[Unexpected pregnancy, experience of sexual violence and contraception among women who use cannabis or other illegal substance in the Great Paris Region: Data from the 2016 Health Barometer]. / Grossesses non prévues, violences sexuelles et contraception chez les femmes consommant du cannabis ou d'autres substances psychoactives illégales en Île-de-France : données du Baromètre Santé 2016.

BACKGROUND: Women who use psychoactive substances could have higher levels of unplanned pregnancy and of difficulties accessing long-term contraceptive methods than those who do not use these substances. General population data on this topic are rare, particularly in France. METHODS: This study is based on data from the French Health Survey 2016, collected from women aged 15 to 49 years and living in the Great Paris region (N=1626). Use of illegal psychoactive substances (cannabis, substances used via intranasal or intravenous administration) were evaluated over the lifecourse and, for cannabis, over the 12 months preceding the study. Unplanned pregnancies were ascertained over the preceding 5 years, emergency contraception, abortion, and the experience of sexual violence during the lifecourse. We also studied the number of sexual partners in the preceding 12 months, as well as current contraception. Data were analyzed using weighted logistic regression models, adjusted for participants' sociodemographic characteristics and tobacco use. RESULTS: Women who use illegal substances have a higher probability than non-users to experience an unplanned pregnancy in the preceding 5 years (OR associated with lifecourse cannabis use: 1.61, 95% CI 1.00-2.58), to have used emergency contraception (ORs between 2.20 to 2.90), to have had an abortion (OR associated with lifecourse cannabis use: 1.77, 95% CI 1.26-2.49), and to have experienced sexual violence (ORs between 1.87 to 3.14). They also had more sexual partners than non-users, but did not differ in terms of contraception. CONCLUSION: In the general population, there is a relationship between women's use of illegal substances and their probability of experiencing sexual violence. These results should be brought to the attention of health professionals in contact with women, to help identify those who have addictive behaviors and identify their sexual and reproductive health needs.

Circulating plasma phospholipid fatty acids and risk of pancreatic cancer in a large European cohort.

There are both limited and conflicting data on the role of dietary fat and specific fatty acids in the development of pancreatic cancer. In this study, we investigated the association between plasma phospholipid fatty acids and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The fatty acid composition was measured by gas chromatography in plasma samples collected at recruitment from375 incident pancreatic cancer cases and375 matched controls. Associations of specific fatty acids with pancreatic cancer risk were evaluated using multivariable conditional logistic regression models with adjustment for established pancreatic cancer risk factors. Statistically significant inverse associations were found between pancreatic cancer incidence and levels of heptadecanoic acid (ORT3-T1 [odds ratio for highest versus lowest tertile] =0.63; 95%CI[confidence interval] = 0.41-0.98; ptrend = 0.036), n-3 polyunsaturated α-linolenic acid (ORT3-T1 = 0.60; 95%CI = 0.39-0.92; ptrend = 0.02) and docosapentaenoic acid (ORT3-T1 = 0.52; 95%CI = 0.32-0.85; ptrend = 0.008). Industrial trans-fatty acids were positively associated with pancreatic cancer risk among men (ORT3-T1 = 3.00; 95%CI = 1.13-7.99; ptrend = 0.029), while conjugated linoleic acids were inversely related to pancreatic cancer among women only (ORT3-T1 = 0.37; 95%CI = 0.17-0.81; ptrend = 0.008). Among current smokers, the long-chain n-6/n-3 polyunsaturated fatty acids ratio was positively associated with pancreatic cancer risk (ORT3-T1 = 3.40; 95%CI = 1.39-8.34; ptrend = 0.007). Results were robust to a range of sensitivity analyses. Our findings suggest that higher circulating levels of saturated fatty acids with an odd number of carbon atoms and n-3 polyunsaturated fatty acids may be related to lower risk of pancreatic cancer. The influence of some fatty acids on the development of pancreatic cancer may be sex-specific and modulated by smoking.

Multigene testing of moderate-risk genes: be mindful of the missense.

