Prolonged gut microbial alterations in post-transplant survivors of allogeneic haematopoietic stem cell transplantation.

Dysbiosis of the gut microbiota has been reported to increase early complications after allogeneic haematopoietic stem cell transplantation (allo-HSCT). However, it remains unclear whether gut microbial alterations persist during late complications, such as chronic graft-versus-host disease (cGVHD) or secondary cancers. Here, we analysed the gut microbiota of 59 patients who survived for 1-21.7 years (median, 6.4 years) after allo-HSCT. Long-term survivors showed lower gut microbial diversity than the age- and sex-matched healthy controls. This decreased diversity was reflected in the reduced abundance of the butyrate-producing bacteria. Patients with a history of grade 3 acute graft-versus-host disease (aGVHD) exhibited higher Veillonella abundance than patients with a history of grade 1-2 or non-aGVHD cases. The abundance of Faecalibacterium showed no decrease only in limited cGVHD cases. Additionally, the microbial structure in the secondary cancer group was significantly different (p < 0.05) from that in the non-secondary cancer group. This study is the first to show that microbial dysbiosis is present over a 10-year lifetime after discharge following allo-HSCT. Our results suggest that these prolonged gut microbial alterations may be associated with the development and exacerbation of late complications in post-transplant survivors.

Jasmonic Acid-Induced ß-Cyclocitral Confers Resistance to Bacterial Blight and Negatively Affects Abscisic Acid Biosynthesis in Rice.

Jasmonic acid (JA) regulates the production of several plant volatiles that are involved in plant defense mechanisms. In this study, we report that the JA-responsive volatile apocarotenoid, ß-cyclocitral (ß-cyc), negatively affects abscisic acid (ABA) biosynthesis and induces a defense response against Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial blight in rice (Oryza sativa L.). JA-induced accumulation of ß-cyc was regulated by OsJAZ8, a repressor of JA signaling in rice. Treatment with ß-cyc induced resistance against Xoo and upregulated the expression of defense-related genes in rice. Conversely, the expression of ABA-responsive genes, including ABA-biosynthesis genes, was downregulated by JA and ß-cyc treatment, resulting in a decrease in ABA levels in rice. ß-cyc did not inhibit the ABA-dependent interactions between OsPYL/RCAR5 and OsPP2C49 in yeast cells. Furthermore, we revealed that JA-responsive rice carotenoid cleavage dioxygenase 4b (OsCCD4b) was localized in the chloroplast and produced ß-cyc both in vitro and in planta. These results suggest that ß-cyc plays an important role in the JA-mediated resistance against Xoo in rice.

Benchmark of 16S rRNA gene amplicon sequencing using Japanese gut microbiome data from the V1-V2 and V3-V4 primer sets.

BACKGROUND: 16S rRNA gene amplicon sequencing (16S analysis) is widely used to analyze microbiota with next-generation sequencing technologies. Here, we compared fecal 16S analysis data from 192 Japanese volunteers using the modified V1-V2 (V12) and the standard V3-V4 primer (V34) sets to optimize the gut microbiota analysis protocol. RESULTS: QIIME1 and QIIME2 analysis revealed a higher number of unclassified representative sequences in the V34 data than in the V12 data. The comparison of bacterial composition demonstrated that at the phylum level, Actinobacteria and Verrucomicrobia were detected at higher levels with V34 than with V12. Among these phyla, we observed higher relative compositions of Bifidobacterium and Akkermansia with V34. To estimate the actual abundance, we performed quantitative real-time polymerase chain reaction (qPCR) assays for Akkermansia and Bifidobacterium. We found that the abundance of Akkermansia as detected by qPCR was close to that in V12 data, but was markedly lower than that in V34 data. The abundance of Bifidobacterium detected by qPCR was higher than that in V12 and V34 data. CONCLUSIONS: These results indicate that the bacterial composition derived from the V34 region might differ from the actual abundance for specific gut bacteria. We conclude that the use of the modified V12 primer set is more desirable in the 16S analysis of the Japanese gut microbiota.

Identifying the inserted locus of randomly integrated expression plasmids by whole-genome sequencing of Aspergillus strains.

