Vitreoretinal surgery for severe retinal capillary hemangiomas in von hippel-lindau disease

PURPOSE

To evaluate the long-term success rate of vitreoretinal surgery for severe cases of retinal capillary hemangiomas (RCHs) caused by von Hippel-Lindau (VHL) disease.

DESIGN

Retrospective case series.

PARTICIPANTS

Twenty-three eyes of 21 patients with severe exudative or tractional retinal detachment caused by RCH, who had undergone vitreoretinal surgery. Patients' age at initial surgery ranged from 12 to 47 years (median, 27 years), and the fellow eye was already blind in 6 of 21 patients.

INTERVENTIONS

All eyes underwent pars plana vitrectomy with posterior hyaloid detachment epiretinal membrane dissection and silicone oil or gas injection. In 9 eyes, retinectomy was performed to remove the RCH (group R). In the other 14 eyes, the RCH was treated by laser endophotocoagulation alone or combined with transscleral cryotherapy (group L).

MAIN OUTCOME MEASURES

Visual acuity (preoperative, 6 and 18 months postoperatively), rate of RCH recurrence, and postoperative complications.

RESULTS

In group R, an average of 2 operations per patient was needed. Six months after surgery, the retina was flat in 8 eyes. Mean follow-up was 8 years. Long-term complications included RCH reproliferation and neovascular glaucoma in 4 eyes, 4 to 8 years after initial surgery. In the remaining 5 eyes, visual acuity ranged from 20/320 to counting fingers 18 months postoperatively. In group L, an average of 1.7 operations was needed. Six months after surgery, the retina was flat in 13 of 14 eyes. Mean follow-up was 4 years. New RCH occurred in 10 eyes and required laser treatment. In the long term, 1 eye became blind after 5 years because of aggressive RCH reproliferation and neovascular glaucoma, and 2 eyes became blind after 10 years because of exudative retinal detachment. In the 11 remaining eyes, visual acuity ranged from 20/320 to 20/20 (median: 20/50) 18 months postoperatively.

CONCLUSIONS

Vitreoretinal surgery is an effective treatment for severe VHL retinal hemangiomas. Large RCHs were satisfactorily treated by (1) vitrectomy with epiretinal dissection and endolaser photocoagulation or (2) retinectomy for RCH resection, although a high rate of vision-threatening RCH recurrence was observed in the long term. However in most cases, surgery improved or prolonged visual function in these eyes.

Oncogramme, a new promising method for individualized breast tumour response testing for cancer treatment

BACKGROUND

Breast cancer is the most widely spread cancer in the world, attracting much research and individualized tumour response testing (ITRT) methods are now used to individualize patient chemotherapeutic administrations. A new ITRT method was developed with optimized processing.

MATERIALS AND METHODS

Breast tumour fragments were separated and the cells seeded in a foetal calf serum-free defined medium. After various chemotherapeutic treatments, cytotoxicity was determined by cell death detection with calcein acetoxymethyl and ethidium homodimer labelling.

RESULTS

The culture medium allowed breast tumour cell proliferation in culture, while preventing fibroblastic cell survival. Moreover, the cell death analysis gave rise to a chemoresistance profile called an Oncogramme, with statistically significant values.

CONCLUSION

The Oncogramme is a new ITRT method which can predict patient cell sensitivities to chemotherapeutics and should be validated by a new phase I clinical trial.

Conservative management of endolymphatic sac tumors in von Hippel-Lindau disease: case report

In endolymphatic sac tumors associated with von Hippel-Lindau disease, early detection and surgery have been warranted to avoid associated neurological morbidity. However, in lately discovered tumors, hearing preserving surgery is often impossible and timing of surgical resection is difficult to define. We report two cases of tumors revealed by a sudden and profound hearing loss and managed conservatively for more than 15 years without worsening of the neurological symptoms associated with the endolymphatic sac tumor. Tumor size remained stable for the first patient and a stuttering growth pattern was observed for the second patient. Initial observation may be considered a not unreasonable management paradigm in these cases.

Birt-Hogg-Dubé renal tumors are genetically distinct from other renal neoplasias and are associated with up-regulation of mitochondrial gene expression

Background

Germline mutations in the folliculin (FLCN) gene are associated with the development of Birt-Hogg-Dubé syndrome (BHDS), a disease characterized by papular skin lesions, a high occurrence of spontaneous pneumothorax, and the development of renal neoplasias. The majority of renal tumors that arise in BHDS-affected individuals are histologically similar to sporadic chromophobe renal cell carcinoma (RCC) and sporadic renal oncocytoma. However, most sporadic tumors lack FLCN mutations and the extent to which the BHDS-derived renal tumors share genetic defects associated with the sporadic tumors has not been well studied.

Methods

BHDS individuals were identified symptomatically and FLCN mutations were confirmed by DNA sequencing. Comparative gene expression profiling analyses were carried out on renal tumors isolated from individuals afflicted with BHDS and a panel of sporadic renal tumors of different subtypes using discriminate and clustering approaches. qRT-PCR was used to confirm selected results of the gene expression analyses. We further analyzed differentially expressed genes using gene set enrichment analysis and pathway analysis approaches. Pathway analysis results were confirmed by generation of independent pathway signatures and application to additional datasets.

Results

Renal tumors isolated from individuals with BHDS showed distinct gene expression and cytogenetic characteristics from sporadic renal oncocytoma and chromophobe RCC. The most prominent molecular feature of BHDS-derived kidney tumors was high expression of mitochondria-and oxidative phosphorylation (OXPHOS)-associated genes. This mitochondria expression phenotype was associated with deregulation of the PGC-1α-TFAM signaling axis. Loss of FLCN expression across various tumor types is also associated with increased nuclear mitochondrial gene expression.

Conclusions

Our results support a genetic distinction between BHDS-associated tumors and other renal neoplasias. In addition, deregulation of the PGC-1α-TFAM signaling axis is most pronounced in renal tumors that harbor FLCN mutations and in tumors from other organs that have relatively low expression of FLCN. These results are consistent with the recently discovered interaction between FLCN and AMPK and support a model in which FLCN is a regulator of mitochondrial function.

