Hereditary breast and ovarian cancer susceptibility genes (review)

Menin signaling and therapeutic targeting in breast cancer

To date, mounting evidence have shown that patients with multiple endocrine neoplasia type 1 (MEN1) may face an increased risk for breast carcinogenesis. The product of the MEN1 gene, menin, was also indicated to be an important regulator in breast cancer signaling network. Menin directly interacts with MLL, EZH2, JunD, NF-κB, PPARγ, VDR, Smad3, β-catenin and ERα to modulate gene transcriptions leading to cell proliferation inhibition. Moreover, interaction of menin-FANCD2 contributes to the enhancement of BRCA1-mediated DNA repair mechanism. Ectopic expression of menin causes Bax-, Bak- and Caspase-8-dependent apoptosis. However, despite numbers of menin inhibitors were exploited in other cancers, data on the usage of menin inhibitors in breast cancer treatment remain limited. In this review, we focused on the menin associated signaling pathways and gene transcription regulations, with the aim of elucidating its molecular mechanisms and of guiding the development of novel menin targeted drugs in breast cancer therapy.

Molecular characterization as new driver in prognostic signatures and therapeutic strategies for endometrial cancer

Endometrial cancer (EC) incidence and mortality rates have been increasing, particularly among young females. Although more than 90% of ECs are sporadic, 5-10% are hereditary, a majority of which occurs within Hereditary Non-Polyposis Colorectal Cancer syndrome (HNPCC) or Lynch syndrome. The traditional histopathological classification differentiates EC between two main groups: type I (or endometrioid) and type II (including all other histopathological subtypes). However, this classification lacks reproducibility and does not account for the emerging molecular heterogeneity. In 2013, The Cancer Genome Atlas (TCGA) project proposed EC molecular classification defining four groups with different prognostic and predictive values and the current international guidelines are progressively establishing EC risk stratification and treatment based on both histopathological and molecular criteria. Our manuscript aims to summarize the current state of EC molecular characterizations, including germline alterations at the basis of hereditary EC predisposition, to discuss their clinical utility as prognostic and predictive markers.

Germline mutations of homologous recombination genes and clinical outcomes in pancreatic cancer: a multicenter study in Taiwan

BACKGROUND

Cancer susceptibility germline mutations are associated with pancreatic ductal adenocarcinoma (PDAC). However, the hereditary status of PDAC and its impact on survival is largely unknown in the Asian population.

METHODS

Exome sequencing was performed on 527 blood samples from PDAC individuals and analyzed for mutations in 80 oncogenic genes. Pathogenic and likely pathogenic (P/LP) germline variants were diagnosed according to the ACMG variant classification categories. The association between germline homologous recombination gene mutations (gHRmut, including BAP1, BRCA1, BRCA2, PALB2, ATM, BLM, BRIP1, CHEK2, NBN, MUTYH, FANCA and FANCC) and the treatment outcomes was explored in patients with stage III/IV diseases treated with first-line (1L) platinum-based versus platinum-free chemotherapy.

RESULTS

Overall, 104 of 527 (19.7%) patients carried germline P/LP variants. The most common mutated genes were BRCA2 (3.60%), followed by ATR (2.66%) and ATM (1.9%). After a median follow-up duration of 38.3-months (95% confidence interval, 95% CI 35.0-43.7), the median overall survival (OS) was not significantly different among patients with gHRmut, non-HR germline mutations, or no mutation (P = 0.43). Among the 320 patients with stage III/IV disease who received 1L combination chemotherapy, 32 (10%) had gHRmut. Of them, patients receiving 1L platinum-based chemotherapy exhibited a significantly longer median OS compared to those with platinum-free chemotherapy, 26.1 months (95% CI 12.7-33.7) versus 9.6 months (95% CI 5.9-17.6), P = 0.001. However, the median OS of patients without gHRmut was 14.5 months (95% CI 13.2-16.9) and 12.6 months (95% CI 10.8-14.7) for patients receiving 1L platinum-based and platinum-free chemotherapy, respectively (P = 0.22). These results were consistent after adjusting for potential confounding factors including age, tumor stage, performance status, and baseline CA 19.9 in the multivariate Cox regression analysis.

CONCLUSIONS

Our study showed that nearly 20% of Taiwanese PDAC patients carried germline P/LP variants. The longer survival observed in gHRmut patients treated with 1L platinum-based chemotherapy highlights the importance of germline testing for all patients with advanced PDAC at diagnosis.

Hereditary breast and ovarian cancer: from genes to molecular targeted therapies

Hereditary familial tumors constitute 10-15% of all malignancies and present opportunities for the identification of therapeutic approaches against specific germline genetic defects. Hereditary breast and ovarian cancer (HBOC) syndrome, which is linked to the pathogenic mutations of the breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) genes, is an important research model for personalized therapeutic approaches for specific germline mutations. HBOC is characterized by multiple cases of breast and ovarian carcinoma in association with other tumors (prostate, pancreas and stomach carcinoma) within the same family branch, a young age of onset (<36 years), bilaterality and an autosomal dominant pattern of inheritance. Counseling, evaluation of the clinical criteria for the diagnosis of HBOC, and the performance of genetic testing allow for the identification of subjects with BRCA1/2 mutations and provide crucial information for clinical and therapeutic management. The identification of a BRCA gene mutation has therapeutic implications for women with metastatic and non-metastatic breast cancer. In the therapeutic setting of BRCA+ breast cancer, treatment with poly (ADP-ribose) polymerase (PARP) inhibitors, which keep cancer cells from repairing their damaged DNA and cause cell death, is remarkable. This review summarizes the evidence demonstrating the value of BRCA1/2 status as a diagnostic and prognostic tool and as a predictive biomarker in the personalized approach to hereditary BRCA + cancers.

Possible impact of HLA class I and class II on malignancies driven by a single germ-line BRCA1 mutation

This study provides the first immunogenetic preliminary evidence that specific human leucocyte antigen (HLA) class I and class II alleles and haplotypes may be relevant for BRCA1 c.5263_5264insC driven oncogenesis. Observed HLA associations might have practical implications for establishment of predictive markers for the response to immunotherapies in malignancies driven by this germ-line mutation.

Incidence of lumbar spondylolysis in athletes with low back pain: A systematic evaluation and single-arm meta-analysis

BACKGROUND

Low back pain (LBP) is a common chief complaint from athletes. Lumbar spondylolysis (LS) is a common sport injury. Severe LS is likely to cause spinal instability, resulting in lumbar spondylolisthesis or lumbar disc herniation, and even damage to the spinal nerve roots. The incidence of LS is approximately 5% in the adult population, and nearly half of young athletes with LBP are diagnosed with LS. This meta-analysis analyzed the incidence of LS in athletes with LBP.

METHODS

PubMed, Embase, Cochrane (Cochrane Central Register of Controlled Trials), and Web of Science databases were systematically searched for published case report and retrospective analyses related to the topic from the date of database creation to January 1,2023. Relevant literature was screened and information extracted, and risk of bias was assessed for included studies using the methodological index for non-randomized-studies scale. Single-arm Meta-analysis was performed using R4.04 software. Heterogeneity was quantified by Cochran Q test and Higgins I2. Funnel plots were used to visualize publication bias, and Egger test and Begg test were used to statistical tests.

RESULTS

A total of 9 studies (835 patients) were included in this study. Meta-analysis revealed that the prevalence of LS in athletes with LBP was estimated at 41.7%, [95% CI = (0.28-0.55)], but this prevalence varied considerably with the gender and age of the athletes.

CONCLUSION

The estimated prevalence of LS in athletes with LBP is 41.7%, and future correlations between the prevalence of LS in adolescent athletes worldwide need to be assessed from different perspectives, including biomechanical, hormonal, anatomical, behavioral, and gender differences.