Whole-genome sequencing was conducted on two Aspergillus oryzae strains used for the manufacturing of food enzymes, Acrylaway® and Shearzyme®, with the aim of identifying the inserted locus of randomly integrated expression plasmid and obtaining flanking sequences for safety assessment. Illumina paired-end sequencing was employed, and the obtained reads were mapped to two references: the public genome sequence of Aspergillus oryzae RIB40 and the in-house sequence of the used expression plasmid. Introducing the concept of linking-reads, one locus for each was successfully identified as the integrated site. In the case of Acrylaway®, the obtained sequences suggested that the expression plasmid had been integrated as multiple copies in tandem form. In the case of Shearzyme®, however, information on one edge of the insert was missing, which required extra polymerase chain reaction (PCR) cloning for safety assessment. A 4-kb deletion was detected at the integrated site. There was also evidence of rearrangement occurring in Shearzyme® strain.

Detection of alternative subpleural lymph flow pathways using indocyanine green fluorescence.

PURPOSE: Pulmonary lymphatic fluid predominately flows along the bronchi. However, there are reports suggesting that an alternative lymphatic pathway exist, which may result in skip metastases. The aim of this study was to evaluate the subpleural lymph flow in vivo using indocyanine green (ICG) fluorescence. METHODS: One hundred cases were enrolled. ICG was injected into the macroscopically healthy subpleural space. Intraoperative fluorescence images were then observed in real time. RESULTS: ICG fluorescence was observed moving through subpleural channels in 58/100 cases. ICG flowed into adjacent lobes over interlobar lines in 18 cases and flowed from the visceral pleura directly into the mediastinum in 5 cases. The frequency of mediastinal detection without hilar lymph node detection was significantly higher in the left lung compared to the right (p < 0.05). The subpleural lymph flow detection rates were significantly lower in patients with smoking pack-years ≥ 40 than those with < 40 (p < 0.05). CONCLUSIONS: The flow of lymphatic fluid directly into the mediastinum suggests one mechanism of skip metastasis. In addition, the reduction of the subpleural lymph flows in smokers with ≥ 40 pack-years suggests that smoking might modify lymph flow patterns. These findings may assist in selecting the optimal therapy for patients with possible skip metastasis.

Oral and Intestinal Bacterial Flora in Patients with Increased Periodontal Inflamed Surface Area: A Cross-Sectional Study.

Background/Objectives: Periodontitis is caused by bacterial plaque. The oral microflora may interact with the intestinal microflora and play a role in the development of periodontitis. The periodontal inflamed surface area (PISA) has been shown to be a useful indicator of periodontal disease related to systemic diseases; however, few studies have shown an association between PISA and the bacterial flora. This study aimed to determine the association between PISA and oral and intestinal bacteria. Methods: Participants were recruited between 2018 and 2021 at the Medical and Dental Collaboration Center of Kanagawa Dental University Hospital. A periodontal clinical examination was performed, and the PISA was calculated. Salivary tests were conducted, and leukocyte scores in the saliva were calculated. Moreover, 16S rRNA amplicon sequencing was performed using saliva and stool samples to analyze oral and intestinal bacteria, respectively. Results: Higher PISA levels resulted in an increased presence of Bacteroides and a decreased presence of Proteobacteria and Actinobacteria in the saliva. An increase in Bacteroides was detected in the saliva of patients with high leukocyte scores. No correlation was observed between PISA and intestinal bacteria. Conclusions: Bacteroides was highly abundant in the saliva of patients with worsened periodontal conditions, as indicated by PISA. No association was found between PISA and intestinal bacteria.

Effect of Tegafur-Uracil in Resected Stage IB Lung Adenocarcinoma According to Presence or Absence of Epidermal Growth Factor Receptor Gene Mutation: A Retrospective Cohort Study.

