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Association of a PARK2 Germline Variant and Epithelial Ovarian Cancer in a Southern Brazilian Population.

ABSTRACT: Ovarian cancer (OC) is the eighth most common cancer among women in Brazil and seventh in the world population. OC has a high mortality rate and is difficult to diagnose. Currently, OC detection most often occurs at an advanced stage of the disease due to its silent progression, which contributes to the high mortality rate. Available genetic markers are not considered specifically enough for an initial and definite diagnosis. The association with new genes involved with OC can provide a better understanding of this pathology as well as contribute to the development of a marker scenario, providing an improvement in the treatment and survival of patients. The aim of this study was to examine the potential association between the PARK2 gene and epithelial ovarian cancer (EOC). Accordingly, we conducted a study for which 25 patients and 87 controls were recruited. Linkage disequilibrium analysis showed that the four studied tag SNPs (rs2803073, rs6930532, rs1040079, and rs2276201) were independent. Our results using the multivariate analysis between the additive and dominant model demonstrated that tag SNP rs2803073 of PARK2 is associated with susceptibility to EOC (p = 0.018, OR = 0.42). These findings suggest that hereditary variation in the PARK2 gene could influence EOC development mechanisms.

SUBMITTER: Klimczak PF

PROVIDER: S-EPMC4982793 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Association of a PARK2 Germline Variant and Epithelial Ovarian Cancer in a Southern Brazilian Population.

Klimczak Phamela Ferreira PF Ventury Danielle Hornung DH Faucz Fabio Rueda FR Settas Nikolaos N Machado de Souza Cleber C Sotomaior Vanessa Santos VS

Oncology 20160610 2

Ovarian cancer (OC) is the eighth most common cancer among women in Brazil and seventh in the world population. OC has a high mortality rate and is difficult to diagnose. Currently, OC detection most often occurs at an advanced stage of the disease due to its silent progression, which contributes to the high mortality rate. Available genetic markers are not considered specifically enough for an initial and definite diagnosis. The association with new genes involved with OC can provide a better u ...[more]

PMID: 27286703

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Project description:BackgroundApproximately 3/4 of ovarian cancers are diagnosed in advanced stages, with the high-grade epithelial ovarian carcinoma (EOC) accounting for 90% of the cases. EOC present high genomic instability and somatic loss-of-function variants in genes associated with homologous recombination mutational repair pathway (HR), such as BRCA1 and BRCA2, and in TP53. The identification of germline variants in HR genes in EOC is relevant for treatment of platinum resistant tumors and relapsed tumors with therapies based in synthetic lethality such as PARP inhibitors. Patients with somatic variants in HR genes may also benefit from these therapies. In this work was analyzed the frequency of somatic variants in BRCA1, BRCA2, and TP53 in an EOC cohort of Brazilian patients, estimating the proportion of variants in tumoral tissue and their association with progression-free survival and overall survival.MethodsThe study was conducted with paired blood/tumor samples from 56 patients. Germline and tumoral sequences of BRCA1, BRCA2, and TP53 were obtained by massive parallel sequencing. The HaplotypeCaller method was used for calling germline variants, and somatic variants were called with Mutect2.ResultsA total of 26 germline variants were found, and seven patients presented germline pathogenic or likely pathogenic variants in BRCA1 or BRCA2. The analysis of tumoral tissue identified 52 somatic variants in 41 patients, being 43 somatic variants affecting or likely affecting protein functionality. Survival analyses showed that tumor staging was associated with overall survival (OS), while the presence of somatic mutation in TP53 was not associated with OS or progression-free survival.ConclusionFrequency of pathogenic or likely pathogenic germline variants in BRCA1 and BRCA2 (12.5%) was lower in comparison with other studies. TP53 was the most altered gene in tumors, with 62.5% presenting likely non-functional or non-functional somatic variants, while eight 14.2% presented likely non-functional or non-functional somatic variants in BRCA1 or BRCA2.

