BRCA2 gene mutation in cancer

Proof of Concept for Genome Profiling of the Neurofibroma/Sarcoma Sequence in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder characterized by the predisposition to develop tumors such as malignant peripheral nerve sheath tumors (MPNSTs) which represents the primary cause of death for NF1-affected patients. Regardless of the high incidence and mortality, the molecular mechanisms underneath MPNST growth and metastatic progression remain poorly understood. In this proof-of-concept study, we performed somatic whole-exome sequencing (WES) to profile the genomic alterations in four samples from a patient with NF1-associated MPNST, consisting of a benign plexiform neurofibroma, a primary MPNST, and metastases from lung and skin tissues. By comparing genomic patterns, we identified a high level of variability across samples with distinctive genetic changes which allow for the definition of profiles of the early phase with respect to the late metastatic stages. Pathogenic and likely pathogenic variants were abundant in the primary tumor, whereas the metastatic samples exhibited a high level of copy-number variations (CNVs), highlighting a possible genomic instability in the late phases. The most known MPNST-related genes, such as TP53 and SUZ12, were identified in CNVs observed within the primary tumor. Pathway analysis of altered early genes in MPNST pointed to a potential role in cell motility, division and metabolism. Moreover, we employed survival analysis with the TCGA sarcoma genomic dataset on 262 affected patients, in order to corroborate the predictive significance of the identified early and metastatic MPNST driver genes. Specifically, the expression changes related to the mutated genes, such as in RBMX, PNPLA6 and AGAP2, were associated with reduced patient survival, distinguishing them as potential prognostic biomarkers. This study underlines the relevance of integrating genomic results with clinical information for early diagnosis and prognostic understanding of tumor aggressiveness.

Exogenous and endogenous formaldehyde-induced DNA damage in the aging brain: mechanisms and implications for brain diseases

Exogenous gaseous formaldehyde (FA) is recognized as a significant indoor air pollutant due to its chemical reactivity and documented mutagenic and carcinogenic properties, particularly in its capacity to damage DNA and impact human health. Despite increasing attention on the adverse effects of exogenous FA on human health, the potential detrimental effects of endogenous FA in the brain have been largely neglected in current research. Endogenous FA have been observed to accumulate in the aging brain due to dysregulation in the expression and activity of enzymes involved in FA metabolism. Surprisingly, excessive FA have been implicated in the development of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and brain cancers. Notably, FA has the ability to not only initiate DNA double strand breaks but also induce the formation of crosslinks of DNA-DNA, DNA-RNA, and DNA-protein, which further exacerbate the progression of these brain diseases. However, recent research has identified that FA-resistant gene exonuclease-1 (EXO1) and FA scavengers can potentially mitigate FA toxicity, offering a promising strategy for mitigating or repairing FA-induced DNA damage. The present review offers novel insights into the impact of FA metabolism on brain ageing and the contribution of FA-damaged DNA to the progression of neurological disorders.

ADAR1 promotes cisplatin resistance in intrahepatic cholangiocarcinoma by regulating BRCA2 expression through A-to-I editing manner

Aberrant A-to-I RNA editing, mediated by ADAR1 has been found to be associated with increased tumourigenesis and the development of chemotherapy resistance in various types of cancer. Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive malignancy with a poor prognosis, and overcoming chemotherapy resistance poses a significant clinical challenge. This study aimed to clarify the roles of ADAR1 in tumour resistance to cisplatin in iCCA. We discovered that ADAR1 expression is elevated in iCCA patients, particularly in those resistant to cisplatin, and associated with poor clinical outcomes. Downregulation of ADAR1 can increase the sensitivity of iCCA cells to cisplatin treatment, whereas its overexpression has the inverse effect. By integrating RNA sequencing and Sanger sequencing, we identified BRCA2, a critical DNA damage repair gene, as a downstream target of ADAR1 in iCCA. ADAR1 mediates the A-to-I editing in BRCA2 3'UTR, inhibiting miR-3157-5p binding, consequently increasing BRCA2 mRNA and protein levels. Furthermore, ADAR1 enhances cellular DNA damage repair ability and facilitates cisplatin resistance in iCCA cells. Combining ADAR1 targeting with cisplatin treatment markedly enhances the anticancer efficacy of cisplatin. In conclusion, ADAR1 promotes tumour progression and cisplatin resistance of iCCA. ADAR1 targeting could inform the development of innovative combination therapies for iCCA.