Overview of the Genetic Causes of Hereditary Breast and Ovarian Cancer Syndrome in a Large French Patient Cohort

The use of multigene panel testing for patients with a predisposition to Hereditary Breast and Ovarian Cancer syndrome (HBOC) is increasing as the identification of mutations is useful for diagnosis and disease management. Here, we conducted a retrospective analysis of BRCA1/2 and non-BRCA gene sequencing in 4630 French HBOC suspected patients. Patients were investigated using a germline cancer panel including the 13 genes defined by The French Genetic and Cancer Group (GGC)-Unicancer. In the patients analyzed, 528 pathogenic and likely pathogenic variants (P/LP) were identified, including BRCA1 (n = 203, 38%), BRCA2 (n = 198, 37%), PALB2 (n = 46, 9%), RAD51C (n = 36, 7%), TP53 (n = 16, 3%), and RAD51D (n = 13, 2%). In addition, 35 novel (P/LP) variants, according to our knowledge, were identified, and double mutations in two distinct genes were found in five patients. Interestingly, retesting a subset of BRCA1/2-negative individuals with an expanded panel produced clinically relevant results in 5% of cases. Additionally, combining in silico (splicing impact prediction tools) and in vitro analyses (RT-PCR and Sanger sequencing) highlighted the deleterious impact of four candidate variants on splicing and translation. Our results present an overview of pathogenic variations of HBOC genes in the southeast of France, emphasizing the clinical relevance of cDNA analysis and the importance of retesting BRCA-negative individuals with an expanded panel.

Precision oncology comes of age

ABSTRACT

Each cancer has a unique fingerprint, and precision oncology can be used to more effectively fight malignancies. The identified genes, expressed RNA, and proteins expressed in patients' cancers are now used routinely to predict prognosis and inform treatment recommendations. This article describes how malignancies develop and some of the targeted drugs that can be used against them.

Frequency and distribution of BRCA1/BRCA2 large genomic rearrangements in Turkish population with breast cancer

Germline mutations in BRCA1 and BRCA2 genes are mainly responsible for breast and/or ovarian cancer patients. Most of the mutations in these genes are single nucleotide changes or deletions/insertions of small numbers of bases, while a minority of mutations in these genes are large genomic rearrangements (LGRs). The frequency of LGRs in the Turkish population is not clearly known. Also insufficient awareness of the importance of LGRs in breast and/or ovarian cancer development can lead to some disruptions in patient management. So, we aimed to determine the frequency and distribution of the LGRs in the BRCA1/2 genes in the Turkish population. We investigated rearrangements of BRCA genes using multiplex ligation-dependent probe amplification (MLPA) analysis in 1540 patients with a personal and/or family history of breast and/or ovarian cancer or who had familial known large deletion/duplication and applied for segregation. The estimated overall frequency of LGRs in our group was 3,4% (52/1540) with 91% in BRCA1 gene and 9% in BRCA2 gene. 13 different rearrangements were detected (10 BRCA1, 3 BRCA2). To the best our knowledge, BRCA1 exon 1-16 duplication and BRCA2 exon 6 deletion have not been previously reported before. Our study results supported that the detection of rearrangements in BRCA genes is of great importance and it should be planned routinely in patients whose mutations cannot be detected by sequence analysis in screening programs.

Through the Looking Glass: Updated Insights on Ovarian Cancer Diagnostics

Epithelial ovarian cancer (EOC) is the deadliest gynaecological malignancy and the eighth most prevalent cancer in women, with an abysmal mortality rate of two million worldwide. The existence of multiple overlapping symptoms with other gastrointestinal, genitourinary, and gynaecological maladies often leads to late-stage diagnosis and extensive extra-ovarian metastasis. Due to the absence of any clear early-stage symptoms, current tools only aid in the diagnosis of advanced-stage patients, wherein the 5-year survival plummets further to less than 30%. Therefore, there is a dire need for the identification of novel approaches that not only allow early diagnosis of the disease but also have a greater prognostic value. Toward this, biomarkers provide a gamut of powerful and dynamic tools to allow the identification of a spectrum of different malignancies. Both serum cancer antigen 125 (CA-125) and human epididymis 4 (HE4) are currently being used in clinics not only for EOC but also peritoneal and GI tract cancers. Screening of multiple biomarkers is gradually emerging as a beneficial strategy for early-stage diagnosis, proving instrumental in administration of first-line chemotherapy. These novel biomarkers seem to exhibit an enhanced potential as a diagnostic tool. This review summarizes existing knowledge of the ever-growing field of biomarker identification along with potential future ones, especially for ovarian cancer.

Identification of novel exonic variants contributing to hereditary breast and ovarian cancer in west Indian population

Breast and ovarian cancers are the most common cancer types in females worldwide and in India. Patients with these cancers require an early diagnosis which is essential for better prognosis, treatment and improved patient survival. Recently, the utilization of next-generation sequencing (NGS)-based screening has accelerated molecular diagnosis of various cancers. In the present study, we performed whole-exome sequencing (WES) of 30 patients who had a first or second-degree relative with breast or ovarian cancer and are tested negative for BRCA1/2 or other high and moderate-risk genes reported for HBOC. WES data from patients were analyzed and variants were called using bcftools. Functional annotation of variants and variant prioritization was performed by Exomiser. The clinical significance of variants was determined as per ACMG classification using Varsome tool. The functional analysis of genes was determined by STRING analysis and disease association was determined by open target tool. We found novel variants and gene candidates having significant association with HBOC conditions. The genes identified by exomiser (phenotype score > 0.75) are associated with various biological processes such as DNA integrity maintenance, transcription regulation, cell cycle regulation, and apoptosis. Our findings provide novel and prevalent gene variants associated with the HBOC condition in the West Indian population which could be further studied for early diagnosis and better prognosis of HBOC.

Changes of Mutations and Copy-Number and Enhanced Cell Migration during Breast Tumorigenesis

Although cancer stem cells (CSCs) play a major role in tumorigenesis and metastasis, the role of genetic alterations in invasiveness of CSCs is still unclear. Tumor microenvironment signals, such as extracellular matrix (ECM) composition, significantly influence cell behaviors. Unfortunately, these signals are often lost in in vitro cell culture. This study determines putative CSC populations, examines genetic changes during tumorigenesis of human breast epithelial stem cells, and investigates single-cell migration properties on ECM-mimetic platforms. Whole exome sequencing data indicate that tumorigenic cells have a higher somatic mutation burden than non-tumorigenic cells, and that mutations exclusive to tumorigenic cells exhibit higher predictive deleterious scores. Tumorigenic cells exhibit distinct somatic copy number variations (CNVs) including gain of duplications in chromosomes 5 and 8. ECM-mimetic topography selectively enhances migration speed of tumorigenic cells, but not of non-tumorigenic cells, and results in a wide distribution of tumorigenic single-cell migration speeds, suggesting heterogeneity in cellular sensing of contact guidance cues. This study identifies mutations and CNVs acquired during breast tumorigenesis, which can be associated with enhanced migration of breast tumorigenic cells, and demonstrates that a nanotopographically-defined platform can be applied to recapitulate an ECM structure for investigating cellular migration in the simulated tumor microenvironment.

Functional characterization of MLH1 missense variants unveils mechanisms of pathogenicity and clarifies role in cancer

Lynch syndrome is a heritable condition caused by a heterozygous germline inactivating mutation of the DNA mismatch repair (MMR) genes, most commonly the MLH1 gene. However, one third of the identified alterations are missense variants, for which the clinical significance is unclear in many cases. We have identified three MLH1 missense alterations (p.(Glu736Lys), p.(Pro640Thr) and p.(Leu73Pro)) in six individuals from large Tunisian families. For none of these alterations, a classification of pathogenicity was available, consequently diagnosis, predictive testing and targeted surveillance in affected families was impossible. We therefore performed functional laboratory testing using a system testing stability as well as catalytic activity that includes clinically validated reference variants. Both p.(Leu73Pro) and p.(Pro640Thr) were found to be non-functional due to severe defects in protein stability and catalytic activity. In contrast, p.(Glu736Lys) was comparable to the wildtype protein and therefore considered a neutral substitution. Analysis of residue conservation and of the structural roles of the substituted residues corroborated these findings. In conjunction with the available clinical data, two variants fulfil classification criteria for class 4 "likely pathogenic". The findings of this work clarify the mechanism of pathogenicity of two unclear MLH1 variants and enables predictive testing and targeted surveillance in members of carrier families worldwide.