Intensity-dependent constitutional MLH1 promoter methylation leads to early onset of colorectal cancer by affecting both alleles

Constitutional epimutation is one of the causes for MLH1 gene inactivation associated with hereditary non-polyposis colon cancer (HNPCC) syndrome. Here we investigate MLH1 promoter hypermethylation in 110 sporadic early-onset colorectal cancer patients. Variable levels of hypermethylation were detected in 55 patients (50%). Importantly a reduced MLH1 gene expression was found in patients with high-level methylation, with the association of microsatellite instability (MSI) in their tumor cells. Such high-level methylation accounts for 7.4% of all patients included in this study. Furthermore, we found that in one case constitutional methylation affected both alleles, indicating a post-zygotic methylation dysregulation. Our findings suggest that constitutional epimutation is a mechanism underlying early-onset colorectal cancer, although it is involved in only a small proportion of patients, who require appropriate surveillance. Our findings provide further insight into the role of aberrant constitutional methylation in colon carcinogenesis and raise the question of whether prevalent low-level methylation constitutes a potential risk factor for cancer development.

Evidence for SMAD3 as a modifier of breast cancer risk in BRCA2 mutation carriers

INTRODUCTION

Current attempts to identify genetic modifiers of BRCA1 and BRCA2 associated risk have focused on a candidate gene approach, based on knowledge of gene functions, or the development of large genome-wide association studies. In this study, we evaluated 24 SNPs tagged to 14 candidate genes derived through a novel approach that analysed gene expression differences to prioritise candidate modifier genes for association studies.

METHODS

We successfully genotyped 24 SNPs in a cohort of up to 4,724 BRCA1 and 2,693 BRCA2 female mutation carriers from 15 study groups and assessed whether these variants were associated with risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

RESULTS

SNPs in five of the 14 candidate genes showed evidence of association with breast cancer risk for BRCA1 or BRCA2 carriers (P < 0.05). Notably, the minor alleles of two SNPs (rs7166081 and rs3825977) in high linkage disequilibrium (r² = 0.77), located at the SMAD3 locus (15q22), were each associated with increased breast cancer risk for BRCA2 mutation carriers (relative risk = 1.25, 95% confidence interval = 1.07 to 1.45, P(trend) = 0.004; and relative risk = 1.20, 95% confidence interval = 1.03 to 1.40, P(trend) = 0.018).

CONCLUSIONS

This study provides evidence that the SMAD3 gene, which encodes a key regulatory protein in the transforming growth factor beta signalling pathway and is known to interact directly with BRCA2, may contribute to increased risk of breast cancer in BRCA2 mutation carriers. This finding suggests that genes with expression associated with BRCA1 and BRCA2 mutation status are enriched for the presence of common genetic modifiers of breast cancer risk in these populations.

Genomic expression and single-nucleotide polymorphism profiling discriminates chromophobe renal cell carcinoma and oncocytoma

Background

Chromophobe renal cell carcinoma (chRCC) and renal oncocytoma are two distinct but closely related entities with strong morphologic and genetic similarities. While chRCC is a malignant tumor, oncocytoma is usually regarded as a benign entity. The overlapping characteristics are best explained by a common cellular origin, and the biologic differences between chRCC and oncocytoma are therefore of considerable interest in terms of carcinogenesis, diagnosis and clinical management. Previous studies have been relatively limited in terms of examining the differences between oncocytoma and chromophobe RCC.

Methods

Gene expression profiling using the Affymetrix HGU133Plus2 platform was applied on chRCC (n = 15) and oncocytoma specimens (n = 15). Supervised analysis was applied to identify a discriminatory gene signature, as well as differentially expressed genes. High throughput single-nucleotide polymorphism (SNP) genotyping was performed on independent samples (n = 14) using Affymetrix GeneChip Mapping 100 K arrays to assess correlation between expression and gene copy number. Immunohistochemical validation was performed in an independent set of tumors.

Results

A novel 14 probe-set signature was developed to classify the tumors internally with 93% accuracy, and this was successfully validated on an external data-set with 94% accuracy. Pathway analysis highlighted clinically relevant dysregulated pathways of c-erbB2 and mammalian target of rapamycin (mTOR) signaling in chRCC, but no significant differences in p-AKT or extracellular HER2 expression was identified on immunohistochemistry. Loss of chromosome 1p, reflected in both cytogenetic and expression analysis, is common to both entities, implying this may be an early event in histogenesis. Multiple regional areas of cytogenetic alterations and corresponding expression biases differentiating the two entities were identified. Parafibromin, aquaporin 6, and synaptogyrin 3 were novel immunohistochemical markers effectively discriminating the two pathologic entities.

Conclusions

Gene expression profiles, high-throughput SNP genotyping, and pathway analysis effectively distinguish chRCC from oncocytoma. We have generated a novel transcript predictor that is able to discriminate between the two entities accurately, and which has been validated both in an internal and an independent data-set, implying generalizability. A cytogenetic alteration, loss of chromosome 1p, common to renal oncocytoma and chRCC has been identified, providing the opportunities for identifying novel tumor suppressor genes and we have identified a series of immunohistochemical markers that are clinically useful in discriminating chRCC and oncocytoma.