BRCA2 mutations in familial breast cancer with prostate cancer: a case report and literature review

Prostate cancer (PCa) is the second most common tumor in men globally. Its etiology has been attributed to multiple factors, including age and ethnicity, with family history identified as a significant risk factor. The role of family history in prostate cancer risk appears to be more extensive than previously thought, with evidence suggesting that prostate cancer and breast cancer may occur concurrently within families. BRCA2 mutations have been linked to an increased risk of prostate cancer, particularly in patients diagnosed with early-onset disease. It is estimated that BRCA2 mutations account for approximately 5% of familial prostate cancer cases. It is noteworthy that cases of prostate cancer in patients with BRCA2 mutations are rare in clinical practice. Here we report a case of prostatitis carcinoma with a mutation in the BRCA2 gene in a patient who underwent robotic-assisted radical prostatectomy for prostatitis carcinoma after medication was not effective. Genetic testing of him, his son, and his daughter showed that they all had mutations in this gene, and it is noteworthy that the type of BRCA2 mutation in his son has never been reported before, which is rare in clinical practice.

Effects of Hormonal Replacement Therapy and Mindfulness-Based Stress Reduction on Climacteric Symptoms Following Risk-Reducing Salpingo-Oophorectomy

Breast Cancer Associated Susceptibility Proteins Type 1/2 (BRCA1/2) promote cellular functioning by modulating NRF2-mediated antioxidant signaling. Redox failure in women with BRCA1/2 insufficiency increases the risk for breast/ovarian/uterine cancers. Risk-reducing salpingo-oophorectomy (RRSO) is a prophylactic surgery of the reproductive organs, which is frequently conducted by the age of 40 to lower the occurrence of cancer in women with BRCA1/2 mutations. However, abrupt estrogen decline following RRSO causes ovarian failure, which implicates various cellular physiological processes, resulting in the increased release of free radicals and subsequent severe onset of menopausal symptoms. Comfort measures (e.g., hormonal replacement therapy (HRT) and mindfulness-based stress reduction (MBSR)) may improve chronological menopause-related quality of life, but their specific effects are not clear in women with gene mutations. Aiming to fill the gap, this study used path analysis to examine the effects of HRT and MBSR on menopausal symptoms among RRSO patients (N = 199, mean age = 50.5 ± 6.7 years). HRT directly alleviated the levels of urogenital symptoms (β = -0.195, p = 0.005), which mediated its indirect significant effects on the somatic-vegetative and psychological symptoms of menopause (β = -0.046, -0.067; both p values = 0.004, respectively), especially in BRCA2 carriers and in women who were currently physically active, premenopausal at the time of RRSO, had a high BMI, and had no history of breast cancer. It increased the severity of urogenital symptoms in women with a history of cancer. MBSR, on the other hand, was associated with indirect increases in the intensity of the somatic-vegetative and psychological symptoms of menopause (β = 0.108, 0.029; p = 0.003, 0.033, respectively). It exerted positive direct effects on different menopausal symptoms in multigroup analysis. The results suggest that young women undergoing recent RRSO may benefit from HRT at an individual level, while their need for extensive measures to optimize their psychological wellbeing is ongoing. The adverse effects of MBSR, which are captured in the present study, imply that MBSR may interfere with redox sensitivity associated with estradiol fluctuations in BRCA1/2 carriers. Investigations are needed to test this hypothesis and elaborate on the underlying mechanisms in these women.

In silico analysis of the wild-type and mutant-type of BRCA2 gene

BACKGROUND

The aim of this study was to conduct an in silico analysis of a novel compound heterozygous variant in breast cancer susceptibility gene 2 (BRCA2) to clarify its structure-function relationship and elucidate the molecular mechanisms underlying triple-negative breast cancer (TNBC).

METHODS

A tumor biopsy sample was obtained from a 42-year-old Chinese woman during surgery, and a maxBRCA™ test was conducted using the patient's whole blood. We obtained an experimentally determined 3D structure (1mje.pdb) of the BRCA2 protein from the Protein Data Bank (PDB) as a relatively reliable reference. Subsequently, the wild-type and mutant structures were predicted using SWISS-MODEL and AlphaFold, and the accuracy of these predictions was assessed through the SAVES online server. Furthermore, we utilized a high ambiguity-driven protein-protein docking (HADDOCK) algorithm and protein-ligand interaction profiler (PLIP) to predict the pathogenicity of the mutations and elucidate pathogenic mechanisms that potentially underlies TNBC.

RESULTS

Histological examination revealed that the tumor biopsy sample exhibited classical pathological characteristics of TNBC. Furthermore, the maxBRCA™ test revealed two compound heterozygous BRCA2 gene mutations (c.7670 C > T.pA2557V and c.8356G > A.pA2786T). Through performing in silico structural analyses and constructing of 3D models of the mutants, we established that the mutant amino acids valine and threonine were located in the helical domain and oligonucleotide binding 1 (OB1), regions that interact with DSS1.