Overview on population screening for carriers with germline BRCA mutation in China

Carriers with BRCA1/2 germline pathogenic variants are associated with a high risk of breast and ovarian cancers (also pancreatic and prostate cancers). While the spectrum on germline BRCA mutations among the Chinese population shows ethnic specificity, the identification of carriers with germline BRCA mutation before cancer onset is the most effective approach to protect them. This review focused on the current status of BRCA1/2 screening, the surveillance and prevention measures, and discussed the issues and potential impact of BRCA1/2 population screening in China. We conducted literature research on databases PubMed and Google Scholar, as well as Chinese databases CNKI and Wangfang Med Online database (up to 31 March 2022). Latest publications on germline BRCA1/2 prevalence, spectrum, genetic screening as well as carrier counseling, surveillance and prevention were captured where available. While overall 15,256 records were retrieved, 72 publications using germline BRCA1/2 testing were finally retained for further analyses. Germline BRCA1/2 mutations are common in Chinese patients with hereditary breast, ovarian, prostate and pancreatic cancers. Within previous studies, a unique BRCA mutation spectrum in China was revealed. Next-generation sequencing panel was considered as the most common method for BRCA1/2 screening. Regular surveillance and preventive surgeries were tailored to carriers with mutated-BRCA1/2. We recommend that all Chinese diagnosed with breast, ovarian, pancreatic or prostate cancers and also healthy family members, shall undergo BRCA1/2 gene test to provide risk assessment. Subsequently, timely preventive measures for mutation carriers are recommended after authentic genetic counseling.

Familial history and prevalence of BRCA1, BRCA2 and TP53 pathogenic variants in HBOC Brazilian patients from a public healthcare service

Several studies have demonstrated the cost-effectiveness of genetic testing for surveillance and treatment of carriers of germline pathogenic variants associated with hereditary breast/ovarian cancer syndrome (HBOC). In Brazil, seventy percent of the population is assisted by the public Unified Health System (SUS), where genetic testing is still unavailable. And few studies were performed regarding the prevalence of HBOC pathogenic variants in this context. Here, we estimated the prevalence of germline pathogenic variants in BRCA1, BRCA2 and TP53 genes in Brazilian patients suspected of HBOC and referred to public healthcare service. Predictive power of risk prediction models for detecting mutation carriers was also evaluated. We found that 41 out of 257 tested patients (15.9%) were carriers of pathogenic variants in the analyzed genes. Most frequent pathogenic variant was the founder Brazilian mutation TP53 c.1010G > A (p.Arg337His), adding to the accumulated evidence that supports inclusion of TP53 in routine testing of Brazilian HBOC patients. Surprisingly, BRCA1 c.5266dupC (p.Gln1756fs), a frequently reported pathogenic variant in Brazilian HBOC patients, was not observed. Regarding the use of predictive models, we found that familial history of cancer might be used to improve selection or prioritization of patients for genetic testing, especially in a context of limited resources.

Spectrum of BRCA1/2 Mutations in Romanian Breast and Ovarian Cancer Patients

Background: About 10,000 women are diagnosed with breast cancer and about 2000 women are diagnosed with ovarian cancer each year in Romania. There is an insufficient number of genetic studies in the Romanian population to identify patients at high risk of inherited breast and ovarian cancer. Methods: We evaluated 250 women of Romanian ethnicity with BC and 240 women of Romanian ethnicity with ovarian cancer for the presence of damaging germline mutations in breast cancer genes 1 and 2 (BRCA1 and BRCA2, respectively) using Next-Generation Sequencing (NGS) technology. Results: Of the 250 breast cancer patients, 47 carried a disease-predisposing BRCA mutation (30 patients (63.83%) with a BRCA1 mutation and 17 patients (36.17%) with a BRCA2 mutation). Of the 240 ovarian cancer patients, 60 carried a BRCA mutation (43 patients (72%) with a BRCA1 mutation and 17 patients (28%) with a BRCA2 mutation). In the BRCA1 gene, we identified 18 variants (4 in both patient groups (ovarian and breast cancer patients), 1 mutation variant in the BC patient group, and 13 mutation variants in the ovarian cancer patient group). In the BRCA2 gene, we identified 17 variants (1 variant in both ovarian and breast cancer patients, 6 distinct variants in BC patients, and 10 distinct variants in ovarian cancer patients). The prevailing mutation variants identified were c.3607C>T (BRCA1) (18 cases) followed by c.5266dupC (BRCA1) (17 cases) and c.9371A>T (BRCA2) (12 cases). The most prevalent mutation, BRCA1 c.3607C>T, which is less common in the Romanian population, was mainly associated with triple-negative BC and ovarian serous adenocarcinoma. Conclusion: The results of our analysis may help to establish specific variants of BRCA mutations in the Romanian population and identify individuals at high risk of hereditary breast and ovarian cancer syndrome by genetic testing.

An update on the safety of olaparib for treating ovarian cancer

INTRODUCTION

PARP inhibitors have dramatically improved outcomes for ovarian cancer patients, transforming oncologists' armamentarium and fueling hope for more cures and longer survival.

AREAS COVERED

The recent PARP inhibitor randomized trials of FDA approved PARP inhibitors for ovarian cancer, olaparib, rucaparib and niraparib, and implications for clinical care are discussed with a focus on toxicity and risks. PARP adds NAD polymers to DNA-binding proteins, improving survival of cells after DNA damage, and acting as a scaffold for important DNA Damage Response (DDR) enzymes. If this system is inhibited, PARP activation cannot support DNA repair when there is synthetic lethality from BRCA mutations or homologous repair dysfunction (HRD), and the accumulation of DNA damage can kill cancer and lead to the catastrophic complications of MDS/AML. Although the risk of AML can be a <1% risk, the incidence of MDS/AML presently approaches 10% in patients with BRCA mutations, multiple prior lines of platinum therapy, and protracted exposure to PARP inhibitors.

EXPERT OPINION

PARP inhibitors are a well-tolerated and exciting new class of agents that improve survival despite the risk of AML. Understanding of the biology has led to optimal use and potential new strategies for overcoming PARP resistance.

Identification and Characterization of an Exonic Duplication in PALB2 in a Man with Synchronous Breast and Prostate Cancer

PALB2 (partner and localizer of BRCA2), as indicated by its name, is a BRCA2-interacting protein that plays an important role in homologous recombination (HR) and DNA double-strand break (DSB) repair. While pathogenic variants of PALB2 have been well proven to confer an increased risk of breast cancer, data on its involvement in prostate cancer (PrC) have not been clearly demonstrated. We investigated, using targeted next generation sequencing (NGS), a 59-year-old Caucasian man who developed synchronous breast and prostate cancers. This genetic investigation allowed to identify an intragenic germline heterozygous duplication in PALB2, implicating intronic repetitive sequences spanning exon 11. This variant was confirmed by multiplex ligation probe amplification (MLPA), and genomic breakpoints have been identified and characterized at the nucleotide level (c.3114-811_3202-1756dup) using an approach based on walking PCR, long range PCR, and Sanger sequencing. RT-PCR using mRNA extracted from lymphocytes and followed by Sanger sequencing revealed a tandem duplication r.3114_3201dup; p.(Gly1068Glufs * 14). This duplication results in the synthesis of a truncated, and most-likely, non-functional protein. These findings expand the phenotypic spectrum of PALB2 variants and may improve the yield of genetic diagnoses in this field.

