Search

Melanoma is a highly aggressive cancer, accounting for up to 75% of skin cancer deaths. A small proportion of melanoma cases can be ascribed to the presence of highly penetrant germline mutations, and approximately 40% of hereditary melanoma cases are caused by CDKN2A mutations. The current study sought to investigate whether the presence of germline CDKN2A mutations or the occurrence of cutaneous melanoma would result in constitutive genome-wide DNA methylation changes. The leukocyte methylomes of two groups of melanoma patients (those with germline CDKN2A mutations and those without CDKN2A mutations) were analyzed together with the profile of a control group of individuals. A pattern of DNA hypomethylation was detected in the CDKN2A-negative patients relative to both CDKN2A-mutated patients and controls. Additionally, we delineated a panel of 90 CpG sites that were differentially methylated in CDKN2A-mutated patients relative to controls. Although we identified a possible constitutive epigenetic signature in CDKN2A-mutated patients, the occurrence of reported SNPs at the detected CpG sites complicated the data interpretation. Thus, further studies are required to elucidate the impact of these findings on melanoma predisposition and their possible effect on the penetrance of CDKN2A mutations.

Aim: This work evaluates a possible causative role for germline copy number variants (CNVs) in melanoma predisposition. Patients & methods: A total of 41 melanoma-prone Brazilian patients were investigated for CNVs using 850K single nucleotide polymorphism arrays. Results: Ten rare CNVs were identified in nine patients, comprising 54 known genes, mostly related to cancer. In silico analyses revealed gene enrichment for cellular development and growth, and proliferation, highlighting five genes directly associated with the melanoma phenotype (ANGPT1, IDH1, PDE5A, HIST1H1B and GCNT2). Conclusion: Patients harboring rare CNVs exhibited a decreased age of disease onset, in addition to an overall higher skin cancer predisposition. Our findings suggest that rare CNVs contribute to melanoma susceptibility, and should be taken into account when investigating cancer risk factors.

Hepatoblastomas (HB) are embryonal tumors of the liver with histological features that resemble different stages of liver differentiation. The identification of molecular pathways involved in HB development can expand the understanding of the connections between disruption of normal differentiation and cancer. Exome sequencing (244K Agilent SureSelect Target Enrichment) analysis was performed for 6 HBs matched with their non tumoral liver tissues (fresh frozen tissues). Bioinformatic analysis of exome data identified somatic variants in 69 genes which were chosen for validation using a target sequencing panel (SureSelectXT Target Enrichment System for Illumina Paired-End Sequencing Library). The gene panel was composed of the detected 69 genes and other 48 genes related with HB or cancer, and it was used to investigated additional 13 HB samples as a validation group. 60% of the patients were male, and the mean age at diagnosis was 36 months. 13% of this cohort presented pulmonary metastasis. All patients received pre-surgery chemotherapy (SIOPEL and COG protocol). Results: A total of 71 somatic rare coding mutations (missense and loss-of-function) were validated in 53 genes considering the entire HB group. The somatic analysis reveals pathogenic mutations in the CTNNB1 gene and a recurrent missense mutation in the CX3CL1 gene; the role of these mutations was explored by IHQ studies of their proteins as well as by gene expression analysis by RT-PCR. We also used results from Illumina 450k to evaluated the methylation levels of CX3CL1 and CX3CR1 genes. Methylation values for CpG sites in each sample were measured as β-and CpG sites were grouped into categories, promoter (1stExon; 5'UTR; TSS1500; TSS200) or gene body, information provided by Illumina, based on UCSC data (GRhC 37). The methylation level of each category was obtained by averaging the β-values of all CpGs mapped in the category for each gene, followed by Wilcoxon test correction by calculating the false discovery rate (FDR). Conclusion: Most investigated HBs carry few potentially pathogenic genetic mutations (≤ 5 mutations). This observed low frequency of somatic mutations is a result similar to previous studies. The proposed explanation is based on the fact that pediatric tumors would originate from precursor cells with pluripotent characteristics; therefore, such tumors may require fewer mutations than adult solid tumors to develop. The congenital HB case of our cohort is discrepant from this scenario since a relatively high number of somatic mutations were found compared to the HB group. To our knowledge, this is the first comprehensive genomic characterization of Brazilian HBs. Next steps include expanding the casuistry of exome sequenced tumors, including two cases of HB associated with Hirschprung disease. Grants: FAPESP (2016/04785-0; 2017/11212-0), FAPESP (2013/08028-1), CNPq (141625/2016-3). Citation Format: Talita F. Aguiar, Tatiane Rodrigues, Maria Prates, Fernanda Aparecida dos Santos, Gustavo Fernandes, Cecília Maria Lima da Costa, Isabela Werneck da Cunha, Monica Cypriano, Silvia Regina Caminada de Toledo, Jorge Estefano S. de Souza, Eugênia Valadares, Raquel Borges, Vicente Odone, Israel Tojal, Dirce Carraro, Carla Rosenberg, Ana C.V. Krepischi. Genomic studies of Brazilian patients with hepatoblastoma: Insight into somatic mutations using whole-exome sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2072.

