Long-acting follicle-stimulating hormone analogs containing N-linked glycosylation exhibited increased bioactivity compared with o-linked analogs in female rats.

The effects of altering the number and type of additional carbohydrate moieties on the pharmacokinetic and pharmacodynamic properties of FSH were examined in this report. A series of single-chain follitropins, containing variable numbers of additional N- (or O-) linked carbohydrates, were designed and expressed in Chinese hamster ovary cells. Proper folding, efficient receptor binding, and signal transduction were confirmed by in vitro assays. Pharmacokinetic and pharmacodynamic parameters were evaluated in immature female Sprague Dawley rats. Increasing the number of glycosylation sites with either N- (or O-) linked moieties extended the elimination half-life as much as 2-fold compared with recombinant human FSH (rhFSH). However, there was a maximum elimination half-life such that further glycosylation provided no additional lengthening of the half-life. Conversely, biopotency, as assessed by inhibin A levels 74 h post injection, and follicle production were significantly higher for the N-linked analogs. Rats stimulated with the longest acting analogs (either N- or O-linked) showed significantly higher ovarian weights than rats receiving a single injection of rhFSH. The analog containing four additional N-linked sites (rhFSH-N4) had the greatest number of large, preovulatory follicles. Although the half-life of rhFSH-N4 displayed no further enhancement beyond the other longest acting analogs, this analog exhibited significantly increased biopotency in rats. This work provides the basis for the generation of a series of reagents potentially useful for therapeutic applications.

Ethnic differences in risk perception among women at increased risk for breast cancer.

There has been increasing interest in the role of cultural and ethnic factors in breast cancer risk perceptions and screening practices. This study examined ethnic differences in breast cancer risk perception in 112 African American and 224 white women ages 35 and older who had at least one first-degree relative diagnosed with breast cancer. These samples were matched for education and age. Data on breast cancer risk factors, risk perceptions, breast cancer worries, and breast cancer screening practices were collected through structured telephone interviews. The results show that African American women were significantly less likely than white women to report heightened perceptions of personal risk after their relative was diagnosed with breast cancer (61% vs 82%; p < .001). Despite this, African American women had significantly greater concerns about their personal risk of breast cancer and worries about their affected relative. African American women also scored significantly higher than white women on a measure of avoidance of breast cancer-related thoughts and feelings. These psychological variables were associated independently with breast cancer risk perception in multivariate models, taking precedence over demographic and risk factor predictors. Observed ethnic differences in breast cancer risk perceptions and psychological distress may be attributable to the influence of cultural factors particular to people of African descent, such as the importance of interpersonal relationships, spirituality, and time orientation. An Africentric perspective is used to interpret these findings and to provide suggestions for delivering effective breast cancer risk counseling to African American women.

Identification of an NAD(P)H:quinone oxidoreductase polymorphism and its association with lung cancer and smoking.

The enzyme NAD(P)H:quinone oxidoreductase (NQO1) catalyses bioreduction and bioactivation reactions. A mutation in the NQO1 gene had previously been demonstrated in a cancer cell line with reduced NQO1 activity. In this study, several regions of the NQO1 locus were examined for constitutional variation at the DNA level. The previously described mutation in exon 6 was detected by the single-strand conformation polymorphism technique. This was confirmed by sequencing to result from a C-->T substitution. Genotype analysis in the Centre d'Etude Polymorphisme Humain (CEPH) reference panel revealed two alleles with frequencies of 0.87 and 0.13 and demonstrated Mendelian transmission. Genotype distributions were consistent with Hardy-Weinberg equilibrium. Linkage analysis mapped the gene locus to chromosome 16q. NQO1 was felt to be a candidate gene for the susceptibility to lung cancer, given its potential role in protection against carcinogenic compounds. The frequency of NQO1 variants was examined in 150 lung cancer cases and in two reference populations. The allele distribution in CEPH parent controls was significantly different from cases (chi 2 = 5.52, p = 0.019), but no difference was noted between cases and a healthy local reference population. When the local reference distribution was stratified on smoking status, a significant difference was observed (chi 2 = 3.88, p = 0.048).(ABSTRACT TRUNCATED AT 250 WORDS)

Susceptibility to hepatocellular carcinoma is associated with genetic variation in the enzymatic detoxification of aflatoxin B1.