Clinical significance of gene polymorphisms for hereditary predisposition to breast and ovarian cancer (review of literature)

The review presents classical and modern views on the molecular genetic causes underlying hereditary predisposition to breast and ovarian cancer. A computerized literature search was carried out in the electronic databases MEDLINE, Scopus, and Web of Science, published between January 1994 and May 2021, using the keywords: «hereditary breast and ovarian cancer», «BRCA» and «DNA repair». Current views on the role of germline mutations in genes for susceptibility to breast cancer (BC): BRCA1, BRCA2, PALB2, TP53, CHEK2, PTEN, ATM, and PPM1D are presented. The role of a complex of genes involved in homologous DNA repair and causing other hereditary oncological diseases is considered. The role of the loss of heterozygosity in these genes, which increases the level of chromosomal instability and leads to an increased risk of malignant transformation, is considered. Germinal mutations in the genes under consideration in 90% of clinical cases are the cause of initiation of tissue malignancy and greatly increase the risk of developing hereditary breast cancer and OC. The review emphasizes the complex nature of pathogenesis and significant polymorphism of genetic targets for hereditary breast cancer and OC. It is concluded that it is necessary to use NGS panels for complex screening of genes of hereditary susceptibility to these oncological diseases. The review provides data on the clinical significance of each group of genes of hereditary predisposition in the pathogenesis of breast cancer and OC, and also demonstrates the possible role of methylation of the promoter regions of genes and the state of mitochondrial DNA in the development of these pathologies. The purpose of this review was to broaden the horizons of specialists in the field of oncology and clinical diagnostics in the context of the rapidly expanding spectrum of molecular genetic markers of hereditary breast and ovarian cancers.

Feasibility of genetic testing for cancer risk assessment programme in Nigeria

Background

A high frequency of BRCA mutations has been established in Nigerian breast cancer (BC) patients. Recently, patients’ and first-degree relatives’ interest have been raised on cancer genetic risk assessment through our awareness activities in Nigeria. This led to the emergence of nurse-led cancer genetic counselling (CGC) and testing aimed at providing standard-of-care for individuals at increased risk of hereditary breast and ovarian cancers.

Methods

In June 2018, CGC and testing of patients with BC and ovarian cancer (OC) commenced in collaboration with Color Genomics Inc. for a 30-panel gene testing. Previously trained nurses in CGC at the University College Hospital, Ibadan offered genetic counselling (GC) to willing patients with BC and gynaecological cancer in four out-patient oncology clinics and departments for the pilot study. Consultation consisted of CGC, patient’s history, pedigree and sample collection for genetic testing (GT).

Results

Forty-seven patients – 40 with BC, five with OC and two with endometrial cancer received GC, and all chose to undergo GT. The average age at testing was 48.2 ± 12.1 years. Eight women reported a known family cancer history and there were more perceived benefits than barriers to GT with the patients experiencing the desire for none of their relative to have cancer. Results revealed no mutations in 27 (57.4%), 16 (4.0%) variants of unknown significance and 4 (8.5%) pathogenic mutations.

Conclusion

Personalised cancer care utilises GC and testing for cancer risk assessment towards prevention and early detection in high risk women. The study indicates the necessity of expanded cancer genetic services for integration into patient care and cancer prevention.

Identification and Characterization of New Alu Element Insertion in the BRCA1 Exon 14 Associated with Hereditary Breast and Ovarian Cancer

Hereditary breast and ovarian cancer syndrome (HBOC) is an autosomal dominant cancer predisposition syndrome characterized by an increased risk of breast and ovarian cancers. Germline pathogenic variants in BRCA1 are found in about 7–10% of all familial breast cancers and 10% of ovarian cancers. Alu elements are the most abundant mobile DNA element in the human genome and are known to affect the human genome by different mechanisms leading to human disease. We report here the detection, by next-generation sequencing (NGS) analysis coupled with a suitable bioinformatics pipeline, of an AluYb8 element in exon 14 of the BRCA1 gene in a family with HBOC history first classified as BRCA-negative by Sanger sequencing and first NGS analysis. The c.4475_c.4476insAluYb8 mutation impacts splicing and induces the skipping of exon 14. As a result, the produced mRNA contains a premature stop, leading to the production of a short and likely non-functional protein (pAla1453Glyfs*10). Overall, our study allowed us to identify a novel pathogenic variant in BRCA1 and showed the importance of bioinformatics tool improvement and versioning.

Rare germline variants in DNA repair-related genes are accountable for papillary thyroid cancer susceptibility

BACKGROUND

Understanding the molecular mechanisms underlying papillary thyroid cancer (PTC) proved to be vital not only for diagnostic purposes but also for tailored treatments. Despite the strong evidence of heritability, only a small subset of alterations has been implicated in PTC pathogenesis. To this reason, we used targeted next-generation sequencing (NGS) to identify candidate variants implicated in PTC pathogenesis, progression, and invasiveness.

METHODS

A total of 42 primary PTC tissues were investigated using a targeted next-generation sequencing (NGS) panel enlisting 47 genes involved in DNA repair and tumor progression.

RESULTS

We identified 57 point mutations in 78.5% of samples (n = 32). Thirty-two somatic mutations were identified exclusively in known thyroid cancer genes (BRAF, KRAS, NRAS, and TERT). Unpredictably, 45% of the all identified mutations (n = 25) resulted to be germline, most affecting DNA repair genes. Interestingly, none of the latter variants was in the main population databases. Following ACMG classification, 20% of pathogenic/likely pathogenic and 68% of variant of unknown significance were identified.

CONCLUSIONS

Overall, our results support the hypothesis that rare germline variants in DNA repair genes are accountable for PTC susceptibility. More data, including the segregation analysis in affected families, should be collected before definitely annotate these alterations and to establish their potential prognostic and treatment implications.

Overview of Ferroptosis and Synthetic Lethality Strategies

Ferroptosis, a term first proposed in 2012, is iron-dependent, non-apoptotic regulatory cell death induced by erastin. Ferroptosis was originally discovered during synthetic lethal screening for drugs sensitive to RAS mutant cells, and is closely related to synthetic lethality. Ferroptosis sensitizes cancer stem cells and tumors that undergo epithelial-mesenchymal transition and are resistant to anticancer drugs or targeted therapy. Therefore, ferroptosis-inducing molecules are attractive new research targets. In contrast, synthetic lethal strategies approach mechanisms and genetic abnormalities that cannot be directly targeted by conventional therapeutic strategies, such as RAS mutations, hypoxia, and abnormalities in the metabolic environment. They also target the environment and conditions specific to malignant cells, have a low toxicity to normal cells, and can be used in combination with known drugs to produce new ones. However, the concept of synthetic lethality has not been widely adopted with ferroptosis. In this review, we surveyed the literature on ferroptosis-related factors and synthetic lethality to examine the potential therapeutic targets in ferroptosis-related molecules, focusing on factors related to synthetic lethality, discovery methods, clinical application stages, and issues in drug discovery.

Current update on the molecular genetics and management of hereditary ovarian cancers: a primer for radiologists

More than one-fifth of ovarian cancers are hereditary, with most of them caused by BRCA genes. Malignant ovarian neoplasms are primarily epithelial tumors, a heterogeneous group of tumors with variable genetic backgrounds that translate into different biologic behaviors and morphologic features. Radiologists play an increasingly important role in the diagnosis and management of oncology patients. Familiarity with hereditary ovarian cancers will have a positive impact on patient management and radiologists' involvement in the multidisciplinary approach needed for this delicate patient population. In this paper, we review the basic histologic and genetic backgrounds of ovarian tumors with an emphasis on hereditary ovarian cancers, as well as the effects that these factors have on patient workup, primarily with regard to imaging studies.

Are there monogenic hereditary forms of bladder cancer or only genetic susceptibilities?

Bladder cancer (BC) is the most common cancer involving the urinary system and the ninth most common cancer worldwide. Tobacco smoking is the most important environmental risk factor of BC. Several single nucleotide polymorphisms have been validated by genome-wide association studies as genetic risk factors for BC. However, the identification of DNA mismatch-repair genes, including MSH2 in Lynch syndrome and MUTYH in MUTYH-associated polyposis, raises the possibility of monogenic hereditary forms of BC. Moreover, other genetic mutations may play a key role in familial and hereditary transmissions of BC. Therefore, the aim of this review is to focus on the major hereditary syndromes involved in the development of BC and to report BC genetic susceptibilities established with genome-wide significance level.