Hepatoblastomas (HB) are embryonal tumors of the liver with histologic features that resemble different stages of liver differentiation. Molecular data on HB tumorigenesis are still scarce because of its rarity. The identification of molecular pathways involved in HB development can expand the understanding of the connections between disruption of normal differentiation and cancer. Exome sequencing is a powerful tool to identify somatic mutations in tumors, possibly related to cancer development. We performed a whole-exome sequencing in a discovery cohort of 6 HBs and their paired non-tumoral adjacent liver tissues (capture method 244K Agilent SureSelect Target Enrichment). Bioinformatic analysis of the exome data identified 76 rare somatic variants in coding sequences of 69 genes, which were validated using a target sequencing panel covering the affected genes (SureSelectXT Target Enrichment System for Illumina Paired-End Sequencing Library). These 69 genes and other 48 genes related with HB or cancer were also investigated, in addition to 13 HBs as a validation group. A total of 64 rare somatic mutations in 53 genes were validated in all hepatoblastomas. Four different pathogenic mutations in the CTNNB1 gene were disclosed in five tumors. Immunohistochemistry analysis of β-catenin was carried out in eight of the sequenced tumors as well as in a tissue microarray consisting of 19 novel hepatoblastomas cases. The constitutive activity of Wnt-β-catenin pathway, which is caused by the gain-of-function mutations of CTNNB1, was confirmed by the study of protein expression, which shows the accumulation of β-catenin in the nucleus. In addition, CX3CL1 gene was found to be somatically mutated in two different tumors; however, CX3CL1 gene expression was not altered in mutated tumors. We are currently investigating the possible role of CX3CL1 and its receptor (CX3CR1) in hepatoblastomas. Our data highlighted a relatively stable tumoral genome in this type of pediatric liver tumors, which present a small number of potentially pathogenic mutations, a feature that is also a hallmark of adult liver cancer. Grants: FAPESP (2016/04785-0), FAPESP (2013/08028-1), CNPq (141625/2016-3). Citation Format: Talita Aguiar, Tatiane Rodrigues, Cecília Maria Lima da Costa, Isabela Werneck, Monica Cypriano, Silvia Regina Caminada de Toledo, Jorge Estefano Santana de Souza, Israel Tojal, Dirce M Carraro, Carla Rosenberg, Ana Krepischi. Insights into the somatic mutation burden of hepatoblastomas using whole exome sequencing [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A18.