BACKGROUND: Moderate-risk genes have not been extensively studied, and missense substitutions in them are generally returned to patients as variants of uncertain significance lacking clearly defined risk estimates. The fraction of early-onset breast cancer cases carrying moderate-risk genotypes and quantitative methods for flagging variants for further analysis have not been established. METHODS: We evaluated rare missense substitutions identified from a mutation screen of ATM, CHEK2, MRE11A, RAD50, NBN, RAD51, RINT1, XRCC2 and BARD1 in 1297 cases of early-onset breast cancer and 1121 controls via scores from Align-Grantham Variation Grantham Deviation (GVGD), combined annotation dependent depletion (CADD), multivariate analysis of protein polymorphism (MAPP) and PolyPhen-2. We also evaluated subjects by polygenotype from 18 breast cancer risk SNPs. From these analyses, we estimated the fraction of cases and controls that reach a breast cancer OR≥2.5 threshold. RESULTS: Analysis of mutation screening data from the nine genes revealed that 7.5% of cases and 2.4% of controls were carriers of at least one rare variant with an average OR≥2.5. 2.1% of cases and 1.2% of controls had a polygenotype with an average OR≥2.5. CONCLUSIONS: Among early-onset breast cancer cases, 9.6% had a genotype associated with an increased risk sufficient to affect clinical management recommendations. Over two-thirds of variants conferring this level of risk were rare missense substitutions in moderate-risk genes. Placement in the estimated OR≥2.5 group by at least two of these missense analysis programs should be used to prioritise variants for further study. Panel testing often creates more heat than light; quantitative approaches to variant prioritisation and classification may facilitate more efficient clinical classification of variants.

Rare mutations in XRCC2 increase the risk of breast cancer.

An exome-sequencing study of families with multiple breast-cancer-affected individuals identified two families with XRCC2 mutations, one with a protein-truncating mutation and one with a probably deleterious missense mutation. We performed a population-based case-control mutation-screening study that identified six probably pathogenic coding variants in 1,308 cases with early-onset breast cancer and no variants in 1,120 controls (the severity grading was p < 0.02). We also performed additional mutation screening in 689 multiple-case families. We identified ten breast-cancer-affected families with protein-truncating or probably deleterious rare missense variants in XRCC2. Our identification of XRCC2 as a breast cancer susceptibility gene thus increases the proportion of breast cancers that are associated with homologous recombination-DNA-repair dysfunction and Fanconi anemia and could therefore benefit from specific targeted treatments such as PARP (poly ADP ribose polymerase) inhibitors. This study demonstrates the power of massively parallel sequencing for discovering susceptibility genes for common, complex diseases.

[Recommendations for genetic testing and management of individuals genetically at-risk of cutaneous melanoma]. / Recommandations pour le diagnostic de prédisposition génétique au mélanome cutané et pour la prise en charge des personnes à risque.

Cutaneous melanoma is a multifactorial disease resulting from both environmental and genetic factors. Five susceptibility genes have been identified over the past years, comprising high-risk susceptibility genes (CDKN2A, CDK4, and BAP1 genes) and intermediate-risk susceptibility genes (MITF, and MC1R genes). The aim of this expert consensus was to define clinical contexts justifying genetic analyses, to describe the conduct of these analyses, and to propose surveillance recommendations. Given the regulatory constraints, it is recommended that dermatologists work in tandem with a geneticist. Genetic analysis may be prescribed when at least two episodes of histologically proven invasive cutaneous melanoma have been diagnosed before the age of 75 years in two 1st or 2nd degree relatives or in the same individual. The occurrence in the same individual or in a relative of invasive cutaneous melanoma with ocular melanoma, pancreatic cancer, renal cancer, mesothelioma or a central nervous system tumour are also indications for genetic testing. Management is based upon properly managed photoprotection and dermatological monitoring according to genetic status. Finally, depending on the mutated gene and the familial history, associated tumour risks require specific management (e.g. ocular melanoma, pancreatic cancer). Due to the rapid progress in genetics, these recommendations will need to be updated regularly.

Circulating concentrations of insulin-like growth factor-I, insulin-like growth factor-binding protein-3, genetic polymorphisms and mammographic density in premenopausal Mexican women: results from the ESMaestras cohort.

