Clinical characteristics of familial B-CLL in the National Cancer Institute Familial Registry.

In an ongoing study, families with two or more living cases of B-CLL in first-degree relatives have been recruited through physician and self-referral. Since 1967, 28 kindreds with 73 cases of B-CLL have been enrolled within the National Cancer Institute (NCI) Familial B-CLL Registry. Medical, clinical, and demographic information have been obtained from private physicians, patient interview, hospital records, and death certificates. We used SEER Registry data to compare characteristics of sporadic B-CLL to familial B-CLL. The mean age at diagnosis was approximately 10 years younger among familial cases (57.9 +/- 12.1) than that observed in sporadic cases (70.1 +/- 11.9). A higher percentage of second primary tumors among familial CLL cases compared to reports in sporadic was also observed (16% vs. 8.8%). However, the transformation rate to non-Hodgkin's lymphoma does not appear to be different from that reported for sporadic cases. In conclusion, we observed some differences between familial and sporadic cases; whether any of these characteristics affect survival time or severity of disease is unknown. The study of families with multiple B-CLL cases will aid in delineating the genes and environmental factors that may play a role in the development of both forms of B-CLL.

Chordoma: incidence and survival patterns in the United States, 1973-1995.

BACKGROUND: Chordoma, a rare tumor arising from notochordal remnants, has been described to date only by single-institution case series or small population-based surveys. METHODS: We used data from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute, 1973-1995, to calculate age-adjusted incidence and survival rates for 400 cases of microscopically confirmed chordoma and to derive information regarding case distribution and risk of second cancer. RESULTS: The age-adjusted chordoma incidence rate (IR) of 0.08 per 100,000 was age-dependent, more common in males (IR 0.10) than females (IR 0.06) and rare among patients aged <40 years and blacks. Within the axial skeleton 32% of cases were cranial, 32.8% spinal and 29.2% sacral. Young age (<26 years; p = 0.0001) and female sex (p = 0.037) were associated with greater likelihood of cranial presentation. There was no overall increased risk for second primary cancers after chordoma. Median survival was 6.29 years; 5- and 10-year relative survival rates were 67.6% and 39.9%, respectively. Comparison with other bone sarcomas revealed racial disparities in incidence for the two developmental tumors, chordoma and Ewing's sarcoma. CONCLUSIONS: This study provides new data regarding incidence and survival patterns of chordoma in the US. Additional epidemiologic studies are required to elucidate the genetic and environmental determinants underlying this rare, distinctive neoplasm.

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.

Expression of p27(Kip1) and bcl-2, cigarette smoking, and colorectal cancer risk.

Although a positive association between cigarette smoking and colorectal adenoma development is consistently found, the association with colorectal cancer remains controversial. We evaluated the potential roles of p27(Kip1) and bcl-2 protein expressions in conjunction with cigarette smoking exposure and colorectal cancer risk in a hospital-based case-control study. A total of 163 colorectal cancer patients from Roswell Park Cancer Institute and Buffalo General Hospital and 326 healthy controls responded to a standardized questionnaire on colorectal cancer risk factors including detailed information on their history of cigarette smoking; 110 of the patients' tumours were available for immunohistochemical analysis of p27(Kip1) and bcl-2 protein overexpression. An avidin-biotin immunoperoxidase procedure was used to determine expression after incubation with mouse monoclonal p27(Kip1) and mouse monoclonal bcl-2 antibodies, respectively. A statistically significant trend for total pack-years of smoking was found when p27(Kip1) positive cases were compared with p27(Kip1) negative cases (trend test, p = 0.007). Although a weak inverse association was observed with smoking exposure among p27(Kip1) negative tumour cases in comparison to controls, a significant dose-response association was seen with p27(Kip1) positive tumours. The relative risk of developing a p27(Kip1) positive tumour was estimated to be 1.17 (95% CI 0.54-2.54) for those with less than 20 pack-years, 1.95 (95 % CI 0.95-3.97) for those with 20-39 pack-years, and 2.25 (95% CI 1.14-4.45) for those with greater than 39 pack-years of smoking exposure (trend test, p = 0.009) when compared with controls. When cases with bcl-2 expression were compared with cases without bcl-2 expression, suggestion of a trend was also observed with pack-years smoked (trend test, p = 0.09). In our study of 110 patients with sporadic colorectal cancer and 326 controls, we observed differences in associations between cigarette smoking and expressions in p27(Kip1) and bcl-2. Our data suggest that bcl-2 overexpression (or a bcl-2 dependent pathway) is associated with cigarette smoking in the development of colorectal cancer, whereas a loss of p27(Kip1) expression is not. These associations indicate that there is aetiological heterogeneity in colorectal cancer development, and that they can indirectly allude to where these changes in protein expression occur in the adenoma-carcinoma sequence (i.e. early versus late events).

