GUGenki Usui

Genki Usui

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Genki Usui has a total of 85 co-authors. Here are the top co-authors by number of shared publications:

  • Teppei Morikawa

    Department of Diagnostic Pathology, NTT Medical Center Tokyo, Tokyo, Japan

    7 shared publications
  • Nobuyuki Matsuhashi

    Department of Gastroenterology, NTT Medical Center Tokyo, Tokyo, Japan

    6 shared publications
  • Hajime Horiuchi

    Departments of Diagnostic Pathology

    5 shared publications
  • Hirotsugu Hashimoto

    Department of Pathology Tokyo Women's Medical University Tokyo Japan

    5 shared publications
  • Kazutoshi Fujibayashi

    Center for Preventive Medicine, NTT Medical Center Tokyo, Tokyo, Japan; Department of General Medicine, Juntendo University Hospital, Tokyo, Japan

    5 shared publications
  • Tomohiro Shinozaki

    Faculty of Engineering, Department of Information and Computer Technology, Tokyo University of Science, Tokyo, Japan

    5 shared publications

Latest Publications

  • Open Access

    Early‐Onset Digestive System Cancers: Risk Factors and Clinicopathological and Molecular Features Across Organ Sites

    by Nobuhiro Nakazawa, Satoko Ugai, Atsushi Kondo, Kosuke Matsuda, Shu Kato, Genki Usui, Shiori Tanaka, Hwa‐Young Lee, Xinyuan Zhang, Hideo Miyagawa, et al.

    The incidence of early‐onset cancers, commonly defined as cancers diagnosed before age 50 years, has been increasing globally over recent decades. In particular, the incidence of several early‐onset digestive system cancers, including cancers of the esophagus, stomach, colorectum, liver, extrahepatic bile duct, gallbladder, and pancreas, has been reported to be increasing in multiple regions. To elucidate carcinogenic mechanisms and develop effective prevention, earlier detection, and treatment strategies, further evidence is needed on risk factors and clinical, pathological, and molecular characteristics. In this review, we summarize the current evidence on these characteristics, highlight shared and distinct features across organ sites, and discuss research opportunities to address the rising burden of early‐onset digestive system cancers.

  • Open Access

    Spatial proteomics with 100+ markers with Highly Multiplexed MALDI-IHC

    by Mengze Zhang, John Abbey, Pierre Bost, Genki Usui, Simon Häfliger, Simone Muenst, Mark J. Lim, Gargey B. Yagnik, Natalie De Souza, Kenneth J. Rothschild, et al.

    Highly multiplexed, antibody-based protein imaging of tissue has yielded many insights but does not yet allow the routine analysis of more than 50 markers simultaneously. By leveraging the ability of Matrix-Assisted Laser Desorption/Ionization (MALDI) imaging to resolve hundreds of m/z peaks without spectral overlap, MALDI-IHC with photocleavable mass-tag (PCMT)-labelled antibodies offers the possibility to dramatically increase the number of markers that can be imaged. Here, we demonstrate 100+ plex MALDI-IHC imaging and describe our development of gutenTAG, an open-source analysis pipeline for the resulting highly multiplex data. We validated a panel of 133 tumor-ecosystem-focused antibodies, show that it captures expected histopathology in diverse tissues, and demonstrate reproducibility of the method. We further applied a 120-plex subset of this panel to samples from an endometrial cancer cohort, again capturing expected histopathology and identifying novel spatial structures between TCGA molecular subtypes. Our work demonstrates the feasibility of simultaneously detecting hundreds of protein markers in a reproducible and scalable manner.


  • Open Access

    Integrated environmental, lifestyle, and epigenetic risk prediction of primary gastric neoplasia using the longitudinally monitored cohorts

    by Genki Usui, Keisuke Matsusaka, Kie Kyon Huang, Feng Zhu, Tomohiro Shinozaki, Masaki Fukuyo, Bahityar Rahmutulla, Norikazu Yogi, Tomoka Okada, Mizuki Minami, et al.


  • Open Access

    Relationship between time-varying status of reflux esophagitis and Helicobacter pylori and progression to long-segment Barrett’s esophagus: time-dependent Cox proportional-hazards analysis

    by Genki Usui, Tomohiro Shinozaki, Toyohisa Jinno, Kazutoshi Fujibayashi, Teppei Morikawa, Toshiaki Gunji, Nobuyuki Matsuhashi