The insulin-like growth factor (IGF) axis plays an essential role in the development of the mammary gland. High circulating levels of IGF-I and of its major binding protein IGFBP3 have been related with increased mammographic density in Caucasian premenopausal women. Some common single nucleotide polymorphisms (SNPs) in genes of the IGF pathway have also been suggested to play a role in mammographic density. We conducted a cross-sectional study nested within the large Mexican ESMaestras cohort to investigate the relation between circulating levels of IGF-I, IGFBP-3, the IGF-I/IGFBP-3 ratio, five common SNPs in the IGF-1, IGFBP-3 and IGF-1R genes and mammographic density in 593 premenopausal Mexican women. Mean age at mammogram was 43.1 (standard deviation, SD = 3.7) years, and average body mass index (BMI) at recruitment was 28.5 kg/m(2). Mean percent mammographic density was 36.5% (SD: 17.1), with mean dense tissue area of 48.3 (SD: 33.3) cm(2) . Mean IGF-I and IGFBP-3 concentrations were 15.33 (SD: 5.52) nmol/l and 114.96 (SD: 21.34) nmol/l, respectively. No significant associations were seen between percent density and biomarker concentrations, but women with higher IGF-I and IGF-I/IGFBP-3 concentrations had lower absolute dense (p(trend) = 0.03 and 0.09, respectively) and nondense tissue areas (p(trend) < 0.001 for both parameters). However, these associations were null after adjustment by BMI. SNPs in specific genes were associated with circulating levels of growth factors, but not with mammographic density features. These results do not support the hypothesis of a strong association between circulating levels of growth hormones and mammographic density in Mexican premenopausal women.

A sample storage management system for biobanks.

SUMMARY: Establishment of large-scale biobanks of human specimens is essential to conduct molecular pathological or epidemiological studies. This requires automation of procedures for specimen cataloguing and tracking through complex analytical processes. The International Agency for Research on Cancer (IARC) develops a large portfolio of studies broadly aimed at cancer prevention and including cohort, case-control and case-only studies in various parts of the world. This diversity of study designs, structure, annotations and specimen collections is extremely difficult to accommodate into a single sample management system (SMS). Current commercial or academic SMS are often restricted to a few sample types and tailored to a limited number of analytic workflows [Voegele et al. (2007) A laboratory information management system (LIMS) for a high throughput genetic platform aimed at candidate gene mutation screening. Bioinformatics, 23, 2504-2506]. Thus, we developed a system based on a three-tier architecture and relying on an Oracle database and an Oracle Forms web application. Data are imported through forms or csv files, and information retrieval is enabled via multi-criteria queries that can generate different types of reports including tables, Excel files, trees, pictures and graphs. The system is easy to install, flexible, expandable and implemented with a high degree of data security and confidentiality. Both the database and the interface have been modeled to be compatible with and adaptable to almost all types of biobanks. AVAILABILITY AND IMPLEMENTATION: The SMS source codes, which are under the GNU General Public License, and supplementary data are freely available at 'http://www-gcs.iarc.fr/sms.php' SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The contribution of large genomic deletions at the CDKN2A locus to the burden of familial melanoma.

Mutations in two genes encoding cell cycle regulatory proteins have been shown to cause familial cutaneous malignant melanoma (CMM). About 20% of melanoma-prone families bear a point mutation in the CDKN2A locus at 9p21, which encodes two unrelated proteins, p16(INK4a) and p14(ARF). Rare mutations in CDK4 have also been linked to the disease. Although the CDKN2A gene has been shown to be the major melanoma predisposing gene, there remains a significant proportion of melanoma kindreds linked to 9p21 in which germline mutations of CDKN2A have not been identified through direct exon sequencing. The purpose of this study was to assess the contribution of large rearrangements in CDKN2A to the disease in melanoma-prone families using multiplex ligation-dependent probe amplification. We examined 214 patients from independent pedigrees with at least two CMM cases. All had been tested for CDKN2A and CDK4 point mutation, and 47 were found positive. Among the remaining 167 negative patients, one carried a novel genomic deletion of CDKN2A exon 2. Overall, genomic deletions represented 2.1% of total mutations in this series (1 of 48), confirming that they explain a very small proportion of CMM susceptibility. In addition, we excluded a new gene on 9p21, KLHL9, as being a major CMM gene.

Germline homozygous mutations at codon 804 in the RET protooncogene in medullary thyroid carcinoma/multiple endocrine neoplasia type 2A patients.

The effect of mutations at codon 804 in the RET protooncogene is disputed. Some studies have suggested that the V804L mutation causes the low penetrance multiple endocrine neoplasia type 2 syndrome, with late onset and relatively indolent course, whereas others have reported that V804L and V804M have an aggressive potential. In this paper, we report three apparently unrelated medullary thyroid carcinoma cases homozygous for these mutations. To clarify the phenotypic heterogeneity associated with these mutations, we compare the clinical data and age of diagnosis among these three homozygous patients, six other heterozygous cases from the same populations, and other homozygous and heterozygous subjects reported previously. The data are consistent with a model in which codon 804 mutations have low penetrance, the developing of medullary thyroid carcinoma being associated with a second germline or somatic mutation. The activity and (in the case of somatic mutations) timing of these other genetic alterations in the RET gene may explain the wide clinical variability associated with germline mutations at codon 804.