Clinical features of patients with stage IIIB and IV bronchioloalveolar carcinoma of the lung.

BACKGROUND: The incidence of bronchioloalveolar carcinoma of the lung (BAC), a pathologically distinct type of nonsmall cell lung carcinoma (NSCLC), appears to be rising. In this study, the authors compared data on the clinical presentation and clinical courses of patients with Stage IIIB and IV BAC with data on other types of NSCLC. METHODS: The authors collected clinical, radiographic, and pathology information about 28 patients with Stage IIIB and IV BAC and 124 patients with other histologic types of NSCLC. RESULTS: Twelve of 28 BAC patients (43%) were women, compared with 40 of 124 control patients (32%). Nine (32%) of the patients with BAC had never smoked cigarettes, versus 20 controls (16%) (P = 0.02). Eighteen patients (64%) with BAC had bilateral multilobar or multicentric pulmonary involvement, compared with 13 controls (15%) (P < 0.001). Patients with advanced stage (IIIB and IV) BAC had a median survival of 15 months from the time of diagnosis; for patients with other types of Stage IIIB and IV NSCLC, had a median survival of 10 months (P = 0.01). CONCLUSIONS: Patients with BAC of the lung have clinical, radiographic, and pathologic characteristics that distinguish them from patients with other types of NSCLC. A greater proportion of women and nonsmokers present with BAC than with other types of NSCLC. Patients with advanced stage BAC are more likely to have bilateral diffuse pulmonary involvement, are less likely to develop brain metastases, and have longer survival than patients with other types of Stage IIIB and IV NSCLC. Further research is warranted to define etiology, molecular abnormalities, and more effective therapeutic interventions.

p53 and vascular endothelial growth factor regulate tumor growth of NOS2-expressing human carcinoma cells.

The finding of frequent nitric oxide synthase expression in human cancers indicates that nitric oxide has a pathophysiological role in carcinogenesis. To determine the role of nitric oxide in tumor progression, we generated human carcinoma cell lines that produced nitric oxide constitutively. Cancer cells expressing inducible nitric oxide synthase that had wild-type p53 had reduced tumor growth in athymic nude mice, whereas those with mutated p53 had accelerated tumor growth associated with increased vascular endothelial growth factor expression and neovascularization. Our data indicate that tumor-associated nitric oxide production may promote cancer progression by providing a selective growth advantage to tumor cells with mutant p53, and that inhibitors of inducible nitric oxide synthase may have therapeutic activity in these tumors.

Inhibitors of acyl-CoA:cholesterol O-acyltransferase. 3. Discovery of a novel series of N-alkyl-N-[(fluorophenoxy)benzyl]-N'-arylureas with weak toxicological effects on adrenal glands.