Abstract 5011: Potential tumor suppressor role of PHD2 : functional study of mutations identified in germline DNA of patients with congenital polycythemia with or without paraganglioma

The Hypoxia Inducible Factor (HIF) plays a major role in tissue response to hypoxia. HIF induces expression of many genes involved in anaerobic glycolysis, angiogenesis, erythropoiesis and cell proliferation. HIF-alpha subunit is tightly regulated by a family of specific hydroxylases in normoxia. PHD (prolyl-hydroxylase domain) proteins hydroxylate HIF-alpha, thereby allowing its attachment to the VHL protein, a component of an E3 ubiquitin ligase complex involved in protein ubiquitination and degradation. Mutations in HIF regulators have been described and lead to the stabilization of HIF, activation of target genes and development of either tumors or polycythemia. Heterozygous germline mutations in the VHL gene predispose to the von Hippel-Lindau disease characterized by a panel of highly vascularized tumors (central nervous system and retinal hemangioblastomas, pheochromocytomas, renal cell carcinoma, pancreatic endocrine tumors) whereas homozygous or compound heterozygous VHL mutations are responsible for isolated polycythemia (”Chuvash polycythemia”) with high circulating erythropoietin levels. Recently, heterozygous germline mutations in the PHD2 gene have been described in few patients with such congenital polycythemia and a particular mutation (H374R) has been identified in a patient with a polycythemia and a recurrent paraganglioma1. This observation raised the question of a possible role of PHD2 loss of function in the genesis of tumors usually seen in the VHL disease. We report here four new heterozygous PHD2 germline mutations in patients with familial or apparently sporadic polycythemia. We performed a functional study of these mutants compared to the H374R mutant and we showed differences in the capacity of the PHD2 mutants to downregulate HIF-alpha. These differences, tested in various conditions, are highly reproducible and suggest that there may be a genotype/phenotype correlation for the PHD2 mutants like the VHL mutants with their different ability to regulate HIF associated with different phenotypes in the VHL disease.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5011.

Abstract 1848: Folliculin (FLCN) sequence variants involved in Birt-Hogg-Dube syndrome

Background:

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominantly inherited familial cancer syndrome characterized most commonly by the development of facial fibrofolliculomas, pulmonary cysts (predisposing to spontaneous pneumothorax) and renal cancer. Germline mutations in FLCN on 17p11.2 have been reported in patients with BHD and also in patients with isolated familial primary spontaneous pneumothorax and familial clear cell renal cell carcinoma without other features of BHD. The function of the FLCN gene product, folliculin, is not well characterized but recent studies have suggested that it may be implicated in the regulation of several key signalling pathways including the AMPK-mTOR route.

Methods:

We previously established an online locus-specific database (LSDB) for FLCN sequence variants at www.lovd.nl/flcn. Variants in the database have been curated from the published literature and novel unpublished sequence variants submitted to the database from diagnostic and research laboratories working on BHD syndrome. The entries in the database were analyzed looking at the variant type and distribution and associated phenotype.

Results:

The database currently contains a total of 115 unique sequence variants (including 70 pathogenic, 7 probably pathogenic, 1 variant of unknown significance and 37 single nucleotide polymorphisms) in FLCN. The majority of pathogenic mutations results in protein truncation whilst a minority are splice-site alterations. An up to date summary of the variants and their associated phenotype will be presented.

Conclusion:

Pathogenic mutations are found throughout the coding regions (exons 4-14) and there are no apparent genotype-phenotype correlations. The FLCN mutation database available at www.lovd.nl/flcn offers a valuable resource and tool for clinicians involved in the management of BHD patients, clinical geneticists and researchers. Researchers can directly submit new sequence variants online to the database or by e-mailing the author.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1848.

High diagnostic and clinical impact of small-bowel capsule endoscopy in patients with hereditary hemorrhagic telangiectasia with overt digestive bleeding and/or severe anemia

BACKGROUND

Patients with hereditary hemorrhagic telangiectasia (HHT) often present with recurrent anemia because of epistaxis or GI bleeding in relation to telangiectases mostly located in the stomach or small bowel. Capsule endoscopy is considered a major diagnostic tool for small-bowel diseases, but the impact of capsule endoscopy imaging on patient management in HHT is poorly understood.

OBJECTIVE

To clarify the contribution of capsule endoscopy in selected patients with HHT.

DESIGN

Prospective, descriptive study.

SETTING

Multicenter, two university hospital tertiary-care centers, from January 2003 to June 2007.

PATIENTS

This study involved 30 patients with HHT and severe anemia (hemoglobin <9 g/dL; normal: 11-15 g/dL) and minimal epistaxis or moderate anemia but overt GI bleeding.

INTERVENTION

Capsule endoscopy investigation.

MAIN OUTCOME MEASUREMENTS

Clinical characteristics and capsule endoscopy results and their clinical consequences.

RESULTS

Capsule endoscopy detected gastric and small-bowel telangiectases in 14 (46.7%) and 26 (86.7%) cases, respectively. Active bleeding was present in 36.7% of cases. Diffuse telangiectases were detected in 42.3% without correlation with age, sex, or type of HHT mutation. Further investigations were carried out as a consequence of the capsule endoscopy results in 67% of cases. Treatment, consisting mostly of endoscopic argon plasma coagulation, was scheduled in 46.7% of patients.

LIMITATIONS

Our population was essentially composed of patients with the ALK1 mutation.

CONCLUSION

This study shows that there is a high diagnostic yield for capsule endoscopy in selected patients with HHT. Capsule endoscopy makes possible precise mapping of lesions and has a considerable impact on the management of these selected patients by using a predefined algorithm: a limited number of accessible lesions is suitable for endoscopic treatment, whereas innumerable diffuse lesions require a medical approach. We suggest that capsule endoscopy could be a first-line, noninvasive, digestive tract examination in selected patients with HHT.

A new locus-specific database (LSDB) for mutations in the folliculin (FLCN) gene

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant condition characterised by the presence of facial fibrofolliculomas, pulmonary cysts which may be associated with spontaneous pneumothorax and renal tumours. Germline mutations in the gene Folliculin (FLCN) were first identified in BHD patients in 2002. In addition FLCN mutations have also been described in families with isolated primary spontaneous pneumothorax (PSP) and also familial clear cell renal carcinomas (FcRCC). We have established a locus-specific database based on the Leiden Open (source) Variation Database (LOVD) software. The version of the database contains 60 previously published mutations and 10 previously unpublished novel germline FLCN mutations. The mutations are comprised of deletions (44.3%), substitutions (35.7%), duplications (14.3%) and deletion/insertions (5.7%). The database is accessible online at http://www.lovd.nl/flcn.