PURPOSE: Tegafur-uracil (UFT) is the standard postoperative adjuvant therapy for stage IB lung adenocarcinoma (LUAD) in Japan. This study aimed to determine whether UFT is effective in stage IB LUAD with and without epidermal growth factor receptor (EGFR) mutations. METHODS: This retrospective study included 169 patients with stage IB LUAD who underwent complete resection at our department between 2010 and 2021. We investigated the clinicopathological and prognostic impact of EGFR mutations as well as the postoperative use of UFT. RESULTS: EGFR mutation-positive cases tended to show a higher cumulative recurrence rate than EGFR mutation-negative cases (p = 0.081), while overall survival was comparable between the groups (p = 0.238). In the entire cohort, UFT administration was not an independent prognostic factor in the multivariate regression analysis (p = 0.112). According to a stratification analysis, UFT administration was independently associated with favorable overall survival (p = 0.031) in EGFR mutation-negative cases, while it was not associated with recurrence-free survival (p = 0.991) or overall survival (p = 0.398) in EGFR mutation-positive cases. CONCLUSION: UFT administration can improve the prognosis of EGFR mutation-negative LUAD but not EGFR mutation-positive LUAD. Thus, clinical trials of adjuvant-targeted therapy for EGFR mutation-positive stage IB LUAD should also be conducted in Japan.

SF6 is a useful expander for post-pneumonectomy syndrome in the long-term course: a case report.

BACKGROUND: Post-pneumonectomy syndrome (PPS) is a rare but serious condition that can occur after pneumonectomy. It is characterized by a mediastinal shift towards the vacated hemithorax, which can potentially lead to respiratory failure. The management of PPS poses a clinical challenge, especially in the context of the limited availability of certain therapeutic devices due to regulatory restrictions in Japan. CASE PRESENTATION: A 36-year-old female with stage IB non-small cell lung cancer underwent left pneumonectomy. Approximately 2 years later, she developed dyspnea. After consulting with our hospital, subsequent imaging revealed an extreme mediastinal shift causing bronchial obstruction. Emergency thoracotomy and subsequent sulfur hexafluoride (SF6) injections were successfully used to manage her condition. Over the course of follow-up, the interval between SF6 injections was extended from 3 to 11 months, indicating an improvement in the intrathoracic condition. CONCLUSIONS: This case illustrates the efficacy of SF6 gas in treating PPS and in reducing the frequency of medical interventions. SF6 gas administration is safe and effective for the treatment of patients with PPS.

Gut microbial stability in older Japanese populations: insights from the Mykinso cohort.

Gut microbiota imbalance plays an important role in the pathogenesis of various diseases. Here, we determined microbe-microbe interactions and gut microbiome stability in a Japanese population with varying body mass indices (BMIs) and enterotypes. Using 16S ribosomal RNA gene sequencing, we analyzed gut microbial data from fecal samples obtained from 3,365 older Japanese individuals. The individuals were divided into lean, normal, and obese groups based on their BMIs. They were further categorized according to their gut microbiota enterotypes: Bacteroides (enterotype B), Prevotella (enterotype P), and Ruminococcus (enterotype R). We obtained data on different host factors, such as age, BMI, and disease status, using a survey questionnaire evaluated by the Mykinso gut microbiome testing service. Subsequently, we evaluated the co-occurrence network. Individual differences in BMI were associated with differences in co-occurrence networks. By exploring the network topology based on BMI status, we observed that the network density was lower in the lean group than that in the normal group. Furthermore, a simulation-based stability analysis revealed a lower resistance index in the lean group than those in the other two groups. Our results provide insights into various microbe-microbe interactions and gut microbial stability and could aid in developing appropriate therapeutic strategies targeting gut microbiota modulation to manage frailty.

Intestinal microbiome and maternal mental health: preventing parental stress and enhancing resilience in mothers.

The number of mothers suffering from mental illness is increasing steadily, particularly under conditions of the coronavirus pandemic. The identification of factors that contribute to resilience in mothers is urgently needed to decrease the risks of poor physical and psychological health. We focused on the risk of parenting stress and psychological resilience in healthy mothers with no psychiatric and physical disorders and conducted two studies to examine the relationships between intestinal microbiota, physical condition, and psychological state. Our results showed that alpha diversity and beta diversity of the microbiome are related to high parenting stress risk. Psychological resilience and physical conditions were associated with relative abundances of the genera Blautia, Clostridium, and Eggerthella. This study helps further understand the gut-brain axis mechanisms and supports proposals for enhancing resilience in mothers.

A case of attempted transbronchial spigot insertion for fistulous pyothorax in the residual pleural airspace after pleurectomy/decortication for malignant pleural mesothelioma.