Os tumores malignos hepáticos são raros nas crianças, sendo o tumor embrionário hepatoblastoma a neoplasia hepática mais comum em crianças abaixo dos 5 anos e, ainda assim, responsável por apenas 1% dos tumores incidentes nessa faixa etária. Devido, entre outros fatores, à sua baixa incidência, o hepatoblastoma é um tumor ainda pouco caracterizado a nível molecular. O presente trabalho contemplou três frentes de análises moleculares em hepatoblastomas: análise de alterações em número de cópias (através da técnica array-CGH), investigação de mutações somáticas em regiões codificadoras (sequenciamento de exoma por next-generation) e delineamento de perfil global de metilação de DNA (beadarrays). Encontramos um baixo número de alterações em número de cópias, na maioria ganhos de grande extensão cromossômica, evidenciando uma baixa instabilidade cromossômica em comparação ao encontrado em outros tumores sólidos de adultos. Uma região em 2q24 previamente associada a um pior prognóstico em hepatoblastomas foi encontrada como ganho de alta amplitude (amplicon). A análise de expressão gênica na área destacou 5 dos 48 genes como super-expressos em nossas amostras de hepatoblastomas (DAPL1, ERMN, GALNT5, SCN1A e SCN3A). Foi observada também uma baixa ocorrência de mutações somáticas não-sinônimas, quando comparada à magnitude de variações encontradas em outros tumores sólidos de adultos. Descrevemos uma nova mutação não-sinônima danosa no exon 3 do gene CTNNB1 (beta-catenina), marcador molecular de destaque em hepatoblastomas, que provavelmente desenvolve um papel importante na tumorigênese deste tipo de neoplasia. Dentre a lista de alterações somáticas encontradas, cabe destacar o enriquecimento da via Wnt, via da beta-catenina, já bem estudada em hepatoblastomas e que apresenta correlação tanto com desenvolvimento embrionário como com o processo de carcinogênese. Destacamos uma lista de mutações somáticas não-sinônimas presentes com boa cobertura em nossos experimentos, e ausentes ou presentes em baixa frequência (< 1%) na população. O presente estudo é o pioneiro na análise de alterações globais no padrão de metilação de citosinas em hepatoblastomas, e revelou um padrão incomum de hipometilação global nos tumores, não associado à metilação de regiões repetitivas LINE-1; especificamente, hepatobastomas apresentam um nível intermediário entre o encontrado para os fígados maduros e aquele encontrado para os fígados fetais. Tal achado dá suporte ao modelo no qual a tumorigênese do hepatoblastoma recapitularia fases do desenvolvimento fetal do fígado. Foram destacados 11 genes que apresentaram padrão de metilação de DNA diferencial em seus promotores. Em suma, nossos achados revelam que o tumor embrionário hepatoblastoma apresenta relativa estabilidade genética, com uma frequência menor de alterações (alterações em número de cópias e mutações somáticas em regiões codificadoras) que tumores sólidos de adultos. Simultaneamente, foi detectado um padrão marcante de hipometilação global de DNA associado ao tumor, evidenciando a importância de aspectos epigenéticos em sua tumorigênese Hepatic malignant tumors are rare in children, the embryonal tumor hepatoblastoma is the most common liver cancer in children under 5 years old but, in spite of that, accounts for only 1% of incident tumors in this age group. Due to its low incidence, among other factors, hepatoblastoma is a tumor poorly characterized at molecular level. This study included three approaches of molecular analyzes in hepatoblastomas: examination of copy number alterations (through array-CGH technique), investigation of somatic mutations in coding regions (next-generation exome sequencing) and determination of the global DNA methylation profile (bead arrays). We found a low frequency of copy number alterations, mostly consisting of large extent chromosomal gains, reflecting lower chromosomal instability than other solid adult tumors. A region at 2q24, previously associated with worse prognosis in hepatoblastomas, was found amplified in high amplitude (amplicon). Gene expression analysis of the 48 genes comprised in the amplicon segment highlighted five genes as overexpressed (DAPL1, ERMN, GALNT5, SCN1A and SCN3A). We also observed a low frequency of non-synonymous somatic mutations in our hepatoblastomas samples compared to the amount of variation found in other adult solid tumors. We described a predicted harmful non-synonymous mutation in exon 3 of CTNNB1 gene (beta-catenin), the best characterized molecular marker in hepatoblastomas. The list of somatic alterations points to a remarkable enrichment of genes from the Wnt pathway, which is well-studied in hepatoblastomas and is associated both with embryonic development and with the process of carcinogenesis. We highlighted a list of non-synonymous somatic mutations that presented high coverage in our experiments, and were absent or present at low frequency (

