Clinical Considerations of BRCA1- and BRCA2-Mutation Carriers: A Review

The association between BRCA1 gene polymorphism and cancer risk: a meta-analysis

Many studies have reported that BRCA1 polymorphisms are associated with cancer risk, but the results remain controversial. The purpose of this meta-analysis is to evaluate the relationship between BRCA1 polymorphisms (rs799917, rs1799950, rs1799966, or rs16941) and cancer risk. Relevant studies were identified via a systematic search of the PubMed, Embase, and Web of Science databases up to July 31, 2017. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to examine the strength of the associations. Thirty-five studies published in 19 publications involving 28,094 cases and 50,657 controls were included in this meta-analysis. There was no obvious association between rs799917, rs1799966, or rs16941 polymorphisms and overall cancer risk in any genetic models. However, subgroup analyses revealed that the rs799917 polymorphism could decrease the risk of cervical cancer, esophageal squamous cell carcinoma (ESCC), gastric cancer, and non-Hodgkin lymphoma (NHL) among Asian populations in one or more genetic models and that rs16941 could increase overall cancer risk among Caucasian populations in the homozygote and recessive models. Our meta-analysis also indicated that rs1799950 could decrease the breast cancer (BC) risk among Caucasian populations in the homozygote and recessive models. In summary, our results suggest that BRCA1 polymorphisms may play an important role in the etiology of cancer. However, due to the limited number of studies, these findings should be confirmed by new studies with larger sample sizes that address various types of cancer.

Practical recommendations for fertility preservation in women by the FertiPROTEKT network. Part I: Indications for fertility preservation

Purpose

Most guidelines about fertility preservation are predominantly focused on scientific evidence, but are less practically orientated. Therefore, practically oriented recommendations are needed to support the clinician in daily practice.

Methods

A selective literature search was performed based on the clinical and scientific experience of the authors, focussing on the most relevant diseases and gynaecological cancers. This article (Part I) provides information on topics that are essential for the fertility preservation indication, such as disease prognosis, disease therapy and its associated risks to fertility, recommending disease-specific fertility preservation measures. Part II specifically focusses on fertility preservation techniques.

Results

In breast cancer patients, fertility preservation such as ovarian tissue and oocyte cryopreservation is especially recommended in low-stage cancer and in women < 35 years of age. In Hodgkin’s lymphoma, the indication is mainly based on the chemotherapy regime as some therapies have very low, others very high gonadotoxicity. In borderline ovarian tumours, preservation of fertility usually is achieved through fertility sparing surgery, ovarian stimulation may also be considered. In cervical cancer, endometrial cancer, rheumatic diseases and other malignancies such as Ewing sarcoma, colorectal carcinoma, non-Hodgkin lymphoma, leukaemia etc., several other factors must be considered to enable an individual, stage-dependent decision.

Conclusion

The decision for or against fertility preservation depends on the prognosis, the risks to fertility and individual factors such as prospective family planning.

Mutational analysis of BRCA1 and BRCA2 genes in Peruvian families with hereditary breast and ovarian cancer

Background

Breast cancer is one of the most prevalent malignancies in the world. In Peru, breast cancer is the second cause of death among women. Five to ten percent of patients present a high genetic predisposition due to BRCA1 and BRCA2 germline mutations.

Methods

We performed a comprehensive analysis of BRCA1 and BRCA2 genes by Sanger sequencing and multiplex ligation‐dependent probe amplification (MLPA) to detect large rearrangements in patients from 18 families, which met the criteria for hereditary breast cancer.

Results

In this series, we found four pathogenic mutations, three previously reported (BRCA1: c.302‐1G>C and c.815_824dup10; BRCA2: c.5946delT) and a duplication of adenines in exon 15 in BRCA1 gene (c.4647_4648dupAA, ClinVar SCV000256598.1). We also found two exonic and four intronic variants of unknown significance and 28 polymorphic variants.