A new preservation solution (SCOT 15) Improves the islet isolation process from pancreata of non-heart-beating donors: a Murine model

INTRODUCTION

Due to the organ shortage, there is increased use of organs harvested from non-heart-beating donors (NHBD). These organs have been subjected to a period of warm ischemia that is most deleterious to functional recovery. We have designed a new preservation solution, "Solution de Conservation des Organes et des Tissus" (SCOT 15; Macopharma, Tourcoing, France) which contains an extracellular ionic composition including PEG 20 kD (15 g/L) as a colloid.

METHODS

Our objective was to compare SCOT 15 with University of Wisconsin (UW) solution or islet culture medium CMRL 1066 + 1% of Bovine Serum Albumin (BSA), as the working and preservation solution for islet isolation from pancreata subjected to warm ischemia using a murine model.

RESULTS

Warm ischemia decreased the islet yield and cellular viability regardless of the preservation solution. Either when the pancreas was or was not subjected to warm ischemia, the best islet yield was obtained with SCOT 15 (P < .05 vs UW or CMRL 1066). The same results were observed for islet viability as assessed using the 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test; namely, better viability with SCOT 15 as compared with UW or CMRL 1066 (P < .01).

CONCLUSION

In a murine model SCOT 15 was a better preservation solution for islet isolation than UW solution or culture medium (CMRL 1066).

Birt-Hogg-Dubé syndrome: diagnosis and management

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant condition characterised clinically by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cancer. The condition is caused by germline mutations in the FLCN gene, which encodes folliculin; the function of this protein is largely unknown, although FLCN has been linked to the mTOR pathway. The availability of DNA-based diagnosis has allowed insight into the great variation in expression of FLCN, both within and between families. Patients can present with skin signs and also with pneumothorax or renal cancer. Preventive measures are aimed mainly at early diagnosis and treatment of renal cancer. This Review gives an overview of current diagnosis and management of BHD.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA)

Background:

In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers.

Methods:

We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach.

Results:

We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93–1.04, P=0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89–1.06, P=0.5) mutation carriers.

Conclusion:

This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.

The TP53 Arg72Pro and MDM2 309G>T polymorphisms are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers

Background:

The TP53 pathway, in which TP53 and its negative regulator MDM2 are the central elements, has an important role in carcinogenesis, particularly in BRCA1- and BRCA2-mediated carcinogenesis. A single nucleotide polymorphism (SNP) in the promoter region of MDM2 (309T>G, rs2279744) and a coding SNP of TP53 (Arg72Pro, rs1042522) have been shown to be of functional significance.

Methods:

To investigate whether these SNPs modify breast cancer risk for BRCA1 and BRCA2 mutation carriers, we pooled genotype data on the TP53 Arg72Pro SNP in 7011 mutation carriers and on the MDM2 309T>G SNP in 2222 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Data were analysed using a Cox proportional hazards model within a retrospective likelihood framework.

Results:

No association was found between these SNPs and breast cancer risk for BRCA1 (TP53: per-allele hazard ratio (HR)=1.01, 95% confidence interval (CI): 0.93–1.10, P_trend=0.77; MDM2: HR=0.96, 95%CI: 0.84–1.09, P_trend=0.54) or for BRCA2 mutation carriers (TP53: HR=0.99, 95%CI: 0.87–1.12, P_trend=0.83; MDM2: HR=0.98, 95%CI: 0.80–1.21, P_trend=0.88). We also evaluated the potential combined effects of both SNPs on breast cancer risk, however, none of their combined genotypes showed any evidence of association.

Conclusion:

There was no evidence that TP53 Arg72Pro or MDM2 309T>G, either singly or in combination, influence breast cancer risk in BRCA1 or BRCA2 mutation carriers.

Head and neck paragangliomas in von Hippel-Lindau disease and multiple endocrine neoplasia type 2

BACKGROUND

Head and neck paragangliomas (HNPs) occur as sporadic or familial entities, the latter mostly in association with germline mutations of the SDHB, SDHC, or SDHD (SDHx) genes. Heritable non-SDHx HNP might occur in von Hippel-Lindau disease (VHL, VHL gene), multiple endocrine neoplasia type 2 (MEN2, RET gene), and neurofibromatosis type 1 (NF1, NF1 gene). Reports of non-SDHx HNP presentations are scarce and guidance for genetic testing nonexistent.

PATIENTS AND METHODS

An international consortium registered patients with HNPs and performed mutation analyses of the SDHx, VHL, and RET genes. Those with SDHx germline mutations were excluded for purposes of this study. Personal and family histories were evaluated for paraganglial tumors, for the major tumor manifestations, and for family history of VHL, MEN2, or NF1.

RESULTS

Twelve patients were found to have hereditary non-SDHx HNPs of a total of 809 HNP and 2084 VHL registrants, 11 in the setting of germline VHL mutations and one of a RET mutation. The prevalence of hereditary HNP is five in 1000 VHL patients and nine in 1000 non-SDHx HNP patients. Comprehensive literature review revealed previous reports of HNPs in five VHL, two MEN2, and one NF1 patient. Overall, 11 here presented HNP cases, and four previously reported VHL-HNPs had lesions characteristic for VHL and/or a positive family history for VHL.

CONCLUSIONS

Our observations provide evidence that molecular genetic testing for VHL or RET germline mutations in patients with HNP should be done only if personal and/or family history shows evidence for one of these syndromes.

Evaluation of previously nonscreened hereditary hemorrhagic telangiectasia patients shows frequent liver involvement and early cardiac consequences

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disease characterized by cutaneous, mucosal, and sometimes visceral arteriovenous malformations. Severe hepatic manifestations have been characterized in a subgroup of patients, but few data are available in previously nonscreened patients. We prospectively evaluated liver involvement and its cardiac consequences in such patients. Between 2000 and 2005, we prospectively evaluated the clinical, biological, and hepatic Doppler sonography (DS) characteristics of 102 consecutive HHT patients (mean age, 52.5 years; range, 19-88; 80.4%) with an identified genetic mutation. Patients were segregated into three different severity groups according to DS values. Factors predictive of an abnormal DS, according to predetermined criteria, and of a high cardiac index were identified by logistic and linear regression analysis, respectively. Abnormal liver biology and clinical signs of hepatic involvement were present in 35.3% and 27.5% of cases, respectively. Abnormal DS (defined as at least enlargement of the main hepatic artery) was observed in 56 (54.9%) cases, and direct or indirect signs of significant fistulas were present in 26 (25.5%) cases. Abnormal liver biology and a mutation involving the ACVRL1 gene were predictive of hepatic ultrasound (US) abnormalities. The diameter of the main hepatic artery and the presence of focal nodular hyperplasia (FNH) were predictive of a higher cardiac index.