    Background: Reflux esophagitis (RE) and absence ofHelicobacter pylori(non-H. pylori) are considered to be associated with the progression to long-segment Barrett’s esophagus (LSBE). However, it is difficult to assess this association because RE andH. pyloristatus can change during follow-up. Additionally, the association betweenH. pylorieradication and LSBE remains unclear.Methods: A total of 11,493 asymptomatic Japanese subjects who underwent medical check-ups and were endoscopically diagnosed with short-segment Barrett’s esophagus (SSBE) between May 2006 and December 2015 were enrolled. The hazards of progression to LSBE were compared between time-varying RE andH. pyloriinfection/eradication by time-dependent multivariable Cox proportional hazards models.Results: A total of 7637 subjects who underwent additional medical check-ups after being diagnosed with endoscopic SSBE were analyzed. Subjects with RE and without current/pastH. pyloriinfection were strongly associated with a higher rate of progression to LSBE (adjusted hazard ratio [HR]: 7.17, 95% confidence interval [CI]: 2.48–20.73,p < 0.001 for RE and non-H. pylorivs. non-RE andH. pylorigroups). Subjects withH. pylorihad a lower rate of progression to LSBE (adjusted HR: 0.48, 95% CI: 0.22–1.07,p = 0.07 forH. pylorivs. non-H. pylori). Hazards of progression to LSBE were still lower in theH. pylorieradication group than that of the non-H. pylorigroup (adjusted HR: 0.51, 95% CI: 0.18–1.46,p = 0.21).Conclusions: RE and non-H. pyloriwere associated with the progression to LSBE, considering the changes in exposures.H. pyloriinfection was associated with the prevention of the development of LSBE irrespective of RE. The environment preventive of the development of LSBE persists for at least a few years afterH. pylorieradication.


  • Open Access

    Relationship between time-varying status of reflux esophagitis and Helicobacter pylori and progression to long-segment Barrett’s esophagus: time-dependent Cox proportional-hazards analysis

    by Genki Usui, Tomohiro Shinozaki, Toyohisa Jinno, Kazutoshi Fujibayashi, Teppei Morikawa, Toshiaki Gunji, Nobuyuki Matsuhashi

    Background: Reflux esophagitis (RE) and absence of Helicobacter pylori (non-H. pylori) are considered to be associated with the progression to long-segment Barrett’s esophagus (LSBE). However, it is difficult to assess this association because RE and H. pylori status can change during follow-up. Additionally, the association between H. pylori eradication and LSBE remains unclear.Methods: A total of 11,493 asymptomatic Japanese subjects who underwent medical check-ups and were endoscopically diagnosed with short-segment Barrett’s esophagus (SSBE) between May 2006 and December 2015 were enrolled. The hazards of progression to LSBE were compared between time-varying RE and H. pylori infection/eradication by time-dependent multivariable Cox proportional hazards models.Results: A total of 7,637 subjects who underwent additional medical check-ups after being diagnosed with endoscopic SSBE were analyzed. Subjects with RE and without current/past H. pylori infection were strongly associated with a higher rate of progression to LSBE (adjusted hazard ratio [HR]: 7.17, 95% confidence interval [CI]: 2.48-20.73, p<0.001 for RE and non-H. pylori vs. non-RE and H. pylori groups). Subjects with H. pylori had a lower rate of progression to LSBE (adjusted HR: 0.48, 95% CI: 0.22-1.07, p=0.07 for H. pylori vs. non-H. pylori). Hazards of progression to LSBE were still lower in the H. pylori eradication group than that of the non-H. pylori group (adjusted HR: 0.51, 95% CI: 0.18-1.46, p=0.21).Conclusions: RE and non-H. pylori were associated with the progression to LSBE, considering the changes in exposures. H. pylori infection was associated with the prevention of the development of LSBE irrespective of RE. The environment preventive of the development of LSBE persists for at least a few years after H. pylori eradication.

  • Association between visceral abdominal obesity and long-segment Barrett’s esophagus in a Japanese population

    by Genki Usui, Tomohiro Shinozaki, Toyohisa Jinno, Kazutoshi Fujibayashi, Teppei Morikawa, Toshiaki Gunji, Nobuyuki Matsuhashi

    Background Visceral abdominal obesity is associated with Barrett’s esophagus (BE), especially long-segment BE (≥ 3 cm) (LSBE), in white individuals. However, the association between central obesity and LSBE has not been well investigated in Asia. The aim of this study was to investigate the association between central obesity and LSBE in the Japanese population. Methods A total of 38,298 healthy subjects who took medical surveys between April 2006 and November 2018 were enrolled. We investigated the association between LSBE and central obesity indices [visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and the VAT to SAT ratio (VAT/SAT)] using a multivariable logistic regression model. Results A total of 37,686 subjects were eligible for the analysis. LSBE rates in the middle and high VAT/SAT groups were higher than those in the low VAT/SAT group [odds ratio (OR) 1.70, 95% confidence interval (CI) 1.07–2.69 for middle vs low; OR 2.02, 95% CI 1.17–3.49 for high vs low). These associational trends between VAT/SAT and LSBE remained in subgroups with and without reflux esophagitis. From subgroup analyses by SAT, we found that the OR between VAT and LSBE is higher in the low SAT subgroup (OR 2.43, 95% CI 1.34–4.40 for middle vs low; OR 2.55, 95% CI 1.01–6.40 for high vs low); but not large or imprecise due to limited event numbers in the middle and high SAT subgroups. Conclusions VAT was associated with LSBE, especially among subjects with low SAT accumulation, who are seemingly not obese. VAT/SAT was associated with LSBE regardless of the presence of reflux esophagitis in a Japanese population.


