamin C, folate and vitamin A. Consistent with these findings, men and women from disadvantaged socioeconomic groups had lower intakes of vitamin C and folate compared with their more affluent counterparts. These differences were small to moderate in magnitude. Vitamin A intakes were not significantly related to income.

CONCLUSION

As well as promoting healthy dietary practices, nutrition-promotion strategies should target the nutrient intakes of lower socioeconomic groups. These programmes should focus on improving the quantity and choice of fruit and vegetables consumed by people from low-income households.

Environmental factors in relation to breast cancer characterized by p53 protein expression

Findings from studies of cigarette smoking and low-dose ionizing radiation exposure and breast cancer are unclear. Laboratory studies indicate that both exposures can cause DNA damage, potentially increasing cancer risk if such mutations occur in growth control genes, such as p53. We examined the potential etiologic heterogeneity of breast cancer by evaluating whether associations between cigarette smoking and low-dose ionizing radiation and breast cancer differed by p53 protein expression status. Data were obtained from the Carolina Breast Cancer Study, a population-based, case-control study conducted among African-American and white women ages 20-74 years. Questionnaire data were available from 861 women with incident, primary invasive breast cancer and 790 community-based controls. p53 immunostaining was performed on tissue from 683 women with breast cancer; 46% were classified as p53+. Two separate unconditional logistic regression models were used to calculate odds ratios (ORs) for p53+ and p53- breast cancer, as compared with controls, in relation to smoking and low-dose ionizing radiation exposure. Smoking was not differentially associated with p53+ or p53- breast cancer, even when duration, dose, and passive smoking status were considered. Exposure to individual sources of radiation did not differ for p53+ and p53- breast cancers. However, ORs for combined exposure to chest X-rays and occupational radiation were higher for p53+ [OR, 2.2; 95% confidence interval (CI), 1.0-5.3] than p53- breast cancer (OR, 1.2; 95% CI, 0.5-3.4). Combined exposure to radiation from other medical sources as well as occupational exposure was also higher for p53+ (OR, 3.7; 95% CI, 0.8-16.8) than for p53- breast cancer (OR, 1.7; 95% CI, 0.3-10.5). Although preliminary, our results suggest that exposure to multiple sources of low-dose ionizing radiation may contribute to the development of p53+ breast cancer.

Area-level characteristics and smoking in women

OBJECTIVES

This study examined whether area-level characteristics are associated with individual smoking behavior among women.

METHODS

Analyses included 648 women enrolled as control patients in the Carolina Breast Cancer Study (1993-1996). Smoking and covariate information was obtained from interviews. Area-level characteristics included census block-group education level, poverty, unemployment, car-home ownership, crowding, and, for 431 women, city-level crime rates.

RESULTS

In multivariate logistic regression models, no area characteristics were clearly associated with a history of smoking. Among those who had ever smoked, continued smoking was associated with living in low-education areas (odds ratio [OR] = 1.7, 95% confidence interval [CI] = 1.0, 2.9), high-unemployment areas (OR = 1.7, 95% CI = 1.0, 2.8), and high-crime areas (OR = 1.6, 95% CI = 0.8, 3.2).

CONCLUSIONS

The present findings are consistent with a growing literature suggesting that area-level social and economic disadvantage influences individual smoking behavior.

Oral contraceptives and breast cancer among African-american women and white women

The higher incidence of breast cancer among African-American women younger than 50 as compared to white women points to the need to examine exposures that are common among younger women, including exposure to oral contraceptives (OC). We examined patterns of OC use and their associations with breast cancer in a population-based, case-control study conducted in North Carolina between 1993 and 1996. The study population was comprised of 858 cases and 789 controls, of whom 40% were African-American women. There was little evidence that breast cancer was associated with OC use among older women (age >50) of either race, most of whom discontinued use in the distant past. Among younger women, there was a modest, but nonsignificant, increase in risk associated with ever use of OCs for both African-American and white women. There was a trend of increasing risks with more recent use among African-American women, whereas no such trend was apparent for white women. Overall, we found more substantial age differences than race differences in patterns of OC use and the risk of breast cancer associated with their use. The similarity of the associations between African-American and white women suggest that racial differences in breast cancer incidence are not likely to be attributable to OC use.