CONCLUSION

This large prospective series of previously nonscreened HHT patients identified a subgroup at risk of liver involvement (patients with abnormal liver biology and ACVRL1 mutations) and a subgroup with a higher cardiac index: future studies will show whether such patients would benefit from systematic DS screening and long-term cardiac surveillance.

Normal state of highly polarized Fermi gases: full many-body treatment

We consider a single atom within a Fermi sea of atoms. We elucidate by a full many-body analysis the quite mysterious agreement between Monte Carlo results and approximate calculations taking only into account single particle-hole excitations. It results from a nearly perfect destructive interference of the contributions of states with more than one particle-hole pair. This is linked to the remarkable efficiency of the expansion in powers of hole wave vectors, the lowest order leading to perfect interference. Going up to two particle-hole pairs gives an essentially perfect agreement with known exact results. Hence our treatment amounts to an exact solution of this problem.

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.

Transient depletion of dividing T lymphocytes in mice induces the emergence of regulatory T cells and dominant tolerance to islet allografts

We previously showed that transient depletion of dividing T cells at the time of an allogeneic transplantation induces long-term tolerance to the allograft. Here we investigated the role of homeostatic perturbation and regulatory T cells (Treg) in such tolerance. Transient depletion of dividing T cells was induced at the time of an allogeneic pancreatic islets graft, by administration of ganciclovir for 14 days, into diabetic transgenic mice expressing a thymidine kinase (TK) conditional suicide gene in T cells. Allograft tolerance was obtained in 63% of treated mice. It was not due to global immunosuppression, permanent deletion or anergy of donor-alloantigens specific T cells but to a dominant tolerance process since lymphocytes from tolerant mice could transfer tolerance to naïve allografted recipients. The transient depletion of dividing T cells induces a 2- to 3-fold increase in the proportion of CD4(+)CD25(+)Foxp3(+) Treg, within 3 weeks that persisted only in allograft-bearing mice but not in nongrafted mice. Tolerance with similar increased proportion of Treg cells was also obtained after a cytostatic hydroxyurea treatment in normal mice. Thus, the transient depletion of dividing T cells represents a novel means of immuno-intervention based on disturbance of T-cell homeostasis and subsequent increase in Treg proportion.

Modulation of Fas-induced apoptosis by p75 neurotrophin receptor in a human neuroblastoma cell line

Fas and p75 neurotrophin receptors (p75(NTR)) are death receptors that alone induce apoptosis of SH-SY5Y neuroblastoma cell line respectively by Fas ligand or brain-derived neurotrophic factor (BDNF, a p75(NTR) ligand). We report on the modulation of Fas-mediated apoptosis by concomitant p75(NTR) activation. The exposure to both ligands suppressed the apoptotic effect. A co-localisation of Fas and p75(NTR) receptors was evidenced by co-capping and immunoprecipitation assays. Moreover, a caspase-8 inhibitor suppressed the protective effect of the concomitant BDNF and Fas ligand stimulation, suggesting that p75(NTR) and Fas receptors could share common signalling pathways.

Hereditary hemorrhagic telangiectasia: evidence for regional founder effects of ACVRL1 mutations in French and Italian patients

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease characterized by widespread arteriovenous malformations and caused by mutations in two major genes: ENG and ACVRL1. Two decades ago, a French epidemiological study pointed out that its prevalence was higher than previously thought and that its distribution varied greatly from one area to another, one of the highest concentrations of patients being found in the Haut-Jura mountains. Although germline mutations are usually family specific, some of them have been reported in unrelated patients, especially for ACVRL1. We performed haplotype analysis of 116 French and Italian patients carrying 13 ACVRL1 different mutations. For five of these mutations, we estimated the age of the most recent common ancestors (MRCAs) using the ESTIAGE program. Most mutations were related to both recurrent mutational events and founder effects with age estimates ranging from 100 to 550 years. The c.1112dupG mutation, which is likely to be responsible for the very high concentration of HHT patients found in the former epidemiological study, probably occurred in one inhabitant of the Haut-Jura Mountains more than three centuries ago. The p.Arg374Gln mutation occurred independently in at least two distinct geographical areas, including the area with the second highest prevalence in the epidemiological study and where the MRCA is rather recent (about 100 years ago). Partially shared haplotypes between French and Italian patients were found for three mutations. This suggests a common origin and a possible diffusion of these mutations from Italy to France.

Clonal expansion of mutated mitochondrial DNA is associated with tumor formation and complex I deficiency in the benign renal oncocytoma

Mutations in mitochondrial DNA (mtDNA) are frequent in cancers but it is not yet clearly established whether they are modifier events involved in cancer progression or whether they are a consequence of tumorigenesis. Here we show a benign tumor type in which mtDNA mutations that lead to complex I (CI) enzyme deficiency are found in all tumors and are the only genetic alteration detected. Actually renal oncocytomas are homogeneous tumors characterized by dense accumulation of mitochondria and we had found that they are deficient in electron transport chain complex I (CI, NADH-ubiquinone oxidoreductase). In this work total sequencing of mtDNA showed that 9/9 tumors harbored point mutations in mtDNA, seven in CI genes, one in complex III, and one in the control region. 7/8 mutations were somatic. All tumors were somatically deficient for CI. The clonal amplification of mutated mtDNA in 8/9 tumors demonstrates that these alterations are selected and therefore favor or trigger growth. No nuclear DNA rearrangement was detected beside mtDNA defects. We hypothesize that functional deficiency of the oxidative phosphorylation CI could create a loop of amplification of mitochondria during cell division, impair substrates oxidation and increase intermediary metabolites availability.

