Germline EGFR Mutations and Familial Lung Cancer

PURPOSE

The genomic underpinnings of inherited lung cancer risk are poorly understood. This prospective study characterized the clinical phenotype of patients and families with germline EGFR pathogenic variants (PVs).

METHODS

The Investigating Hereditary Risk from T790M study (ClinicalTrials.gov identifier: NCT01754025) enrolled patients with lung cancer whose tumor profiling harbored possible germline EGFR PVs and their relatives, either in person or remotely, providing germline testing and follow-up.

RESULTS

A total of 141 participants were enrolled over a 5-year period, 100 (71%) remotely. Based upon previous genotyping, 116 participants from 59 kindreds were tested for EGFR T790M, demonstrating a pattern of Mendelian inheritance with variable lung cancer penetrance. In confirmed or obligate carriers of a germline EGFR PV from 39 different kindreds, 50/91 (55%) were affected with lung cancer with 34/65 (52%) diagnosed by age 60 years. Somatic testing of lung cancers in carriers revealed that 35 of 37 (95%) had an EGFR driver comutation. Among 36 germline carriers without a cancer diagnosis, 15 had computed tomography (CT) imaging and nine had lung nodules, including a 28-year-old with >10 lung nodules. Given geographic enrichment of germline EGFR T790M in the southeast United States, genome-wide haplotyping of 46 germline carriers was performed and identified a 4.1-Mb haplotype shared by 41 (89%), estimated to originate 223-279 years ago.

CONCLUSION

To our knowledge, this is the first prospective description of familial EGFR-mutant lung cancer, identifying a recent founder germline EGFR T790M variant enriched in the Southeast United States. The high prevalence of EGFR-driver lung adenocarcinomas and lung nodules in germline carriers supports effort to identify affected patients and family members for investigation of CT-based screening for these high-risk individuals.

Reviewing the occurrence of large genomic rearrangements in patients with inherited cancer predisposing syndromes: importance of a comprehensive molecular diagnosis

INTRODUCTION

Hereditary cancer predisposition syndromes are caused by germline pathogenic or likely pathogenic variants in cancer predisposition genes (CPG). The majority of pathogenic variants in CPGs are point mutations, but large gene rearrangements (LGRs) are present in several CPGs. LGRs can be much more difficult to characterize and perhaps they may have been neglected in molecular diagnoses.

AREAS COVERED

We aimed to evaluate the frequencies of germline LGRs in studies conducted in different populations worldwide through a qualitative systematic review based on an online literature research in PubMed. Two reviewers independently extracted data from published studies between 2009 and 2020. In total, 126 studies from 37 countries and 5 continents were included in the analysis. The number of studies in different continents ranged from 3 to 48 and for several countries there was an absolute lack of information. Asia and Europe represented most of the studies, and LGR frequencies varied from 3.04 to 15.06% in different continents. MLPA was one of the methods of choice in most studies (93%).

EXPERT OPINION

The LGR frequencies found in this review reinforce the need for comprehensive molecular testing regardless of the population of origin and should be considered by genetic counseling providers.

Functional Polymorphisms in the p53 Pathway Genes on the Genetic Susceptibility to Zika Virus Teratogenesis

Congenital Zika Syndrome (CZS) occurs in up to 42% of individuals exposed to ZIKV prenatally. Deregulation in gene expression and protein levels of components of the p53 signaling pathway, such as p53 and MDM2, due to ZIKV infection has been reported. Here, we evaluate functional polymorphisms in genes of the p53 signaling pathway as risk factors to CZS. Forty children born with CZS and forty-eight children exposed to ZIKV, but born without congenital anomalies were included in this study. Gestational and sociodemographic information as well as the genotypic and allelic frequencies of functional polymorphisms in TP53, MDM2, MIR605 and LIF genes were compared between the two groups. We found children with CZS exposed predominantly in the first trimester and controls in the third trimester (p<0.001). Moreover, children with CZS were predominantly from families with a lower socioeconomic level (p=0.008). We did not find a statistically significant association between the investigated polymorphisms and development of CZS; however, by comparing individuals with CZS and lissencephaly or without lissencephaly, we found a significative difference in the allelic frequencies of the TP53 rs1042522, which is associated with a more potent p53-induced apoptosis (p=0.007). Our findings suggest that the TP53 rs1042522 polymorphism should be better investigate as a genetic risk factor for the development of lissencephaly in children with CZS.

Haplotypic characterization of BRCA1 c.5266dupC, the prevailing mutation in Brazilian hereditary breast/ovarian cancer

Specific pathogenic mutations associated with breast cancer development can vary between ethnical groups. One example is BRCA1 c.5266dupC that was first described as a founder mutation in the Ashkenazi Jewish population, but was later also found in other populations. In Brazil, this mutation corresponds to 20% of pathogenic BRCA1 variants reported. Our objective was to investigate the haplotype component of a group of Brazilian families who inherited c.5266dupC in the BRCA1 gene and to verify the ancestry contribution from European, African, and Amerindian origins. Fourteen probands carrying c.5266dupC and 16 relatives (carriers and non-carriers) were investigated. The same haplotype was observed segregating within all the families analyzed, revealing no recombinants in a region of 0.68 Mb. Ancestry analysis demonstrated that the European component was predominant among probands. The BRCA1 c.5266dupC analysis indicates that there was a founder effect in the Brazilian population.

Comprehensive germline mutation analysis and clinical profile in a large cohort of Brazilian xeroderma pigmentosum patients

BACKGROUND

Xeroderma pigmentosum (XP) patients present a high risk of developing skin cancer and other complications at an early age. This disease is characterized by mutations in the genes related to the DNA repair system.

OBJECTIVES

To describe the clinical and molecular findings in a cohort of 32 Brazilian individuals who received a clinical diagnosis of XP.

METHODS

Twenty-seven families were screened for germline variants in eight XP-related genes.

RESULTS

All patients (N = 32) were diagnosed with bi-allelic germline pathogenic or potentially pathogenic variants, including nine variants previously undescribed. The c.2251-1G>C XPC pathogenic variant, reported as the founder mutation in Comorian and Pakistani patients, was observed in 15 cases in homozygous or compound heterozygous. Seven homozygous patients for POLH/XPV variants developed their symptoms by an average age of 7.7 years. ERCC2/XPD, DDB2/XPE and ERCC5/XPG variants were found in a few patients. Aside from melanoma and non-melanoma skin tumours, a set of patients developed skin sebaceous carcinoma, leiomyosarcoma, angiosarcoma, mucoepidermoid carcinoma, gastric adenocarcinoma and serous ovarian carcinoma.

CONCLUSIONS

We reported a high frequency of XPC variants in 32 XP Brazilian patients. Nine new variants in XP-related genes, unexpected non-skin cancer lesions and an anticipation of the clinical manifestation in POLH/XPV cases were also described.

Haplotypic characterization of BRCA1 c.5266dupC, the prevailing mutation in Brazilian hereditary breast/ovarian cancer

Specific pathogenic mutations associated with breast cancer development can vary between ethnical groups. One example is BRCA1 c.5266dupC that was first described as a founder mutation in the Ashkenazi Jewish population, but was later also found in other populations. In Brazil, this mutation corresponds to 20% of pathogenic BRCA1 variants reported. Our objective was to investigate the haplotype component of a group of Brazilian families who inherited c.5266dupC in the BRCA1 gene and to verify the ancestry contribution from European, African, and Amerindian origins. Fourteen probands carrying c.5266dupC and 16 relatives (carriers and non-carriers) were investigated. The same haplotype was observed segregating within all the families analyzed, revealing no recombinants in a region of 0.68 Mb. Ancestry analysis demonstrated that the European component was predominant among probands. The BRCA1 c.5266dupC analysis indicates that there was a founder effect in the Brazilian population.