Aflatoxin B1 (AFB1) has been postulated to be a hepatocarcinogen in humans, possibly by causing p53 mutations at codon 249. AFB1 is metabolized via the phase I and II detoxification pathways; hence, genetic variation at those loci may predict susceptibility to the effects of AFB1. To test this hypothesis, genetic variation in two AFB1 detoxification genes, epoxide hydrolase (EPHX) and glutathione S-transferase M1 (GSTM1), was contrasted with the presence of serum AFB1-albumin adducts, the presence of hepatocellular carcinoma (HCC), and with p53 codon 249 mutations. Mutant alleles at both loci were significantly overrepresented in individuals with serum AFB1-albumin adducts in a cross-sectional study. Mutant alleles of EPHX were significantly overrepresented in persons with HCC, also in a case-control study. The relationship of EPHX to HCC varied by hepatitis B surface antigen status and indicated that a synergistic effect may exist. p53 codon 249 mutations were observed only among HCC patients with one or both high-risk genotypes. These results indicate that individuals with mutant genotypes at EPHX and GSTM1 may be at greater risk of developing AFB1 adducts, p53 mutations, and HCC when exposed to AFB1. Hepatitis B carriers with the high-risk genotypes may be an even greater risk than carriers with low-risk genotypes. These findings support the existence of genetic susceptibility in humans to the environmental carcinogen AFB1 and indicate that there is a synergistic increase in risk of HCC with the combination of hepatitis B virus infection and susceptible genotype.

Effects of individualized breast cancer risk counseling: a randomized trial.

BACKGROUND: Studies have shown that a majority of women with a family history of breast cancer have exaggerated perceptions of their own risk of this disease and experience excessive anxiety. In response to the need to communicate more accurate risk information to these women, specialized programs for breast cancer risk counseling have been initiated in medical centers across the United States. PURPOSE: Our purpose was 1) to evaluate the impact of a standardized protocol for individualized breast cancer risk counseling on comprehension of personal risk among first-degree relatives of index breast cancer patients and 2) to identify women most and least likely to benefit from such counseling. METHODS: This study is a prospective randomized trial comparing individualized breast cancer risk counseling to general health counseling (control). We studied 200 women aged 35 years and older who had a family history of breast cancer in a first-degree relative. Women with a personal history of cancer were excluded. Risk comprehension was assessed as the concordance between perceived "subjective" lifetime breast cancer risk and estimated "objective" lifetime risk. RESULTS: The results of logistic regression analysis showed that women who received risk counseling were significantly more likely to improve their risk comprehension, compared with women in the control condition (odds ratio [OR] = 3.5; 95% confidence interval [CI] = 1.3-9.5; P = .01). However, in both groups, about two thirds of women continued to overestimate their lifetime risks substantially following counseling. Examination of subjects by treatment interaction effects indicated that risk counseling did not produce improved comprehension among the large proportion of women who had high levels of anxious preoccupation with breast cancer at base line (P = .02). In addition, white women were less likely to benefit than African-American women (OR = 0.34; 95% CI = 0.11-0.99; P = .05). CONCLUSION: Efforts to counsel women about their breast cancer risks are not likely to be effective unless their breast cancer anxieties are also addressed. IMPLICATIONS: Attention to the psychological aspects of breast cancer risk will be critical in the development of risk-counseling programs that incorporate testing for the recently cloned breast cancer susceptibility gene, BRCA1 (and BRCA2 when that gene has also been cloned).

Using loss of heterozygosity data in affected pedigree member linkage tests.

Linkage analysis can be used to test the hypothesis that a marker locus of known location segregates independently from a presumed disease gene. One way to test this hypothesis is to measure the similarity of marker alleles among pairs of relatives affected with the disease. When the disease under consideration is cancer, it is possible to take advantage of the marker alleles in tumors to revise the similarity measure obtained from the observations made in constitutional tissue. Only cancers that arise through the model of recessive oncogenesis are amenable to this revised analysis. This model postulates that cancer is caused by somatic genetic changes which result in the loss of one or both copies of a normal allele at a tumor suppressor locus. If an individual's inherited genotype is heterozygous at the marker locus, the model of recessive oncogenesis suggests that we may observe loss of constitutional heterozygosity at the marker locus in the tumor. In this report, we how how to incorporate this loss of heterozygosity data into affected pedigree member linkage tests. The revised procedure is illustrated using data obtained from relatives with breast cancer. Substantial improvement in the power to reject the different chromosome hypothesis is obtained when loss of heterozygosity is observed in multiple relatives with the same marker alleles retained in the tumors.