Conclusion

This is the first report to determine the spectrum of mutations in the BRCA1/BRCA2 genes in Peruvian families selected by clinical and genetic criteria. The alteration rate in BRCA1/BRCA2 with proven pathogenic mutation was 22.2% (4 out 18) and this finding could be influenced by the reduced sample size or clinical criteria. In addition, we found three known BRCA1/BRCA2 mutations and a BRCA1 c.4647_4648dupAA as a novel pathogenic mutation.

[BRCA diagnostics of ovarian cancer : Molecular tumor testing since the introduction of PARP inhibitor therapy]

Approximately 9000 women are diagnosed with ovarian cancer in Germany each year. The most common subtype is high-grade serous ovarian cancer. A relevant proportion of these tumors are associated with mutations in the breast and ovarian cancer susceptibility genes (BRCA1 and BRCA2) representing highly penetrant tumor suppressor genes with autosomal inheritance and play a crucial role in DNA repair mechanisms. These patients have predominantly germline mutations and less frequently have somatic BRCA mutations. Tumors harboring BRCA mutations show a significant improvement in progression-free survival under therapy with poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors. In 2015 the first PARP inhibitor was approved for the therapy of high-grade serous ovarian cancer with BRCA mutations. Mutation analysis can be performed on formalin-fixed paraffin-embedded (FFPE) tumor tissue within a few days.

Understanding the cellular roles of Fyn-related kinase (FRK): implications in cancer biology

The non-receptor tyrosine kinase Fyn-related kinase (FRK) is a member of the BRK family kinases (BFKs) and is distantly related to the Src family kinases (SFKs). FRK was first discovered in 1993, and studies pursued thereafter attributed a potential tumour-suppressive function to the enzyme. In recent years, however, further functional characterization of the tyrosine kinase in diverse cancer types suggests that FRK may potentially play an oncogenic role as well. Specifically, while ectopic expression of FRK suppresses cell proliferation and migration in breast and brain cancers, knockdown or catalytic inhibition of FRK suppresses these cellular processes in pancreatic and liver cancer. Such functional paradox is therefore evidently exhibited in a tissue-specific context. This review sheds light on the recent developments emerged from investigations on FRK which include: (a) a review of the expression pattern of the protein in mammalian cells/tissues, (b) underlying genomic perturbations and (c) a mechanistic function of the enzyme across different cellular environments. Given its functional heterogeneity observed across different cancers, we also discuss the therapeutic significance of FRK.

Guidelines for complex genetic analysis of hereditary breast ovarian cancer syndrome in slovak population

Genetic diagnostics of hereditary breast and ovarian cancer (HBOC) has been performed in Slovakia in many different forms before the year 2000. Complex HBOC genetic analysis consists of many steps, including the initial genetic consultation, laboratory testing of genes associated with HBOC, interpretation and report of DNA analysis results, secondary explanatory genetic consultation and recommendation of clinical management for pathological mutation carriers. Many clinicians are participating on this workflow, such as clinical geneticists, laboratory diagnosticians as well as gynaecologists, oncologists or radio-diagnosticians. Currently, genetic testing is still technically and financially demanding and aimed only at selected families or patients who fulfil the defined clinical indication criteria.

Positive result of DNA analysis, that is, detection of pathological mutation in genes associated with HBOC syndrome means that the risk of breast/ovarian cancer onset in mutation carriers is amplified. This predisposition markedly affects the clinical management and treatment of patient and other members of the family, thus creating the demand to establish widely accepted specific recommendations for genetic diagnostics of HBOC. In the past, the analysis of HBOC in Slovakia followed various technical approaches and indication criteria depending on the workflow of specific laboratory. The guidelines reported below adhere to the current trends in DNA analysis and clinical healthcare, define the criteria for diagnostic laboratories, conditions for genetic testing and determine indications for selection of HBOC families and further clinical management of mutation carriers.