Genetic cancer risk assessment: A screenshot of the psychosocial profile of women at risk for hereditary breast and ovarian cancer syndrome

OBJECTIVE

There is a lack of information describing Brazilian women at risk of hereditary breast and ovarian cancer syndrome (HBOC) who undergo genetic cancer risk assessment (GCRA). This study aims to characterize the psychosocial profile of women at risk for HBOC at their first GCRA to obtain an overview of their families' profiles and the challenges of the oncogenetics setting.

METHODS

This was a cross-sectional study in which interviews were conducted with 83 cancer-affected women at their first GRCA appointment after the pedigree draw. Tools to evaluate psychological outcomes were applied. The pedigree genogram and ecomap were constructed and analyzed with content analysis using the "life course perspective" theory.

RESULTS

Individuals perceived their breast/ovarian cancer risk to be equal to that of the general population, although they were highly concerned about developing cancer. No evidence of anxiety or depressive symptoms was identified. Participants used the coping strategy of searching for religiosity. The genograms and ecomaps resulted in five major themes: support and social support; attitudes, feelings and emotions; cancer causes; communication; and relationships with relatives. Individuals between 20-29 years of age and those with no family history of cancer tended not to communicate with relatives, which may indicate future problems in the GCRA process regarding genetic testing.

CONCLUSIONS

This study demonstrated that knowing the families who undergo the GCRA process can help professionals provide more individualized and thorough attention during GCRA and genetic testing, which results in better follow-up and prevention strategies.

Information and Diagnosis Networks - tools to improve diagnosis and treatment for patients with rare genetic diseases

Brazil is a country of continental dimensions and most genetic services are concentrated in the Southeast and South, including the Medical Genetics Service of the Hospital de Clínicas de Porto Alegre (MGS/HCPA). As many areas on the country do not have adequate medical genetics support, networks were designed to extend the service of the MGS/HCPA reference center. This paper presents the information and diagnosis networks that have their headquarters at MGS/HCPA: SIAT (National Information System on Teratogenic Agents), SIEM (Information Service on Inborn Errors of Metabolism), Alô Genética (Hello Genetics - Medical Genetics Information Service for Primary Health Care Professionals); Rede MPS Brasil (MPS-Mucopolysaccharidosis Brazil Network); Rede EIM Brasil (IEM-Inborn Errors of Metabolism Brazil Network), Rede NPC Brasil (Niemann-Pick C - NPC Brazil Network), Rede DLD Brasil (LSD-Lysosomal Storage Disorders Brazil Network), Rede DXB (MSUD-Maple Syrup Urine Disease Network), RedeBRIM (Brazilian Network of Reference and Information in Microdeletion Syndromes Project), Rede Neurogenética (Neurogenetics Network), and Rede Brasileira de Câncer Hereditário (Brazilian Hereditary Cancer Network). These tools are very useful to provide access to a qualified information and/or diagnostic service for specialized and non-specialized health services, bypassing difficulties that preclude patients to access reference centers.

Rare germline alterations in cancer-related genes associated with the risk of multiple primary tumor development

Multiple primary tumors (MPT) have been described in carriers of inherited cancer predisposition genes. However, the genetic etiology of a large proportion of MPT cases remains unclear. We reviewed 267 patients with hereditary cancer predisposition syndromes (HCPS) that underwent genetic counseling and selected 22 patients with MPT to perform genomic analysis (CytoScan HD Array, Affymetrix) aiming to identify new alterations related to a high risk of developing MPT. Twenty patients had a positive family history of cancer and 11 met phenotypic criteria for HCPS. Genetic testing for each of the genes associated with these syndromes revealed negative results for pathogenic mutations. Seventeen rare germline copy number variations (CNVs) covering 40 genes were identified in 11 patients, including an EPCAM/MSH2 deletion in one Lynch syndrome patient. An enrichment analysis revealed a significant number of genes (where the CNVs are mapped) associated with carcinogenesis and/or related to functions implicated with tumor development, such as proliferation and cell survival. An interaction network analysis highlighted the importance of TP53 pathway in cancer emergence. A high number of germline copy-neutral loss of heterozygosity (cnLOH) was identified in nine cases, particularly in two patients. Eighteen genes were covered by both rare CNVs and cnLOH, including 14 related to tumorigenesis and seven genes (ABCC1, KDM4C, KIAA0430, MYH11, NDE1, PIWIL2, and ULK2) specifically associated with cellular growth and proliferation. Overall, we identified 14 cases with rare CNVs and/or cnLOH that may contribute to the risk of MPT development.

KEY MESSAGE

CNVs may explain the risk of hereditary cancer syndromes in MPT patients. CNVs affecting genes related to cancer are candidates to be involved in MPT risk. EPCAM/MSH2 deletions should be investigated in patients suspected to have LS. Gene enrichment related to the TP53 network is associated with MPT development. cnLOH and CNVs contribute to the risk of MPT development.

Abstract 318: Vitamin E Affects Pathological Cardiac Hypertrophy and MicroRNAs Expression in Mice

Aims: Vitamin E is a usual antioxidant, but little is known about its effects on cardiac hypertrophy and microRNAs (miRs) expression induced by transverse aortic constriction (TAC) in mice.

Methods and Results: Male Balb/c mice were randomly divided into four cohorts: SHAM ( n= 22), TAC ( n =34), SHAM supplemented with vitamin E (SHAM+VIT, n =22), and TAC supplemented with vitamin E (TAC+VIT, n =34). VIT groups received 200 mg/kg of α-tocopherol once a day, and the other groups received placebo, both by gavage. After 7 and 35 days of surgery analysis of cardiac hypertrophy, fibrosis, miRs and gene expression and carbonyl concentrations in cardiac tissue were performed. Left ventricle mass increased 23% and 35% in 7 and 35 days, respectively, in TAC group, similar data were observed in TAC+VIT group (all p <0.05 vs. SHAM groups). Cardiac fibrosis was increased by TAC surgery as early as 7 days and remained high after 35 days. Still, TAC mice exhibit higher levels of protein damage at 35 days. This pathological phenotype was not seen in animals of the TAC+VIT group. Vitamin E seemed to inhibit cardiac fibrosis and oxidative damage. Moreover, cardiac hypertrophy was followed by increased miR-21 and -499 expression in TAC group, mainly 35 days ( miR-21 : 2.9 ± 0.6 fold vs . SHAM: 1 ± 0.1 fold , miR 499 : 3 ± 0.4 fold vs. 1.1 ± 0.1 fold , p <0.05). However, TAC+VIT mice displayed a different miR expression profile, with decreased miR-21 and - 499 expression ( miR-21 : 0.5 ± 0.1 fold , miR-499 : 0.4 ± 0.1 fold ; TAC vs. p <0.05) and increased miR-210 expression (3.2 ± 0.5 fold vs. TAC: 1.9 ± 0.2 fold, p =0.034). Computational target prediction of these miRs demonstrated that they can be involved in the control of major pathways in the heart disease scenario such as MAPK, mTOR, PI3K-AKT, among others.