Project description:PurposeTo provide recommendations on genetic and tumor testing for women diagnosed with epithelial ovarian cancer based on available evidence and expert consensus.MethodsA literature search and prospectively defined study selection criteria sought systematic reviews, meta-analyses, randomized controlled trials (RCTs), and comparative observational studies published from 2007 through 2019. Guideline recommendations were based on the review of the evidence.ResultsThe systematic review identified 19 eligible studies. The evidence consisted of systematic reviews of observational data, consensus guidelines, and RCTs.RecommendationsAll women diagnosed with epithelial ovarian cancer should have germline genetic testing for BRCA1/2 and other ovarian cancer susceptibility genes. In women who do not carry a germline pathogenic or likely pathogenic BRCA1/2 variant, somatic tumor testing for BRCA1/2 pathogenic or likely pathogenic variants should be performed. Women with identified germline or somatic pathogenic or likely pathogenic variants in BRCA1/2 genes should be offered treatments that are US Food and Drug Administration (FDA) approved in the upfront and the recurrent setting. Women diagnosed with clear cell, endometrioid, or mucinous ovarian cancer should be offered somatic tumor testing for mismatch repair deficiency (dMMR). Women with identified dMMR should be offered FDA-approved treatment based on these results. Genetic evaluations should be conducted in conjunction with health care providers familiar with the diagnosis and management of hereditary cancer. First- or second-degree blood relatives of a patient with ovarian cancer with a known germline pathogenic cancer susceptibility gene variant should be offered individualized genetic risk evaluation, counseling, and genetic testing. Clinical decision making should not be made based on a variant of uncertain significance. Women with epithelial ovarian cancer should have testing at the time of diagnosis.

Project description:Polymorphisms in microRNA (miR) genes and their target sites are a distinct classification of variation in the human genome, which are rapidly being identified and investigated in human cancer. A polymorphism in the miR-196a-2 locus has demonstrated significant associations with various types of cancer, including lung, breast, esophageal and gastric tumors. However, miR-196a-2 has not been fully explored in ovarian cancer, which shares similar biological characteristics with other types of cancer. Therefore, the present study aimed to elucidate the association between a single nucleotide polymorphism (SNP) in the mature sequence of miR-196a-2 (rs11614913, T/C) and the clinical features of 479 Chinese patients with epithelial ovarian cancer (EOC). In addition, the biological significance of this polymorphism was investigated in the OVCAR3 ovarian cancer cell line. Risk association was evaluated in 479 cases of EOC patients and 431 controls. SNPs were analyzed by using polymerase chain reaction based restriction fragment length polymorphism assay. miR-196a expression was evaluated with reverse transcription polymerase chain reaction. The influence of miR-196a-2 rs11614913 T/C on EOC cell migration and invasion ability was further investigated in vitro. The results revealed significant differences in the homozygous CC genotype distribution in patients with EOC (n=479), compared with that of the control subjects (n=431; P=0.026). Analysis of the association between genotype and the risk of EOC revealed that individuals who carried the homozygous CC genotype were 1.34-fold more susceptible to EOC, compared with those carrying the wild-type TT and heterozygous CT genotypes [odds ratio, 1.34; 95% confidence interval, 1.04-2.17; P=0.023]. In addition, the role of this polymorphism in the production of mature miR-196a was investigated. Significantly enhanced production of mature miR-196a was revealed in the C-allelic compared with that of the T-allelic miR-196a-2 precursor (P<0.05). Further examination indicated that miR-196a significantly promoted cell migration and invasion ability in the human OVCAR3 ovarian cell line (P<0.05). In conclusion, the results indicated that the miR-196a-2 rs11614913 CC genotype may increase the risks of ovarian cancer by affecting the expression of mature miR-196a and enhancing cell migration/invasion. The current results provided evidence that the T>C polymorphism in the miR-196a-2 precursor may influence tumorigenesis and metastasis in EOC, and suggested that the functional SNP rs11614913 in the promoter region of pri-miR-196a-2 may be a potential indicator of EOC susceptibility in the population analyzed.