BackgroundThe etiology of prenatal-onset short stature with postnatal persistence is heterogeneous. Submicroscopic chromosomal imbalances, known as copy number variants (CNVs), may play a role in growth disorders.ObjectiveTo analyze the CNVs present in a group of patients born small for gestational age (SGA) without a known cause.Patients and methodsA total of 51 patients with prenatal and postnatal growth retardation associated with dysmorphic features and/or developmental delay, but without criteria for the diagnosis of known syndromes, were selected. Array-based comparative genomic hybridization was performed using DNA obtained from all patients. The pathogenicity of CNVs was assessed by considering the following criteria: inheritance; gene content; overlap with genomic coordinates for a known genomic imbalance syndrome; and overlap with CNVs previously identified in other patients with prenatal-onset short stature.ResultsIn 17 of the 51 patients, 18 CNVs were identified. None of these imbalances has been reported in healthy individuals. Nine CNVs, found in eight patients (16%), were categorized as pathogenic or probably pathogenic. Deletions found in three patients overlapped with known microdeletion syndromes (4q, 10q26, and 22q11.2). These imbalances are de novo, gene rich and affect several candidate genes or genomic regions that may be involved in the mechanisms of growth regulation.ConclusionPathogenic CNVs in the selected patients born SGA were common (at least 16%), showing that rare CNVs are probably among the genetic causes of short stature in SGA patients and revealing genomic regions possibly implicated in this condition.

Studies in mice demonstrated that the Shh gene is crucial for normal development of both incisors and molars, causing a severe retardation in tooth growth, which leads to abnormal placement of the tooth in the jaw and disrupted tooth morphogenesis. In humans the SHH gene is located on chromosome 7q36. Defects in its protein or signaling pathway may cause holoprosencephaly spectrum, a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres and that can be manifested in microforms such as single maxillary central incisor. A novel role for this gene in the developing human primary dentition was recently demonstrated. We report a 12-year old boy with a de novo 7q36.1-qter deletion characterized by high-resolution karyotyping, oligonucleotide aCGH and FISH. His phenotype includes intellectual disability, non-verbal communication, hypospadia, partial sacral agenesis and absence of coccyx, which are distinctive features of the syndrome and mainly correlated with the MNX1, HTR5A and EN2 genes. No microforms of holoprosencephaly spectrum were observed; but the patient had diastema and dental developmental abnormalities, such as conical, asymmetric and tapered inferior central incisors. The dental anomalies are reported herein for the first time in subtelomeric 7q36 deletion syndrome and may confirm clinically a novel role for the SHH gene in dental development., Highlights • We report a boy with 7q-, dental developmental abnormalities and sacral agenesis. • We propose novel roles for SHH gene related to dental developmental abnormalities. • The MNX1 gene may be associated with caudal deficiency sequence in 7q- patients. • HTR5A and EN2 may be related to abnormal brain development in 7q- patients.

Lymphovascular invasion (LVI) and histologic grade are clinical parameters of high prognostic value in breast cancer and indicate the level of tumor aggressiveness. Many studies have focused on the association of breast cancer subtypes with gene expression and chromosomal profiles, but considerably less genomic information is available regarding traditional prognostic factors such as histologic grade and LVI. We studied by array-CGH a group of 57 invasive ductal carcinomas of the breast to outline the DNA copy number aberration (CNA) profile linked to high histologic grades and LVI. Selected CNAs were validated using real-time quantitative PCR (qPCR). Furthermore, gene expression analysis was performed in a subset of 32 of these tumors, and findings were integrated with array-CGH data. Our findings indicated an accumulation of genomic alterations in high-grade breast tumors compared to low-grade samples. Grade III tumors showed higher number of CNAs and larger aberrations than low-grade tumors and displayed a wide range of chromosomal aberrations, which were mainly 5p, 8q, 10p, 17q12, and 19 gains, and 3p, 4, 5q proximal, 9p, 11p, 18q, and 21 losses. The presence of LVI, a well-established prognostic marker, was not significantly associated with increased genomic instability in comparison to breast tumors negative for LVI, considering the total number of chromosomal alterations. However, a slightly increase in the frequency of specific alterations could be detected in LVI-positive group, such as gains at 5p, 16p, 17q12, and 19, and losses at 8p, 11q, 18q, and 21. Three newly reported small-scale rearrangements were detected in high-risk tumors (LVI-positive grade III) harboring putative breast cancer genes (amplicons at 4q13.3 and 11p11.2, and a deletion at 12p12.3). Furthermore, gene expression analysis uncovered networks highlighting S100A8, MMP1, and MED1 as promising candidate genes involved in high-grade and LVI-positive tumors. In summary, a group of genomic regions could be associated with high-risk tumors, and expression analysis pinpointed candidate genes deserving further investigation. The data has shed some light on the molecular players involved in two highly relevant prognostic factors and may further add to the understanding of the mechanisms of breast cancer aggressiveness. Electronic supplementary material The online version of this article (doi:10.1007/s13277-014-2786-z) contains supplementary material, which is available to authorized users.