Viral, host and environmental risk factors for hepatocellular carcinoma: a prospective study in Haimen City, China.

To identify specific environmental, viral, and genetic risk factors for hepatocellular carcinoma (HCC) and the interaction of such factors, we are conducting a prospective study in a high-incidence area of China. Questionnaires were completed and biosamples collected by 60,984 men ages 30-64 years, at study entry. Within 2.5 years, 183 deaths from HCC had occurred. Each HCC case was matched with 5 controls and compared for items on the questionnaire. In addition to chronic hepatitis B virus (HBV) infection, the significant risk factors were: occupation (peasant), corn consumption (in the 1970s), family history of HCC, and history of an episode of acute hepatitis as an adult. HBV, consumption of aflatoxins, a genetic factor, and possibly a second hepatitis virus infection contribute to the risk of HCC.

Recruiting high risk women into a breast cancer health promotion trial.

This study sought to identify factors that facilitate or hinder participation in a breast cancer health promotion trial among high-risk women. The subjects were 271 women ages 35 years and older who had a family history of breast cancer in at least one first-degree relative. All subjects were eligible for participation in a randomized trial which compares breast cancer risk counseling with general health counseling. Structured telephone interviews evaluated demographic characteristics, risk factors, risk perceptions, breast cancer concerns, and past screening practices. The results showed that education level was a key determinant of the importance of these factors in participation. Logistic regression modeling indicated that women with a high school education or less were most likely to participate if: (a) their relatives' diagnoses had greatly increased their perceptions of their personal risks [OR (OR) = 4.1], particularly if they perceived that risk to be very high (OR for interaction = 6.4); and (b) if they were ages 40-49 years versus 35-39 or 50 + years (OR = 2.6). By contrast, among women with education beyond high school, participation was predicted by (a) marital status (OR = 2.6), (b) employment (OR = 0.03 for employed), (c) number of affected relatives (OR = 0.07 for 1 versus 2 first-degree relatives), and (d) previous biopsy (OR = 0.42). These findings suggest that recruitment strategies that tailor messages to women's educational levels might be most effective.

Validation of a breast cancer risk assessment model in women with a positive family history.

BACKGROUND: Gail et al. developed a statistical model for estimating the risk of developing breast cancer in white women screened annually with mammography. This model is used for counseling and for admission to clinical trials. PURPOSE: We evaluated the model prospectively in a cohort of women with a family history of breast cancer. METHODS: We followed women who participated in the American Cancer Society 1987 Texas Breast Screening Project. The model was evaluated by comparing the observed (O) and expected (E) numbers of breast cancers using composite background rates from both the Breast Cancer Detection and Demonstration Project and the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. Data were partitioned by adherence to American Cancer Society screening guidelines. RESULTS: The Gail et al. model predicted the risk well among women who adhered to the American Cancer Society guidelines (O/E = 1.12; 95% confidence interval = 0.75-1.61) but overpredicted risk for women who did not adhere to the guidelines. There was an indication that the model overpredicted risk for women younger than 60 years old and underpredicted risk in women aged 60 years and older. CONCLUSIONS: Overall, the Gail et al. model accurately predicts risk in women with a family history of breast cancer and who adhere to American Cancer Society screening guidelines. Thus, the model should be used as it was intended, for women who receive annual mammograms.

Characterization of the antiviral effects of 2' carbodeoxyguanosine in ducks chronically infected with duck hepatitis B virus.

