scholarly journals Cis-Acting Factors Causing Secondary Epimutations: Impact on the Risk for Cancer and Other Diseases

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4807
Author(s):  
Miguel Ruiz de la Cruz ◽  
Aldo Hugo de la Cruz Montoya ◽  
Ernesto Arturo Rojas Jiménez ◽  
Héctor Martínez Gregorio ◽  
Clara Estela Díaz Velásquez ◽  
...  

Epigenetics affects gene expression and contributes to disease development by alterations known as epimutations. Hypermethylation that results in transcriptional silencing of tumor suppressor genes has been described in patients with hereditary cancers and without pathogenic variants in the coding region of cancer susceptibility genes. Although somatic promoter hypermethylation of these genes can occur in later stages of the carcinogenic process, constitutional methylation can be a crucial event during the first steps of tumorigenesis, accelerating tumor development. Primary epimutations originate independently of changes in the DNA sequence, while secondary epimutations are a consequence of a mutation in a cis or trans-acting factor. Secondary epimutations have a genetic basis in cis of the promoter regions of genes involved in familial cancers. This highlights epimutations as a novel carcinogenic mechanism whose contribution to human diseases is underestimated by the scarcity of the variants described. In this review, we provide an overview of secondary epimutations and present evidence of their impact on cancer. We propose the necessity for genetic screening of loci associated with secondary epimutations in familial cancer as part of prevention programs to improve molecular diagnosis, secondary prevention, and reduce the mortality of these diseases.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kristoffer von Stedingk ◽  
Karl-Johan Stjernfelt ◽  
Anders Kvist ◽  
Cecilia Wahlström ◽  
Ulf Kristoffersson ◽  
...  

AbstractUp to 10% of pediatric cancer patients harbor pathogenic germline variants in one or more cancer susceptibility genes. A recent study from the US reported pathogenic variants in 22 out of 60 analyzed autosomal dominant cancer susceptibility genes, implicating 8.5% of pediatric cancer patients. Here we aimed to assess the prevalence of germline pathogenic variants in these 22 genes in a population-based Swedish cohort and to compare the results to those described in other populations. We found pathogenic variants in 10 of the 22 genes covering 3.8% of these patients. The prevalence of TP53 mutations was significantly lower than described in previous studies, which can largely be attributed to differences in tumor diagnosis distributions across the three cohorts. Matched family history for relatives allowed assessment of familial cancer incidence, however, no significant difference in cancer incidence was found in families of children carrying pathogenic variants compared to those who did not.


Author(s):  
Thanh Thi Ngoc Nguyen ◽  
Giau Thi Ngoc Mai ◽  
Hue Thi Nguyen

Breast cancer is the most common cancer for women around the world. The presence of single nucleotide polymorphisms (SNP) on or near the coding region of breast cancer susceptibility genes can affect the regulation of gene expression, which may increase or decrease the risk of breast cancer. BARX2 was showed to stimulate the expression of ERS1, which involved in the development of breast cancer. SNP rs7107217 on 152kb downstream of the BARX2 could affect the level of protein BARX2 and had been proved to associate with the breast cancer risk in populations similar to Vietnamese, including Chinese and Korean. In this study, rs7107217 was genotyped and initially detemined the association with the breast cancer risk in Vietnamese. Real-time PCR HRM was optimized and used to genotype rs7107217 in 117 breast cancer cases and 105 healthy controls. Thereafter, the correlation of this SNP with the risk of breast cancer was initially determined by analyzing the differences in allelic and genotypic frequencies between cases and control groups. The results showed the optimal rs7107217 genotyping condition was successfully developed with the high sensitivity, specificity, and consistency. SNP rs7107217 had high polymorphism with the frequency of minor allele C of 29.9% and 35.3% in case and control, respectively. SNP rs7107217 had been found no association with the breast cancer risk (C vs A: P = 0.23, OR (95% CI) = 0.79 (0.53 – 1.17)). However with the low reliability of the analysis (11.71%) and the high potential related to the formation of breast cancer, the association between rs7107217 and breast cancer risk in Vietnamese population should be further conducted on a larger sample size to get higher accuracy.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 4118-4118
Author(s):  
Pedro Luiz Serrano Uson Junior ◽  
Douglas Riegert-Johnson ◽  
Lisa A. Boardman ◽  
Mitesh J. Borad ◽  
Daniel H. Ahn ◽  
...  