Patient education and the prevention of incisional hernia

Laparoscopic or 'key hole' surgery has become an acceptable technique for abdominal surgery. This technique is utilised by surgeons who work in tertiary hospitals as well as those in private, day only, surgical facilities. Despite the increasing use of this technique in Australia, a paucity of information is available in the journals about the real or potential complications the patient may suffer following this method of surgery. The first author of this paper who works in the operating room practice domain, observed over three years a number of patients readmitted for repair of incisional hernia following abdominal laparoscopic surgery. A review of the international literature and dialogue with operating nurses from institutions in Sydney and Hong Kong confirmed there was enough evidence to warrant examining the complication of incisional hernia as a clinical problem. It would appear from the literature that incidence rate is unknown in Australia. Several reasons may account for this. First, it appears that few surgeons are documenting patient outcomes of laparoscopic surgery, not withstanding the proliferation of its use in the last five years. The second possible reason is the paucity of published information available in the journals, perhaps because the technique is still viewed as relatively new and experimental. This paper outlines a brief history of laparoscopic surgery and some responsibilities nurses have in relation to patient education and the prevention of post-operative complications.

Coordinated expression of matrix Gla protein is required during endochondral ossification for chondrocyte survival

Matrix Gla protein (MGP) is a 14-kD extracellular matrix protein of the mineral-binding Gla protein family. Studies of MGP-deficient mice suggest that MGP is an inhibitor of extracellular matrix calcification in arteries and the epiphyseal growth plate. In the mammalian growth plate, MGP is expressed by proliferative and late hypertrophic chondrocytes, but not by the intervening chondrocytes. To investigate the functional significance of this biphasic expression pattern, we used the ATDC5 mouse chondrogenic cell line. We found that after induction of the cell line with insulin, the differentiating chondrocytes express MGP in a stage-specific biphasic manner as in vivo. Treatment of the ATDC5 cultures with MGP antiserum during the proliferative phase leads to their apoptosis before maturation, whereas treatment during the hypertrophic phase has no effect on chondrocyte viability or mineralization. After stable transfection of ATDC5 cells with inducible sense or antisense MGP cDNA constructs, we found that overexpression of MGP in maturing chondrocytes and underexpression of MGP in proliferative and hypertrophic chondrocytes induced apoptosis. However, overexpression of MGP during the hypertrophic phase has no effect on chondrocyte viability, but it does reduce mineralization. This work suggests that coordinated levels of MGP are required for chondrocyte differentiation and matrix mineralization.

Delayed adverse reaction to nonionic contrast agents

Delayed reactions to nonionic contrast agents are not well known. We describe a child with a life-threatening reaction.

CONCLUSIONS

(1) Late adverse contrast reactions can follow nonionic contrast administration without any immediate reaction; (2) the manifestations may be unusual with symptoms not typically associated with a contrast reaction; (3) the reactions are most often self-limiting and minor, but can be serious; (4) the protective effect of steroid pretreatment, especially same-day intravenous therapy, is uncertain.

Blood donor suitability and allogeneic whole blood donation

Blood donor suitability criteria are designed to protect both the blood donor and blood recipient from harm. The risks for allogeneic (community) whole blood donors who give blood and for blood recipients who receive it are described. Blood donor suitability criteria are based on science, informed medical opinion, and regulatory rules. The criteria for many common conditions are described. Blood donor suitability criteria influence donor demographics and lead to specific deferral patterns. Age, gender, and hemoglobin deferral patterns are described. Finally, the negative effect of short-term temporary deferrals on future blood donations was reviewed.

Tumor characteristics in African American and white women

BACKGROUND

Previous studies provide evidence that breast cancers occurring in different age and ethnic groups are not evenly distributed with regard to their biologic, pathologic and clinical characteristics. We evaluated the distributions of 11 pathological and biological variables between African-American (AA) and white patients and between three different age groups (20-39, 40-59 and 60-74 years). We examined whether racial differences existed across levels of age.