Co-occurrence and mutual exclusivity: what cross-cancer mutation patterns can tell us

Cancer is the dysregulated proliferation of cells caused by acquired mutations in key driver genes. The most frequently mutated driver genes promote tumorigenesis in various organisms, cell types, and genetic backgrounds. However, recent cancer genomics studies also point to the existence of context-dependent driver gene functions, where specific mutations occur predominately or even exclusively in certain tumor types or genetic backgrounds. Here, we review examples of co-occurring and mutually exclusive driver gene mutation patterns across cancer genomes and discuss their underlying biology. While co-occurring driver genes typically activate collaborating oncogenic pathways, we identify two distinct biological categories of incompatibilities among the mutually exclusive driver genes depending on whether the mutated drivers trigger the same or divergent tumorigenic pathways. Finally, we discuss possible therapeutic avenues emerging from the study of incompatible driver gene mutations.

In-Silico Analyses of Nonsynonymous Variants in the BRCA1 Gene

BReast CAncer gene 1 (BRCA1)-a tumor suppressor gene plays an important role in the DNA repair mechanism. Several BRCA1 variants perturb its structure and function, including synonymous and nonsynonymous single nucleotide polymorphisms (SNPs). In the present study, we performed in-silico analyses of nonsynonymous SNPs (nsSNPs) of the BRCA1 gene. In total, 122 nsSNPs were retrieved from the NCBI SNP database and in-silico analyses were performed using computational prediction tools: SIFT, PROVEAN, Mutation Taster, PolyPhen-2, MutPred, and ConSurf. Of these tools, SIFT, PROVEAN, and Mutation Taster predicted 61 out of 122 nsSNPs as "damaging", based on structural homology analysis. PolyPhen-2 classified 22 nsSNPs as "probably damaging". These nsSNPs were further analyzed by MutPred to predict basic molecular mechanisms of amino acid alteration. ConSurf analysis predicted eleven conserved amino acid residues with structural and functional consequences. We identified five amino acid residues in the RING finger domain (L22, C39, H41, C44, and C47) and two in the BRCT domain (P1771 and I1707) with the potential to deter the BRCA1 protein function. This study provides insights into the effect of nsSNPs and amino acid substitutions in BRCA1.

DNA damage response and repair in pancreatic cancer development and therapy

Pancreatic cancer (PC) is among fatal malignancies, with a dismal prognosis and a low survival rate of 5-10%. In both sporadic and inherited PC, gene alterations, such as BRCA1/2, PALB2, and ATM, can occur frequently. Currently, surgery, chemo- and radio-therapy are the most common therapeutic strategies for treating this cancer. DNA damage response (DDR) establishes multiple pathways that eliminate DNA damage sites to maintain genomic integrity. Various types of cancers and age-related diseases are associated with DDR machinery defects. According to the severity of the damage, DDR pathways respond appropriately to lesions through repairing damage, arresting the cell cycle, or apoptosis. Recently, novel agents, particularly those targeting DDR pathways, are being utilized to improve the response of many cancers to chemotherapy and radiotherapy. In this paper, we briefly reviewed DDR processes and their components, including DDR sensors, DDR mediators, and DDR transducers in the progression, prognosis, and treatment of PC.

DNA methylation variations in familial female and male breast cancer

In total, ~25% of familial breast cancer (BC) is attributed to germline mutations of the BRCA1 and BRCA2 genes, while the rest of the cases are included in the BRCAX group. BC is also known to affect men, with a worldwide incidence of 1%. Epigenetic alterations, including DNA methylation, have been rarely studied in male breast cancer (MBC) on a genome-wide level. The aim of the present study was to examine the global DNA methylation profiles of patients with BC to identify differences between familial female breast cancer (FBC) and MBC, and according to BRCA1, BRCA2 or BRCAX mutation status. The genomic DNA of formalin-fixed paraffin-embedded tissues from 17 women and 7 men with BC was subjected to methylated DNA immunoprecipitation and hybridized on human promoter microarrays. The comparison between FBC and MBC revealed 2,846 significant differentially methylated regions corresponding to 2,486 annotated genes. Gene Ontology enrichment analysis revealed molecular function terms, such as the GTPase superfamily genes (particularly the GTPase Rho GAP/GEF and GTPase RAB), and cellular component terms associated with cytoskeletal architecture, such as 'cytoskeletal part', 'keratin filament' and 'intermediate filament'. When only FBC was considered, several cancer-associated pathways were among the most enriched KEGG pathways of differentially methylated genes when the BRCA2 group was compared with the BRCAX or BRCA1+BRCAX groups. The comparison between the BRCA1 and BRCA2+BRCAX groups comprised the molecular function term 'cytoskeletal protein binding'. Finally, the functional annotation of differentially methylated genes between the BRCAX and BRCA1+BRCA2 groups indicated that the most enriched molecular function terms were associated with GTPase activity. In conclusion, to the best of our knowledge, the present study was the first to compare the global DNA methylation profile of familial FBC and MBC. The results may provide useful insights into the epigenomic subtyping of BC and shed light on a possible novel molecular mechanism underlying BC carcinogenesis.

DNA damage repair as a target in pancreatic cancer: state-of-the-art and future perspectives

Complex rearrangement patterns and mitotic errors are hallmarks of most pancreatic ductal adenocarcinomas (PDAC), a disease with dismal prognosis despite some therapeutic advances in recent years. DNA double-strand breaks (DSB) bear the greatest risk of provoking genomic instability, and DNA damage repair (DDR) pathways are crucial in preserving genomic integrity following a plethora of damage types. Two major repair pathways dominate DSB repair for safeguarding the genome integrity: non-homologous end joining and homologous recombination (HR). Defective HR, but also alterations in other DDR pathways, such as BRCA1, BRCA2, ATM and PALB2, occur frequently in both inherited and sporadic PDAC. Personalised treatment of pancreatic cancer is still in its infancy and predictive biomarkers are lacking. DDR deficiency might render a PDAC vulnerable to a potential new therapeutic intervention that increases the DNA damage load beyond a tolerable threshold, as for example, induced by poly (ADP-ribose) polymerase inhibitors. The Pancreas Cancer Olaparib Ongoing (POLO) trial, in which olaparib as a maintenance treatment improved progression-free survival compared with placebo after platinum-based induction chemotherapy in patients with PDAC and germline BRCA1/2 mutations, raised great hopes of a substantially improved outcome for this patient subgroup. This review summarises the relationship between DDR and PDAC, the prevalence and characteristics of DNA repair mutations and options for the clinical management of patients with PDAC and DNA repair deficiency.

Multiethnic PDX models predict a possible immune signature associated with TNBC of African ancestry

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive subtype most prevalent among women of Western Sub-Saharan African ancestry. It accounts for 15-25% of African American (AA) breast cancers (BC) and up to 80% of Ghanaian breast cancers, thus contributing to outcome disparities in BC for black women. The aggressive biology of TNBC has been shown to be regulated partially by breast cancer stem cells (BCSC) which mediate tumor recurrence and metastasis and are more abundant in African breast tumors.

METHODS

We studied the biological differences between TNBC in women with African ancestry and those of Caucasian women by comparing the gene expression of the BCSC. From low-passage patient derived xenografts (PDX) from Ghanaian (GH), AA, and Caucasian American (CA) TNBCs, we sorted for and sequenced the stem cell populations and analyzed for differential gene enrichment.

RESULTS

In our cohort of TNBC tumors, we observed that the ALDH expressing stem cells display distinct ethnic specific gene expression patterns, with the largest difference existing between the GH and AA ALDH+ cells. Furthermore, the tumors from the women of African ancestry [GH/AA] had ALDH stem cell (SC) enrichment for expression of immune related genes and processes. Among the significantly upregulated genes were CD274 (PD-L1), CXCR9, CXCR10 and IFI27, which could serve as potential drug targets.

CONCLUSIONS

Further exploration of the role of immune regulated genes and biological processes in BCSC may offer insight into developing novel approaches to treating TNBC to help ameliorate survival disparities in women with African ancestry.