CONCLUSION

Our analysis revealed that substituting valine and threonine in the helical domain region alters the structure and function of BRCA2 proteins. This mutation potentially affects the binding of proteins and DNA fragments and disrupts interactions between the helical domain region and OB1 with DSS1, potentially leading to the development of TNBC. Our findings suggest that the identified compound heterozygous mutation contributes to the clinical presentation of TNBC, providing new insights into the pathogenesis of TNBC and the influence of compound heterozygous mutations in BRCA2.

Fertility Preservation in BRCA1/2 Germline Mutation Carriers: An Overview

BRCA1 and BRCA2 mutations are responsible for a higher incidence of breast and ovarian cancer (from 55% up to 70% vs. 12% in the general population). If their functions have been widely investigated in the onset of these malignancies, still little is known about their role in fertility impairment. Cancer patients treated with antineoplastic drugs can be susceptible to their gonadotoxicity and, in women, some of them can induce apoptotic program in premature ovarian follicles, progressive depletion of ovarian reserve and, consequently, cancer treatment-related infertility (CTRI). BRCA variants seem to be associated with early infertility, thus accelerating treatment impairment of ovaries and making women face the concrete possibility of an early pregnancy. In this regard, fertility preservation (FP) procedures should be discussed in oncofertility counseling-from the first line of prevention with risk-reducing salpingo-oophorectomy (RRSO) to the new experimental ovarian stem cells (OSCs) model as a new way to obtain in vitro-differentiated oocytes, several techniques may represent a valid option to BRCA-mutated patients. In this review, we revisit knowledge about BRCA involvement in lower fertility, pregnancy feasibility, and the fertility preservation (FP) options available.

Remarkable response to pazopanib plus vivolumab in a patient with pericardial synovial sarcoma carrying a novel genotype BRCA2 c.968dupT: A case report

Pericardial synovial sarcomas (PSS) have a low incidence rate and are highly invasive with a dismal prognosis. Standard treatment includes surgery, radiotherapy and chemotherapy but with limited response. Here, we report the case of a 15-year-old nonsmoking youngster diagnosed with PSS who developed disease relapsed from surgery after 1 month. Next-generation sequencing (NGS) using baseline tissue was performed, and BRCA2 c.968dupT was detected. Then pazopanib (a multitargeted inhibitor) plus nivolumab (an immune checkpoint inhibitor) was administered, with a partial response and progression-free survival of 14 months. BRCA2 c.968dupT has not previously been reported in PSS and its response to targeted combination immunotherapy are not well characterized. Here, we report the efficacy of pazopanib combined with nivolumab in a PSS patient harboring BRCA2 c.968dupT and also provide the clinical evidence of the utility of NGS in exploring actionable mutations for solid tumor. Combination therapy based on immunotherapy may be a potential treatment choice for PSS harboring BRCA2 mutation.

Correlation between main pancreatic duct diameter measurements: Special pancreatic ultrasonography versus magnetic resonance cholangiopancreatography

Main pancreatic duct (MPD) dilatation is reported to be a risk factor for pancreatic cancer (PC). Although magnetic resonance cholangiopancreatography (MRCP) and ultrasonographic modalities are valuable for monitoring the pancreas, there is limited information on the efficacy of different imaging modalities in measuring MPD diameter. To improve pancreatic imaging, we developed a specialized ultrasound approach focusing on the pancreas (special pancreatic US). We aimed to examine the correlation between MPD diameter measurements using special pancreatic US versus MRCP. We retrospectively reviewed the clinical data of patients with MPD dilation (≥2.5 mm) via special pancreatic US used for screening at our institution between January 2020 and October 2022 and included patients who underwent magnetic resonance imaging 2 months before and after pancreatic US. The MPD diameter on MRCP was measured at the pancreatic locus, where the maximum MPD diameter was obtained on special pancreatic US. This study included 96 patients, with a median interval of 8.5 days between the date of special pancreatic US and the date of undergoing MRCP. MPD dilatation and/or pancreatic cysts were diagnosed in 86 patients, PC in 5 patients, and other diseases in 5 patients. The median MPD diameter, measured using special pancreatic US, was 3.4 mm (interquartile range: 2.9-4.9 mm), whereas it was 3.5 mm using MRCP (interquartile range: 2.8-4.5 mm). There were strong positive correlations between MPD diameter measured on special pancreatic US and that measured on MRCP (R = 0.925, P < .001). This study revealed strong positive correlations between the MPD diameter measurements using special pancreatic US and MRCP. MPD diameter measurements from each imaging method can be helpful during follow-up in individuals at a high risk of PC.