METHODS

Data were obtained from the Carolina Breast Cancer Study (CBCS), a population-based, case-control study of breast cancer in North Carolina. Eighty hundred and sixty one women with a first diagnosis of invasive breast cancer participated in Phase I of the CBCS. Diagnostic paraffin blocks were obtained from 807 cases. One representative block was scored for histologic type and grade (architectural, nuclear, mitotic and overall). Medical chart review yielded tumor size, lymph node status, distant metastases, stage, hormone receptor status (ER/PR) and DNA ploidy.

RESULTS

Pathologically advanced tumors (large size, high grade, high stage, ER/PR negative) were significantly more common in young and AA women. Racial differences varied by age. Among younger, AAs and whites differed only with respect to ER/PR status, while among older women AAs and whites differed only with respect to stage at diagnosis.

CONCLUSIONS

The results of this study confirm the presence of poorer prognosis breast cancer among AA and younger women. They also highlight the need for age and race to be considered together when evaluating pathologic and biologic characteristics of disease and when making inferences regarding tumor aggressiveness.

Vitamin supplement use and breast cancer in a North Carolina population

OBJECTIVE

Laboratory data suggest that several different vitamins may inhibit the growth of mammary cancers, however epidemiologic data on the relationship between vitamin supplement use and breast cancer are inconsistent. We examined the association between self-reported vitamin supplement use and breast cancer among black women and white women.

DESIGN AND SETTING

The data came from a population-based, case-control study conducted in North Carolina between 1993 and 1996. Logistic regression models were used to calculate adjusted odds ratios (ORs) for breast cancer associated with the use of multivitamins or individual vitamin supplements.

SUBJECTS

Eligible cases were aged 20 to 74, and approximately 40% of the study population were black women. The analyses included 861 cases and 790 controls.

RESULTS

Among all women, there was little evidence for an association between any vitamin supplement and breast cancer. Modest inverse associations were observed among white women for use of multivitamins 95% confidence interval (CI): 0.59-1.12), vitamin C 95% CI: 0.54-1.14) and vitamin E 95% CI: 0.49-1.13). There was no evidence that vitamin supplements reduced the risk of breast cancer among black women.

CONCLUSIONS

This study provided very limited support for the hypothesis that vitamin supplements may reduce the risk of breast cancer. Although dietary factors are likely an important influence in breast cancer aetiology, reductions in risk are most likely to be achieved through dietary modification rather than through vitamin supplementation.

Congenital surfactant protein B deficiency--emphasis on imaging

BACKGROUND AND OBJECTIVES

Surfactant protein B deficiency has become increasingly recognized as a cause of severe prolonged respiratory distress. Little has been written about the imaging appearance and the role of imaging in diagnosis.

MATERIALS AND METHODS

Three newborn infants with severe respiratory distress exhibited prolonged diffuse pulmonary opacification radiographically.

RESULTS

Diffuse ground-glass opacity and markedly prominent interlobular septa suggesting alveolar proteinosis were present on early thin-section chest computed tomographic (CT) images. Fibrotic changes with prominent interlobular septal thickening were present on a later CT. Surfactant protein B deficiency was confirmed by alveolar lavage and peripheral blood DNA analysis.

CONCLUSION

Thin-section chest CT imaging contributes important information when this diagnosis is considered.

Reproducibility of reported farming activities and pesticide use among breast cancer cases and controls. A comparison of two modes of data collection

PURPOSE

Farming is associated with exposure to many potential hazards including pesticides and other agents, but the quality of self-reported data on farm exposures has not been well studied.

METHODS

The reproducibility of self-reported farming history was evaluated among women in a population-based, case-control study of breast cancer in North Carolina. Thirty cases and 31 controls were randomly re-interviewed by telephone an average of 13.8 months after the initial interview. The initial interview was based on a farm-by-farm questionnaire, while the repeat interview was based on a shorter ever/never questionnaire. Agreement was estimated using proportions in exact agreement, kappa (kappa), and intraclass correlation coefficients (ICC).