Effect of risk-reducing salpingo-oophorectomy on the quality of life in Korean BRCA mutation carriers

BACKGROUND

This study aimed to compare the quality of life (QOL), psychosocial status, sexual function, and menopausal symptoms between the risk-reducing salpingo-oophorectomy (RRSO) and non-RRSO groups comprising BRCA mutation carriers and to evaluate the effect of timing of RRSO on those aspects.

METHODS

This cross-sectional study recruited BRCA mutation carriers aged ≥35 years between September 2015 and September 2016. Demographic data of carriers were collected. Outcomes were measured using the questionnaires addressing QOL, anxiety, depression, optimism, sexual function, and menopausal symptoms.

RESULTS

Of 52 participants, 30 (57.7%) underwent RRSO, whereas 22 (42.3%) did not. In the RRSO group, 16 (53.3%) and 14 (46.7%) women underwent RRSO before and after menopause, respectively. The mean age in the RRSO group was higher than that in the non-RRSO group (49.8 vs. 42.1 years, respectively, p = 0.002). The scores for QOL, anxiety, depression, optimism, sexual function, and menopausal symptoms were similar between both groups. In the multivariate analysis, RRSO uptake was associated with worse physical QOL (coefficient, -5.350; 95% confidence interval, -10.593 to -0.108). With respect to the timing of RRSO, only the mental QOL was significantly lower in the postmenopausal RRSO group than in the premenopausal RRSO group (39.2 vs. 43.7, respectively, p = 0.043).

CONCLUSION

We could not find any difference in mental QOL, psychosocial status, sexual function, and menopausal symptoms between the RRSO and non-RRSO groups. RRSO uptake only affected worse physical QOL. These results will help physicians counsel BRCA mutation carriers about the effect of RRSO on QOL.

Prevalence of mutations in BRCA and MMR genes in patients affected with hereditary endometrial cancer

Endometrial cancer (EC) is the fifth most common cancer in women from developed countries, accounting for 4.8% of new cases and 2.1% of deaths. The genetic basis for the familial risk of endometrial cancer has not been completely defined. Mostly, hereditary EC is part of two syndromes as Lynch syndrome (LS) and Hereditary Breast and Ovarian Cancer syndrome (HBOC). LS is the prototypical hereditary cancer syndrome in EC and accounts for 2-6% of all endometrial cancers. This disease is caused by autosomal dominant mutations in DNA mismatch repair (MMR) genes. Patients carrying a germline mutation in one of the MMR genes have a cumulative lifetime risk to develop EC of 20-70%. HBOC is an autosomal dominantly inherited disease, which mostly predisposes to breast and ovarian cancers, but it can be also associated with other malignancies. HBOC results from germline mutations in BRCA1/2 genes. The aim of this study was to determine the mutational status of a cohort of 40 EC patients, 19 belonging to families with LS and 21 to HBOC. Mutation analysis of MLH1, MSH2, BRCA1 and BRCA2 genes showed pathogenic variants in 17/40 (42.5%) patients. Out of 19 patients belonging to LS families, 8 (42.1%) showed a pathogenic variant. Out of 21 patients belonging to HBOC families, 9 (42.8%) showed a pathogenic variant. 1/21 (4.8%) patient report 1 variant of unknown significance (UV), c.599 C > T (p.T200I), in BRCA2. Moreover, in 1/21 (4.8%) patient we identified a novel missense variant in BRCA2, c.9541A > T (p.Met3181Leu). Mutational analysis was extended to family members, both healthy and cancer affected, of mutated patients; all the tested relatives affected with cancer displayed the pathogenic variant. Our data suggest that patients with hereditary EC have a high percentage of mutations in the LS and HBOC main susceptibility genes; therefore, the surveillance for EC, already indicated in LS patients, should also be recommended for patients with HBOC.

CAMK2N1/RUNX3 methylation is an independent prognostic biomarker for progression-free and overall survival of platinum-sensitive epithelial ovarian cancer patients

BACKGROUND

To date, no predictive or prognostic molecular biomarkers except BRCA mutations are clinically established for epithelial ovarian cancer (EOC) despite being the deadliest gynecological malignancy. Aim of this biomarker study was the analysis of DNA methylation biomarkers for their prognostic value independent from clinical variables in a heterogeneous cohort of 203 EOC patients from two university medical centers.

RESULTS

The marker combination CAMK2N1/RUNX3 exhibited a significant prognostic value for progression-free (PFS) and overall survival (OS) of sporadic platinum-sensitive EOC (n = 188) both in univariate Kaplan-Meier (LogRank p < 0.05) and multivariate Cox regression analysis (p < 0.05; hazard ratio HR = 1.587). KRT86 methylation showed a prognostic value only in univariate analysis because of an association with FIGO staging (Fisher's exact test p < 0.01). Thus, it may represent a marker for EOC staging. Dichotomous prognostic values were observed for KATNAL2 methylation depending on BRCA aberrations. KATNAL2 methylation exhibited a negative prognostic value for PFS in sporadic EOC patients without BRCA1 methylation (HR 1.591, p = 0.012) but positive prognostic value in sporadic EOC with BRCA1 methylation (HR 0.332, p = 0.04) or BRCA-mutated EOC (HR 0.620, n.s.).

CONCLUSION

The retrospective analysis of 188 sporadic platinum-sensitive EOC proved an independent prognostic value of the methylation marker combination CAMK2N1/RUNX3 for PFS and OS. If validated prospectively this combination may identify EOC patients with worse prognosis after standard therapy potentially benefiting from intensive follow-up, maintenance therapies or inclusion in therapeutic studies. The dichotomous prognostic value of KATNAL2 should be validated in larger sample sets of EOC.

Challenges of Genomic Testing for Hereditary Breast and Ovarian Cancers

Completion of genetic testing is increasingly important for the complex care of patients with suspected hereditary breast and ovarian cancers (HBOC) and their at-risk family members. Identification of individuals with pathogenic variants has implications for targeted treatment recommendations, risk reduction strategies, increased surveillance recommendations, as well as the genetic testing of family members, known as cascade testing or screening. Due to advances in technology and decreasing costs, what was once single-gene genetic testing has evolved into large-scale multi-gene panel genomic testing. As germline genomic testing for HBOC becomes more and more available, it is important to identify the challenges that are associated with its use. In this manuscript, we review the current issues faced by germline genomic testing for HBOC which include effectively managing the marked increases in genetic referrals, interpreting the vast amount of information yielded by newer testing methods such as next generation sequencing (NGS), recognizing the need for better cascade screening strategies, potential exacerbation of health disparities and improving support for patients navigating the emotional impact related to positive, negative and indeterminate testing results.

Evaluating the Predictability of Cancer Types from 536 Somatic Mutations: A New Dataset

In this paper, we introduce a new dataset for cancer research containing somatic mutation states of 536 genes of the Cancer Gene Census (CGC). We used somatic mutation information from the Cancer Genome Atlas (TCGA) projects to create this dataset. As preliminary investigations, we employed machine learning techniques, including k-Nearest Neighbors, Decision Tree, Random Forest, and Artificial Neural Networks (ANNs) to evaluate the potential of these somatic mutations for classification of cancer types. We compared our models on accuracy, precision, recall, and F1-score. We observed that ANNs outperformed the other models with F1-score of 0.36 and overall classification accuracy of 40%, and precision ranging from 12% to 92% for different cancer types. The 40% accuracy is significantly higher than random guessing which would have resulted in 3% overall classification accuracy. Although the model has relatively low overall accuracy, it has an average classification specificity of 98%. The ANN achieved high precision scores (> 0.7) for 5 of the 33 cancer types. The introduced dataset can be used for research on TCGA data, such as survival analysis, histopathology image analysis and content-based image retrieval. The dataset is available online for download: https://kimialab.uwaterloo.ca/kimia/.

Risk Factors for Ipsilateral Breast Tumor Recurrence in Triple-Negative or HER2-Positive Breast Cancer Patients Who Achieve a Pathologic Complete Response After Neoadjuvant Chemotherapy

BACKGROUND

Attention has been focused on attempts to eliminate breast surgery for breast cancer patients who achieve a pathologic complete response after neoadjuvant chemotherapy (NAC). However, there are few data on ipsilateral breast tumor recurrence (IBTR) among patients with triple-negative or epidermal growth factor receptor 2-positive (HER2+) tumors who achieve a pathologic complete response after NAC and breast-conserving treatment.