A series of N-alkyl-N-[(fluorophenoxy)benzyl]-N'-arylureas were prepared and evaluated for their ability to inhibit intestinal acyl-CoA:cholesterol O-acyltransferase and to inhibit accumulation of cholesteryl esters in macrophages in vitro. In vivo hypocholesterolemic activity was assessed in cholesterol-fed rats by oral administration as a dietary admixture and/or by gavage in a PEG400 vehicle. Modification of the alkyl substituent on the N'-aryl moiety and on the urea nitrogen significantly influenced macrophage assay in vitro. Toxicological study revealed a distinct relationship between macrophage assay and the toxicity observed in adrenal glands of rabbits treated with representatives of this series of compounds. Investigations utilizing the macrophage assay as an indicator for adrenal toxicity led to the identification of compounds 1g (FR190809) and 1k (FR186485, or FR195249 as its hydrochloride salt) as potent, nonadrenotoxic, orally efficacious ACAT inhibitors irrespective of the administration method.

Relationship of membrane curvature to the formation of pores by magainin 2.

Magainin 2, an antimicrobial peptide from the Xenopus skin, kills bacteria by permeabilizing the cell membranes. We have proposed that the peptide preferentially interacts with acidic phospholipids to form a peptide-lipid supramolecular complex pore, which allows mutually coupled transbilayer traffic of ions, lipids, and peptides, thus simultaneously dissipating transmembrane potential and lipid asymmetry [Matsuzaki, K., Murase, O., Fujii, N., and Miyajima, K. (1996) Biochemistry 35, 11361-11368]. In this paper, we examined the effect of membrane curvature strain on pore formation. Magainin effectively forms the pore only in phosphatidylglycerol bilayers at low peptide-to-lipid ratios, well below 1/100. In contrast, the permeabilization of phosphatidylserine, phosphatidic acid, or cardiolipin bilayers occurred at much higher peptide-to-lipid ratios (1/50 to 1/10) with some morphological change of the vesicles. The latter three classes of phospholipids are known to form hexagonal II structures under conditions of reduced interlipid electrostatic repulsions. Incorporation of phosphatidylethanolamine also inhibited the magainin-induced pore formation in the inhibitory order of dioleoylphosphatidylethanolamine > dielaidoylphosphatidylethanolamine. Addition of a small amount of palmitoyllysophosphatidylcholine enhanced the peptide-induced permeabilization of phosphatidylglycerol bilayers. Magainin greatly raised the bilayer to hexagonal II phase transition temperature of dipalmitoleoylphosphatidylethanolamine. These results suggest that the peptide imposes positive curvature strain, facilitating the formation of a torus-type pore, and that the presence of negative curvature-inducing lipids inhibits pore formation.

Inhibitors of acyl-CoA:cholesterol O-acyltransferase. 2. Identification and structure-activity relationships of a novel series of N-alkyl-N-(heteroaryl-substituted benzyl)-N'-arylureas.

A series of N-alkyl-N-(heteroaryl-substituted benzyl)-N'-arylurea and related derivatives represented by 2 and 3 have been prepared and evaluated for their ability to inhibit acyl-CoA:cholesterol O-acyltransferase in vitro and to lower plasma cholesterol levels in cholesterol-fed rats in vivo. Among these novel compounds, the type 3 series was superior. A pyrazol-3-yl group on the N-benzyl group of this trisubstituted urea (i.e. 3, Ar1 = pyrazol-3-yl) was identified as a heteroaromatic ring providing a good profile of biological activity. As a result of optimization of the combination with the N-alkyl group (R) and N-aryl group (Ar3), compound 3aq (FR186054) was identified as a new, orally efficacious ACAT inhibitor, which exhibited potent in vitro ACAT inhibitory activity (rabbit intestinal microsomes IC50 = 99 nM) and excellent hypocholesterolemic effects in cholesterol-fed rats, irrespective of administration mode (ED50 = 0.046 mg/kg dosed via the diet, ED50 = 0. 44 mg/kg administered by gavage in PEG400 vehicle). Moreover, a toxicological study revealed compound 3aq to be nontoxic to the adrenal glands of dogs when tested at a single dose of 10 mg/kg po.

