Ploidy inference from single-cell data: application to human and mouse cell atlases.

Ploidy is relevant to numerous biological phenomena, including development, metabolism, and tissue regeneration. Single-cell RNA-seq and other omics studies are revolutionizing our understanding of biology, yet they have largely overlooked ploidy. This is likely due to the additional assay step required for ploidy measurement. Here, we developed a statistical method to infer ploidy from single-cell ATAC-seq data, addressing this gap. When applied to data from human and mouse cell atlases, our method enabled systematic detection of polyploidy across diverse cell types. This method allows for the integration of ploidy analysis into single-cell studies. Additionally, this method can be adapted to detect the proliferating stage in the cell cycle and copy number variations in cancer cells. The software is implemented as the scPloidy package of the R software and is freely available from CRAN.

Eliminating extracellular autoinducing peptide signals inhibits the Staphylococcus aureus quorum sensing agr system.

An accessory gene regulator (agr) in the quorum sensing (QS) system in Staphylococcus aureus contributes to host infection, virulence factor production, and resistance to oxidative damage. Artificially maintaining the inactive state of agr QS impedes the host infection strategy of S. aureus and inhibits toxin production. The QS system performs intercellular signal transduction, which is activated by the mature autoinducer peptide (AIP). It is released from cells after AgrD peptide processing as an intercellular signal associated with increased bacterial cell density. This study evaluated the effectiveness of inhibiting agr QS wherein AIP trap carriers were made to coexist when culturing Staphylococcus aureus. Immersing a nitrocellulose (NC) membrane in Staphylococcus aureus ATCC 12600 culture inhibited QS-dependent α-hemolysin production, which significantly reduced the hemolysis ratio of sheep red blood cells by the culture supernatant. A quartz crystal microbalance analysis supported AIP adsorption onto the NC membrane. Adding the NC membrane during culture was found to maintain the expression levels of the agr QS gene agrA and α-hemolysin gene hla lower than that when it was not added. Eliminating extracellular AIP signals allowed agr QS to remain inactive and prevented QS-dependent α-hemolysin expression. Isolating intercellular signals secreted outside the cell is an effective strategy to suppress gene expression in bacterial cells that collaborate via intercellular signaling.

Four-week inhibition of the renin-angiotensin system in spontaneously hypertensive rats results in persistently lower blood pressure with reduced kidney renin and changes in expression of relevant gene networks.

AIMS: Prevention of human hypertension is an important challenge and has been achieved in experimental models. Brief treatment with renin-angiotensin system (RAS) inhibitors permanently reduces the genetic hypertension of the spontaneously hypertensive rat (SHR). The kidney is involved in this fascinating phenomenon, but relevant changes in gene expression are unknown. METHODS: In SHR, we studied the effect of treatment between 10 and 14 weeks of age with the angiotensin receptor blocker, losartan, or the angiotensin-converting enzyme (ACE) inhibitor, perindopril (with controls for non-specific effects of lowering BP) on differential RNA expression, DNA methylation and renin immunolabelling in the kidney at 20 weeks of age. RESULTS: RNA sequencing revealed a 6-fold increase in renin gene (Ren) expression during losartan treatment (P < 0.0001). Six weeks after losartan, arterial pressure remained lower (P = 0.006), yet kidney Ren showed reduced expression by 23% after losartan (P = 0.03) and by 43% after perindopril (P = 1.4 x 10-6) associated with increased DNA methylation (P = 0.04). Immunolabelling confirmed reduced cortical renin after earlier RAS blockade (P = 0.002). RNA sequencing identified differential expression of mRNAs, miRNAs and lncRNAs with evidence of networking and co-regulation. These included 13 candidate genes (Grhl1, Ammecr1l, Hs6st1, Nfil3, Fam221a, Lmo4, Adamts1, Cish, Hif3a, Bcl6, Rad54l2, Adap1, Dok4), the miRNA miR-145-3p and the lncRNA AC115371. Gene ontogeny analyses revealed that these networks were enriched with genes relevant to BP, RAS and the kidneys. CONCLUSIONS: Early RAS inhibition in SHR resets genetic pathways and networks resulting in a legacy of reduced Ren expression and BP persisting for a minimum of 6 weeks.

A Case of Ventricular Fibrillation in Masked Long-QT Syndrome Coexisting with Coronary Vasospasm.