Developments in Genetics: Better Management of Ovarian Cancer Patients

The purpose of this article is to highlight the new advancements in molecular and diagnostic genetic testing and to properly classify all ovarian cancers. In this article, we address statistics, histopathological classification, molecular pathways implicated in ovarian cancer, genetic screening panels, details about the genes, and also candidate genes. We hope to bring new information to the medical field so as to better prevent and diagnose ovarian cancer.

Mutational spectrum of DNA damage and mismatch repair genes in prostate cancer

Over the past few years, a number of studies have revealed that a significant number of men with prostate cancer had genetic defects in the DNA damage repair gene response and mismatch repair genes. Certain of these modifications, notably gene alterations known as homologous recombination (HRR) genes; PALB2, CHEK2 BRCA1, BRCA2, ATM, and genes for DNA mismatch repair (MMR); MLH1, MSH2, MSH6, and PMS2 are connected to a higher risk of prostate cancer and more severe types of the disease. The DNA damage repair (DDR) is essential for constructing and diversifying the antigen receptor genes required for T and B cell development. But this DDR imbalance results in stress on DNA replication and transcription, accumulation of mutations, and even cell death, which compromises tissue homeostasis. Due to these impacts of DDR anomalies, tumor immunity may be impacted, which may encourage the growth of tumors, the release of inflammatory cytokines, and aberrant immune reactions. In a similar vein, people who have altered MMR gene may benefit greatly from immunotherapy. Therefore, for these treatments, mutational genetic testing is indicated. Mismatch repair gene (MMR) defects are also more prevalent than previously thought, especially in patients with metastatic disease, high Gleason scores, and diverse histologies. This review summarizes the current information on the mutation spectrum and clinical significance of DDR mechanisms, such as HRR and MMR abnormalities in prostate cancer, and explains how patient management is evolving as a result of this understanding.

The Clinical Significance of Genetic Variation in Ovarian Cancer

Genetic variation is a well-known contributor to the onset and progression of cancer. The goal of this study is to provide a comprehensive examination of the nucleotide and chromosomal variation associated with the onset and progression of serous ovarian cancer. Using a variety of computational and statistical methods, we examine the exome sequence profiles of genetic variants present in the primary tumors of 432 ovarian cancer patient samples to compute: (1) the tumor mutational burden for all genes and (2) the chromosomal copy number alterations associated with the onset/progression of ovarian cancer. Tumor mutational burden is reduced in the late vs. early stages, with the highest levels being associated with loss-of-function mutations in DNA-repair genes. Nucleotide variation and copy number alterations associated with known cancer driver genes are selectively favored over ovarian cancer development. The results indicate that genetic variation is a significant contributor to the onset and progression of ovarian cancer. The measurement of the relative levels of genetic variation associated with individual ovarian cancer patient tumors may be a clinically valuable predictor of potential tumor aggressiveness and resistance to chemotherapy. Tumors found to be associated with high levels of genetic variation may help in the clinical identification of high-risk ovarian cancer patients who could benefit from more frequent monitoring.

Clinical characterization and genomic landscape of gynecological cancers among patients attending a Chinese hospital

Background

Gynecological cancers are the most lethal malignancies among females, most of which are associated with gene mutations. Few studies have compared the differences in the genomic landscape among various types of gynecological cancers. In this study, we evaluated the diversity of mutations in different gynecological cancers.

Methods

A total of 184 patients with gynecological cancer, including ovarian, cervical, fallopian tube, and endometrial cancer, were included. Next-generation sequencing was performed to detect the mutations and tumor mutational burden (TMB). Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses were also conducted.

Results

We found that 94.57% of patients had at least one mutation, among which single nucleotide variants, insertions and InDels were in the majority. TP53, PIK3CA, PTEN, KRAS, BRCA1, BRCA2, ARID1A, KMT2C, FGFR2, and FGFR3 were the top 10 most frequently mutated genes. Patients with ovarian cancer tended to have higher frequencies of BRCA1 and BRCA2 mutations, and the frequency of germline BRCA1 mutations (18/24, 75.00%) was higher than that of BRCA2 (11/19, 57.89%). A new mutation hotspot in BRCA2 (I770) was firstly discovered among Chinese patients with gynecological cancer. Patients with TP53, PIK3CA, PTEN, and FGFR3 mutations had significantly higher TMB values than those with wild-type genes. A significant cross was discovered between the enriched KEGG pathways of gynecological and breast cancers. GO enrichment revealed that the mutated genes were crucial for the cell cycle, neuronal apoptosis, and DNA repair.

Conclusion

Various gynecological cancer types share similarities and differences both in clinical characterization and genomic mutations. Taken together with the results of TMB and enriched pathways, this study provided useful information on the molecular mechanism underlying gynecological cancers and the development of targeted drugs and precision medicine.