4118 Background: Germline variations in cancer susceptibility genes have important implications on treatment and family counseling in pancreatic cancer (PC). We report the prevalence and clinical outcomes of unselected PC patients with pathogenic germline variants (PGV) detected using a universal testing approach. Methods: We undertook a prospective multi-site study of germline sequencing using an >80 gene next-generation sequencing platform among 250 PC patients (not selected for age or family cancer history) between April 1, 2018 and March 31, 2020. Demographic, tumor characteristics and clinical outcomes were compared between PGV carriers and non-carriers. Results: Of 250 patients, the mean age was 65 years (SD 8.7), 56% were male, 83.6% were white and 65.6% had advanced disease (Stage III and IV). PGV were found in 15.2% (N=38) of patients, two patients had more than one PGV. Variants of uncertain significance were found in 44.4% (N=111). Family history of cancer (OR 2.36, 95% CI: 1.14-5.19, p=0.025) was associated with a higher risk of PGV. In a median follow up of 16.5 months, median overall survival was 16.8 months in PGV carriers compared with 16.5 months in non-carriers (HR 0.51, 95 %CI, 0.25-1.01, p=0.05). Higher levels of CA 19-9 and advanced stages (III and IV) were associated with worse outcomes in both groups. Overall, 68% of PGV carriers had mutations in homologous recombination repair (HRR) genes, including BRCA1, BRCA2, PALB2, ATM, CHEK2, NBN, RAD51C. In 65% of HRR gene carrier’s systemic therapy with platinum was used. Conclusions: Universal multi-gene panel testing in pancreatic cancer reveals that 1 in 6 patients are carriers of PGV and is associated with improved survival. Multi-gene germline testing should be used to aid in treatment selection, prognostication, and familial cancer counseling. Distribution of the 40 PGV by penetrance status.[Table: see text]


JAMA ◽  
2020 ◽  
Vol 323 (10) ◽  
pp. 995 ◽  
Author(s):  
Allison W. Kurian ◽  
Ryan Bernhisel ◽  
Katie Larson ◽  
Jennifer L. Caswell-Jin ◽  
Aladdin H. Shadyab ◽  
...  

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e13113-e13113
Author(s):  
Howard John Lim ◽  
Kasmintan A Schrader ◽  
Sean Young ◽  
Jessica Nelson ◽  
Alexandra Fok ◽  
...  

e13113 Background: The Personalized OncoGenomics (POG) project at the BC Cancer Agency utilizes tumor-normal whole genome sequencing (WGS) to understand key driver pathways and guide personalized treatment decisions. Analysis of the germline data can reveal variants; these may be presumed pathogenic, presumed benign or of unknown significance (VUS). We have developed a process for evaluating and returning presumed pathogenic variants in known cancer susceptibility genes to patients, for counseling and validation in a clinical-accredited laboratory. Methods: Patients receive germline cancer related information as part of the consent process for participation in the POG program. A sub-committee comprised of medical geneticists, bioinformaticians, pathologists, oncologists and an ethicist review the germline results. Any variants suspicious of being an artifact undergo a technical validation step. Presumed pathogenic findings of known cancer susceptibility genes are returned to the patient by their treating oncologist and patients are referred to the Hereditary Cancer Program (HCP), for genetic counseling and clinical confirmation. Results: From June 2012 - January 2017 – 466 patients have consented to the project. To date, 39 cases (8.4%) had at least one variant that was deemed pathogenic, 86 cases had at least one VUS in a known cancer susceptibility gene. 11 out of 23 cases (47.8%) with high penetrance mutations were already known to HCP. All VUS were reviewed by the sub-committee taking in to consideration the VUS and clinical context. 8 of the subjects with pathogenic results and 3 with VUS were known to HCP before POG data was generated. A VUS in 7 cases (1.5%) was returned after review. Conclusions: The number of pathogenic variants in known cancer susceptibility genes is consistent with published oncology results. We created a process to manage clinically relevant germline findings discovered during the course of genomic research to ensure appropriate care for patients. Genetic counseling within HCP and validation of variants in the clinically accredited Cancer Genetics Laboratory enables seamless return of research generated clinically relevant germline results to affected subjects. Clinical trial information: NCT02155621.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. TPS4162-TPS4162
Author(s):  
Matthew B. Yurgelun ◽  
C. Sloane Furniss ◽  
Barbara Kenner ◽  
Alison Klein ◽  
Catherine C. Lafferty ◽  
...  