Evidence for interaction between the TCO and NMTC1 loci in familial non-medullary thyroid cancer.

BACKGROUND: Familial non-medullary thyroid cancer (fNMTC) is a complex genetic disorder that is more aggressive than its sporadic counterpart. Thus far, three genetic loci have been implicated in susceptibility to fNMTC by linkage analysis. METHODS: We used linkage analysis to test the significance of two of the known susceptibility loci for fNMTC, TCO on 19p13 and NMTC1 on 2q21 in 10 fNMTC families, nine of which present with cell oxyphilia, a rare histological phenotype associated with TCO. Furthermore, we used two-locus linkage analysis to examine the possibility that the TCO and NMTC1 loci interact to increase the risk of NMTC. RESULTS: The 10 families provided evidence for linkage at both TCO and NMTC, with LOD scores of 1.56 and 2.85, respectively. Two-locus linkage analysis, using a multiplicative risk model for the development of NMTC, achieved a maximum LOD of 3.92, with an LOD of 4.51 when assuming 70% of families were linked, indicating that the segregation in these families is consistent with an interaction model. Most of this evidence came from a large Tyrolean family that singularly achieved a two-locus LOD of 3.21. CONCLUSIONS: These results provide further evidence that susceptibility genes for fNMTC exist at 19p13 and 2q21, and furthermore, raise the possibility that in a subset of fNMTC pedigrees, these loci interact resulting in significantly increased risk of NMTC for patients that carry both susceptibility loci.

Specific haplotypes of the RET proto-oncogene are over-represented in patients with sporadic papillary thyroid carcinoma.

BACKGROUND: Papillary thyroid carcinoma (PTC), which may be sporadic (95%) or familial (5%), has a prevalence adjusted for age in the general population of 1:100 000. Somatic rearrangements of the RET proto-oncogene are present in up to 66% of sporadic tumours, while they are rarely found in familial cases. PURPOSE: In order to determine if some variants of this gene, or a combination of them, might predispose to PTC, we looked for an association of RET haplotype(s) in PTC cases and in controls from four countries matched for sex, age, and population. METHODS: Four single nucleotide polymorphisms (SNPs) across the RET coding sequence were typed and haplotype frequencies were estimated. Genotype and haplotype distributions were compared among these cases and controls. RESULTS: Ten haplotypes were observed, the seven most frequent of which have been previously described in sporadic Hirschsprung patients and controls. The single locus analyses suggested association of exon 2 and exon 13 SNPs with sporadic PTC. The haplotype analysis showed over-representation of one haplotype in French and Italian sporadic PTC, whereas a different haplotype was significantly under-represented in French familial PTC. CONCLUSIONS: Our data suggest that some variants of RET and some specific haplotypes may act as low penetrance alleles in the predisposition to PTC.

Genetic heterogeneity in familial nonmedullary thyroid carcinoma: exclusion of linkage to RET, MNG1, and TCO in 56 families. NMTC Consortium.

Epidemiological studies show a very high relative risk for first degree relatives of probands with thyroid cancer. The familial form of nonmedullary thyroid carcinoma (NMTC) gives a more severe phenotype and appears earlier than its sporadic counterpart. Moreover, benign thyroid pathologies are often observed in NMTC kindreds. Little is known about the genetic risk factors of the disease. To study them, an international consortium has been organized at the International Agency for Research on Cancer over the past 2 yr to collect biological samples from NMTC families. The only genes known to be directly involved in susceptibility to NMTC are MNG1 on chromosome 14q32 and TCO on chromosome 19q13.2, previously localized by us and others. In addition to those two genes, the genes for Cowden's syndrome and familial adenomatous polyposis are associated with thyroid cancer, but not as an indicative phenotype. Another important gene in thyroid carcinogenesis is RET, which is mutated in the majority of cases of hereditary medullary thyroid cancer and rearranged in an important fraction of sporadic cases of NMTC. Here we report the result of a linkage analysis performed on the 56 more informative kindreds we have collected through the international consortium. Linkage analysis using both parametric and nonparametric methods excluded MNG1, TCO, and RET as major genes of susceptibility to NMTC and demonstrated that this trait is characterized by genetic heterogeneity.