Pleurectomy/decortication for malignant pleural mesothelioma is a relatively recent surgical approach for which there is a dearth of information on complications, especially in the late postoperative period. A 70-year-old man was diagnosed with right epithelioid malignant pleural mesothelioma and underwent pleurectomy/decortication. Computed tomography at 6 months after surgery revealed nodules on the surface of the right lung. These nodules gradually increased in size and were diagnosed as recurrent disease. Immunotherapy was started, but treatment was discontinued a few days after the first course due to pneumonitis. Subsequent oral prednisolone therapy for about 2 months ameliorated pneumonitis, but fistulous pyothorax developed. During attempted transbronchial occlusion of the responsible bronchus, some spigots penetrated the empyema cavity. Open window thoracotomy was performed on the following day. This case suggests that if there is no change in diameter between the proximal and distal parts of the responsible bronchus, transbronchial occlusion should not be chosen.

Prognostic Outcome of Pulmonary Resection for Pulmonary Metastases from Gastric Cancer.

PURPOSE: Regardless of the devastating outcomes of pulmonary resection for metastases from gastric cancer, a handful of patients survive long after pulmonary metastasectomy. This study aimed to identify a good candidate for pulmonary resection for metastases from gastric cancer. METHODS: Between 2005 and 2023, 564 patients underwent pulmonary metastasectomy in our department, of which 12 patients underwent pulmonary resection for metastases from gastric cancer. Variables evaluated were the number and size of metastatic lesions, surgical procedure, disease-free interval (DFI), and the serum carcinoembryonic antigen at pulmonary metastasectomy. RESULTS: The DFI following gastrectomy ≤12.5 months group had a significantly worse overall survival (OS) than the other group (p = 0.005). A comparison between DFI following gastrectomy ≤12.5 months group and DFI following gastrectomy >12.5 months group showed a significant difference in serum carcinoembryonic antigen (CEA) value at pulmonary metastasectomy (p = 0.048). The serum CEA value at pulmonary metastasectomy >5.8 ng/ml group had a significantly worse OS than the other group (p = 0.001). CONCLUSION: Pulmonary metastasectomy can be indicated in some patients with metastasis from gastric cancer who have longer DFI from gastrectomy and lower serum CEA at pulmonary metastasectomy.

Prognostic significance of preoperative to postoperative serum carcinoembryonic antigen ratio after lobectomy for lung adenocarcinoma.

INTRODUCTION: Lung adenocarcinoma with a preoperatively elevated serum carcinoembryonic antigen (CEA) value has a relatively poor postoperative prognosis. Although surgical resection generally results in a reduction in the CEA value, the significance of the change in the CEA value on the prognostic outcome remains unclear. METHODS: Our study included 133 patients who underwent lobectomy with curative intent for lung adenocarcinoma representing a preoperative CEA value > 5.0. Statistical analysis was performed using a receiver operating characteristic analysis and a stepwise Cox proportional hazards analysis. RESULTS: Both the postoperative CEA value and postoperative-to-preoperative CEA ratio (CEA ratio) significantly affected the survival. Although the CEA ratio was not predictive of the survival in patients with postoperative CEA ≤ 6.2 ng/ml (n = 105), it was predictive in the remaining patients with postoperative CEA > 6.2 ng/ml (n = 28). Patients with postoperative CEA > 6.2 ng/ml and a CEA ratio ≥ 0.39 (n = 7) showed the worst survival outcome. According to the multivariate analysis, the CEA ratio and postoperative nodal status were significant predictors of the survival in overall patients. CONCLUSION: The CEA ratio may be a useful prognostic marker in patients who undergo lobectomy for lung adenocarcinoma and show postoperative CEA > 6.2 ng/ml. A high CEA ratio may indicate the presence of a subclinical residual tumor, which may lead to the development of subsequent recurrence.

Altered Gut Microbiota Composition Is Associated with Difficulty in Explicit Emotion Regulation in Young Children.

Executive function (EF) consists of explicit emotion regulation (EER) and cognitive control (CC). Childhood EER in particular predicts mental and physical health in adulthood. Identifying factors affecting EER development has implications for lifelong physical and mental health. Gut microbiota (GM) has attracted attention as a potential biomarker for risk of physical and mental problems in adulthood. Furthermore, GM is related to brain function/structure, which plays a crucial role in emotional processing. However, little is known about how GM compositions are associated with the development of emotion regulation in early childhood. Therefore, in this study, we examined 257 children aged 3-4 to investigate links between GM and risk to EF. EF was measured using the Mother-Reported Behavior Rating Inventory of Executive Function-Preschool version. GM composition (alpha/beta diversity and genus abundance) was evaluated using 16S rRNA gene sequencing and compared between EF-risk and non-risk groups. Our results show that children with EER-risk (an index of inhibitory self-control) had a higher abundance of the genera Actinomyces and Sutterella. Although we have not established a direct link between GM and CC risk, our findings indicate that GM of preschoolers is closely associated with emotional processing and that EERrisk children have more inflammation-related bacteria.