Conclusion: TAC model induced pathological cardiac hypertrophy, fibrosis and protein damage followed by changes in miRs expression. Vitamin E supplementation was associated with a different miR expression profile and mitigated the pathological phenotype.

Abstract P1-07-19: Spatial analyses of breast cancer in women 15-49 years-old in Rio Grande do Sul, southern Brazil

Breast cancer (BC) rates under 50 years have been increasing over time in several countries. Although the exact impact of BC is not know in low and middle income countries, it's estimated that at least 20% of deaths caused by BC affect women under the ahe of 50 years. In Porto Alegre, the capital of Rio Grande do Sul (RS), Brazil's southernmost state, the incidence of BC in women aged 40-49 years is 165 cases per 100,000, while the mortality rate reaches 25 in 100,000 women. In order to understand BC profile in this age group in the entire state of RS, we established incidence, morbidity and mortality between 2002-2011 through crude and smoothed rates for each municipality. Furthermore, we perform the spatial analysis of these indicators. Incidence data were only available for the state capital, where the rate incidence was 19 and 160 cases per 100,000 women in the age groups of 15-39 and 40-49, respectively. Statewide mortality was 2 and 21 per 100,000 women in the age groups of 15-39 and 40-49, respectively. Hospitalar morbidity associated with BC was 0.6% and 2% in women 15-39 and 40-49 years, respectively. The distribution of morbidity and mortality showed regions with continuously high rates throughout this period with result above 3% and 20 deaths per 100,000 women. In the same areas we did not identified centers specialized in cancer treatment and care. Although there is specific epidemiological surveillance for cancer in Brazil, the coverage is insufficient, especially when it comes to incidence. Morbidity and mortality data showed regions continually affected by high rates, suggesting that specific measures as well as specialized care for women in these regions are necessary. This result is particularly important since current guidelines of the Ministry of Health in Brazil recommend mammographic screening starting at the age of 50 years. The expansion of coverage and access to appropriate treatment is essential for the recognition of risk factors, adoption of effective strategies and reduction of cases and deaths in this group of women. Knowledge of the age distribution of BC cases and BC related deaths is important for the definition of health care policies, which will likely be different in different regions of the world.

Citation Format: Vianna FSL, Vargas F, Gross LG, Nunes LN, Ashton-Prolla P, Camey SA. Spatial analyses of breast cancer in women 15-49 years-old in Rio Grande do Sul, southern Brazil. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-19.

Abstract P2-09-12: Prevalence of Hispanic BRCA1 and BRCA2 mutations among HBOC patients from Southern Brazil reveal differences among Latin American populations

Background.Breast cancer (BC) is the most common malignancy in women around the world, and 5% of BC cases and 15% of ovarian cancer (OC) cases can be attributed to BRCA1 and BRCA2 germline mutations, configuring Hereditary Breast and Ovarian Cancer Syndorme (HBOC). Considering that the genetic similarities between Latin American populations are largely unknown, we aimed to address if a panel of Hispanic BRCA mutations could be useful for a Brazilian population. Methods.Unrelated patients fulfilling NCCN criteria for HBOC syndrome were recruited. ASCO, Myriad and Penn II clinical testing criteria were analyzed for all patients. Blood-derived DNA samples were screened for 114 BRCA mutations, in a panel estimated to account for up to 90% of all BRCA Hispanic mutations (HISPANEL), using the Sequenom MassArray platform. Results. Among a total of 233 unrelated patients included (225 women and 8 men), 85% were BC patients and 14 patients were cancer unaffected. The mean age at diagnosis was 43 years for BC affected individuals and 45 years for patients with OC. Fifty-three patients fulfilled ASCO criteria, and 182 had Penn II≥10%, while only 64 had a Myriad score ≥10%. BRCA mutations were detected in 9 of 233 patients (prevalence of 3.86%). Among BC and/or OC affected individuals, this prevalence was 4.22%. Features of mutation carriers are depicted in table 1.

Table 1. BRCA mutations identified in Brazilian HBOC patients Mutation Gender Tumor type and age at diagnosis Family history of cancer BRCA1 c.3331_3334delCAAGFemaleOvCa, 47; BrCa, 50Daughter BrCa≤20;Brother PrCa 54;Cousin BrCa≥ 50 BRCA1 c.5266dupCFemaleBilateral BrCa, 35 and 45Mother OvCa 58;Aunt OvCa 49;Cousin BrCa 49;Great-grandmother BrCa 90 BRCA1 c.5266dupCFemaleBrCa, 36Aunt BrCa 62;Cousin BrCa 45;Cousin BrCa 44;Cousin Bilateral BrCa 45;Cousin BrCa 44;Cousin OvCa 52 BRCA1 c.5266dupCFemaleOvCa, 52Mother OvCa 77;Sister BrCa 44;Aunt OvCa 66 BRCA1 c.5266dupCFemaleBilateral BrCa, 23 and 44Mother BrCa 45;Aunt Bilateral BrCa 48;Cousin BrCa 30;Aunt Bilateral BrCa 58;Grandmother BrCa BRCA1 c.5266dupCFemaleBilateral BrCa, 26Sister BrCa 50;Niece BrCa 28;Niece BrCa 30 BRCA1 c.5266dupCMaleBrCa, 64Daughter BrCa 34;Sister BrCa≤ 50;Sister BrCa 32 BRCA2 c.2806_2809delAAACFemaleBrCa, 49Sister BrCa 32;Sister BrCa 44;Aunt Bilateral BrCa 40 and 55 BRCA2 c.2806_2809delAAACFemaleBilateral triple negative BrCa, 42 and 55NoneBrCa=breast cancer; OvCa=ovarian cancer.

Conclusions. The HISPANEL detects 59 BRCA1 and 55 BRCA2 mutations, including some mutations previously reported in Brazilian individuals. Most mutation carriers had the BRCA1 c.5266dupC (5382insC) mutation, a common founder mutation in several populations. Our results are largely different from other Latin American published data. Although low BRCA prevalence mutational rates were also seen in Peru and Mendellín (Colombia), in Mexico and Bogota (Colombia) a prevalence of 27% and 15%, respectively, was found in studies using HISPANEL and all studies included patients unselected for family history. Our findings reinforce that different Latin-American populations have different BRCA mutational profiles.

Citation Format: Alemar B, Herzog J, Ashton-Prolla P, Weitzel J. Prevalence of Hispanic BRCA1 and BRCA2 mutations among HBOC patients from Southern Brazil reveal differences among Latin American populations. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-12.