Although long-QT syndrome (LQTS) with a normal range QT interval at rest leads to fatal ventricular arrhythmias, it is difficult to diagnose. In this article, we present a rare case of a patient who suffered a cardiac arrest and was recently diagnosed with LQTS and coronary vasospasm. A 62-year-old man with no syncopal episodes had a cardiopulmonary arrest while running. During coronary angiography, vasospasm was induced and we prescribed coronary vasodilators, including calcium channel blockers. An exercise stress test was performed to evaluate the effect of medications and accidentally unveiled exercise-induced QT prolongation. He was diagnosed with LQTS based on diagnostic criteria. Pharmacotherapy and an implantable cardioverter defibrillator were used for his medical management. It is extremely rare for LQTS and coronary vasospasm to coexist. In cases of exercise-induced arrhythmic events, the exercise stress test might be helpful to diagnose underlying disease.

Genotypes of Stim1 and the proximal region on chromosome 1 exert opposite effects on stroke susceptibility in stroke-prone spontaneously hypertensive rat.

BACKGROUND: The stroke-prone spontaneously hypertensive rat (SHRSP) is a genetic model for cerebral stroke. Although a recent study on a congenic SHRSP suggested that a nonsense mutation in stromal interaction molecule 1 ( Stim1 ) encoding a major component of store-operated Ca 2+ entry was a causal variant for stroke in SHRSP, this was not conclusive because the congenic region including Stim1 in that rat was too wide. On the other hand, we demonstrated that the Wistar-Kyoto (WKY)-derived congenic fragment adjacent to Stim1 exacerbated stroke susceptibility in a congenic SHRSP called SPwch1.71. In the present study, we directly examined the effects of the Stim1 genotype on stroke susceptibility using SHRSP in which wild-type Stim1 was knocked in (called Stim1 -KI SHRSP). The combined effects of Stim1 and the congenic fragment of SPwch1.71 were also investigated. METHODS: Stroke susceptibility was assessed by the stroke symptom-free and survival periods based on observations of behavioral symptoms and reductions in body weight. RESULTS: Stim1 -KI SHRSP was more resistant to, while SPwch1.71 was more susceptible to stroke than the original SHRSP. Introgression of the wild-type Stim1 of Stim1 -KI SHRSP into SPwch1.71 by the generation of F1 rats ameliorated stroke susceptibility in SPwch1.71. Gene expression, whole-genome sequencing, and biochemical analyses identified Art2b , Folr1 , and Pde2a as possible candidate genes accelerating stroke in SPwch1.71. CONCLUSION: The substitution of SHRSP-type Stim1 to wild-type Stim1 ameliorated stroke susceptibility in both SHRSP and SPwch1.71, indicating that the nonsense mutation in Stim1 is causally related to stroke susceptibility in SHRSP.

Deciphering the genetic landscape of obesity: a data-driven approach to identifying plausible causal genes and therapeutic targets.

OBJECTIVES: Genome-wide association studies (GWAS) have successfully revealed numerous susceptibility loci for obesity. However, identifying the causal genes, pathways, and tissues/cell types responsible for these associations remains a challenge, and standardized analysis workflows are lacking. Additionally, due to limited treatment options for obesity, there is a need for the development of new pharmacological therapies. This study aimed to address these issues by performing step-wise utilization of knowledgebase for gene prioritization and assessing the potential relevance of key obesity genes as therapeutic targets. METHODS AND RESULTS: First, we generated a list of 28,787 obesity-associated SNPs from the publicly available GWAS dataset (approximately 800,000 individuals in the GIANT meta-analysis). Then, we prioritized 1372 genes with significant in silico evidence against genomic and transcriptomic data, including transcriptionally regulated genes in the brain from transcriptome-wide association studies. In further narrowing down the gene list, we selected key genes, which we found to be useful for the discovery of potential drug seeds as demonstrated in lipid GWAS separately. We thus identified 74 key genes for obesity, which are highly interconnected and enriched in several biological processes that contribute to obesity, including energy expenditure and homeostasis. Of 74 key genes, 37 had not been reported for the pathophysiology of obesity. Finally, by drug-gene interaction analysis, we detected 23 (of 74) key genes that are potential targets for 78 approved and marketed drugs. CONCLUSIONS: Our results provide valuable insights into new treatment options for obesity through a data-driven approach that integrates multiple up-to-date knowledgebases.

Gene-regulation modules in nonalcoholic fatty liver disease revealed by single-nucleus ATAC-seq.