Project description:BACKGROUND:Recent studies have identified several single nucleotide polymorphisms (SNPs) in the population that are associated with variations in the risks of many different diseases including cancers such as breast, prostate and colorectal. For ovarian cancer, the known highly penetrant susceptibility genes (BRCA1 and BRCA2) are probably responsible for only 40% of the excess familial ovarian cancer risks, suggesting that other susceptibility genes of lower penetrance exist. METHODS:We have taken a candidate approach to identifying moderate risk susceptibility alleles for ovarian cancer. To date, we have genotyped 340 SNPs from 94 candidate genes or regions, in up to 1,491 invasive epithelial ovarian cancer cases and 3,145 unaffected controls from three different population based studies from the UK, Denmark and USA. RESULTS:After adjusting for population stratification by genomic control, 18 SNPs (5.3%) were significant at the 5% level, and 5 SNPs (1.5%) were significant at the 1% level. The most significant association was for the SNP rs2107425, located on chromosome 11p15.5, which has previously been identified as a susceptibility allele for breast cancer from a genome wide association study (P-trend = 0.0012). When SNPs/genes were stratified into 7 different pathways or groups of validation SNPs, the breast cancer associated SNPs were the only group of SNPs that were significantly associated with ovarian cancer risk (P-heterogeneity = 0.0003; P-trend = 0.0028; adjusted (for population stratification) P-trend = 0.006). We did not find statistically significant associations when the combined data for all SNPs were analysed using an admixture maximum likelihood (AML) experiment-wise test for association (P-heterogeneity = 0.051; P-trend = 0.068). CONCLUSION:These data suggest that a proportion of the SNPs we evaluated were associated with ovarian cancer risk, but that the effect sizes were too small to detect associations with individual SNPs.

Project description:BackgroundThe Hereditary Breast and Ovarian Cancer Syndrome (HBOC) occurs in families with a history of breast/ovarian cancer, presenting an autosomal dominant inheritance pattern. BRCA1 and BRCA2 are high penetrance genes associated with an increased risk of up to 20-fold for breast and ovarian cancer. However, only 20-30% of HBOC cases present pathogenic variants in those genes, and other DNA repair genes have emerged as increasing the risk for HBOC. In Brazil, variants in ATM, ATR, CHEK2, MLH1, MSH2, MSH6, POLQ, PTEN, and TP53 genes have been reported in up to 7.35% of the studied cases. Here we screened and characterized variants in 21 DNA repair genes in HBOC patients.MethodsWe systematically analyzed 708 amplicons encompassing the coding and flanking regions of 21 genes related to DNA repair pathways (ABRAXAS1, ATM, ATR, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MRE11, MSH2, MSH6, NBN, PALB2, PMS2, PTEN, RAD50, RAD51, TP53 and UIMC1). A total of 95 individuals with HBOC syndrome clinical suspicion in Southeast Brazil were sequenced, and 25 samples were evaluated for insertions/deletions in BRCA1/BRCA2 genes. Identified variants were assessed in terms of population allele frequency and their functional effects were predicted through in silico algorithms.ResultsWe identified 80 variants in 19 genes. About 23.4% of the patients presented pathogenic variants in BRCA1, BRCA2 and TP53, a frequency higher than that identified among previous studies in Brazil. We identified a novel variant in ATR, which was predicted as pathogenic by in silico tools. The association analysis revealed 13 missense variants in ABRAXAS1, BARD1, BRCA2, CHEK2, CDH1, MLH1, PALB2, and PMS2 genes, as significantly associated with increased risk to HBOC, and the patients carrying those variants did not present large insertions or deletions in BRCA1/BRCA2 genes.ConclusionsThis study embodies the third report of a multi-gene analysis in the Brazilian population, and addresses the first report of many germline variants associated with HBOC in Brazil. Although further functional analyses are necessary to better characterize the contribution of those variants to the phenotype, these findings would improve the risk estimation and clinical follow-up of patients with HBOC clinical suspicion.

Dataset Information

Association of a PARK2 Germline Variant and Epithelial Ovarian Cancer in a Southern Brazilian Population.

Publications

Association of a PARK2 Germline Variant and Epithelial Ovarian Cancer in a Southern Brazilian Population.

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