[Genetics and angiogenesis: the example of von Hippel-Lindau disease]

Von Hippel-Lindau (VHL) disease is the main cause of inherited kidney cancer and the model of tumoral angiogenesis. This rare syndrome is caused by germline mutations of the VHL tumor-suppressor gene that predispose to the development of a panel of highly vascularized tumors. Main manifestations include CNS and retinal haemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), phaeochromocytomas and pancreatic neuroendocrine tumors. The VHL gene plays a major role in regulation of the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. Somatic inactivation of the VHL gene occurs also in most sporadic RCC. Recent progress are pawing the way for the development of antiangiogenic targeted therapies that have already shown promising results in metastatic sporadic RCC.

Genotype-phenotype correlations in hereditary hemorrhagic telangiectasia: data from the French-Italian HHT network

PURPOSE

Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by arteriovenous malformations (AVM), mostly cutaneous and mucous (telangiectases), but also involving the lungs (PAVM), liver (HAVM) and brain (CAVM). We studied the relationship between the phenotype and genotype in patients with a proven mutation in either ENG (HHT1) or ACVRL1 (HHT2).

METHODS

Clinical features and their age of onset were compared between HHT1 and HHT2. The type of mutation was also analyzed. Clinical manifestations were distinguished from lesions found by screening.

RESULTS

Ninety-three HHT1 patients and 250 HHT2 patients were included. Epistaxis occurred later in HHT2, with incomplete penetrance (P<0.0001). Symptomatic PAVMs were more frequent in HHT1 (34.4 vs. 5.2%, P<0.001), as were cerebral abscesses (7.5 vs. 0.8%, P=0.002). Gastrointestinal bleeding occurred more frequently in HHT2 (16.4 vs. 6.5%, P=0.017). Symptomatic hepatic involvement was only seen in HHT2 patients. PAVMs were more frequently detected in asymptomatic HHT1 patients (54 vs. 12.8%, P<0.0001). PAVMs and HAVMs were often family clustered in HHT1 and HHT2, respectively. Truncating mutations were associated with a higher frequency of epistaxis and telangiectasis, in HHT2.

CONCLUSION

This study shows major differences between HHT1 and HHT2 phenotypes, which should be taken into account for future clinical studies.

Hemorrhagic hereditary telangiectasia (Rendu-Osler disease) and infectious diseases: an underestimated association

Among 353 patients with hereditary hemorrhagic telangiectasia retrospectively analyzed during the period 1985-2005, we identified 67 cases of severe infection that affected 48 patients (13.6%). Extracerebral infections accounted for 67% of all infections, and most involved Staphylococcus aureus and were associated with prolonged epistaxis. Cerebral infections accounted for 33% of all infections, were mainly due to multiple and anaerobic bacteria, and were associated with the presence of pulmonary arteriovenous malformations and a short duration of epistaxis.

Effects of the molecular weight of peg molecules (8, 20 and 35 KDA) on cell function and allograft survival prolongation in pancreatic islets transplantation

The normopotassic solution SCOT (Macopharma, France) used for the isolation of the islets of Langerhans may improve both graft function and survival. We believe that this is due to the immunoprotective properties of polyethyleneglycol (PEG) (20 kDa; 1.5 mM/L), which is contained in this solution. However, the optimal PEG chain length remains to be determined. Three extracellular type solutions (SCOT without PEG) containing various PEG-8 kDa, 20 kDa, or 35 kDa- at 1.5 mM/L were compared in vitro for viscosity and osmolarity as well as in vivo using a murine model of pancreatic islet allotransplantation. We compared the effects of the various solutions on functional cell recovery (primary nonfunction rate, PNF) and immunoprotection (allograft survival time). We showed that the viscosity of PEG 35 kDa solutions was too high for physiological use. PEG 20 kDa solution provided the best graft function (0% PNF, P < .05). PEG 8 kda and 20 kDa solutions significantly increased allograft survival time compared to the PEG 35 kDa solution (P < .05). Graft survival was similar with PEG 20 kDa and PEG 8 kDa solutions: 27.50 +/- 3.70 days versus 23.13 +/- 4.39 days (NS). However, the number of PNF with PEG 8 kDa solution (50%) was significantly higher (P < .01) than that with the PEG 20 kDa solution (0%). These preliminary results indicated that the optimal chain length at 1.5 mM/L of PEG is 20 kDa.

Effects of the molecular weight of peg molecules (8, 20 and 35 KDA) on cell function and allograft survival prolongation in pancreatic islets transplantation

The normopotassic solution SCOT (Macopharma, France) used for the isolation of the islets of Langerhans may improve both graft function and survival. We believe that this is due to the immunoprotective properties of polyethyleneglycol (PEG) (20 kDa; 1.5 mM/L), which is contained in this solution. However, the optimal PEG chain length remains to be determined. Three extracellular type solutions (SCOT without PEG) containing various PEG-8 kDa, 20 kDa, or 35 kDa- at 1.5 mM/L were compared in vitro for viscosity and osmolarity as well as in vivo using a murine model of pancreatic islet allotransplantation. We compared the effects of the various solutions on functional cell recovery (primary nonfunction rate, PNF) and immunoprotection (allograft survival time). We showed that the viscosity of PEG 35 kDa solutions was too high for physiological use. PEG 20 kDa solution provided the best graft function (0% PNF, P < .05). PEG 8 kda and 20 kDa solutions significantly increased allograft survival time compared to the PEG 35 kDa solution (P < .05). Graft survival was similar with PEG 20 kDa and PEG 8 kDa solutions: 27.50 +/- 3.70 days versus 23.13 +/- 4.39 days (NS). However, the number of PNF with PEG 8 kDa solution (50%) was significantly higher (P < .01) than that with the PEG 20 kDa solution (0%). These preliminary results indicated that the optimal chain length at 1.5 mM/L of PEG is 20 kDa.

Mutations in BHD and TP53 genes, but not in HNF1beta gene, in a large series of sporadic chromophobe renal cell carcinoma

BHD, TP53, and HNF1β on chromosome 17 were studied in 92 cases of renal cell carcinoma (46 chromophobe, 19 clear cell, 18 oncocytoma, and nine papillary). Six, thirteen, and zero cases had, respectively BHD, TP53, and HNF1β mutations, (84% mutations involved chromophobe), suggesting a role for BHD and TP53 in chromophobe subtype.