RET rearrangements in familial papillary thyroid carcinomas.

Familial papillary thyroid carcinoma (FPTC) is an inherited tumor characterized by a more aggressive phenotype than that of its sporadic counterpart. Its mode of inheritance as well as its genetic and molecular bases are still poorly understood. On the contrary, genetic alterations in sporadic papillary thyroid carcinoma (PTC) are better characterized, the most common one involving the activation of the proto-oncogene RET through somatic rearrangements. In the present study, we investigated by interphase fluorescence in situ hybridization the presence of RET rearrangements in a series of 20 FPTC. We show that one FPTC and the adenoma from the same patient carry a RET rearrangement (type PTC1) and that this rearrangement is absent in the germline. Furthermore, we excluded a RET haplotype sharing in two brothers of the same family. These results show that RET rearrangements can indeed be found in FPTC and confirm that RET is not involved in the inherited predisposition to FPTC.

At least three genes account for familial papillary thyroid carcinoma: TCO and MNG1 excluded as susceptibility loci from a large Tasmanian family.

Recent studies have mapped two susceptibility loci which appear to account for familial multinodular goitre (MNG1) and a variant of familial papillary thyroid cancer (PTC), with associated multinodular goitre (TCO). A Tasmanian family (Tas1) has been identified with an autosomal dominant form of PTC. This study has examined the MNG1 and TCO loci to determine if they are similarly predisposing the Tas1 family to PTC. Linkage analysis using identical microsatellite markers described in the two previous studies was used to determine the significance of these loci in the Tasmanian family. The resultant LOD scores were sufficiently negative using multipoint parametric analysis to exclude these two loci from involvement in the Tasmanian family. In addition, six candidate genes, RET, TRK, MET, TSHR, APC and PTEN were also excluded as susceptibility genes in Tas1 by using microsatellites that are positioned in or in close proximity to these genes. These results suggest that there are at least three susceptibility genes that predispose families to familial PTC.

Mapping of a gene predisposing to familial thyroid tumors with cell oxyphilia to chromosome 19 and exclusion of JUN B as a candidate gene.

BACKGROUND: Familial nonmedullary thyroid carcinoma (FNMTC) is a clinical entity characterized by a more aggressive phenotype than the sporadic counterpart. The transmission of susceptibility of FNMTC is compatible with autosomal dominant inheritance. We report the identification of a new entity of FNMTC and the mapping of the responsible gene named TCO (for thyroid tumor with cell oxyphilia). METHODS: In one family, multinodular goiters were diagnosed in six individuals and papillary thyroid carcinoma was diagnosed in three. Eight patients were operated on. Blood samples were collected from the nine affected patients and from eight unaffected relatives. The gene was mapped by linkage analysis with a whole-genome panel of microsatellite markers. RESULTS: The neoplastic cells from all lesions showed characteristic faint to marked cytoplasmic oxyphilia. We found a logarithm of odd ratio (LOD) score of 2.41 at theta = 0 for marker D19S586. Additional markers were typed in the region and were found to be in linkage, with LOD scores peaking at markers D19S916 (Zmax = 3.01 at theta = 0) and D19S413 (Zmax = 2.95 at theta = 0). All these markers have been physically mapped to 19p13.2. CONCLUSIONS: TCO was mapped to chromosome 19p13.2. Interestingly, both the benign and malignant thyroid tumors in this family exhibit some degree of oxyphilia, which has not been described until now in the familial forms of NMTC.

Protective effect of copy number polymorphism of glutathione S-transferase T1 gene on melanoma risk in presence of CDKN2A mutations, MC1R variants and host-related phenotypes.

The effect of CDKN2A, the major high-risk melanoma susceptibility gene, has been shown to be modified by host-related phenotypes and variants of MC1R gene. The glutathione S-transferase (GSTs) genes, implicated in detoxification of metabolites after UV exposure, are candidates for modulating CDKN2A penetrance. Few case-control studies have investigated the effect of GSTs on melanoma risk, and have led to controversial results while these genes have not yet been studied in CDKN2A melanoma-prone families. We examined the effect of GSTP1, GSTM1 and GSTT1 genotypes on melanoma risk in 25 multi-generational melanoma-prone families with CDKN2A mutations, in presence of MC1R gene variants, sun exposure, and host-related phenotypes. These data included 195 genotyped subjects for all studied genes. We applied the GEE (Generalized Estimating Equations) approach to test for the effect of GSTs while adjusting for age, sex and CDKN2A mutation status and including successively MC1R, sun exposure and host factors in the model. No significant effect of null GSTM1 allele and GSTP1 variants (p.I105V, p.A114V) on melanoma risk was found. However, a significant protective effect of carrying >or=1 null GSTT1 allele was shown: OR(adjusted for age,sex,CDKN2A ) = 0.41 (0.18-0.94) and OR(adjusted for age,sex,CDKN2A,MC1R ) = 0.24 (0.15-0.58). Altogether, the factors modifying significantly the melanoma risk associated with CDKN2A mutations (stepwise procedure) were: MC1R and dysplastic nevi (increasing the risk) and GSTT1 (decreasing the risk). This study shows that even when a high-risk gene (CDKN2A) has been identified, multiple genetic modifiers influence melanoma risk.