RESULTS

In general, group prevalences and means were higher on re-interview. Kappa estimates ranged from 0.15 to 0.84 among cases, and 0.26 to 0.87 among controls, with most estimates falling between 0.5 and 0.8. Moderate to almost perfect agreement (kappa) was observed for questions on crop work (0.47-0.70), crop type (0.56-0.82), pesticide application to tobacco (0.77), and farm residence (0.84). ICC estimates for continuous variables showed fair to substantial agreement (0.30 to 0.69 among cases, 0.38 to 0.69 among controls). Older cases, less educated cases, cases who lived on more than one farm, and cases with longer time intervals between interviews gave lower total agreement than similar groups of controls.

CONCLUSIONS

Agreement estimates in this study are similar to those for other types of exposure information typically collected in epidemiologic studies. Nevertheless, a farm-by-farm method of exposure assessment may be preferable to an ever/never determination.

An evidence based approach to a perennial problem: pressure ulcers

The nursing care required to prevent the development of pressure ulcers on patients of various ages and with a range of physical and medical problems is an increasing challenge for nursing staff. The challenge for the nursing staff is multifactorial. Concerns include a complexity of factors associated with discerning, interpreting and implementing the results from evidence based studies, and maintaining cognisance of the ever-spiralling health cost while balancing this with the patient's wishes. The prevention of pressure ulcers is a cost-effective strategy about which little is written. This paper defines pressure ulcers using the International Classification for Nursing Practice (International Council of Nurses, 1999), and outlines the evidence featured in the research literature on the strategies for prevention.

Polymorphisms in the DNA repair gene XRCC1 and breast cancer

X-ray repair cross complementing group 1 (XRCC1) encodes a protein involved in base excision repair. We examined the association of polymorphisms in XRCC1 (codon 194 Arg-->Trp and codon 399 Arg-->Gln) and breast cancer in the Carolina Breast Cancer Study, a population-based case-control study in North Carolina. No association was observed between XRCC1 codon 194 genotype and breast cancer, and odds ratios (ORs) were not modified by smoking or radiation exposure. A positive association for XRCC1 codon 399 Arg/Gln or Gln/Gln genotypes compared with Arg/Arg was found among African Americans (253 cases, 266 controls; OR = 1.7, 95% confidence interval, 1.1-2.4) but not whites (386 cases, 381 controls; OR =1.0, 95% confidence interval, 0.8-1.4). Among African-American women, ORs for the duration of smoking were elevated among women with XRCC1 codon 399 Arg/Arg genotype (trend test; P < 0.001) but not Arg/Gln or Gln/Gln (P = 0.23). There was no difference in OR for smoking according to XRCC1 codon 399 genotype in white women. ORs for occupational exposure to ionizing radiation were stronger for African-American and white women with codon 399 Arg/Arg genotype. High-dose radiation to the chest was more strongly associated with breast cancer among white women with XRCC1 codon 399 Arg/Arg genotype. Our results suggest that XRRC1 codon 399 genotype may influence breast cancer risk, perhaps by modifying the effects of environmental exposures. However, interpretation of our results is limited by incomplete knowledge regarding the biological function of XRCC1 alleles.

Race, anthropometric factors, and stage at diagnosis of breast cancer

A recent study suggested that the greater prevalence of severe obesity among African-American women explained almost one third of the observed differences between African-American and White women in stage at diagnosis of breast cancer. The objective of this investigation was to attempt to replicate these findings in a second, larger population and to expand the analyses by including a measure of body fat distribution, the waist:hip ratio. The authors used data from a population-based study in North Carolina comprising 791 breast cancer cases (302 in African-American women and 489 in White women) diagnosed between 1993 and 1996. African-American women were more likely to have later-stage (TNM stage >/=II) breast cancer (odds ratio (OR) = 2.2; 95% confidence interval (CI): 1.6, 2.9). They also were much more likely to be severely obese (body mass index >/=32.3) (OR = 9.7; 95% CI: 6.5, 14.5) and to be in the highest tertile of waist:hip ratio (OR = 5.7; 95% CI: 3.8, 8.6). In multivariate logistic regression models, adjustment for waist:hip ratio reduced the odds ratio for later-stage disease in African-American women by 20%; adjustment for both waist:hip ratio and severe obesity reduced the odds ratio by 27%. These observations suggest that obesity and body fat distribution, in addition to socioeconomic and medical care factors, contribute to racial differences in stage at breast cancer diagnosis.