Erythropoietin and blood doping

OBJECTIVE AND METHOD

To outline the direct and indirect approaches in the fight against blood doping in sports, the different strategies that have been used and are currently being used to fight efficiently against blood doping are presented and discussed.

RESULTS AND CONCLUSIONS

The paper outlines the different approaches and diagnostic tools that some federations have to identify and target sports people demonstrating abnormal blood profiles. Originally blood tests were introduced for medical reasons and for limiting misuse of recombinant human erythropoietin (rHuEPO). In this way it became possible to prevent athletes with haematocrit levels well above normal, and potentially dangerous for their health, competing in sport. Today, with nearly a decade of blood testing experience, sports authorities should be familiar with some of the limitations and specially the ability of blood tests performed prior to competitions to fight efficiently against the misuse of rHuEPO, blood transfusion, and artificial haemoglobin.

Systematic mRNA analysis for the effect of MLH1 and MSH2 missense and silent mutations on aberrant splicing

A substantial proportion of MLH1 and MSH2 gene mutations in hereditary nonpolyposis colon cancer syndrome (HNPCC) families are characterized by nucleotide substitutions, either within the coding sequence (missense or silent mutations) or in introns. The question of whether these mutations affect the normal function of encoding mismatch DNA repair proteins and thus lead to the predisposition to cancer is determinant in genetic testing. Recent studies have suggested that some nucleotide substitutions can induce aberrant splicing by disrupting cis-transcription elements such as exonic enhancers (ESEs). ESE disruption has been proposed to be the mechanism that underlies the presumed pathological missense mutations identified in HNPCC families. To investigate the prevalence of aberrant splicing resulting from nucleotide substitutions, and its relevance to predicted ESEs, we conducted a systematic RNA screening of a series of 60 patients who carried unrelated exonic or intronic mutations in MLH1 or MSH2 genes. Aberrant splicing was found in 15 cases, five of which were associated with exonic mutations. We evaluated the link between those splicing mutations and predicted putative ESEs by using the computational tools ESEfinder and RESCUE-ESE. Our study shows that the algorithm-based ESE prediction cannot be definitely correlated to experimental observations from RNA screening. By using minigene constructs and in vitro transcription assay, we demonstrated that nucleotide substitutions are the direct cause of the splicing defect. This is the first systematic screening for the effect of missense and silent mutations on splicing in HNPCC patients. The pathogenic splicing mutations identified in this study will contribute to the assessment of "unclassified variants" in genetic counseling. Our results also suggest that one must use caution when determining the pathogenic effect of a missense or silent mutation using ESE prediction algorithms. Analysis at the RNA level is therefore necessary.

Distribution of ENG and ACVRL1 (ALK1) mutations in French HHT patients

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disease characterized by arteriovenous malformations and resulting from mutations in two major genes: ENG and ACVRL1. The aim of the present study was to estimate the prevalence of the mutations of ENG and ACVRL1 in HHT, based on the largest series of patients reported so far, recruited through a national network. We previously reported the first mutation screening of both genes, in French HHT patients, using heteroduplex analysis. This previous study, bringing 60 novel mutations, provided a significant improvement to the knowledge of molecular pathology in HHT. However, 32% (n=48) of the patients with a confirmed clinical diagnosis remained without mutation. In these patients, we performed an extensive molecular analysis that included the sequencing of the whole coding sequence, the search for large rearrangements, and screening of the potential 5' regulatory regions. Additionally, due to the lack of large pedigrees suitable for linkage analysis, and since SMAD4 germline mutations have been reported in families with combined HHT and juvenile polyposis, we screened this gene and five other genes involved in the TGF-beta/BMP pathway in the patients without mutation of ENG or ACVRL1. Only a novel SMAD1 non-conservative substitution was found in one patient, changing a poorly conserved methionine to an isoleucin. Twenty-three mutations were found in ACVRL1 and 8 in ENG (including a duplication of exons 4 to 8 and deletions of exons 1 to 3 and 9 to 14). Our results, combined with our previous data, increase the mutation rate to 88% (n=119/136) in French patients with a confirmed clinical diagnosis. Our results also emphasize the higher prevalence of large insertions/deletions in ENG and the predominance of ACVRL1 over ENG mutations.

Genetic Testing in Pheochromocytoma or Functional Paraganglioma

Purpose

To assess the yield and the clinical value of systematic screening of susceptibility genes for patients with pheochromocytoma (pheo) or functional paraganglioma (pgl).

Patients and Methods

We studied 314 patients with a pheo or a functional pgl, including 56 patients having a family history and/or a syndromic presentation and 258 patients having an apparently sporadic presentation. Clinical data and blood samples were collected, and all five major pheo-pgl susceptibility genes (RET, VHL, SDHB, SDHD, and SDHC) were screened. Neurofibromatosis type 1 was diagnosed from phenotypic criteria.

Results

We have identified 86 patients (27.4%) with a hereditary tumor. Among the 56 patients with a family/syndromic presentation, 13 have had neurofibromatosis type 1, and germline mutations on the VHL, RET, SDHD, and SDHB genes were present in 16, 15, nine, and three patients, respectively. Among the 258 patients with an apparently sporadic presentation, 30 (11.6%) had a germline mutation (18 patients on SDHB, nine patients on VHL, two patients on SDHD, and one patient on RET). Mutation carriers were younger and more frequently had bilateral or extra-adrenal tumors. In patients with an SDHB mutation, the tumors were larger, more frequently extra-adrenal, and malignant.

Conclusion

Genetic testing oriented by family/sporadic presentation should be proposed to all patients with pheo or functional pgl. We suggest an algorithm that would allow the confirmation of suspected inherited disease as well as the diagnosis of unexpected inherited disease.