ABSTRACT Aim: Cytogenetic data of hepatoblastomas, a rare embryonal tumor of the liver, mostly consist of descriptions of whole-chromosome aneuploidies and large chromosome alterations. High-resolution cytogenetics may provide clues to hepatoblastoma tumorigenesis and indicate markers with clinical significance. Patients & methods: We used array-CGH (180K) to screen for genomic imbalances in nine hepatoblastomas. Additionally, we investigated the expression pattern of selected genes exhibiting copy number changes. Results: Analysis showed mainly whole-chromosome or chromosome-arm aneuploidies, but some focal aberrations were also mapped. Expression analysis of 48 genes mapped at one 10 Mb amplification at 2q24 revealed upregulation of DAPL1, ERMN, GALNT5, SCN1A and SCN3A in the set of tumors compared with differentiated livers. Conclusion: These genes appear as candidates for hepatoblastoma tumorigenesis.

The majority of familial cancer remains with unknown genetic aetiology. Issues impairing the discovery of new genes in complex diseases such as cancer include multifactorial origin, incomplete penetrance of the disease and late-onset. The authors present an outline of the contribution of constitutive deoxyribonucleic acid copy number variations (CNVs) in cancer predisposition. Even though the mechanisms by which germline CNVs influence disease are hitherto largely speculative, nowadays it is consensual that they play a major role in a range of human pathologies. Point mutations have been far more commonly described, mainly because sequencing is the first-tier diagnostic test, but deletions and duplications of known cancer genes have been reported as an alternative mechanism for cancer susceptibility. Additionally, CNV screening in familial cancer cohorts with unknown genetic aetiology has pointed to new candidate genes for high cancer risk. Therefore, this type of genomic variation must be taken into account in the cancer risk assessment. Key Concepts: Structural variation, including copy number variation (CNV), is responsible for a large fraction of the genetic diversity of the human genome. CNVs can be inherited in a Mendelian fashion or occur de novo. Germline CNVs play an important role in a range of human pathologies through several mechanisms, mainly affecting gene dosage or function. Nearly half of the approximately 100 Mendelian cancer predisposition genes were also reported as rare pathogenic germline CNVs. Next-generation sequencing (NGS) combined with automated high throughput data analysis is the most promising approach for elucidating the contribution of both CNVs and point mutations to cancer predisposition. Keywords: structural variation; CNV; cancer predisposition; germline alterations; next-generation sequencing

// Mariana Maschietto 1, * , Tatiane Cristina Rodrigues 2, * , Andre Yoshiaki Kashiwabara 3 , Erica Sara Souza de Araujo 4 , Talita Ferreira Marques Aguiar 4 , Cecilia Maria Lima da Costa 5 , Isabela Werneck da Cunha 6 , Luciana dos Reis Vasques 2 , Monica Cypriano 7 , Helena Brentani 8 , Silvia Regina Caminada de Toledo 7 , Peter Lees Pearson 2 , Dirce Maria Carraro 4 , Carla Rosenberg 2 , Ana C.V. Krepischi 2 1 Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil 2 Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil 3 Universidade Tecnologica Federal do Parana, Campus Cornelio Procopio, Parana, Brazil 4 International Research Center, A. C. Camargo Cancer Center, Sao Paulo, Brazil 5 Department of Pediatric Oncology, A. C. Camargo Cancer Center, Sao Paulo, Brazil 6 Department of Pathology, A. C. Camargo Cancer Center, Sao Paulo, Brazil 7 Department of Pediatrics, Pediatric Oncology Institute (GRAACC), Federal University of Sao Paulo, Sao Paulo, Brazil 8 Department of Psychiatry, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil * These authors have contributed equally to this work Correspondence to: Ana C.V. Krepischi, email: ana.krepischi@ib.usp.br Keywords: DNA methylation; embryonal tumor; hypomethylation; cell differentiation arrest; hepatoblastoma Received: March 08, 2016 Accepted: December 05, 2016 Published: December 25, 2016 ABSTRACT Hepatoblastomas are uncommon embryonal liver tumors accounting for approximately 80% of childhood hepatic cancer. We hypothesized that epigenetic changes, including DNA methylation, could be relevant to hepatoblastoma onset. The methylomes of eight matched hepatoblastomas and non-tumoral liver tissues were characterized, and data were validated in an independent group (11 hepatoblastomas). In comparison to differentiated livers, hepatoblastomas exhibited a widespread and non-stochastic pattern of global low-level hypomethylation. The analysis revealed 1,359 differentially methylated CpG sites (DMSs) between hepatoblastomas and control livers, which are associated with 765 genes. Hypomethylation was detected in hepatoblastomas for ~58% of the DMSs with enrichment at intergenic sites, and most of the hypermethylated CpGs were located in CpG islands. Functional analyses revealed enrichment in signaling pathways involved in metabolism, negative regulation of cell differentiation, liver development, cancer, and Wnt signaling pathway. Strikingly, an important overlap was observed between the 1,359 DMSs and the CpG sites reported to exhibit methylation changes through liver development (p