Lipoprotein candidate genes for multivariate factors of the insulin resistance syndrome: a sib-pair linkage analysis in women twins

The insulin resistance syndrome (IRS) is characterized by a combination of interrelated coronary heart disease risk factors, including low high-density lipoprotein cholesterol (HDLC) levels, obesity and increases in triglyceride (TG), systolic and diastolic blood pressure (BP), small low-density lipoprotein particles (LDL-size), and fasting and postload plasma insulin and glucose. Using factor analysis, we previously identified multivariate factors based on data from women participating in the Kaiser Permanente Women Twins Study: 1) Weight/Fat, 2) Insulin/Glucose, 3) Lipids, and 4) BP. The purpose of this study is to evaluate evidence for genetic linkage between the multivariate factors and candidate genes. Quantitative sib-pair analysis based on the factor scores with markers for 9 candidate genes was carried out based on data from 126 pairs of dizygotic (DZ) women twins from the second exam of the Kaiser Permanente Women Twins study. Suggestive evidence for linkage was found for the Weight/fat factor and the Apo E gene (p = 0.01), and stronger evidence for linkage with the Lipid factor and the cholesterol ester transfer protein (p = 0.002) gene. Therefore, the CETP gene appears to influence covariation in LDL size, TG, and HDL, and may account for a portion of the well-established statistical and metabolic associations observed between these risk factors.

Housework, paid work and psychiatric symptoms

OBJECTIVE

To evaluate the hypothesis that work burden, the simultaneous engagement in paid work and unpaid family housework, is a potential risk factor for psychiatric symptoms among women.

METHODS

A cross-sectional study was carried out with 460 women randomly selected from a poor area of the city of Salvador, Brazil. Women between 18 to 70 years old, who reported having a paid occupation or were involved in unpaid domestic activities for their families, were eligible. Work burden-related variables were defined as: a) double work shift, i.e., simultaneous engagement in a paid job plus unpaid housework; and b) daily working time. Psychiatric symptoms were collected through a validated questionnaire, the QMPA.

RESULTS

Positive, statistically significant associations between high (>7 symptoms) QMPA scores and either double work shift (prevalence ratio - PR=2.04, 95% confidence interval - CI: 1.16, 2.29) or more than 10 hours of daily work time (PR=2.29, 95% CI: 1.96, 3.43) were found after adjustment for age, marital status and number of pre-school children.

CONCLUSIONS

Major correlates of high QMPA scores are work burden variables. Being married or having pre-school children are also associated with high QMPA scores only when associated with work burden.

Matrix Gla protein is differentially expressed during the deposition of a calcified matrix by vascular pericytes

PCR-based subtractive hybridisation was used to identify genes up-regulated when pericytes undergo osteogenic differentiation and deposit a calcified matrix. cDNA pools were generated from confluent pericytes and from pericyte cultures containing calcified nodules. A pericyte cDNA library was screened with the product of the subtraction procedure (calcified minus confluent cDNA) and the majority of the positive clones were identified as matrix Gla protein (MGP). Northern analysis and immunohistochemistry demonstrated that MGP was only expressed by pericytes in calcified nodules. Antibodies to MGP inhibited the deposition of a calcified matrix by pericytes, suggesting that MGP regulates both cell differentiation and calcification.