Coexpression of Erythropoietin and Erythropoietin Receptor in Von Hippel-Lindau Disease–Associated Renal Cysts and Renal Cell Carcinoma

Von Hippel-Lindau (VHL) disease is characterized by multiple tumors in specific target organs. The tumors at different sites share distinct morphologic and genetic characteristics but their cell of origin is unknown. We show that VHL disease–associated renal clear cell carcinomas (RCC) consistently coexpress erythropoietin (Epo) and Epo receptor (EpoR). In addition, coexpression of Epo and EpoR is detected in many renal cysts, providing further evidence that renal cysts are potential precursors for RCC. In conjunction with VHL gene deficiency, coexpression of Epo and EpoR in renal cysts and tumors may reflect a developmental arrest in immature mesenchymal cells. Such arrest may lead to autocrine stimulation, cell proliferation, and renal tumor development, similar to tumorigenesis of VHL disease–associated hemangioblastomas.

Coexpression of erythropoietin and erythropoietin receptor in von Hippel-Lindau disease-associated renal cysts and renal cell carcinoma

Von Hippel-Lindau (VHL) disease is characterized by multiple tumors in specific target organs. The tumors at different sites share distinct morphologic and genetic characteristics but their cell of origin is unknown. We show that VHL disease-associated renal clear cell carcinomas (RCC) consistently coexpress erythropoietin (Epo) and Epo receptor (EpoR). In addition, coexpression of Epo and EpoR is detected in many renal cysts, providing further evidence that renal cysts are potential precursors for RCC. In conjunction with VHL gene deficiency, coexpression of Epo and EpoR in renal cysts and tumors may reflect a developmental arrest in immature mesenchymal cells. Such arrest may lead to autocrine stimulation, cell proliferation, and renal tumor development, similar to tumorigenesis of VHL disease-associated hemangioblastomas.

Breast cancer risk inBRCA1 andBRCA2 mutation carriers and polyglutamine repeat length in theAIB1 gene

Marked variation in phenotypic expression among BRCA1 and BRCA2 mutation carriers may be partly explained by modifier genes that influence mutation penetrance. Variation in CAG/CAA repeat lengths coding for stretches of glutamines in the C-terminus of the AIB1 protein (amplified in breast cancer 1, a steroid receptor coactivator) has been proposed to modify the breast cancer risk in women carrying germline BRCA1 mutations. We genotyped the AIB1 repeat length polymorphism from the genomic DNA of a group of 851 BRCA1 and 324 BRCA2 female germline mutation carriers to estimate an association with breast cancer risk modification. Hazard ratios (HR) were calculated using a Cox proportional hazards model. For BRCA1 and BRCA2 mutation carriers, analyzed separately and together, we found that women who carried alleles with 28 or more polyglutamine repeats had no increased risk of breast cancer compared to those who carried alleles with fewer repeats (HR for BRCA1/2 carriers = 0.88, 95% CI [confidence interval] = 0.75-1.04). Analyzing average repeat lengths as a continuous variable showed no excess risk of breast cancer (BC) in BRCA1 or BRCA2 mutation carriers (HR for average repeat length in BRCA1/2 carriers = 1.01, 95% CI = 0.92-1.11). These results strongly suggest that contrary to previous studies, there is no significant effect of AIB1 genetic variation on BC risk in BRCA1 mutation carriers and provide an indication that there is also no strong risk modification in BRCA2 carriers.

Common BRCA2 variants and modification of breast and ovarian cancer risk in BRCA1 mutation carriers

The HH genotype of the nonconservative amino acid substitution polymorphism N372H in the BRCA2 gene was reported to be associated with a 1.3- to 1.5-fold increase in risk of both breast and ovarian cancer. As these studies concerned sporadic cancer cases, we investigated whether N372H and another common variant located in the 5'-untranslated region (203G > A) of the BRCA2 gene modify breast or ovarian cancer risk in BRCA1 mutation carriers. The study includes 778 women carrying a BRCA1 germ-line mutation belonging to 403 families. The two BRCA2 variants were analyzed by the TaqMan allelic discrimination technique. Genotypes were analyzed by disease-free survival analysis using a Cox proportional hazards model. We found no evidence of a significant modification of breast cancer penetrance in BRCA1 mutation carriers by either polymorphism. In respect of ovarian cancer risk, we also saw no effect with the N372H variant but we did observe a borderline association with the 5'-untranslated region 203A allele (hazard ratio, 1.43; CI, 1.01-2.00). In contrast to the result of Healey et al. on newborn females and adult female controls, we found no departure from Hardy-Weinberg equilibrium in the distribution of N372H alleles for our female BRCA1 carriers. We conclude that if these single-nucleotide polymorphisms do modify the risk of cancer in BRCA1 mutation carriers, their effects are not significantly larger than that of N372H previously observed in the general population.

Common BRCA2 Variants and Modification of Breast and Ovarian Cancer Risk in BRCA1 Mutation Carriers

The HH genotype of the nonconservative amino acid substitution polymorphism N372H in the BRCA2 gene was reported to be associated with a 1.3- to 1.5-fold increase in risk of both breast and ovarian cancer. As these studies concerned sporadic cancer cases, we investigated whether N372H and another common variant located in the 5′-untranslated region (203G &gt; A) of the BRCA2 gene modify breast or ovarian cancer risk in BRCA1 mutation carriers. The study includes 778 women carrying a BRCA1 germ-line mutation belonging to 403 families. The two BRCA2 variants were analyzed by the TaqMan allelic discrimination technique. Genotypes were analyzed by disease-free survival analysis using a Cox proportional hazards model. We found no evidence of a significant modification of breast cancer penetrance in BRCA1 mutation carriers by either polymorphism. In respect of ovarian cancer risk, we also saw no effect with the N372H variant but we did observe a borderline association with the 5′-untranslated region 203A allele (hazard ratio, 1.43; CI, 1.01-2.00). In contrast to the result of Healey et al. on newborn females and adult female controls, we found no departure from Hardy-Weinberg equilibrium in the distribution of N372H alleles for our female BRCA1 carriers. We conclude that if these single-nucleotide polymorphisms do modify the risk of cancer in BRCA1 mutation carriers, their effects are not significantly larger than that of N372H previously observed in the general population.