The role of Rak in the regulation of stability and function of BRCA1

BRCA1 is an important player in the DNA damage response signaling, and its deficiency results in genomic instability. A complete loss or significantly reduced BRCA1 protein expression is often found in sporadic breast cancer cases despite the absence of genetic or epigenetic aberrations, suggesting the existence of other regulatory mechanisms controlling BRCA1 protein expression. Herein, we demonstrate that Fyn-related kinase (Frk)/Rak plays an important role in maintaining genomic stability, possibly in part through positively regulating BRCA1 protein stability and function via tyrosine phosphorylation on BRCA1 Tyr1552. In addition, Rak deficiency confers cellular sensitivity to DNA damaging agents and poly(ADP-ribose) polymerase (PARP) inhibitors. Overall, our findings highlight a critical role of Rak in the maintenance of genomic stability, at least in part, through protecting BRCA1 and provide novel treatment strategies for patients with breast tumors lacking Rak.

BRCA1 and BRCA2 mutations in Iranian breast cancer patients: A systematic review

BACKGROUND

BRCA1/2 genes mutation prevalence varies among ethnic groups and may be influenced by founder mutations. Understanding BRCA1/2 genes mutations is important for reducing breast cancer (BC) incidence, accurate risk assessment and counseling. This systematic review of the literature was conducted to addressing BRCA1/2 mutations in Iranian BC patients.

MATERIALS AND METHODS

A search for relevant articles was run on before January 2014 using MedLine, PubMed, Science Iranian Database, Google, and Web sites related to the study topic. The key words included: BC and Iran with Genes, BRCA Genes, BRCA1 and BRCA2; "Cancer Genes," and "Iran."

RESULTS

Thirteen articles retrieved from this search strategy were eligible for this review. The overall BRCA1 mutation rate for Iranian female BC patients was detected 31.8% (377/1183). Although this gene mutation rate for male patients is <0.01%. Eight BRCA1 mutations (c. 4837A > G, c. 3419G > A, c. 3119G > A, c. 2612C > T, c. 3113A > G, c. 2311T > C, c. 4301T > C and c. 4308T > C in BRCA1, and one BRCA2 mutation (c. 6494G > C) were found in multiple case subjects and represent candidate founder mutations.

CONCLUSION

According to these studies, there is heterogeneity in BRCA mutations in Iranian BC patients.

Risk-reducing salpingo-oophorectomy: a meta-analysis on impact on ovarian cancer risk and all cause mortality in BRCA 1 and BRCA 2 mutation carriers

Background

Women with BRCA1 and BRCA2 mutation carriers are at substantially elevated risk of developing ovarian cancer. The aim of the meta-analysis is to clarify the role of risk-reducing salpingo-oophorectomy (RRSO) to reduce ovarian cancer risk and mortality in women with BRCA 1 and BRCA 2 mutation carriers.

Methods

Pubmed, Medline and Scopus were searched to select English-language articles. Two investigators independently extracted characteristics and results of selected studies. Articles were included only if prospective and if absolute numbers of ovarian cancer and death events were available or derivable from the test. Pooled hazard ratio (HR) with 95% confidence interval (CI) was calculated using fixed effects model.

Results

Meta-analysis of 3 prospective studies demonstrated a significant risk reduction of ovarian cancer with RRSO in BRCA 1 and BRCA 2 mutation carriers, as well as benefit in all-causes mortality incidence.

Conclusions

It may be justified to recommend RRSO to reduce ovarian cancer risk and all-causes mortality in women with a mutation in BRCA 1 and BRCA 2.

Management of genetic syndromes predisposing to gynecologic cancers

Women with personal and family histories consistent with gynecologic cancer-associated hereditary cancer susceptibility disorders should be referred for genetic risk assessment and counseling. Genetic counseling facilitates informed medical decision making regarding genetic testing, screening, and treatment, including chemoprevention and risk-reducing surgery. Because of limitations of ovarian cancer screening, hereditary breast and ovarian cancer-affected women are offered risk-reducing bilateral salpingo-oophorectomy (BSO) between ages 35 and 40 years, or when childbearing is complete. Women with documented Lynch syndrome, associated with mutations in mismatch repair genes, should be screened at a young age and provided prevention options, including consideration of risk-reducing total abdominal hysterectomy and BSO, as well as intensive gastrointestinal screening. Clinicians caring for high-risk women must consider the potential adverse ethical, legal, and social issues associated with hereditary cancer risk assessment and testing. Additionally, at-risk family members should be alerted to their cancer risks, as well as the availability of risk assessment, counseling, and treatment services.