This study was carried out to evaluate benefits and limitations of long-term therapy of hepatitis B virus infections with a nucleoside analog inhibitor of virus replication. The model we used was the domestic duck chronically infected with duck hepatitis B virus by in ovo infection. 2' Carbodeoxyguanosine was used as an inhibitor of viral DNA synthesis. In all animals examined there was a reduction in virus production during therapy. A dose of 2' carbodeoxyguanosine of 10 micrograms/kg every other day reduced the number of infected hepatocytes from greater than 95% to 25% to 50% in less than 3 mo, whereas a 10-fold higher dose produced a decline to less than 10%. Histological evaluation revealed mild to moderate liver injury in ducks receiving the higher dose of 2' carbodeoxyguanosine, suggesting that disappearance of infected hepatocytes may have been accelerated by a toxic effect of the drug. Drug treatment did not completely eliminate duck hepatitis B virus from any duck, and replication was restored in all hepatocytes within a few weeks to several months after antiviral therapy was terminated. Our results suggest that elimination of a chronic infection with a single inhibitor of replication may be difficult in a host that lacks an antiviral immune response capable of eliminating at least a portion of the infected hepatocytes and of ultimately producing antibodies capable of neutralizing residual virus.

Somatic allele loss in genetic linkage analysis of cancer.

The ability to detect or reject genetic linkage in studies of human cancer is often diminished because multiple affected relatives in a pedigree are unavailable for analysis. The observation of somatic allele loss in tumors can provide knowledge about gametic phase. Therefore, consideration of tumor genotype data could be used to obtain knowledge about gametic phase ordinarily gained from a larger sample of individuals in cancer families. The objective of the present study is to describe a method for improving the power to detect or reject genetic linkage by using knowledge about somatic genetic changes in tumor tissue. A modification to the lod score method of linkage analysis is proposed in which knowledge of gametic phase in the linkage likelihood is inferred from observations of loss of constitutional heterozygosity (LoH) in tumor tissue. This methodology was evaluated using a double backcross nuclear family with a pair of offspring. The expected lod score improved substantially when tumor genotype data were included in the analysis. For example, when the haplotype remaining in tumor tissue was identical to the inherited haplotype in constitutional tissue 99% of the time, linkage analyses without tumor genotype data would require a 2-5 times larger sample of offspring pairs to conclude linkage with an expected lod score value of 3 or greater, compared to analyses incorporating tumor genotype data. These results suggest that consideration of tumor genotype data using the proposed method can substantially improve the power of linkage analyses in cancer families.

Mammography adherence and psychological distress among women at risk for breast cancer.

BACKGROUND: Previous studies estimate that first-degree relatives of women with breast cancer have a twofold to 10-fold increased risk of developing breast cancer. Recently, attention has focused on the mammography screening practices of women who are at high risk for breast cancer. PURPOSE: Our purpose was to characterize mammography screening practices in a sample of first-degree relatives of breast cancer patients and to identify variables that may serve as barriers to or facilitators of adherence to mammography. METHODS: Cross-sectional (rather than prospective) data were collected by telephone interviews with 140 women aged 35-79 years who had a family history of breast cancer in at least one first-degree relative (mother, sister, or daughter). Data were recorded on mammography screening patterns, depression, stress impact, and breast cancer worries. RESULTS: Women whose mammography history adhered to age-specific recommendations varied by age: 76% of first-degree relatives aged 35-39 years, 86% aged 40-49 years, and 63% aged 50 years or more. In bivariate analyses, level of education (P = .001), employment (P = .046), and time since diagnosis of the index patient (P = .044) were significantly and positively associated with mammography adherence. Variables associated negatively with adherence included age (P = .019), intrusive thoughts about breast cancer (P = .042), and breast cancer worries that interfered with daily functioning (P = .004). Multivariate analysis by logistic regression indicated that only breast cancer worries (odds ratio [OR] = 2.5; 95% confidence interval [CI] = 1.09-5.9) and education (OR = 4.8; CI = 1.6-14.3) were significant independent predictors of mammography adherence. CONCLUSIONS: This study suggests that most women at high risk for breast cancer adhere to the recommended mammography screening guidelines of the National Cancer Institute. However, rates of adherence among high-risk women aged 50 years and older are suboptimal; only 63% of these women received annual screening mammograms, and 13% had never been screened. Breast cancer worries may pose a barrier to mammography adherence among high-risk women, particularly those with less formal education. IMPLICATIONS: Prospective longitudinal studies are needed to validate the present findings and to evaluate the impact of psychoeducational interventions for women with affected first-degree relatives.

Segregation analysis of cancer in families of childhood soft-tissue-sarcoma patients.