Inhibitors of acyl-CoA:cholesterol O-acyltransferase (ACAT). Part 1: identification and structure-activity relationships of a novel series of substituted N-alkyl-N-biphenylylmethyl-N'-arylureas.

A series of N-alkyl-N-biphenylylmethyl-N'-arylurea and related derivatives represented by 1 have been prepared and evaluated for their ability to inhibit acyl-CoA:cholesterol O-acyltransferase in vitro and to lower plasma cholesterol levels in cholesterol-fed rats in vivo. Linking of two phenyl groups via oxygen and introduction of fluorine at appropriate positions on the biphenyl moiety improved in vitro and in vivo activity. From this series of analogs, compound 40 (FR179254), which had potent in vitro potency (rabbit intestinal microsomes IC50 = 25 nM), showed excellent plasma cholesterol-lowering activity when administered via the diet (ED50 = 0.045 mg/kg). However, the hypocholesterolemic effect of this compound was moderate when dosed by oral gavage in PEG400 as a vehicle (ED50 = 5.3 mg/kg). Modification of the N'-aryl moiety led to the identification of compound 50 (FR182980) which was efficacious in both dosing models (ED50 = 0.034 mg/kg and 0.11 mg/kg, respectively).

Cigarette smoking, cytochrome P450 1A1 polymorphisms, and breast cancer risk in the Nurses' Health Study.

Environmental exposure to carcinogens may contribute to increasing breast cancer rates and geographic variation in breast cancer incidence in the United States. One class of chemicals that has received much attention are the polyaromatic hydrocarbons that are ubiquitous in the environment and occur in cigarette smoke. The cytochrome P450 1A1 (CYP1A1) gene codes for an enzyme that contributes to aryl hydrocarbon hydroxylase activity, which is involved in the metabolism of polyaromatic hydrocarbons. Genotypic variants of CYP1A1 have been associated with increased aryl hydrocarbon hydroxylase activity, and some epidemiological studies suggest that women with the variant genotype(s) are at increased risk for breast cancer. We prospectively evaluated the associations between the CYP1A1 polymorphisms and breast cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case-control study nested within the Nurses' Health Study. We analyzed the T-->C transition at nucleotide 6235 (MspI) and the A-->G transition at nucleotide 4889 (exon 7) in CYP1A1 by PCR-RFLP assays among 466 incident breast cancer cases and 466 matched controls. Relative risks (RRs) and 95% confidence intervals (CIs) were used to quantify the risk of breast cancer among subjects who had at least one variant allele relative to subjects who were homozygous for the wild-type allele, using conditional logistic regression. No overall increase in breast cancer risk with the variant CYP1A1 genotypes was apparent (RR(MspI), 1.05; 95% CI, 0.74-1.50 and RR(exon7), 0.88; 95% CI, 0.58-1.33). However, a suggestive increase in breast cancer risk was observed among women who had commenced smoking before the age of 18 and had the CYP1A1-MspI variant genotype compared to nonsmokers who were homozygous wild type for the polymorphism (RR, 5.65; 95% CI, 1.50-21.3; percentage of all breast cancer cases attributable to this risk factor, 2.5%). A similar gene-environment association was observed for the exon 7 polymorphism (RR, 3.61; 95% CI, 1.11-11.7; percentage of all breast cancer cases attributable to this risk factor, 2.2%). These data are compatible with the hypothesis that cigarette smoking early in life is a modifiable cause of breast cancer in a subpopulation of genetically susceptible women. However, the proportion of breast cancer attributable to cigarette smoking at a young age among Caucasian women with the variant form of the CYP1A1 polymorphisms is low.

Polymorphisms in the N acetyltransferase 1 NAT1 gene and lung cancer risk in a minority population.