Extracellular volume fraction derived from equilibrium contrast-enhanced CT as a diagnostic parameter in anterior mediastinal tumors.

PURPOSE: To assess the usefulness of extracellular volume (ECV) fraction derived from equilibrium contrast-enhanced CT (CECT) for diagnosing anterior mediastinal tumors. METHOD: This study included 161 histologically confirmed anterior mediastinal tumors (55 low-risk thymomas, 57 high-risk thymomas, 32 thymic carcinomas, and 17 malignant lymphomas) that were assessed by pretreatment CECT. ECV fraction was calculated using measurements obtained within the lesion and the aorta on unenhanced and equilibrium phase CECT. ECV fraction was compared among anterior mediastinal tumors using one-way ANOVA or t-test. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the ability of ECV fraction to differentiate thymic carcinomas/lymphomas from thymomas. RESULTS: ECV fraction differed significantly among the anterior mediastinal tumors (p < 0.001). ECV fraction of thymic carcinomas was significantly higher than those of low-risk thymomas, high-risk thymomas, and lymphomas (p < 0.001, p < 0.001, and p = 0.006, respectively). ECV fraction of lymphomas was significantly higher than that of low-risk thymomas (p < 0.001). ECV fraction was significantly higher in thymic carcinomas/lymphomas than in thymomas (40.1 % vs. 27.7 %, p < 0.001). The optimal cutoff value to differentiate thymic carcinomas/lymphomas from thymomas was 38.5 % (AUC, 0.805; 95 %CI, 0.736-0.863). CONCLUSIONS: ECV fraction derived from equilibrium CECT is helpful in diagnosing anterior mediastinal tumors. High ECV fraction is indicative of thymic carcinomas/lymphomas, particularly thymic carcinomas.

Clinical Significance of Nodal DCsign Expression in Non-small-cell Lung Cancer Patients.

BACKGROUND/AIM: Dendritic cells (DCs) are difficult to evaluate in lung regional lymph nodes because of region-specific structures, such as abundant trabeculae connecting the medullary and subcapsular sinuses, the latter of which contains few anthracotic macrophages. Therefore, DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DCsign)-positive DCs and CD68-positive macrophages are unlikely to show a typical distribution. The present study therefore explored quantitative factors connecting the nodal DC morphology to the patient outcome. MATERIALS AND METHODS: Lymph nodes from 34 non-small-cell lung cancer patients who underwent complete resection were used for immunohistochemical assessments of DCsign and CD68 and terminal deoxynucleotidyl transferase dUTP nick-end labeling. Preoperative patient blood samples were used for the quantitative evaluation of monocytes. RESULTS: The nodal DCs showed a complementary distribution with macrophages, thus few DCs were seen in clusters of macrophages. DCs often presented as a mesh-like rosette that was solitary or connected to a DC cluster. DCs disappeared, and some macrophages were apoptotic when surrounded by cancer cells that have metastasized to lymph nodes. The proportional area of a DC cluster was significantly associated with the histological differentiation of cancer (p=0.013), with a higher ratio tending to lead to a better overall survival (p=0.059), and significantly so in adenocarcinoma (p=0.007). The rosette number was significantly correlated with the smoking index and blood monocyte number (p=0.013 and p=0.005, respectively). CONCLUSION: The nodal DC morphology appears useful as a prognostic factor and may lead to a new phase of clinicopathological studies of solid cancers.

Successful Treatment with Osimertinib Based on Therapeutic Drug Monitoring in a Hemodialysis Patient with Non-Small Cell Lung Cancer: A Case Report.