This paper presents the analysis of familial cancer data collected in a hospital-based study of 159 childhood soft-tissue-sarcoma patients. Two different statistical models detected excess aggregation of cancer, which could be explained by a rare dominant gene. For each kindred, we estimated the probability of the observed cancer distribution under the dominant-gene model and identified 12 families that are the most likely to be segregating the gene. Two of those families have confirmed germ-line mutations in the p53 tumor-suppressor gene. The relative risk of affection for children who are gene carriers was estimated to be 100 times the background rate. Females were found to have a slightly higher age-specific penetrance, but maternal and paternal lineages made equal contributions to the evidence in favor of the dominant gene. The proband's histology, ethnicity, and age at diagnosis were evaluated to determine whether any of these altered the probability of affection in family members. Only embryonal rhabdomyosarcoma was found to be a significant covariate under the dominant-gene model. While molecular genetic studies of familial cancer will eventually provide answers to the questions of genetic heterogeneity, age- and site-specific penetrance, mutation rates, and gene frequency, information from statistical models is useful for setting priorities and defining hypotheses.

Breast cancer screening: effect of physician specialty, practice setting, year of medical school graduation, and sex.

We surveyed physicians of different specialties in a large metropolitan area to determine how their characteristics affected their performance and beliefs about breast cancer screening. Of 664 general internists, obstetrician-gynecologists, and cardiologists surveyed, we received 298 responses (45%). We found significant differences in reported performance of breast cancer screening and physicians' beliefs about mammography screening among practicing obstetrician-gynecologists, internists, and cardiopulmonary specialists. Cardiopulmonary specialists performed the fewest breast examinations and screening mammograms and were most likely to believe annual mammography screening unnecessary even for women in their 50s. We observed no difference between physicians graduating before 1960 and those graduating afterward and no differences according to physician sex. We found similar screening practices and beliefs in the three types of practice settings examined: community-based, private practices, a large health maintenance organization (HMO), and academic medical centers. Obstetrician-gynecologists and internists differed only in the frequency with which they performed breast examinations. Physicians graduating before 1960 in these two groups reported somewhat poorer performance and knowledge of breast cancer screening than those graduating more recently. A majority of all respondents disagreed with American Cancer Society guidelines for mammography screening. Physicians of all specialties reported performing far more breast examinations than screening mammograms on women of all ages, even for those 50-59 years of age. We conclude that all physicians need to improve their screening rates. However, intervention programs should first target those physicians with the greatest deficiencies in breast cancer screening performance and knowledge; these include medical specialists and older physicians in primary care specialties.

Segregation analysis of 159 soft tissue sarcoma kindreds: comparison of fixed and sequential sampling schemes.

In this study we compared parameter estimates and model hypotheses in pedigree data collected by fixed sampling with estimates and hypotheses derived by sequential sampling. Employing a fixed sampling scheme, we previously analyzed data on relatives of 159 childhood sarcoma patients. We have now extracted from that data set individuals who would have been included in a sequentially sampled study. We applied segregation analysis to the truncated data, to determine the mode of inheritance and major locus parameter estimates. With data from both sampling schemes we made a family-by-family comparison to determine each family's contribution to a major gene model. The two sampling schemes yielded similar results: we detected segregation of a dominant major gene and obtained similar major locus parameter estimates. However, the sequential sampling scheme derived these conclusions from data on 982 relatives rather than the 2,451 ascertained in the fixed sampling scheme. The sequential sampling scheme failed to identify only one of the kindreds likely to be segregating the gene. For this data set, the sequential sampling scheme would have provided an efficient mechanism to discriminate genetic hypotheses and would have permitted focus of resources on the specific kindreds likely to segregate a major gene.

Identification of women at increased risk for breast cancer in a population-based screening program.

A multivariate model to assess breast cancer risk was developed by Gail et al. (M. H. Gail, L. A. Brinton, D. B. Byar, D. K. Corle, S. B. Green, C. Schairer, and J. J. Mulvihill, J. Natl. Cancer Inst., 81: 1879-1886, 1989) based on data analysis of the Breast Cancer Detection and Demonstration Project. We evaluated the model's usefulness for assigning women to risk groups for counseling and follow-up by applying it to the 1987 Texas Breast Screening Project data. We identified 3165 women with one or more first-degree relatives affected with breast cancer. The mean risk score for the group was 3.3 (range, 2.7-11.8), indicating a greater than 3-fold elevated risk. The mean risk score for the remaining 27,439 women without affected first-degree relatives was 1.5 (range, 1.24-3.2). Risk perception was found to be a motivator for participation. Women with a risk score greater than 5 perceived themselves to be at high risk for breast cancer. The perception of risk was related to the type of affected first-degree relatives: 80.0% of the women with three affected first-degree relatives and 71.5% of women whose mother and sister were both affected with breast cancer perceived themselves to be at high risk. The Gail model is potentially useful in the clinical setting because women at high risk for breast cancer can be entered into etiological studies, enrolled in primary prevention trials, or referred to programs seeking to improve compliance with screening mammography. The Gail model needs validation, but it is useful for estimating the risk of breast cancer in large populations.