One of the most consistently observed exposure-disease relationship is the one between cigarette smoking and lung cancer. Aromatic amines and their metabolites are found in tobacco smoke and may be a class of carcinogen involved in lung carcinogenesis. T he human N -acetyltransferase 1 (NAT 1) enzyme can activate or deactivate aromatic amines, making it a candidate genetic susceptibility gene. We evaluated the potential role of the NAT 1 gene in lung cancer risk in a hospital-based case-control study in a minority population composed of Mexican- and African-Americans. We also assessed the potential interaction between NAT 1 and other environmental exposures such as cigarette smoking. T here was no overall association between the NAT1*10 genotypes and lung cancer risk. T he adjusted odds ratio for the rapid acetylation genotypes was 0 72 (95 % CI 0 37-1 39) for NAT1 defined as the presence of at least one copy of the NAT1*10 allele when compared with all genotypes without the NAT1*10 allele. Analyses by histological subtype or smoking history did not alter these findings. Other NAT 1 alleles will need to be studied for more conclusive results regarding the relevance of NAT 1 activity to lung carcinogenesis.

Synthesis, X-ray crystal structure, and biological activity of FR186054, a novel, potent, orally active inhibitor of acyl-CoA:cholesterol O-acyltransferase (ACAT) bearing a pyrazole ring.

The synthesis, single crystal X-ray structural analysis, and biological activity of FR186054 (2c), a new, potent, orally efficacious inhibitor of acyl-CoA:cholesterol O-acyltransferase (ACAT), containing a pyrazole ring are described. This compound displayed excellent in vitro efficacy, irrespective of dosing method, indicating superior characteristics compared to other ACAT inhibitors.

Genetic susceptibility to environmental and occupational cancers.

Epidemiologic evidence on the relation between genetic susceptibility and cancer is reviewed. Traditional epidemiologic studies have identified various exposure-related associations with cancer. Most conventional approaches to environmental and occupational cancer have not been able to address specifically the issue of individual susceptibility to the action of carcinogens. However, with the recent rapid advances in molecular biology, novel approaches to define the role of genetic susceptibility in epidemiologic studies of cancer etiology have emerged. Molecular epidemiology has begun to develop within the broad field of cancer research. Here, we provide a description of the current framework of this research. Ongoing studies of the associations of inheritable polymorphisms in metabolic genes with specific carcinogen exposures reflect the most active area of research. Future efforts will include the examination of inherited variation in DNA repair. Methods are being developed now that will allow for the application of linkage analysis to the problem of gene-environment interaction in cancer. These approaches hold considerable promise for defining the nature of genetic susceptibility to exposure-related cancers.

Susceptibility to lung cancer in light smokers associated with CYP1A1 polymorphisms in Mexican- and African-Americans.

The gene-environment associations between potential carcinogenic agents modified by polymorphisms in the cytochrome P450 1A1 (CYP1A1) gene and lung cancer risk were assessed in a hospital-based case-control study composed of African- and Mexican-Americans. The study involved 171 cases and 295 controls identified from the greater Houston and San Antonio metropolitan areas. Both the exon 7 and MspI polymorphisms were analyzed by RFLP of PCR-amplified DNA, and in addition, the African-American-specific polymorphism was assayed for subjects who reported that they were African-American. Logistic regression analysis was performed to assess the association between each of the CYP1A1 polymorphisms and lung cancer, adjusting for the matching variables (age, sex, ethnicity) and other potential risk factors. Interactions between pack-years smoked, CYP1A1 genotypes, and case status were also evaluated. The variant allele frequencies did not differ by case status, but the distributions of genotypes were strikingly different by ethnicity. In addition, both the exon 7 and MspI polymorphisms, but not the African-American-specific polymorphism, were modified by the amount of cigarette consumption measured in pack-years. An approximate 2-fold increase in lung cancer risk among individuals with one or more of the variant alleles was observed among light smokers (defined as having smoked < or = 30 pack-years). The respective risk ratios for the exon 7 and MspI polymorphisms were 2.26 (95% confidence interval, 0.82-6.26) and 2.03 (95% confidence interval, 1.03-4.01) at low smoking dose. No such increase in risk was found among heavy smokers (> 30 pack-years). This phenomenon at low smoking dose was also observed when the two common polymorphisms were combined, which resulted in was a progressive increase in risk with an increasing number of variant alleles. These results indicate that at low smoking levels, the MspI and exon 7 CYP1A1 genetic polymorphisms confer susceptibility to lung cancer.