Genomic analysis in the clinic: benefits and challenges for health care professionals and patients in Brazil

Despite significant advances in the diagnosis and treatment of genetic diseases in the last two decades, there is still a significant proportion where a causative mutation cannot be identified and a definitive genetic diagnosis remains elusive. New genome-wide or high-throughput multiple gene tests have brought new hope to the field, since they can offer fast, cost-effective and comprehensive analysis of genetic variation. This is particularly interesting in disorders with high genetic heterogeneity. There are, however, limitations and concerns regarding the implementation of genomic analysis in everyday clinical practice, including some particular to emerging and developing economies, as Brazil. They include the limited number of actionable genetic variants known to date, difficulties in determining the clinical validity and utility of novel variants, growth of direct-to-consumer genetic testing using a genomic approach and lack of proper training of health care professionals to adequately request, interpret and use genetic information. Despite all these concerns and limitations, the availability of genomic tests has grown at an extremely rapid pace and commercially available services include initiatives in almost all areas of clinical genetics, including newborn and carrier screening. We discuss the benefits and limitations of genomic testing, as well as the ethical implications and the challenges for genetic education and enough available and qualified health care professionals, to ensure the adequate process of informed consent, meaningful interpretation and use of genomic data and definition of a clear regulatory framework in the particular context of Brazil.

p53 signaling pathway polymorphisms associated to recurrent pregnancy loss

The p53 protein is known for performing essential functions in the maintenance of genomic stability in somatic cells and prevention of tumor formation. Studies of the p53 signaling pathway have suggested associations between some polymorphisms and infertility, post-in vitro fertilization implantation failure and recurrent abortions. The TP53 Pro72Arg polymorphism has been implicated as a risk factor for recurrent pregnancy loss (RPL); however, the association is controversial. In this study, our objective was to evaluate selected polymorphisms in genes of the p53 signalling pathway [TP53 c.215G>C (Pro72Arg), MDM2 c.14+309T>G (SNP309) and LIF c.1414T>G in the region 3' UTR] and determine their effect as risk factors for RPL. In a case-control study, we investigated 120 women with two or more pregnancy losses and 143 fertile control women reporting at least two live births and no history of pregnancy loss. When analyzed separately, the allele and genotype distributions of the polymorphisms in the two groups were not different. However, in a multivariate analysis adjusted for alcohol consumption, smoking, ethnicity, and number of pregnancies, the interaction between the genotypes TP53 Arg/Arg (rs1042522) and MDM2 TT (rs2279744) showed to be associated to RPL, increasing the risk for this condition (OR = 2.58, 95% CI: 1.31-5.07, p = 0.006). In conclusion, our study indicates that the combination of TP53 Arg/Arg (rs1042522) and MDM2 TT (rs2279744) genotypes may be a risk factor for RPL.

Abstract P2-07-04: HER2 overexpressing breast cancers are more frequent in carriers of TP53 DNA-binding domain mutations than in carriers of oligomerization-site mutations

Germline TP53 mutations are associated with Li-Fraumeni Syndrome (LFS), an autosomal dominant disorder characterized by predisposition to multiple early-onset cancers including breast cancer (BC), the most prevalent tumor among women. The majority of germline TP53 mutations are missense substitutions clustered within the DNA-binding domain of the gene that disrupt the structure and function of the protein. Recently, the germline mutation p.R337H (c.1010G&gt;A), lying in the oligomerization domain of p53, was reported at a high frequency in Southern and Southeastern Brazil. This mutation appears to result in a more subtle defect in the protein, which becomes functionally deficient only under particular conditions and specific tissues. Recent reports suggest that BC are HER2-postive in a high proportion (63-83%) of TP53 mutation carriers. Histopathologic features of breast cancers among carriers of oligomerization domain mutations have not been reported. Our objective was to analize HER2 status in breast cancers from carriers of germline TP53 mutations, both in the DNA-binding and oligomerization domains. We retrospectively reviewed the immunohistochemistry data of breast cancers from 64 carriers of TP53 p.R337H and 6 carriers of nonfunctional germline TP53 mutations (p.G245S, p.R273H, p.G244D or c.672+1G&gt;T). All patients were recruited from the cancer genetics clinic at Hospital de Clínicas de Porto Alegre, Brazil. Germline TP53 mutations were identified by Sanger sequencing of the entire coding sequence and flanking intronic regions. Immunohistochemistry (IHC) was performed using standard procedures. HER2 expression was assessed using a 0 to 3+ scale according the ASCO-CAP Guidelines. All of the six patients with nonfunctional TP53 mutations showed strong (3+) HER2 staining by IHC in their breast tumors. In the group of p.R337H carriers, 23.4% showed significant HER2 overexpression (3+), 21.9% presented ambiguous HER2 results (2+), and 54.7% showed weak or no HER2 expression (1+ or 0). Thus, HER2 overexpressing breast cancers were more frequent in carriers of TP53 nonfunctional (DNA binding domain) mutations (p≤0.001) than in those carrying the oligomerization domain mutation. Preliminary results from this study suggest that germline mutations in different domains of the TP53 gene may predispose to breast cancer through different mechanisms.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-07-04.

Abstract P2-13-01: The Brazilian founder TP53 p.R337H mutation is uncommon in Portuguese women diagnosed with breast cancer

Since the first studies reporting the TP53 p.R337H mutation as founder mutation in Southern and Southeastern regions of Brazil, both in the general population and in patients from high risk breast cancer families with adrenocortical, choroid plexus and breast carcinomas, there has been controversy on the origin of this mutation. Preliminary analysis of the small subset of Brazilian mutation carriers that defined the founder haplotype using 29 tag SNPs revealed that the haplotype incided on a Caucasian background. The vast majority of carriers identified today reside in Brazil or, if identified in other countries, are Brazilian immigrants. To our knowledge, the only two exceptions of carriers without a recognizable link with Brazil are two European families (one Portuguese and one German) (Chompret et al., 2000; Herrmann et al. 2012). Haplotype analysis in the Portuguese family revealed the same haplotype identified in Brazilian individuals, but in the German family, a distinct haplotype was found. Knowing that a significant proportion of women with breast cancer in Southern Brazil are p.R337H carriers, we initiated TP53 genotyping in a Portuguese cohort of women with breast cancer recruited from the cities of Lisboa and Braga. Median age at diagnosis of breast cancer among the first 573 patients tested was 60 years and 100 (17.4%) patients had been diagnosed at or under the age of 45 years. Mutation screening was performed using Real-Time PCR (taqman assays), and failed to identify the mutation in the 573 patients tested. These results are in contrast with the mutation frequency observed in a study of 815 breast cancer-affected women from Southern and Southeastern Brazil, which has reached frequencies of 12.1 and 5.1% in pre- and post-menopausal women, respectively (Ashton-Prolla et al. 2012; ASCO Annual Meeting, ref 1522). We conclude that there is a significant difference in mutation frequency observed between the two cohorts (p&lt;0.001). These findings suggest that TP53 p.R337H is not a common molecular alteration in Portuguese breast cancer-affected patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-13-01.

Association of adipokines and adhesion molecules with indicators of obesity in women undergoing mammography screening

BACKGROUND

The soluble cell adhesion molecules and adipokines are elevated in patients with obesity, hypertension, type 2 diabetes mellitus, breast cancer and atherosclerosis.

OBJECTIVE

To investigate the relationship between anthropometric profile, dietary intake, lipid profile and fasting glycemia with serum levels of adipokines (adiponectin and PAI-1) and adhesion molecules (ICAM-1 and VCAM-1) in women without breast cancer undergoing routine mammographic screening.

DESIGN

Transversal study.

SUBJECTS

One hundred and forty-five women over 40-years old participated in this study.

RESULTS

In 39.3% of cases the BMI was above 30 kg/m2; 46.9% had hypertension, 14.5% had type 2 Diabetes Mellitus, 31.7% had dyslipidemia and 88.3% presented a waist-to-hip ratio ≥ 0.8. A linear correlation was found between serum levels of PAI-1 and triglycerides, between serum levels of PAI-1 and WHR and between serum levels of VCAM-1 and BMI.