We investigated the progression of nonalcoholic fatty liver disease from fatty liver to steatohepatitis using single-nucleus and bulk ATAC-seq on the livers of rats fed a high-fat diet (HFD). Rats fed HFD for 4 wk developed fatty liver, and those fed HFD for 8 wk further progressed to steatohepatitis. We observed an increase in the proportion of inflammatory macrophages, consistent with the pathological progression. Utilizing machine learning, we divided global gene regulation into modules, wherein transcription factors within a module could regulate genes within the same module, reaffirming known regulatory relationships between transcription factors and biological processes. We identified core genes-central to co-expression and protein-protein interaction-for the biological processes discovered. Notably, a large part of the core genes overlapped with genes previously implicated in nonalcoholic fatty liver disease. Single-nucleus ATAC-seq, combined with data-driven statistical analysis, offers insight into in vivo global gene regulation as a combination of modules and assists in identifying core genes of relevant biological processes.

Trans-ethnic genomic informed risk assessment for Alzheimer's disease: An International Hundred K+ Cohorts Consortium study.

BACKGROUND: As a collaboration model between the International HundredK+ Cohorts Consortium (IHCC) and the Davos Alzheimer's Collaborative (DAC), our aim was to develop a trans-ethnic genomic informed risk assessment (GIRA) algorithm for Alzheimer's disease (AD). METHODS: The GIRA model was created to include polygenic risk score calculated from the AD genome-wide association study loci, the apolipoprotein E haplotypes, and non-genetic covariates including age, sex, and the first three principal components of population substructure. RESULTS: We validated the performance of the GIRA model in different populations. The proteomic study in the participant sites identified proteins related to female infertility and autoimmune thyroiditis and associated with the risk scores of AD. CONCLUSIONS: As the initial effort by the IHCC to leverage existing large-scale datasets in a collaborative setting with DAC, we developed a trans-ethnic GIRA for AD with the potential of identifying individuals at high risk of developing AD for future clinical applications.

Hereditary Hemorrhagic Telangiectasia Presenting with Asymptomatic Liver Lesions and a History of Early-onset Myocardial Infarction and Multiple Intracranial Aneurysms.

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder of the vasculature, characterized by epistaxis, telangiectasia and arteriovenous malformations in multiple organs. We herein report a 49-year-old woman with a history of early-onset myocardial infarction and intracranial aneurysms, in whom we incidentally detected multiple hepatic vascular abnormalities. We subsequently diagnosed her with HHT after discovering gastrointestinal telangiectases and a pulmonary arteriovenous fistula along with a history of recurrent epistaxis. Whole-exome sequencing revealed a novel pathogenic variant in SMAD4, a relatively rare causative gene for HHT. This case highlights the fact that HHT patients may present with asymptomatic liver lesions.

Phase Transfer of AMIET-functionalized Gold Nanoparticles from Aqueous to Organic Solvents.

This paper presents a feasible and reliable phase transfer protocol for polyoxyethylene alkyl amine surfactant (AMIET)-coated gold nanoparticles (AuNPs) in aqueous media to chloroform using a pH-triggered method, through the liquid-liquid interface. In the initial stage, the colloidal aqueous dispersion is destabilized by pH adjustment towards the isoelectric pH of the nanoparticle, which promotes the separation of the particles from water. We further explored a mechanistic view of this phase transfer phenomenon, considering the orientation of hydrophilic and hydrophobic moieties depending on the nature of the surrounding solvent. It was proposed that the AMIET molecules bound to the AuNPs undergo conformational changes through phase transfer. Ultraviolet visible absorption spectra before and after the phase transfer reveal that the original morphology and dispersion states of the particles were preserved.

Identification of genetic effects underlying type 2 diabetes in South Asian and European populations.

South Asians are at high risk of developing type 2 diabetes (T2D). We carried out a genome-wide association meta-analysis with South Asian T2D cases (n = 16,677) and controls (n = 33,856), followed by combined analyses with Europeans (neff = 231,420). We identify 21 novel genetic loci for significant association with T2D (P = 4.7 × 10-8 to 5.2 × 10-12), to the best of our knowledge at the point of analysis. The loci are enriched for regulatory features, including DNA methylation and gene expression in relevant tissues, and highlight CHMP4B, PDHB, LRIG1 and other genes linked to adiposity and glucose metabolism. A polygenic risk score based on South Asian-derived summary statistics shows ~4-fold higher risk for T2D between the top and bottom quartile. Our results provide further insights into the genetic mechanisms underlying T2D, and highlight the opportunities for discovery from joint analysis of data from across ancestral populations.