The pH dependence of cytochrome a conformation in cytochrome c oxidase.

The pH dependence of the conformation of cytochrome a in bovine cytochrome c oxidase has been studied by second derivative absorption spectroscopy. At neutral pH, the second derivative spectra of the cyanide-inhibited fully reduced and mixed valence enzyme display two Soret electronic transitions, at 443 and 451 nm, associated with cytochrome a. As the pH is lowered these two bands collapse into a single transition at approximately 444 nm. pH titration of the cyanide-inhibited mixed valence enzyme suggests that the transition from the two-band to one-band spectrum obeys the Henderson Hasselbalch relationship for a single protonation event with a transition pKa of 6.6 +/- 0.1. No pH dependence is observed for the spectra of the fully reduced unliganded or CO-inhibited enzyme. Tryptophan fluorescence spectra of the enzyme indicate that no major disruption of protein structure occurs in the pH range 5.5-8.5 used in this study. Resonance Raman spectroscopy indicates that the cytochrome a3 chromophore remains in its ferric, cyanide-bound form in the mixed valence enzyme throughout the pH range used here. These data indicate that the transition observed by second derivative spectroscopy is not due simply to pH-induced protein denaturation or disruption of the cytochrome a3 iron-CN bond. The pH dependence observed here is in good agreement with those observed earlier for the midpoint reduction potential of cytochrome a and for the conformational transition associated with energy transduction in the proton pumping model of Malmström (Malmström, B. G. (1990) Arch. Biochem. Biophys. 280, 233-241). These results are discussed in terms of a model for allosteric communication between cytochrome a and the binuclear ligand binding center of the enzyme that is mediated by ionization of a single group within the protein.

Resolution of the electronic transitions of cytochrome c oxidase: evidence for two conformational states of ferrous cytochrome alpha.

Second-derivative absorption spectra are reported for a variety of oxidation and ligation states of bovine cytochrome c oxidase (ferrocytochrome-c:oxygen oxidoreductase, EC 1.9.3.1). The high resolving power of the second-derivative method allows us to assign the individual electronic transitions of cytochrome alpha and cytochrome alpha 3 in many of these states. In the fully reduced enzyme, one observes a single electronic transition at 444 nm, corresponding to the Soret transition for both ferrous cytochrome alpha and ferrous cytochrome alpha 3. When the cytochrome alpha 3 site is occupied by an exogenous ligand (CN or CO), one observes two absorption bands assignable to the ferrous cytochrome alpha chromophore, one at ca, 443 nm and the other at ca, 450 nm. The appearance of the 450-nm band is dependent only on ligand occupancy at the cytochrome alpha 3 site and not on the oxidation state of the cytochrome alpha 3 iron. These results can be interpreted either in terms of a heterogeneous mixture of two ferrous cytochrome alpha conformers in the cytochrome alpha 3-ligated enzyme or in terms of a reduction in the effective molecular symmetry of the ferrous cytochrome alpha site that results in a lifting of the degeneracy of the lowest unoccupied molecular orbital associated with the Soret pi,pi* transition of cytochrome alpha. In either case, the present data indicate that ferrous cytochrome alpha can adopt two distinct conformations. One possible structural difference between these two states could be related to differences in the strength of hydrogen bonding between the ferrous cytochrome alpha formyl oxygen and a proton donor from an unidentified amino acid side chain of the enzyme. The implications of such modulation of hydrogen-bond strength are discussed in terms of possible mechanisms of proton translocation and electron transfer in the enzyme.