The 6p terminal deletions are rare and present variability of clinical features, which increases the importance of reporting additional cases in order to better characterize genotype-phenotype correlations. We report a 12-year-old girl with a de novo deletion in 6p25.1-pter characterized by high-resolution karyotyping and FISH. Further analysis using oligonucleotide array-CGH revealed a 5.06 Mb 6p25.1-pter deletion associated with a contiguous 1 Mb 6p25.1 duplication. The patient presented normal growth, developmental delay, frontal bossing, severe hypertelorism, corectopia, wide and depressed nasal bridge, mild learning disability, hearing loss and diffuse leukopathy. Additionaly, she presented peculiar phenotypic features reported herein for the first time in 6p25 deletion syndrome: cerebrospinal fluid fistula and bones resembling those seen in 3-M syndrome. The distinctive phenotype of the 6p25 deletion syndrome has been mainly correlated with the FOXC1 and FOXF2 genes deletions, both related mainly to eye development. We also consider the SERPINB6 as a candidate for sensorineural hearing loss and TUBB2A as a candidate for our patient's skeletal features. In addition, as our patient had a duplication including NRN1, a gene related with neurodevelopment, synaptic plasticity and cognitive dysfunction in schizophrenia, we suggest that this gene could be associated with her white matter abnormalities and neurocognitive phenotype.

We describe a novel chromosome microdeletion at 15q26.1 detected by oligo-array-CGH in a 6-year-old girl presenting with global development delay, epilepsy, autistic behavior and facial dysmorphisms. Although these features are often present in Angelman syndrome, no alterations were present in the methylation pattern of the Prader-Willi-Angelman critical region. The deletion encompasses only 2 genes: CHD2, which is part of a gene family already involved in CHARGE syndrome, and RGMA which exerts a negative control on axon growth. Deletion of either or both genes could cause the phenotype of this patient. These results provide a further chromosome region requiring evaluation in patients presenting Angelman features.