CONCLUSION

We found a high prevalence of obesity and metabolic syndrome. PAI-1 and VCAM-1 levels were correlated with clinical indicators of obesity and overweight.

High twinning rate in Cândido Godói: a new role for p53 in human fertility

BACKGROUND

Cândido Godói (CG) is a small town in South Brazil, which has the highest prevalence of twin births in Brazil. Recently, a number of studies have shown that p53 plays an important role in reproduction through blastocyst implantation and intra utero embryo survival. Thus, gene polymorphisms in the p53 pathway were investigated in this population.

METHODS

Single nucleotide polymorphisms from five genes in the p53 pathway were investigated, as well as background characteristics of 42 mothers of twins (cases) and 101 mothers of singletons (controls), all residents from CG.

RESULTS

Mothers of twins have higher number of pregnancies and higher frequencies of P72 allele at TP53 and T allele at MDM4 genes compared with controls. Logistic regression shows that both TP53 and number of pregnancies maintained their association with twinning (P =0.004 and P =0.002, respectively), with TP53 having a higher odds ratio than number of pregnancies (2.73 versus 1.70, respectively). No interactive effect between TP53 and MDM4 (P =0.966) is observed. As expected, mothers of twins have three times more cases of cancer in their first-degree relatives than control mothers (P =0.011).

CONCLUSIONS

Our results suggest that the P72 allele of TP53 is a strong risk factor for twinning in CG, while the number of pregnancies and the T allele at MDM4 may represent weaker risk factors. These two alleles are associated with infertility, but the anti-apoptotic effect of low levels of p53 in general, and of the P72 allele in particular, may play a role after implantation, enhancing the chance for a double pregnancy to succeed to term.

GSTM1, GSTT1, and GSTP1 polymorphisms, breast cancer risk factors and mammographic density in women submitted to breast cancer screening

Genetic polymorphisms in genes related to the metabolism of xenobiotics, such as genes of the glutathione S-transferases (GSTM1, GSTT1, and GSTP1) superfamily have been associated with an increased risk for breast cancer (BC). Considering the high incidence of BC in the city of Porto Alegre in southern Brazil, the purpose of this study was to characterize genotypic and allelic frequencies of polymorphisms in GSTM1, GSTT1, and GSTP1, and correlate these molecular findings with established risk factors for breast cancer including mammographic density, in a sample of 750 asymptomatic women undergoing mammographic screening. Molecular tests were performed using the multiplex polymerase chain reaction (PCR) for GSTM1 and GSTT1, and quantitative PCR for GSTP1 polymorphisms. Overall, the frequencies of GSTM1 and GSTT1 null genotypes were 45% and 21%, respectively. For GSTP1 polymorphism, genotypic frequencies were 44% for the Ile/Ile genotype, 44% for the Ile/Val genotype, and 12% for Val/Val genotype, with an allelic frequency of 66% for the wild type allele in this population, similar to results of previous international publications. There was a statistically significant association between the combined GSTM1 and GSTT1 null genotypes (M-/T-) and mammographic density in post menopausal women (p = 0.031). When the GSTT1 null (T-) genotype was analyzed isolated, the association with mammographic density in post menopausal women and in the overall sample was also statistically significant (p = 0.023 and p = 0.027, respectively). These findings suggest an association of GSTM1 and GSTT1 null genotypes with mammographic density.

Prevalence of ERα-397 PvuII C/T, ERα-351 XbaI A/G and PGR PROGINS polymorphisms in Brazilian breast cancer-unaffected women

Polymorphisms of hormone receptor genes have been linked to modifications in reproductive factors and to an increased risk of breast cancer (BC). In the present study, we have determined the allelic and genotypic frequencies of the ERα-397 PvuII C/T, ERα-351 XbaI A/G and PGR PROGINS polymorphisms and investigated their relationship with mammographic density, body mass index (BMI) and other risk factors for BC. A consecutive and unselected sample of 750 Brazilian BC-unaffected women enrolled in a mammography screening program was recruited. The distribution of PGR PROGINS genotypic frequencies was 72.5, 25.5 and 2.0% for A1A1, A1A2 and A2A2, respectively, which was equivalent to that encountered in other studies with healthy women. The distribution of ERα genotypes was: ERα-397 PvuII C/T: 32.3% TT, 47.5% TC, and 20.2% CC; ERα-351 XbaI A/G: 46.3% AA, 41.7% AG and 12.0% GG. ERα haplotypes were 53.5% PX, 14.3% Px, 0.3% pX, and 32.0% px. These were significantly different from most previously published reports worldwide (P < 0.05). Overall, the PGR PROGINS genotypes A2A2 and A1A2 were associated with fatty and moderately fatty breast tissue. The same genotypes were also associated with a high BMI in postmenopausal women. In addition, the ERα-351 XbaI GG genotype was associated with menarche ≥12 years (P = 0.02). ERα and PGR polymorphisms have a phenotypic effect and may play an important role in BC risk determination. Finally, if confirmed in BC patients, these associations could have important implications for mammographic screening and strategies and may be helpful to identify women at higher risk for the disease.

Additive effect of RET polymorphisms on sporadic medullary thyroid carcinoma susceptibility and tumor aggressiveness

OBJECTIVE

RET single nucleotide polymorphisms (SNPs) have been implicated in the pathogenesis and progression of medullary thyroid carcinoma (MTC). Here, we investigated the influence of multiple RET variants (G691S, L769L, S836S, and S904S) on the risk of MTC and tumor behavior.

DESIGN AND METHODS

One hundred and seven MTC patients and 308 cancer-unaffected control individuals were included. SNPs were analyzed using Custom TaqMan Genotyping Assays. Haplotypes based on the combination of allelic variants were inferred using a Bayesian statistical method.

RESULTS

The minor allele frequencies in MTC patients were as follows: L769L: 28.0%, S836S: 8.9%, and G691S/S904S: 22.2%. The RET L769L and S836S SNPs were associated with increased risk of MTC (odds ratio (OR)=1.95, 95% CI: 1.2-3.1, P=0.005 and OR=2.29, 95% CI: 1.2-4.5, P=0.017 respectively). The adjusted OR for individuals harboring haplotypes with three or more polymorphic alleles was 3.79 (95% CI: 1.5-9.5; P=0.004), indicating an additive effect of these variants on the risk for MTC. Among MTC patients, no significant associations were observed between RET variants and age of diagnosis or tumor size but serum calcitonin levels increased according to the number of risk alleles (P=0.003). Remarkably, patients carrying haplotypes with three or four risk alleles had increased risk for lymph node and distant metastases at diagnosis (OR=5.84, 95% CI: 1.1-31.2, P=0.039). Further analysis using Kaplan-Meier model demonstrated that metastatic disease occurred earlier in individuals harboring multiple risk alleles.

CONCLUSION

Our results demonstrated an additive effect of RET polymorphic alleles on the estimated risk of developing aggressive MTC.