TPS4162 Background: 4-10% of PDAC patients harbor pathogenic germline variants in cancer susceptibility genes, including APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, and TP53. For families with such pathogenic variants, the greatest potential impact of germline testing is to identify relatives with the same pathogenic variant (cascade testing), thereby providing the opportunity for early detection and cancer interception of PDAC and other associated malignancies. Numerous factors limit cascade testing in real-world practice, including family dynamics, widespread geographic distribution of relatives, access to genetic services, and misconceptions about the importance of germline testing, such that the preventive benefits of cascade testing are often not fully realized. The primary aim of this study is to analyze two alternative strategies for cascade testing in families with inherited PDAC susceptibility. Methods: 1000 individuals (from approximately 200 families) with a confirmed pathogenic germline variant in any of the above genes in a 1st/2nd degree relative and a 1st/2nd degree relative with PDAC will be remotely enrolled through the study website (www.generatestudy.org) and randomized between two different methods of cascade testing (individuals with prior genetic testing will be ineligible): Arm 1 will undergo pre-test genetic education with a pre-recorded video and live interactive session with a genetic counselor via a web-based telemedicine platform (Doxy.me), followed by germline testing through Color Genomics; Arm 2 will undergo germline testing through Color Genomics without dedicated pre-test genetic education. Color Genomics will disclose results to study personnel and directly to participants in both arms. Participants in both arms will have the option of pursuing additional telephone-based genetic counseling through Color Genomics. The primary outcome will be uptake of cascade testing. Secondary outcomes will include participant self-reported genetic knowledge, cancer worry, distress, decisional preparedness, familial communication, and screening uptake, which will be measured via longitudinal surveys. Enrollment will begin February, 2019. Clinical trial information: NCT03762590.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahjerin Nasrin Reza ◽  
Nadim Ferdous ◽  
Md. Tabassum Hossain Emon ◽  
Md. Shariful Islam ◽  
A. K. M. Mohiuddin ◽  
...  

AbstractGenetic polymorphisms in DNA damage repair and tumor suppressor genes have been associated with increasing the risk of several types of cancer. Analyses of putative functional single nucleotide polymorphisms (SNP) in such genes can greatly improve human health by guiding choice of therapeutics. In this study, we selected nine genes responsible for various cancer types for gene enrichment analysis and found that BRCA1, ATM, and TP53 were more enriched in connectivity. Therefore, we used different computational algorithms to classify the nonsynonymous SNPs which are deleterious to the structure and/or function of these three proteins. The present study showed that the major pathogenic variants (V1687G and V1736G of BRCA1, I2865T and V2906A of ATM, V216G and L194H of TP53) might have a greater impact on the destabilization of the proteins. To stabilize the high-risk SNPs, we performed mutation site-specific molecular docking analysis and validated using molecular dynamics (MD) simulation and molecular mechanics/Poisson Boltzmann surface area (MM/PBSA) studies. Additionally, SNPs of untranslated regions of these genes affecting miRNA binding were characterized. Hence, this study will assist in developing precision medicines for cancer types related to these polymorphisms.


2021 ◽  
Author(s):  
Qiting Wan ◽  
Li Hu ◽  
Lu Yao ◽  
Jiuan Chen ◽  
Jie Sun ◽  
...  

The demand for genetic testing for breast cancer susceptibility genes is increasing for both breast cancer patients and healthy individuals. Here we established a novel high-throughput assay to detect germline pathogenic variants in breast cancer susceptibility genes. In general, up 10 to 50 individual genomic DNA samples were mixed together to create a mixed DNA sample and the mixed DNA sample was subjected to a next-generation multigene panel. Germline pathogenic variants in breast cancer susceptibility genes could be found in the mixed DNA sample; next, site-specific Sanger sequencing was performed to identify individuals who carried he pathogenic variant in the mixed samples. We found that the recall and precision rates were 89.9% and 92.9% when twenty individual genomic samples were mixed. Therefore, our new assay can increase an approximately 20-fold of efficacy to identify the pathogenic variants in breast cancer susceptibility genes in individuals when compared with current assay.


2020 ◽  
Vol 38 (11) ◽  
pp. 1222-1245 ◽  
Author(s):  
Panagiotis A. Konstantinopoulos ◽  
Barbara Norquist ◽  
Christina Lacchetti ◽  
Deborah Armstrong ◽  
Rachel N. Grisham ◽  
...  

PURPOSE To provide recommendations on genetic and tumor testing for women diagnosed with epithelial ovarian cancer based on available evidence and expert consensus. METHODS A 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. RESULTS The systematic review identified 19 eligible studies. The evidence consisted of systematic reviews of observational data, consensus guidelines, and RCTs. RECOMMENDATIONS All 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.


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