Single-nucleotide polymorphisms in the RB1 gene and association with breast cancer in the British population.

A substantial proportion of the familial risk of breast cancer may be attributable to genetic variants each contributing a small effect. pRb controls the cell cycle and polymorphisms within it are candidates for such low penetrance susceptibility alleles, since the gene has been implicated in several human tumours, particularly breast cancer. The purpose of this study was to determine whether common variants in the RB1 gene are associated with breast cancer risk. We assessed 15 tagging single-nucleotide polymorphisms (SNPs) using a case-control study design (n< or = 4474 cases and n < or = 4560 controls). A difference in genotype frequencies was found between cases and controls for rs2854344 in intron 17 (P-trend = 0.007) and rs198580 in intron 19 (P-trend = 0.018). Carrying the minor allele of these SNPs appears to confer a protective effect on breast cancer risk (odd ratio (OR) = 0.86 (0.76-0.96) for rs2854344 and OR = 0.80 (0.66-0.96) for rs198580). However, after adjusting for multiple testing these associations were borderline with an adjusted P-trend = 0.068 for the most significant SNP (rs2854344). The RB1 gene is not known to contain any coding SNPs with allele frequencies > or = 5% but several intronic variants are in perfect linkage disequilibrium with the associated SNPs. Replication studies are needed to confirm the associations with breast cancer.

HapMap-based study of the 17q21 ERBB2 amplicon in susceptibility to breast cancer.

ERBB2 is frequently amplified in breast tumours as part of a wide region of amplification on chromosome 17q21. This amplicon contains many candidate genes for breast cancer susceptibility. We used a genetic association study design to determine if common genetic variation (frequency>or=5%) in a 400-kb region surrounding ERBB2 and containing the PPARBP, CRK7, NEUROD2, PPP1R1B, STARD3, TCAP, PNMT, CAB2, ERBB2, C17ORF37, GRB7 and ZNFN1A3 genes, was associated with breast cancer risk. Sixteen tagging single-nucleotide polymorphisms (tSNPs) selected within blocks of linkage disequilibrium from the HapMap database, one HapMap singleton SNP, and six additional SNPs randomly selected from dbSNP were genotyped using Taqman in a large study set of British women (2275 cases, 2280 controls). We observed no association between any of the genotypes or associated haplotypes and disease risk. In order to simulate unidentified SNPs, we performed the leave-one-out cross-validation procedure on the HapMap data; over 90% of the common genetic variation was well represented by tagging polymorphisms. We are therefore likely to have tagged any common variants present in our population. In summary, we found no association between common genetic variation in the 17q21 ERBB2 amplicon and breast cancer risk in British women.

NBT-II carcinoma behaviour is not dependent on cell-cell communication through gap junctions.

To study the mechanism(s) underlying the proliferation of heterogeneous cell populations within a solid tumour, the NBT-II rat bladder carcinoma system was used. It has been first investigated whether the different cell populations are coupled through gap junctions (GJIC). Cells overexpressing the Cx43 were generated to test for any tumour suppressive activity in vivo. To determine whether GJIC is essential for tumour proliferation and the establishment of a cooperative community effect, NBT-II cells that are incompetent for cell coupling were generated. The data report that (i) carcinoma cells expressing or not FGF-1 are coupled through GJIC in vitro and in coculture and express the gap junction protein Cx43, (ii) overexpression of Cx43 in these cells does not affect their in vitro coupling capacities and in vivo tumourigenic growth properties, (iii) inhibition of GJIC through antisense strategy has no in vivo obvious consequence on the tumour growth properties of the carcinoma, and (iv) the community effect between two carcinoma cell populations does not critically involve cell coupling through gap junctions.