Abstract P3-06-02: Prevalence of TP53 p.R337H Mutation in Cases of Breast Phyllodes Tumours in Southern Brazil

Background: Previous studies in Brazilian patients diagnosed with the core-cancers of Li-Fraumeni syndrome (LFS) and its variants (LFL) indicate that a particular germline mutation, TP53 p.R337H, may be highly prevalent and strongly associated with pediatric adrenocortical tumors in Southern Brazil. However, other tumours types, including breast cancer, have been observed in carriers, raising the possibility that the TP53 p.R337H mutation may also contribute to breast tumorigenesis. Breast phyllodes tumour, a very rare and aggressive breast neoplasia that accounts for less than 1% of all breast cancer cases, may be associated with LFS, and has suggested by some to be particularly frequent in TP53 mutation carriers. Methods: Formalin fixed paraffin-embedded (FFPE) tissue from disease-free lymph nodes of an unselected consecutive series of women diagnosed with benign and malignant phyllodes tumours between 2000 and 2010, was obtained from 7 Pathology Laboratories in Southern Brazil. Genomic DNA was isolated from FFPE with the QIAamp DNA Tissue Kit. Genotyping was performed by qPCR using TaqMan technology and direct bi-directional sequencing for confirmation in mutation-positive cases. Results: Analysis of the first 48 cases included in the study (9 malignant, 3 borderline and 36 benign phyllodes tumors) resulted in identification of the TP53 p.R337H mutation in the germline of a 61 year-old patient with malignant phyllodes and a 38 year-old patient with a benign phyllodes tumor of the breast.

Conclusion: Preliminary analysis of a case series of breast phyllodes tumors indicates that germline the founder mutation TP53 p.R337H may be particularly common in women with these tumors in Southern Brazil. Further analysis of the entire TP53 coding region and evaluation of the founder haplotype in the mutation-positive cases is ongoing. The identification of germline TP53 mutations in patients diagnosed with phyllodes tumors of the breast has important implications for disease management and in cancer risk counseling for these patients and families.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-06-02.

Adherence to a breast cancer screening program and its predictors in underserved women in southern Brazil

BACKGROUND

Adherence to breast cancer screening is a key element to ensure effectiveness of programs aiming at downstaging of breast cancer. In this study, we evaluated adherence to a screening program and its predictors in underserved women in southern Brazil.

METHODS

Attendance to the program, which is based on yearly mammogram and clinical examination, was evaluated prospectively. Mean time frames between visits were calculated. Possible predictors of adherence (defined as mean intervals ≤18 mo), such as socioeconomic indicators and health/lifestyle behaviors, were investigated.

RESULTS

A total of 3,749 women (age 51 ± 8 y, illiteracy rate of 6.8%, 57.4% with parity ≥3) were analyzed. Median time between screening rounds was 16.5 months (interquartile range, 13.1-25.7), and median number of rounds attended was 3 (interquartile range, 2-4); 57.6% had mean intervals ≤18, and 71% ≤24 months. The most important independent predictors of adherence were high genetic risk [relative risk (RR), 1.25; 95% confidence interval (95% CI), 1.11-1.40], illiteracy (RR, 0.77; 95% CI, 0.67-0.90), parity ≥5 (RR, 0.89; 95% CI, 0.83-0.96), and smoking (RR, 0.82; 95% CI, 0.77-0.88).

CONCLUSIONS

Although the proposed screening interval was 1 year, compliance to biannual screening (accepted in several international programs) was high, especially when considering the low socioeconomic level of the sample.

IMPACT

This project aims to test a breast cancer screening model for underserved populations in limited-resource countries where adherence is an issue. The identification of worst adherence predictors can point to interventions to improve outcomes of similar public health screening strategies.

TP53 PIN3 and MDM2 SNP309 polymorphisms as genetic modifiers in the Li-Fraumeni syndrome: impact on age at first diagnosis

BACKGROUND

Li-Fraumeni and Li-Fraumeni-like syndromes (LFS/LFL), characterised by the development of multiple early onset cancers with heterogeneous tumour patterns, are associated with germline TP53 mutations. Polymorphisms in the TP53 pathway (TP53 PEX4 at codon 72, rs1042522; MDM2 SNP309, rs2279744) have modifier effects on germline TP53 mutations that may account for the individual and familial diversity of tumour patterns.

METHODS AND RESULTS

Four polymorphisms were analysed in a series of 135 Brazilian LFS/LFL cancer patients (32 TP53 mutation carriers and 103 wild-type subjects). We report for the first time that another polymorphism in the TP53 gene, TP53 PIN3 (rs17878362), has a strong modifier effect on germline TP53 mutations. This polymorphism, which consists of a 16 bp duplication in intron 3 (A1, non-duplicated allele; A2, duplicated allele), is associated with a difference of 19.0 years in the mean age at the first diagnosis in TP53 mutation carriers (n = 25, A1A1: 28.0 years; n = 7, A1A2: 47.0 years; p = 0.01). In addition, cancer occurrence before the age of 35 years is exclusively observed in A1A1 homozygotes. In this series, the effect of TP53 PEX4 and MDM2 SNP309 on age at diagnosis was similar to the one reported in other series and was smaller than the one of TP53 PIN3 (TP53 PIN3: difference of 19.0 years; TP53 PEX4: 8.3 years; MDM2 SNP309: 12.5 years).

CONCLUSION

These results suggest that TP53 PIN3 is another polymorphism in the TP53 pathway that may have a modifier effect on germline TP53 mutations and may contribute to the phenotypic diversity of germline TP53 mutations associated with LFS/LFL patients.

A model to optimize public health care and downstage breast cancer in limited-resource populations in southern Brazil. (Porto Alegre Breast Health Intervention Cohort)

Background

Breast cancer (BC) is a major public health problem, with rising incidence in many regions of the globe. Although mortality has recently dropped in developed countries, death rates are still increasing in some developing countries, as seen in Brazil. Among the reasons for this phenomenon are the lack of structured screening programs, a long waiting period between diagnosis and treatment, and lack of access to health services for a large proportion of the Brazilian population.

Methods and design

Since 2004, an intervention study in a cohort of women in Southern Brazil, denominated Porto Alegre Breast Health Intervention Cohort, is being conducted in order to test the effectiveness and cost-effectiveness of a model for BC early detection and treatment. In this study, over 4,000 women from underserved communities aged 40 to 69 years are being screened annually with mammography and clinical breast examination performed by a multidisciplinary team, which also involves nutritional counseling and genetic cancer risk assessment. Risk factors for BC development are also being evaluated. Active search of participants by lay community health workers is one of the major features of our program. The accrual of new participants was concluded in 2006 and the study will last for 10 years. The main goal of the study is to demonstrate significant downstaging of BC in an underserved population through proper screening, attaining a higher rate of early-stage BC diagnoses than usually seen in women diagnosed in the Brazilian Public Health System. Preliminary results show a very high BC incidence in this population (117 cases per 100,000 women per year), despite a low prevalence of classical risk factors.

Discussion

This study will allow us to test a model of BC early diagnosis and treatment and evaluate its cost-effectiveness in a developing country where the mortality associated with this disease is very high. Also, it might contribute to the evaluation of risk factors in a population with a different ethnic background from that studied in developed countries. If our model is proven effective, it may be replicated in other parts of the globe where BC is also a major public health problem.