A polygenic risk score improves risk stratification of coronary artery disease: a large-scale prospective Chinese cohort study.

AIMS: To construct a polygenic risk score (PRS) for coronary artery disease (CAD) and comprehensively evaluate its potential in clinical utility for primary prevention in Chinese populations. METHODS AND RESULTS: Using meta-analytic approach and large genome-wide association results for CAD and CAD-related traits in East Asians, a PRS comprising 540 genetic variants was developed in a training set of 2800 patients with CAD and 2055 controls, and was further assessed for risk stratification for CAD integrating with the guideline-recommended clinical risk score in large prospective cohorts comprising 41 271 individuals. During a mean follow-up of 13.0 years, 1303 incident CAD cases were identified. Individuals with high PRS (the highest 20%) had about three-fold higher risk of CAD than the lowest 20% (hazard ratio 2.91, 95% confidence interval 2.43-3.49), with the lifetime risk of 15.9 and 5.8%, respectively. The addition of PRS to the clinical risk score yielded a modest yet significant improvement in C-statistic (1%) and net reclassification improvement (3.5%). We observed significant gradients in both 10-year and lifetime risk of CAD according to the PRS within each clinical risk strata. Particularly, when integrating high PRS, intermediate clinical risk individuals with uncertain clinical decision for intervention would reach the risk levels (10-year of 4.6 vs. 4.8%, lifetime of 17.9 vs. 16.6%) of high clinical risk individuals with intermediate (20-80%) PRS. CONCLUSION: The PRS could stratify individuals into different trajectories of CAD risk, and further refine risk stratification for CAD within each clinical risk strata, demonstrating a great potential to identify high-risk individuals for targeted intervention in clinical utility.

Clinical Implication of Smoking-Related Aryl-Hydrocarbon Receptor Repressor (AHRR) Hypomethylation in Japanese Adults.

BACKGROUND: Tobacco smoking is a leading preventable cause of morbidity and mortality worldwide; still, the success rate of smoking cessation is low in general. From the viewpoint of public health and clinical care, an objective biomarker of long-term smoking behavior is sought.Methods and Results: This study assessed DNA methylation as a biomarker of smoking in a hospital setting through a combination of molecular approaches including genetic, DNA methylation and mRNA expression analyses. First, in an epigenome-wide association study involving Japanese individuals with chronic cardiovascular disease (n=94), genome-wide significant smoking association was identified at 2 CpG sites on chromosome 5, with the strongest signal at cg05575921 located in intron 3 of the aryl-hydrocarbon receptor repressor (AHRR) gene. Highly significant (P<1×10-27) smoking-cg05575921 association was validated in 2 additional panels (n=339 and n=300). For the relationship of cg05575921 methylation extent with time after smoking cessation and cumulative cigarette consumption among former smokers, smoking-related hypomethylation was found to remain for ≥20 years after smoking cessation and to be affected by multiple factors, such as cis-interaction of genetic variation. There was a significant inverse correlation (P=0.0005) between cg05575921 methylation extent and AHRR mRNA expression. CONCLUSIONS: The present study results support that reversion of AHRR hypomethylation can be a quantifiable biomarker for progress in and observance of smoking cessation, although some methodological points need to be considered.

Incidence and prevalence of alcoholic fatty liver disease: a prospective, community-based study among adult Sri Lankans.

Background: Data on the alcoholic fatty liver (AFL) is limited. Therefore, we investigated alcohol use and AFL patterns among urban, adult Sri Lankans. Methods: The study population (selected by age-stratified random sampling) was screened in 2007 (35-64 years) and re-evaluated in 2014. They were assessed by structured interviews, anthropometric measurements, liver-ultrasound, and biochemical and serological tests. AFL was diagnosed on ultrasound criteria, 'unsafe' alcohol consumption (Asian standards: males>14units, females>7units per week) and absence of hepatitis B/C markers. Controls were unsafe alcohol consumers who had no fatty liver on ultrasound. Results: 2985/3012 (99%) had complete data for analysis. 272/2985 (9.1%) were unsafe-drinkers in 2007 [males-270; mean-age-51.9, SD-8.0 years]. 86/272 (31.6%) had AFL [males-85; mean-age-50.2, SD-8.6 years]. Males [p<0.001], increased waist circumference (WC) [OR 4.9, p<0.01] and BMI>23kg/m2 [OR 3.5, p<0.01] and raised alanine aminotransferase (ALT) [OR 2.8, p<0.01] were independently associated with AFL. 173/272 (63.6%) unsafe alcohol consumers from 2007 were re-evaluated in 2014. 134/173 had either had AFL or had changed to 'safe' or no alcohol consumption. 21/39 (53.8%) [males-21 (100%), mean-age-57.9, SD-7.9 years] who remained 'unsafe' alcohol users who had no fatty liver in 2007 developed AFL after 7-years (annual incidence 7.7%). On bivariate analysis, only males were associated with new-onset AFL. Of the 42 who had AFL at baseline but changed their drinking status from unsafe to safe or no alcohol, 6 had resolution of fatty liver in 2014. Conclusion: In conclusion, in this community-based study among urban Sri Lankan adults, the annual incidence of AFL among unsafe alcohol users was 7.7%. Furthermore, new-onset AFL was associated with males.