METHODS

Using a multi-institutional retrospective database, this study evaluated the risk factors for IBTR among patients with newly diagnosed stages 1 to 3 breast cancer involving triple-negative or HER2+ tumors who achieved ypT0 after NAC and breast-conserving treatment.

RESULTS

During a median follow-up period of 4.8 years (range, 0.1-15.5 years), the 5-year IBTR-free survival rate was 95.5%. The breast cancer subtype was not associated with IBTR-free survival. Patients younger than 40 years at diagnosis had significantly worse IBTR-free survival than those who were 40 years of age or older (5-year IBTR-free survival, 87.7 vs 96.9%; p = 0.002).

CONCLUSIONS

This retrospective study demonstrated that age at diagnosis was independently associated with IBTR-free survival. Special caution is needed when clinical trials analyzing omission of breast surgery after NAC are enrolling younger patients (UMIN-CTR No. UMIN000037067).

DL, Esteban-Cardeñosa EM, Avila Cobos F, Lastra E, Abella LE, de la Cruz V, Lobatón CD, Claes KB, Durán M, Infante M. Germline Genetic Findings Which May Impact Therapeutic Decisions in Families with a Presumed Predisposition for Hereditary Breast and Ovarian Cancer

In this study, we aim to gain insight in the germline mutation spectrum of ATM, BARD1, BRIP1, ERCC4, PALB2, RAD51C and RAD51D in breast and ovarian cancer families from Spain. We have selected 180 index cases in whom a germline mutation in BRCA1 and BRCA2 was previously ruled out. The importance of disease-causing variants in these genes lies in the fact that they may have possible therapeutic implications according to clinical guidelines. All variants were assessed by combined annotation dependent depletion (CADD) for scoring their deleteriousness. In addition, we used the cancer genome interpreter to explore the implications of some variants in drug response. Finally, we compiled and evaluated the family history to assess whether carrying a pathogenic mutation was associated with age at diagnosis, tumour diversity of the pedigree and total number of cancer cases in the family. Eight unequivocal pathogenic mutations were found and another fourteen were prioritized as possible causal variants. Some of these molecular results could contribute to cancer diagnosis, treatment selection and prevention. We found a statistically significant association between tumour diversity in the family and carrying a variant with a high score predicting pathogenicity (p = 0.0003).

MUTATIONS OF GENES BRCA1 AND BRCA2 IN WOMEN WITH OVARIAN CANCER EXPOSED TO FACTORS OF CHORNOBYL NUCLEAR ACCIDENT

OBJECTIVE

to determine a frequency of germline mutations 185delAG, 5382insC in BRCA1 gene and 6174delT in BRCA2 gene in Ukrainian patients with OC including women who were exposed to the factors of Chornobyl nuclear accident.

MATERIAL AND METHODS

In the study we enrolled 306 OC patients of different age who were tested for the presence of the major BRCA1 and BRCA2 gene mutations using allele specific multiplex polymerase chain reaction.

RESULTS

The mutation frequency in patients exposed to IR with OC (main group) was 5.3 % (2 from 38). Among unexposed patients (control group) 11,2 % (30 from 268) of cases with mutation were identified. However, the dif- ference between the groups was not significant (p = 0.39). It was shown that the BRCA1/2 mutations frequency in the patient of both groups was 10,4 % (32 from 306). The mutation BRCA1 5382insC was positive in 87.5 % (28 from 32) of cases, nevertheless nobody was identified with the allelic variant BRCA2 6174delT among both groups. There was a tendency toward an earlier age of the OC manifestation in the patients exposed to IR due to Chornobyl nuclear accident compared to BRCA-positive women of the control group (р = 0.06). When comparing BRCA-positive and BRCA-negative patients with OC of the main group, there was a statistical significance regarding the earlier age of the disease manifestation in the patients with mutations (р = 0.04). However, such difference was not observed in the control group (р = 0.22).

CONCLUSIONS

The frequency of the mutations in exposed to IR and unexposed patients with OC does not differ and depends on a spectrum of studied BRCA1/2 gene mutations, level of DNA amplification and sample number. The allel- ic variant BRCA1 5382insC is dominant and accounts for 87.5 % of the total number of the found mutations. Due to the radiation factor the OC in the BRCA1-positive individuals is realized at the earlier age than in patients negative for these mutations. The incidence of OC after the Chornobyl accident was observed 27-38 years later in a cohort of women who were from 4 to 40 years old at the moment of the nuclear explosion.

Hereditary Predisposition to Prostate Cancer: From Genetics to Clinical Implications

Prostate cancer (PrCa) ranks among the top five cancers for both incidence and mortality worldwide. A significant proportion of PrCa susceptibility has been attributed to inherited predisposition, with 10-20% of cases expected to occur in a hereditary/familial context. Advances in DNA sequencing technologies have uncovered several moderate- to high-penetrance PrCa susceptibility genes, most of which have previously been related to known hereditary cancer syndromes, namely the hereditary breast and ovarian cancer (BRCA1, BRCA2, ATM, CHEK2, and PALB2) and Lynch syndrome (MLH1, MSH2, MSH6, and PMS2) genes. Additional candidate genes have also been suggested, but further evidence is needed to include them in routine genetic testing. Recommendations based on clinical features, family history, and ethnicity have been established for more cost-efficient genetic testing of patients and families who may be at an increased risk of developing PrCa. The identification of alterations in PrCa predisposing genes may help to inform screening strategies, as well as treatment options, in the metastatic setting. This review provides an overview of the genetic basis underlying hereditary predisposition to PrCa, the current genetic screening recommendations, and the implications for clinical management of the disease.

Early diagnosis of breast and ovarian cancers by body fluids circulating tumor-derived exosomes

Exosomes (EXs) are small extracellular vesicles, a size range of 40-100 nm in diameter, actively secreted by most eukaryotic cells into surrounding body fluids like blood, saliva, urine, bile, breast milk and etc. These endosomal-derived vesicles mediate cell-cell communication between various cell populations through transmitting different signaling molecules such as lipids, proteins, and nucleic acids, and participate in a wide range of physiological and pathological body processes. Tumor-derived EXs (TDEs) are vehicles for intercellular communications by transferring bioactive molecules; they deliver oncogenic molecules and contain different molecular cargoes compared to EXs delivered from normal cells, therefore, they can be used as non-invasive invaluable biomarkers for early diagnosis and prognosis of most cancers, including breast and ovarian cancers. Their presence and stability in different types of body fluids highlight them as a suitable diagnostic biomarker for distinguishing various cancer stages. In addition, EXs can predict the therapeutic efficacy of chemotherapy agents and drug resistance in cancer cells, as well as determine the risk of metastasis in different disease stages. In this study, the recent literature on the potential role of TDEs in the diagnosis and prognosis of ovarian and breast cancers is summarized, and then exosome isolation techniques including traditional and new approaches are briefly discussed.

Double mutation of APC and BRCA1 in an Italian family

Familial adenomatous polyposis (FAP) is a rare genetic disorder caused mainly by monoallelic mutations of APC gene. The hereditary breast and ovarian cancer (HBOC) syndrome is an autosomal dominantly inherited disease, which mostly predisposes to breast and ovarian cancers as a result of germline mutations in BRCA1 or BRCA2 genes. In a family, mutations in two cancer susceptibility genes are extremely rare. We studied a family with a case of a 46 years-old woman affected with FAP and ovarian cancer. The patient was affected with profuse FAP since the age of 18 years and a serous ovarian cancer was diagnosed at the age of 45 years. She reported other FAP cases and one case of breast cancer in maternal family. Initially, she was tested for FAP predisposition with mutational analysis of APC gene that revealed the presence of a frameshift mutation, c.3927_3931delAAAGA (p.Glu1309AspfsX4). The presence of ovarian cancer in the patient and of a breast cancer case in the maternal family, suggested an extended analysis to HBOC susceptibility genes that led to the detection of a frameshift mutation, c.3756_3759delGTCT (p.Ser1253Argfs), in BRCA1 gene. The genetic analysis was extended also to family members. The occurrence of the double mutation in APC and BRCA1 genes in the patient was responsible for the onset of FAP and ovarian cancer respectively. The genetic counselling in hereditary cancer with a careful analysis of the pedigree allows identifying the gene to be analyzed. The development of multi-gene panels testing for cancer predisposition, with next generation sequencing (NGS), may reveal mutations in genes of high and moderate penetrance for cancer, although at a low frequency and allows diagnosing a possible double heterozygosity. This enables an adjusted treatment for the affected patient and is critical as it allows initiation of early risk-reducing measures for identified mutation carriers among family members.