Although osimertinib is a key drug in the treatment of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation, the safety in hemodialysis patients has not been established. A 76-year-old man was diagnosed with NSCLC with EGFR deletion mutation in exon 19. After treatment failure with first- and second-generation EGFR tyrosine kinase inhibitors, a T790M mutation was revealed by liquid biopsy. Hemodialysis was started three times a week because chronic renal failure worsened during treatment. Although the subsequent administration of osimertinib (80 mg daily) resulted in a tumor shrinkage and a gradual increase in the plasma concentration of osimertinib, which resulted in grade 3 general fatigue, reducing the dosage of osimertinib decreased its plasma concentration, leading to an improvement in his adverse event. Subsequently, with by adjusting the dosage while periodically measuring the plasma concentration of osimertinib, a stable therapeutic effect was sustained over the long term with no symptoms. Periodic plasma concentration measurements may be indispensable for successful treatment with osimertinib in hemodialysis patients.

Average gut flora in healthy Japanese subjects stratified by age and body mass index.

Imbalance of the gut microbiota plays an important role in the pathogenesis of various diseases. Although many clinical studies have analyzed the gut microbiota, the definition of normal gut microbiota remains unclear. In this study, we aim to establish the average gut microbiota in the healthy Japanese population. Using 16S ribosomal RNA gene sequencing, we analyzed gut microbial data from fecal samples obtained from 6,101 healthy Japanese individuals. Based on their ages, the individuals were divided into three groups: young, middle-age, and old. Individuals were further categorized according to body mass index (BMI) into lean, normal, and obese groups. The α and ß diversities in the old group were significantly higher than those in the young and middle-age groups. The Firmicutes/Bacteroidetes ratio of subjects in the obese category was significantly lower compared with those of subjects in the lean and normal categories in the young and middle-age groups. Genus Bacteroides was the dominant gut microbiota across all the BMI categories in all the age groups. Among the top ten genera, the abundances of Bacteroides, Bifidobacterium, Anaerostipes, Blautia, Dorea, Fusicatenibacter, Lachnoclostridium, and Parabacteroides were significantly lower in the old group than in the young and middle-age groups. The correlation network at the genus level revealed different microbe-microbe interactions associated with age and BMI. We determined the average Japanese gut microbiota, and this information could be used as a reference. The gut microbiota greatly differs based on the life stage and metabolic status of the host, and this gives rise to a variety of host-gut microbe interactions that can lead to an increased susceptibility to disease.

The efficacy of 18F-FDG-PET-based radiomic and deep-learning features using a machine-learning approach to predict the pathological risk subtypes of thymic epithelial tumors.

OBJECTIVE: To examine whether the machine-learning approach using 18-fludeoxyglucose positron emission tomography (18F-FDG-PET)-based radiomic and deep-learning features is useful for predicting the pathological risk subtypes of thymic epithelial tumors (TETs). METHODS: This retrospective study included 79 TET [27 low-risk thymomas (types A, AB and B1), 31 high-risk thymomas (types B2 and B3) and 21 thymic carcinomas] patients who underwent pre-therapeutic 18F-FDG-PET/CT. High-risk TETs (high-risk thymomas and thymic carcinomas) were 52 patients. The 107 PET-based radiomic features, including SUV-related parameters [maximum SUV (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)] and 1024 deep-learning features extracted from the convolutional neural network were used to predict the pathological risk subtypes of TETs using six different machine-learning algorithms. The area under the curves (AUCs) were calculated to compare the predictive performances. RESULTS: SUV-related parameters yielded the following AUCs for predicting thymic carcinomas: SUVmax 0.713, MTV 0.442, and TLG 0.479 or high-risk TETs: SUVmax 0.673, MTV 0.533, and TLG 0.539. The best-performing algorithm was the logistic regression model for predicting thymic carcinomas (AUC 0.900, accuracy 81.0%), and the random forest (RF) model for high-risk TETs (AUC 0.744, accuracy 72.2%). The AUC was significantly higher in the logistic regression model than three SUV-related parameters for predicting thymic carcinomas, and in the RF model than MTV and TLG for predicting high-risk TETs (each; p < 0.05). CONCLUSION: 18F-FDG-PET-based radiomic analysis using a machine-learning approach may be useful for predicting the pathological risk subtypes of TETs. ADVANCES IN KNOWLEDGE: Machine-learning approach using 18F-FDG-PET-based radiomic features has the potential to predict the pathological risk subtypes of TETs.