Transcriptomic Response in the Heart and Kidney to Different Types of Antihypertensive Drug Administration.

Certain classes of antihypertensive drug may exert specific, blood pressure (BP)-independent protective effects on end-organ damages such as left ventricular hypertrophy, although the overall evidence has not been definitive in clinical trials. To unravel antihypertensive drug-induced gene expression changes that are potentially related to the amelioration of end-organ damages, we performed in vivo phenotypic evaluation and transcriptomic analysis on the heart and the kidney, with administration of antihypertensive drugs to two inbred strains (ie, hypertensive and normotensive) of rats. We chose 6 antihypertensive classes: enalapril (angiotensin-converting enzyme inhibitor), candesartan (angiotensin receptor blocker), hydrochlorothiazide (diuretics), amlodipine (calcium-channel blocker), carvedilol (vasodilating ß-blocker), and hydralazine. In the tested rat strains, 4 of 6 drugs, including 2 renin-angiotensin system inhibitors, were effective for BP lowering, whereas the remaining 2 drugs were not. Besides BP lowering, there appeared to be some interdrug heterogeneity in phenotypic changes, such as suppressed body weight gain and body weight-adjusted heart weight reduction. For the transcriptomic response, a considerable number of genes showed prominent mRNA expression changes either in a BP-dependent or BP-independent manner with substantial diversity between the target organs. Noticeable changes of mRNA expression were induced particularly by renin-angiotensin system blockade, for example, for genes in the natriuretic peptide system (Nppb and Corin) in the heart and for those in the renin-angiotensin system/kallikrein-kinin system (Ren and rat Klk1 paralogs) and those related to calcium ion binding (Calb1 and Slc8a1) in the kidney. The research resources constructed here will help corroborate occasionally inconclusive evidence in clinical settings.

Case Report of Left Ventricular Noncompaction Cardiomyopathy Characterized by Undulating Phenotypes in Adult Patients.

Left ventricular noncompaction cardiomyopathy (LVNC) is a heart muscle disorder morphologically characterized by reticulated trabeculations and intertrabecular recesses in the left ventricular (LV) cavity. LVNC is a genetically and phenotypically heterogeneous condition, which has been increasingly recognized with the accumulation of evidence provided by genotype-phenotype correlation analyses. Here, we report 2 sporadic adult cases of LVNC; both developed acute heart failure as an initial clinical manifestation and harbored causal sarcomere gene mutations. One case was a 57-year-old male with digenic heterozygote mutations, p.R1344Q in myosin heavy chain 7 (MYH7) and p.R144W in troponin T2, cardiac type (TNNT2), who showed morphological characteristics of LVNC in the lateral to apical regions of the LV together with a comorbidity of non-transmural myocardial infarction, resulting from a coronary artery stenosis. After the removal of ischemic insult and standard heart failure treatment, LVNC became less clear, and LV function gradually improved. The other case was a 36-year-old male with a heterozygote mutation, p.E334K in myosin binding protein C3 (MYBPC3), who exhibited cardiogenic shock on admission with morphological characteristics of LVNC being most prominent in the apical segment of the LV. The dosage of beta-blocker was deliberately increased in an outpatient clinic over 6 months following hospitalization, which remarkably improved the LV ejection fraction from 21% to 54.3%. Via a combination of imaging and histopathological and genetic tests, we have found that these cases are not compatible with a persistent phenotype of primary cardiomyopathy, but their morphological features are changeable in response to treatment. Thus, we point out phenotypic plasticity or undulation as a noticeable element of LVNC in this case report.

SLC15A4 mediates M1-prone metabolic shifts in macrophages and guards immune cells from metabolic stress.