Progesterone receptor gene polymorphism (PROGINS) in 701 women from a mammographic breast cancer screening program (NMPOA) in Southern Brazil

21048

Background: Several genetic polymorphisms in hormone receptor genes have been associated with breast cancer (BC) risk. Among these, a 306 base-pair insertion of the Alu subfamily in intron 7 of the progesterone receptor (PR) gene, (PROGINS), has been associated with decreased BC risk in several populations. In Brazil, BC is a significant public health problem, due to its high incidence and mortality rates. In Porto Alegre, Brazil`s southernmost capital, a multidisciplinary Breast Cancer Prevention Project - the Nucleo Mama Porto Alegre Cohort (NMPOA) was started in 2004 and includes a mammographic screening program for women ages 40–69 years. Goal: Determine the allelic and genotypic frequencies of PROGINS in women undergoing annual BC screening and correlate its presence with mammography results and presence of additional BC risk factors (family history of BC, body mass index, estimated BC risk by the Gail model and age) at baseline and after 10 years. Methods: A sample of 701 women from the NMPOA BC screening program was consecutively enrolled in the study from November/2005 until March/2006. Clinical data, mammography results (as BIRADS categories) and BC risk information was obtained by chart review. PROGINS genotyping was performed by polymerase chain reaction (PCR). Results: Of the 701 patients studied, 504 (71,0%) were wild-type homozygous, 184 (26,2%) heterozygous and 13 (1,8%) homozygous for the PROGINS polymorphism. These genotypic frequencies are similar to those of other reports in different populations. Genotype was correlated with 5-year and vital BC risk estimates (Gail model), body mass index, family history of BC and mammography findings. A statistically significant association was found between the presence of PROGINS and a positive family history of BC (p< 0,05). Conclusions: The genotypic and allelic frequencies of the PROGINS polymorphism were not significantly different from those reported previously for other populations. Prospective clinical evaluation of the women followed in this program and correlation of genotype with clinical findings may be important to elucidate additional risks associated with the PROGINS polymorphism.

No significant financial relationships to disclose.

Prevalence of breast cancer risk factors in two different cohorts in relation to health care access and preventive programs in southern Brazil

1538

Background: Breast cancer (BC) represents a public issue of great impact also in developing countries as Brazil, where BC incidence and mortality rates are continuosly increasing, the latter probably due to late diagnosis and lack of health care programs.Studies are needed to identified BC risk factors in different groups of women in Porto Alegre (POA), where BC incidence is 3-fold higher than other Brazilian cities. Preliminary analysis are presented to enable specialists to design preventive strategies of breast health care models. Methods: The study included a survey of risk factors of two social economic distinct groups of women over 15 years old with different access to health care programs in POA: 1) Núcleo Mama Porto Alegre (NMPOA): underserved women derived from public health care units, and 2) Núcleo Mama Moinhos (NMHMV): women with private insurance. Results: Data of 785 from NMHMV and 8921 from NMPOA are summarized in the table . Obesity and smokers are more frequent in the underserved population whereas a positive familial history is more common in the NMHMV group. Conclusions: Preliminary results showed significant differences among the two studied population demanding distinct strategies of prevention and management. The total number of 15.000 women will be presented together with reproductive factors and the their Gail model access.

[Table: see text]

No significant financial relationships to disclose.

Detection of R337H, a germline mutation predisposing to multiple cancers, in asymptomatic women participating in a breast cancer screening programme in southern Brazil

21029

Background: A specific germline mutation at codon 337 in TP53 (R337H) has been detected in a number of unrelated subjects with familial cancer risk in South Brazil, suggesting that this mutation may be relatively common in this population. Methods: To assess the TP53 R337H prevalence in a group of asymptomatic individuals unselected for family history of cancer, we studied 750 women aged 40–69 ys participating in a mammographic screening programme in Porto Alegre, Brazil`s southernmost capital. DNA was extracted from peripheral blood using standard procedures and PCR-amplified to generate a 238-base product encompassing TP53 exon 10, which was analyzed by RFLP using the restriction enzyme HhaI. The mutant, uncleaved allele was identified in agarose gels and positive RFLP findings were further confirmed by an independent PCR amplification and bi-directional, automated sequencing. Results and Discussion: The R337H mutant was detected in two of the 750 participants (0.15%), suggesting a much higher prevalence for this than for other TP53 germline mutations causing the LFS/LFL syndromes in the general population. Interestingly, these two subjects reported a familial history of cancer, and were found to be 2nd degree relatives. Three additional family members were also positive: one woman affected with breast cancer at the age of 36 years and two asymptomatic 62- and 80-year-old women. The presence of four R337H-positive cancer- unaffected individuals in this family, two of them well above the age of 50, indicates that this is a low-penetrance allele. In addition, the pedigree does not fulfill any of the currently recognized clinical criteria for the diagnosis of LFS/LFLS syndrome. This is the first study to report detection of a germline TP53 mutation in a population-based screening programme. Conclusions: The TP53 R337H mutant appears to be relatively common and may occur in families that do not fulfill the known clinical criteria for LFS/LFLS, the family described here contains asymptomatic carriers suggesting partial penetrance.

No significant financial relationships to disclose.

Null allele polymorphisms in the GSTT1 and GSTM1 genes in 705 women from a mammographic breast cancer screening program (NMPOA) in southern Brazil

21091

Background: Several genetic polymorphisms in genes related with metabolism have been associated with breast cancer (BC) risk. Among these, the gluthatione-S-transferase M1 and T1 null genotypes have been associated with slightly increased BC risk in some populations. In Brazil, BC is a significant public health problem, due to its high incidence and mortality rates. In Porto Alegre, Brazil`s southernmost capital, a multidisciplinary BC Prevention Project - the Nucleo Mama Porto Alegre Cohort (NMPOA)- was started in 2004 and includes a mammographic screening program for women ages 40–69 years. Goal:Determine the allelic and genotypic frequencies of GSTM1 and GSTT1 null alleles in women undergoing annual mammographic screening and correlate its presence with mammography results and presence of additional BC risk factors at baseline and after 10 years. Methods: A sample of 705 women from the NMPOA BC screening program was consecutively enrolled from November/2005 until March/2006. Mammography results (BIRADS categories) and BC risk information (5-yr and vital estimates using the Gail model, family history of BC, body mass index) were obtained by chart review. Genotyping was performed by multiplex polymerase chain reaction (PCR). Results: Of the 705 patients studied, 145 (20.6%) and 314 (44.5%) had the GSTT1 and GSTM1 null alleles, respectively. Genotypically, 67 (9,5%) were null homozygous for both genes (GSTM1- and GSTT1- ); 78 (11,1%) were GSTT1- and non-null for GSTM1 (GSTT1- and GSTM1+); 247 (35%) were GSTT1+ and GSTM1- and 313(44,4%) were GSTM+ and GSTT+. There was a statistically significant association of the GSTT1+ allele with low-risk mammographic findings (category BIRADS 1; p<0,05). Conclusions: The genotypic and allelic frequencies of the GSTT1 and GSTM1 null alleles were not significantly different from those reported previously for other populations. The non-null GSTT1 allele was associated with lower category mammographic findings. Prospective clinical evaluation of the women followed in this program and correlation of genotype with clinical findings may elucidate additional risks associated with the presence of these polymorphisms.

No significant financial relationships to disclose.