Background: Melanoma is a highly aggressive skin cancer; approximately 10% of melanomas are caused by germline mutations, mainly affecting the p16 isoform of the CDKN2A gene (responsible for up to 40% of the familial melanoma). Although other genes exhibiting moderate to high penetrant mutations have been recently associated with melanoma susceptibility, such as CDK4, PALB2, MITF, and TERT promoter, the majority of the melanoma susceptibility remains without a clear genetic etiology. Copy number variations (CNVs) are a common class of structural variants of the human genome, mainly impacting genes that mediate the interaction with environment. However, many rare germline CNVs have been causally associated with diseases, including mental impairment and cancer predisposition. Objective: Aiming to identify new genes potentially related to melanoma predisposition, 34 melanoma-prone patients negative for CDKN2A/CDK4 mutations were investigated for rare germline CNVs. Material and Methods: Patients - patients were ascertained at the A. C. Camargo Cancer Center, Sao Paulo, Brazil; signed informed consents were obtained from all patients. DNA samples from peripheral blood were extracted from 34 unrelated probands fulfilling either the classical criteria for familial melanoma syndrome or based on evidence of a strong genetic predisposition (occurrence of ≥2 primary melanomas). These patients had been previously tested negative for CDKN2A and CDK4 genes. Methods - we performed evaluation of germline CNVs using the CytoSNP-850K (Illumina), analyzing data in the BlueFuse Multi Software v3.2. Selected CNVs were validated by real-time quantitative PCR (qPCR). Results: Among the 34 patients, we detected rare CNVs in 9 of them, mainly large duplications (>230kb) at 4q26-q27, 6p22.1, 8q23.1, 9p24.2, 10q22.3, 12p12.3 and 20p12.1, and deletions affecting 6p24.3 and 19p13.3. Four of these changes in DNA copy number were validated by qPCR using probes for genes mapped within affected regions (ANXA11, ESF1, MGST1 and ANGPT1 genes). Conclusion: We found 26% of the melanoma-prone patients carrying rare germline CNVs that encompass genes potentially associated with melanoma predisposition. Our data suggest that melanoma susceptibility could be originated by a broad spectrum of no recurrent genomic alterations, and part of the genetic etiology of the hereditary melanoma might reside in rare germline copy number changes. In addition to the well-known melanoma genes, germline CNVs, here reported, disclosed other candidate genes to melanoma predisposition deserving further investigation. Funding: This work was supported by grants from FAPESP (2012/21932-6) and the Brazilian National Institute of Science and Technology in Oncogenomics (FAPESP 2008/57887-9, CNPq 573589/08-9). Citation Format: Felipe Fidalgo, Tatiane Rodrigues, Amanda Gonçalves Silva, Luciana Facure, Amanda Nóbrega, Bianca Sá, João Pereira Duprat, Maria Isabel Achatz, Carla Rosenberg, Dirce Maria Carraro, Ana Cristina Krepischi. Rare germline copy number variations in hereditary cutaneous melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3418. doi:10.1158/1538-7445.AM2014-3418

Prostate cancer is the most common cancer in males and, despite its high incidence, only limited data are available on which genes or chromosome regions are specifically involved in its initiation and progression. We studied 72 prostate tumor samples by array-CGH, using a platform containing 60.000 oligonucleotides spread over the whole genome (60K Agilent Technologies). No chromosome alterations (CNA) were detected in 13 samples. The array-CGH profiles of the remaining samples showed losses at 8p and gains on 8q, often with narrow peaks of amplification, in ∼50% of the tumors. Additionally, losses at 6q, 13q and 16q were observed in ∼25% of the samples. Although these results are in general agreement with the location of alterations described earlier, the altered chromosome segments are often several megabases long. Mapping of minimum regions altered in several tumors, or pronounced copy number changes in smaller segments, permits a more precise definition of the relevant chromosome regions that are relevant for tumor development and progression. Current prognostic variables include prostatic specific antigen (PSA), the pathologically defined Gleason score (GS) and T-category (of the TNM staging). There is a great heterogeneity within the intermediate risk group and further genetic markers are needed to refine disease diagnosis and prognosis. So, we analyzed the copy number alteration signatures for the intermediate risk group, Gleason 7. In the comparison between samples related as GS 6 versus GS 7, we found that losses on 5q21.1 and gains on 7q11.21 are more frequent in GS 7. In other hand, losses on 22q13.33 are more frequent in GS 7 than in GS 8 and 9, while losses on 6q21 and 18q21 are correlated with GS 8 and 9. Additionally, we have medical follow-up of only 46 of the 72 samples. Fifteen of these patients had present recurrence after treatment. We analyzed this group versus the group with no recurrence. Losses at 2p21, 6q12, 7q36.3 and 16q13 are more frequent in the group of patients in which there is recurrence of the tumor. This suggests that these alterations could also be hallmarks for recurrence. Further studies with array-CGH of prostate tumors samples will ultimately lead to defining much smaller regions of overlap than at present, which in turn will indicate which specific individual genes and/or combinations of genes are the real “drivers” in prostate cancer or could act as hallmarks for prognosis and recurrence. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1168. doi:1538-7445.AM2012-1168