Detection of BRCA1/2 large genomic rearrangement including BRCA1 promoter-region deletions using next-generation sequencing

BACKGROUND

Germline mutations in BRCA1 and BRCA2 (BRCA1/2) have been conventionally analyzed by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). Nowadays, next-generation sequencing (NGS) is increasingly being used in clinical genetics. The aim of this study was to evaluate the performance of NGS BRCA1/2 assays by comparing them with the conventional method.

MATERIALS AND METHODS

We did BRCA1/2 NGS assays of 108 breast and/or ovarian cancer patients whose BRCA1/2 mutation had been previously analyzed by Sanger sequencing and MLPA using TruSeq Custom Amplicon Design AFP2. Single-nucleotide variations (SNVs) and small insertions or deletions (InDels) were evaluated. In addition, we analyzed large genomic rearrangements (LGRs) using a coverage-based algorithm as well as a revised BRCA1/2 NGS assay (BRCAaccuTest PLUS), which additionally covered a BRCA1 promoter region.

RESULTS

The NGS BRCA1/2 assay detected all 20 SNVs and 21 small InDels in 56 patients. Among seven LGRs detected by MLPA, six exonic LGRs were well identified by both NGS BRCA1/2 assays. One pathogenic LGR, located on a BRCA1 promoter region, was successfully identified using revised BRCAaccuTestPLUS.

CONCLUSIONS

These results indicated that an NGS BRCA1/2 assay could detect most LGRs including BRCA1 promoter-region deletion as well as SNVs and small InDels. Therefore, it was applicable to clinical BRCA1/2 mutation tests.

Role of Rad51 and DNA repair in cancer: A molecular perspective

The maintenance of genome integrity is essential for any organism survival and for the inheritance of traits to offspring. To the purpose, cells have developed a complex DNA repair system to defend the genetic information against both endogenous and exogenous sources of damage. Accordingly, multiple repair pathways can be aroused from the diverse forms of DNA lesions, which can be effective per se or via crosstalk with others to complete the whole DNA repair process. Deficiencies in DNA healing resulting in faulty repair and/or prolonged DNA damage can lead to genes mutations, chromosome rearrangements, genomic instability, and finally carcinogenesis and/or cancer progression. Although it might seem paradoxical, at the same time such defects in DNA repair pathways may have therapeutic implications for potential clinical practice. Here we provide an overview of the main DNA repair pathways, with special focus on the role played by homologous repair and the RAD51 recombinase protein in the cellular DNA damage response. We next discuss the recombinase structure and function per se and in combination with all its principal mediators and regulators. Finally, we conclude with an analysis of the manifold roles that RAD51 plays in carcinogenesis, cancer progression and anticancer drug resistance, and conclude this work with a survey of the most promising therapeutic strategies aimed at targeting RAD51 in experimental oncology.

Increased Cancer Prevalence in Peripartum Cardiomyopathy

Objectives

This study was designed to analyze the prevalence and potential genetic basis of cancer and heart failure in peripartum cardiomyopathy (PPCM).

Background

PPCM manifests as heart failure late in pregnancy or postpartum in women without previous heart disease.

Methods

Clinical history and cancer prevalence were evaluated in a cohort of 236 PPCM patients from Germany and Sweden. Exome sequencing assessed variants in 133 genes associated with cancer predisposition syndromes (CPS) and in 115 genes associated with dilated/hypertrophic cardiomyopathy (DCM/HCM) in 14 PPCM patients with a history of cancer, and in 6 PPCM patients without a history of cancer.

Results

The prevalence of cancer was 16-fold higher (8.9%, 21 of 236 patients) in PPCM patients compared to age-matched women (German cancer registry, Robert-Koch-Institute: 0.59%; p < 0.001). Cancer before PPCM occurred in 12 of 21 patients of whom 11 obtained cardiotoxic cancer therapies. Of those, 17% fully recovered cardiac function by 7 ± 2 months of follow-up compared to 55% of PPCM patients without cancer (p = 0.015). Cancer occurred after PPCM in 10 of 21 patients; 80% had left ventricular ejection fraction of ≥50% after cancer therapy. Whole-exome sequencing in 14 PPCM patients with cancer revealed that 43% (6 of 14 patients) carried likely pathogenic (Class IV) or pathogenic (Class V) gene variants associated with DCM/HCM in CPT2, DSP, MYH7, TTN, and/or with CPS in ATM, ERCC5, NBN, RECQL4, and SLX4. All CPS variants affected DNA damage response genes.

Conclusions

Cardiotoxic cancer therapy before PPCM is associated with delayed full recovery. The high cancer prevalence in PPCM is linked to likely pathogenic/pathogenic gene variants associated with DCM/HCM and/or CPS/DNA damage response-related cancer risk. This may warrant genetic testing and screening for heart failure in pregnant women with a cancer history and screening for cancer in PPCM patients.

Essential Saccharomyces cerevisiae genome instability suppressing genes identify potential human tumor suppressors

Gross Chromosomal Rearrangements (GCRs) play an important role in human diseases, including cancer. Although most of the nonessential Genome Instability Suppressing (GIS) genes in Saccharomyces cerevisiae are known, the essential genes in which mutations can cause increased GCR rates are not well understood. Here 2 S. cerevisiae GCR assays were used to screen a targeted collection of temperature-sensitive mutants to identify mutations that caused increased GCR rates. This identified 94 essential GIS (eGIS) genes in which mutations cause increased GCR rates and 38 candidate eGIS genes that encode eGIS1 protein-interacting or family member proteins. Analysis of TCGA data using the human genes predicted to encode the proteins and protein complexes implicated by the S. cerevisiae eGIS genes revealed a significant enrichment of mutations affecting predicted human eGIS genes in 10 of the 16 cancers analyzed.

Global celebrities' effect on health awareness among Jordanians: A study using the case of Angelina Jolie

Celebrities' health decisions have long been associated with heightened awareness and health trend changes. This is the first study conducted in an Arab population investigating the impact of international celebrity news on local communities using the case of Angelia Jolie's (AJ) prophylactic mastectomy and oophorectomy surgeries. The objective was to measure the effect of publicized medical information on cancer genetic testing knowledge, attitudes, and practices (KAP). This is a cross-sectional study using a semi-structured, self-administered questionnaire for clinic visitors at the King Hussein Cancer Center (KHCC). We had predominantly female (n = 262, 66.3%) and healthy participants (n = 248, 66.5%). Approximately 80.7% (n = 330) recognized AJ, the actress, and of these, 71% (n = 232) were aware of her recent diagnosis and prophylactic surgeries. Males reported a higher knowledge score (p < .001). However, females had more initiative to seek information (18.3% vs. 10.1%; p = .04). People aware of Angelina's prophylactic procedures were inclined to seek information regarding cancer genetics (20.8% vs. 9.6% p = .003). Breast and ovarian cancer patients were more likely than other cancer patients to encourage family members to undergo prophylactic surgery in case of BRCA1/2 mutations (39.2% vs. 17.1% p = .03). Ninety-three percent of the sample lacked knowledge regarding the availability of cancer genetic testing in Jordan. Results highlight a clear effect of celebrity medical news on our population, as well as openness to consider genetic testing as an early detection tool for women with a family history of breast and/or ovarian cancer. Generalization of these results to the population of Jordan requires further studies.