Breast cancer risk estimates using the Gail Model in women from an annual screening program in Southern Brazil

20045

Background: The Gail model is widely used to estimate breast cancer (BC) risk. It has been validated as a reliable risk predictor in North America, but very few studies have been done in other countries. This study intends to examine the estimated BC risk using the Gail Model in a sample of women from Southern Brazil a region with the highest BC incidence and mortality rates of the country. Methods: Lifetime and 5-year BC risk estimates were obtained for the first 1002 asymptomatic women (ages 40–69 years) enrolled in an annual BC screening program. The frequency of each of the model’s variables was recorded and compared to other studies. Information about family history (FH) included: presence of bilateral BC, male BC, first degree relative with BC and/or ovarian cancer (OC), relative with BC under age 50 and ≥ 2 relatives with either BC, OC or colorectal cancer (CRC). Other potential risk factors for BC such as body mass index and smoking were recorded. Results: Mean (± SD) values for age, age at menarche and age at birth of the first live child were 50.4 (± 7.75), 13.0 (± 1.80), and 21.6 (± 5.00) years, respectively. Only 50 (5.0%) women were nulliparous and 62 (6.2%) reported their first live birth after age 30. History of at least one first-degree relative (FDR) affected with BC was reported by 52 (5.2%), and 31 (3.1%) had a previous breast biopsy. The mean estimated BC risk in 5 years was 0.92% (± 0.49); for those under age 60, 24 (2.8%) had an estimated 5-yr risk over 1.66%. The mean estimated lifetime BC risk was 7.80 (± 3.2). Interestingly, a history of cancer in a FDR was reported by 32.6% of the women, and evidence of familial BC was observed in 20.4%. The estimated BC risk using the Gail model was significantly higher in women with a family history of BC < 50ys and with ≥ 2 relatives with either BC, OC or CRC. Smoking and overweight were reported by 28% and 65% of the women, respectively. Conclusions: BC risk estimates obtained with the Gail Model did not differ significantly from those described in other populations. However, specific findings in cancer FH were associated with higher risk estimates. The importance of FH and overweight will be further explored in a larger sample. Population-specific risk factors for BC should be sought in different communities to ensure proper risk estimates.

No significant financial relationships to disclose.

An alternative protocol for DNA extraction from formalin fixed and paraffin wax embedded tissue

BACKGROUND

DNA extraction from paraffin wax embedded tissue requires special protocols, and most described methods report an amplification success rate of 60-80%.

AIMS

To propose a simple and inexpensive protocol consisting of xylene/ethanol dewaxing, followed by a kit based extraction.

METHOD

Xylene/ethanol dewaxing was followed by a long rehydration step and a kit based DNA extraction step.

RESULTS

This method produced a 100% amplification success rate for fragments of 121 to 227 bp for tamponated formalin fixed paraffin wax embedded tissue.

CONCLUSION

This cost effective and non-laborious protocol can successfully extract DNA from tamponated formalin fixed paraffin wax embedded tissue and should facilitate the molecular analysis of a large number of archival specimens in retrospective studies.

Melanoma hereditário: prevalência de fatores de risco em um grupo de pacientes no Sul do Brasil

FUNDAMENTOS: Aproximadamente 10% dos casos de melanoma são atribuíveis a mutações em genes de predisposição, sendo, portanto, hereditários. OBJETIVOS: Este estudo avalia a prevalência de fatores de risco para melanoma hereditário em um grupo de pacientes com melanoma no sul do Brasil. CASUÍSTICA E MÉTODOS: Foram estudados 195 pacientes com diagnóstico de melanoma admitidos consecutivamente no Hospital de Clínicas de Porto Alegre entre janeiro de 1999 e junho de 2000. RESULTADOS: A idade média ao diagnóstico de melanoma foi de 48 anos em homens e 44,9 anos em mulheres. Dos 133 pacientes cuja história familiar encontrava-se registrada no prontuário, 13 (9,8%) apresentavam história familiar de melanoma. A presença de ao menos um fator de risco importante para predisposição hereditária ao melanoma foi constatada em 31 pacientes (16%; IC 95% 10,9% - 21,1%). CONCLUSÃO: A possibilidade de influência do fator hereditário no Brasil estimula a procura ativa de fatores de risco genético em pacientes com melanoma, já que a identificação de famílias de alto risco pode ter grande impacto sobre a morbimortalidade de seus integrantes.

Fabry disease: twenty-two novel mutations in the alpha-galactosidase A gene and genotype/phenotype correlations in severely and mildly affected hemizygotes and heterozygotes

BACKGROUND

Fabry disease, an inborn error of glycosphingolipid catabolism, results from mutations in the X-chromosomal gene encoding the lysosomal exoglycosidase, alpha-galactosidase A (alpha-Gal A; EC 3.2.1.22). The nature of the molecular lesions in the alpha-Gal A gene in 36 unrelated families was determined in order to provide precise heterozygote detection, prenatal diagnosis, and to define genotype/phenotype correlations.

METHODS

Genomic DNA was isolated from affected males and/or carrier females from 36 unrelated families with Fabry disease. The entire alpha-Gal A coding region and flanking intronic sequences were analyzed by PCR amplification and solid-phase or cycle sequencing. Markers closely linked to the alpha-Gal A gene were analyzed to determine if probands with the same mutations were related.

RESULTS

Twenty-two novel mutations were identified including 10 missense (P40L, W95S, S148N, C172R, M187V, N224S, W226R, A230T, D266H, N320Y), three nonsense (Y134X, C142X, W204X in two families), three splice-site defects (IVS2(+1), IVS3(+1), IVS4(+1)) and six small deletions or insertions (26delA in two families, 672ins37, 774delAC, 833insA, 1139delC, 1188insT). Of the remaining 12 families (33.3%), each had a previously identified mutation, eight of which occurred at CpG dinucleotides including R112C (two families), R112H, R227Q, R227X (three families), and R301Q. Haplotype analysis of the mutant alleles that occurred in two or three presumably unrelated families revealed that the families with the rare novel alleles (W204X and 26delA) were probably related, whereas those with mutations involving CpG dinucleotides (R112C and R227X) were not, the latter being consistent with their origins as independent mutational events. Genotype/phenotype correlations revealed that certain mutations previously found in mild variant patients also were found in classic patients. In addition, the genotypes and spectrum of phenotypic severity were determined in five heterozygotes with no family history.

CONCLUSIONS

These results illustrate the molecular heterogeneity of the lesions causing Fabry disease and emphasize the fact that CpG dinucleotides constitute important hot spots for mutation in the alpha-Gal A gene. These studies also permit precise heterozygote detection and prenatal diagnosis in these families, and delineate phenotype-genotype correlations in this disease.

Fabry disease: comparison of enzymatic, linkage, and mutation analysis for carrier detection in a family with a novel mutation (30delG)

Fabry disease (FD) is an X-linked recessive disorder caused by the deficient activity of the lysosomal enzyme alpha-galactosidase A (alpha-Gal A). Affected males are reliably diagnosed by demonstration of deficient alpha-Gal A activity in plasma or leukocytes. However, identification of female carriers is problematic due to Lyonization, requiring mutation identification and/or linkage studies for accurate carrier detection. Here, we describe a large Brazilian kindred with Fabry disease that permitted comparison of biochemical and molecular diagnostic techniques. Initially, the plasma alpha-Gal A activities were determined in at-risk affected males and potential female carriers; affected males were readily diagnosed, while the females had variable results. To detect carrier females, haplotype analysis using 10 polymorphic markers adjacent to the gene was performed. Subsequently, solid-phase direct sequencing of the alpha-Gal A gene demonstrated a novel single base deletion in exon 1 (30delG). Discrepancies were observed between the enzymatic and molecular diagnoses in two at-risk females. These findings emphasize the need for precise heterozygote diagnosis by mutation and/or haplotype analyses in all families with Fabry disease.