Genetic epidemiology of childhood brain tumors.

The study goal was to determine the genetic (heritable) contribution to childhood brain tumors (CBT) which cause nearly one quarter of all childhood cancer deaths. Their etiology remains unknown, but previous studies have suggested a proportion of CBT may be heritable. In this study we collected family histories of 243 confirmed CBT patients referred to The University of Texas M. D. Anderson Cancer Center between the years 1944 and 1983, diagnosed before age 15, and residents of the United States or Canada. Family histories were obtained for all the probands' first degree relatives (parents, siblings, and offspring) and extended to include selected second degree relatives (aunts, uncles, grandparents) using sequential sampling. To determine if these CBT families exhibited excess cancer, we compared their cancer experience to age-, race-, sex-, and calendar-year specific rates from the Connecticut Tumor Registry. No cancer excess was observed among 1,099 first and second degree relatives [39 cancers observed (O) and 44 expected (E) for a standardized incidence ratio (SIR) of 0.88]. For colon cancer, although small numbers, five cases were observed among the probands' first degree relatives with 1.6 expected, for a significant SIR of 3.10. Segregation analysis demonstrated that chance alone could not account for the observed cancer distribution with a multifactorial model providing the best overall explanation of the data. Overall, heredity played a role in the etiology of CBT in 4% of the study families: four (1.7%) due to known hereditary syndromes (nevoid basal cell carcinoma syndrome and von Recklinghausens neurofibromatosis--NF-1), four (1.7%) with multifactorial inheritance, and two additional families with cancers aggregating similar to the clinical criteria described for the Li-Fraumeni cancer family syndrome.

Other cancers in uveal melanoma patients and their families.

To determine associations with other cancers, 400 consecutive uveal melanoma patients examined at Wills Eye Hospital between 1984 and 1985 were surveyed regarding personal and family history of cancer. Responses were received from 333 (83%). Sixty patients reported 43 nonbasal cell second primary cancers, which were confirmed pathologically or by physician records. The overall prevalence of nonbasal cell cancers diagnosed in uveal melanoma patients by December 1985 was over two times greater than the expected prevalence, based on the Connecticut Tumor Registry data for an age- and sex-matched population. Gynecologic cancers tended to be more common in uveal melanoma female patients than in the comparison population. Although the observed prevalence of cutaneous melanoma was not significantly greater than expected, three cases with both primary cutaneous and uveal melanoma were reported. Family histories of cutaneous melanoma were confirmed in 14 patients, and uveal melanoma in two patients. Data suggested that the overall cancer prevalence in uveal melanoma patients may be increased, that hormonal factors may play a role in the genesis of this malignancy, and that there may be a link between cutaneous and uveal melanoma.

Hepatitis B virus replication and tuberculin reactivity: studies in Alaska.

In a previous study in 1982-1984 of southeast Asian refugees in Philadelphia, the authors found that hepatitis B virus carriers who reacted to a tuberculin (purified protein derivative (PPD)) skin test were more likely to be negative for the hepatitis B e antigen (HBeAg) than carriers who did not react to PPD. Because it was not known whether the PPD reactivity was due to natural infection or vaccination with bacille Calmette-Guérin (BCG), the authors conducted a further study in 1985 in Alaskan Native hepatitis B carriers, a group not vaccinated with BCG. The inverse association of HBeAg and PPD reactivity was confirmed across all age groups and was similar in magnitude to that observed in the refugee population. The host response to tubercle bacilli may inhibit the replication of hepatitis B virus. If the host response to BCG is similar, BCG vaccination may be of therapeutic value in chronic hepatitis B infection.