The amino acid and oligopeptide transporter Solute carrier family 15 member A4 (SLC15A4), which resides in lysosomes and is preferentially expressed in immune cells, plays critical roles in the pathogenesis of lupus and colitis in murine models. Toll-like receptor (TLR)7/9- and nucleotide-binding oligomerization domain-containing protein 1 (NOD1)-mediated inflammatory responses require SLC15A4 function for regulating the mechanistic target of rapamycin complex 1 (mTORC1) or transporting L-Ala-γ-D-Glu-meso-diaminopimelic acid, IL-12: interleukin-12 (Tri-DAP), respectively. Here, we further investigated the mechanism of how SLC15A4 directs inflammatory responses. Proximity-dependent biotin identification revealed glycolysis as highly enriched gene ontology terms. Fluxome analyses in macrophages indicated that SLC15A4 loss causes insufficient biotransformation of pyruvate to the tricarboxylic acid cycle, while increasing glutaminolysis to the cycle. Furthermore, SLC15A4 was required for M1-prone metabolic change and inflammatory IL-12 cytokine productions after TLR9 stimulation. SLC15A4 could be in close proximity to AMP-activated protein kinase (AMPK) and mTOR, and SLC15A4 deficiency impaired TLR-mediated AMPK activation. Interestingly, SLC15A4-intact but not SLC15A4-deficient macrophages became resistant to fluctuations in environmental nutrient levels by limiting the use of the glutamine source; thus, SLC15A4 was critical for macrophage's respiratory homeostasis. Our findings reveal a mechanism of metabolic regulation in which an amino acid transporter acts as a gatekeeper that protects immune cells' ability to acquire an M1-prone metabolic phenotype in inflammatory tissues by mitigating metabolic stress.

Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1-Related Microglial Activation in Neonatal Hypoxic-Ischemic Encephalopathy: Morphologic Consideration.

Neonatal hypoxic-ischemic encephalopathy (nHIE) is a major neonatal brain injury. Despite therapeutic hypothermia, mortality and sequelae remain severe. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is associated with the pathophysiology of nHIE. In this study, morphologic change and microglial activation under the nHIE condition and LOX-1 treatment were investigated. The microglial activity and proliferation were assessed with a novel morphologic method, immunostaining, and quantitative PCR in the rat brains of both nHIE model and anti-LOX-1 treatment. Circumference ratio, the long diameter ratio, the cell area ratio, and the roundness of microglia were calculated. The correlation of the morphologic metrics and microglial activation in nHIE model and anti-LOX-1 treated brains was evaluated. LOX-1 was expressed in activated ameboid and round microglia in the nHIE model rat brain. In the evaluation of microglial activation, the novel morphologic metrics correlated with all scales of the nHIE-damaged and treated brains. While the circumference and long diameter ratios had a positive correlation, the cell area ratio and roundness had a negative correlation. Anti-LOX-1 treatment attenuated morphologic microglial activation and proliferation, and suppressed the subsequent production of inflammatory mediators by microglia. In human nHIE, round microglia and endothelial cells expressed LOX-1. The results indicate that LOX-1 regulates microglial activation in nHIE and anti-LOX-1 treatment attenuates brain injury by suppressing microglial activation.

Seventeen primary malignant neoplasms involving the skin, ovary, esophagus, colon, oral cavity, and ear canal: a case report and review of the literature.

Multiple primary malignant neoplasm (MPMN) is a rare disease with two or more malignant neoplasms in one patient. In less than 0.1% of cancer patients, four or more occur. MPMN is frequently associated with hereditary cancer syndrome, although in rare cases, it is not. A female patient developed 17 MPMNs. Although they were successfully treated with surgery, radiation, and adjuvant chemotherapy, the patient died from the recurrence of ovarian cancer. To explore genetic susceptibility to MPMN, immunohistochemical analysis, microsatellite instability analysis, germ line exome sequencing, and unscheduled DNA synthesis assays were performed. However, the results of immunohistochemical analysis and microsatellite instability indicated that there were no known hereditary cancer syndromes, and exome sequencing with 88 representative genes associated with hereditary cancer syndrome revealed no variants. An unscheduled DNA synthesis assay to rule out xeroderma pigmentosum was also performed, but the result was negative. While the presence of multiple neoplasms is rare, the present case represents 17 primary neoplasms with no associations with hereditary cancer syndrome. Although the cause of MPMN was not detected in this patient, careful follow-up and deliberate cancer screening enabled successful disease management over 17 years from the appearance of the first neoplasm.