Occupation and adult gliomas

Lifetime job histories from a population-based, case-control study of gliomas diagnosed among adults in the San Francisco Bay area between August 1991 and April 1994 were evaluated to assess occupational risk factors. Occupational data for 476 cases and 462 controls were analyzed, with adjustment for age, gender, education, and race. Imprecise increased risks were observed for physicians and surgeons (odds ratio (OR) = 3.5, 95% confidence interval (CI): 0.7, 17.6), artists (OR = 1.9, 95% CI: 0.5, 6.5), foundry and smelter workers (OR = 2.6, 95% CI: 0.5, 13.1), petroleum and gas workers (OR = 4.9, 95% CI: 0.6, 42.2), and painters (OR = 1.6, 95% CI: 0.5, 4.9). Legal and social service workers, shippers, janitors, motor vehicle operators, and aircraft operators had increased odds ratios only with longer duration of employment. Physicians and surgeons, foundry and smelter workers, petroleum and gas workers, and painters showed increased risk for both astrocytic and nonastrocytic tumors. Artists and firemen had increased risk for astrocytic tumors only, while messengers, textile workers, aircraft operators, and vehicle manufacturing workers showed increased risk only for nonastrocytic tumors. Despite study limitations, including small numbers for many of the occupational groups, a high percentage of proxy respondents among cases, and lack of specific exposure information, associations were observed for several occupations previously reported to be at higher risk for brain tumors generally and gliomas specifically.

Dichlorodiphenyldichloroethene, polychlorinated biphenyls, and breast cancer among African-American and white women in North Carolina

We examined plasma dichlorodiphenyldichloroethene (DDE) and total polychlorinated biphenyl (PCB) levels in relation to breast cancer in a population-based, case-control study of African-American women (292 cases and 270 controls) and white women (456 cases and 389 controls) in North Carolina. Adjusted odds ratios (ORs) for breast cancer comparing the highest to lowest third of DDE were 1.41 [95% confidence interval (CI), 0.87-2.29] in African-American women and 0.98 (95% CI, 0.67-1.43) in white women. ORs comparing the highest to lowest third of total PCBs were 1.74 (95% CI, 1.00-3.01) in African-American women and 1.03 (95% CI, 0.68-1.56) in white women. Among African-Americans, the OR for total PCBs was highest for obese women (body mass index 234.2; OR, 4.92; 95% CI, 1.63-14.83). In contrast, the OR for DDE was highest for the leanest African-American women (body mass index, <25; OR, 3.84; 95% CI, 0.98-15.08). ORs for DDE were not elevated among women who lived or worked on farms or elevated among farming women who reported exposure to pesticides. Our results suggest absence of a strong effect for DDE or total PCBs in breast cancer but lend support for associations among subgroups of women. In our study, factors such as income, parity, breastfeeding, race/ethnicity, and body mass index influenced the relationship of organochlorines and breast cancer. Differing distributions of such factors may explain some of the inconsistencies across previous studies.

Complex germline rearrangement of BRCA1 associated with breast and ovarian cancer

Germline mutations in BRCA1 predispose to breast and ovarian cancer. Most germline BRCA1 mutations are small insertions, deletions, or single base pair (bp) substitutions. These mutation classes are rarely found as somatic mutations in BRCA1. On the other hand, somatic deletions of multiple mega-base pairs (Mb) including BRCA1, as reflected by loss of heterozygosity, occur frequently in both inherited and sporadic breast and ovarian cancers. To determine whether deletions or rearrangements of hundreds to thousands of bps might contribute to inherited mutation in BRCA1, we developed a Long PCR strategy for screening the entire genomic BRCA1 locus in high-risk families. We evaluated genomic DNA from one high-risk family of European ancestry with BRCA1-linked cancer in which no genomic mutations had been detected using conventional methods. Long PCR revealed a complex mutation, g.12977 ins10 del1039 (based on GenBank L78833), comprising an inverted duplication and deletion in BRCA1 that removes portions of exon 3 and intron 3, including the 5' splice site for intron 3. As a result of the deletion, exon 3 is skipped, leading to a truncated protein and disease predisposition. Unlike previously reported large germline deletions in BRCA1, neither breakpoint resides within an Alu element. The g.12977 ins10 del1039 mutation was not detected among 11 other breast cancer families, nor among 406 breast cancer patients unselected for family history.