  • Association Between Helicobacter pylori Infection and Short-segment/Long-segment Barrett’s Esophagus in a Japanese Population

    by Genki Usui, Hajime Sato, Tomohiro Shinozaki, Toyohisa Jinno, Kazutoshi Fujibayashi, Ken Ishii, Hajime Horiuchi, Teppei Morikawa, Toshiaki Gunji, Nobuyuki Matsuhashi

    Goal: The goal of this study was to investigate the relationship between Helicobacter pylori (H. pylori) infection and short-segment and long-segment Barrett’s esophagus (SSBE and LSBE). Background: H. pylori infection is reported to be inversely associated with Barrett’s esophagus (BE) in western countries. However, the impact of BE segment length on the association between BE and H. pylori infection has scarcely been investigated. Materials and Methods: The study subjects were 41,065 asymptomatic Japanese individuals who took medical surveys between October 2010 and September 2017. Using this large database of healthy Japanese subjects, we investigated the association between H. pylori infection and SSBE/LSBE. We used multivariable logistic regression analysis to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: Among the study subjects, 36,615 were eligible for the analysis. H. pylori seropositivity was significantly associated with a lower rate of LSBE (OR: 0.42; 95% CI: 0.16-0.91) and a higher rate of SSBE (OR: 1.66; 95% CI: 1.56-1.78) after multivariate adjustment. In the subgroup analysis, H. pylori seropositivity was significantly associated with a high rate of SSBE in subjects without reflux esophagitis (RE) (OR: 1.73; 95% CI: 1.61-1.85). However, H. pylori seropositivity was not associated with SSBE in subjects with RE (OR: 1.07; 95% CI: 0.84-1.37). Conclusion: In a Japanese population, H. pylori infection was inversely associated with LSBE but significantly associated with SSBE only in subjects without RE. H. pylori may be a risk factor for SSBE, especially in individuals without RE.


  • Intrahepatic Carcinosarcoma With Cholangiocarcinoma Elements and Prominent Bile Duct Spread

    by Genki Usui, Hirotsugu Hashimoto, Masashi Kusakabe, Go Shirota, Yoshiya Sugiura, Yuji Fujita, Shouichi Satou, Yasushi Harihara, Hajime Horiuchi, Teppei Morikawa

    Carcinosarcomas with elements of cholangiocarcinoma and sarcoma are rare and have a poor prognosis. The spreading pattern and radiological findings of these lesions remain unclear. A 74-year-old man presented with a high γ-glutamyl transferase level. Magnetic resonance imaging revealed dilation of the right intrahepatic and common bile ducts, consistent with an intraductal papillary neoplasm of the bile duct (IPNB), and diffusion-weighted imaging (DWI) indicated an area of high signal intensity in the intrahepatic bile duct. Bile duct biopsy yielded a small amount of atypical spindle cells, and the patient underwent a right hepatectomy. Microscopically, the tumor contained cholangiocarcinoma and sarcomatous components, including osteosarcoma and leiomyosarcoma, leading to a diagnosis of intrahepatic carcinosarcoma. The tumor spread primarily through the intrahepatic bile duct. An accurate radiological diagnosis of carcinosarcoma was challenging, given the apparent similarities with IPNB. The findings from DWI and pathology of a bile duct biopsy may assist with preoperative diagnosis.


  • Open Access

    Cerebral Embolism Caused by Thrombus in the Pulmonary Vein Stump after Left Lower Lobectomy: A Case Report and Literature Review

    by Genki Usui, Yohei Takayama, Hirotsugu Hashimoto, Takehiro Katano, Masahiro Yanagiya, Masashi Kusakabe, Tamaki Miura, Jun Matsumoto, Hajime Horiuchi, Seiji Okubo

    Postoperative cerebral embolism after left upper lobectomy caused by a thrombus in the pulmonary vein stump (PVS) is a serious complication. However, it is unclear if cerebral embolism can develop after other types of lobectomy. We present a case of a 68-year-old man with cerebral embolism after left lower lobectomy with a longer PVS than normal. There were no clinically suspected sources for the thrombus except for the PVS. This thrombus seemed to have formed in the PVS. The endovascularly removed thrombus contained scattered nuclear debris around neutrophils, suggesting a physiological response caused by tissue injury.


  • Open Access

    Cerebral Thromboembolism after Lobectomy for Lung Cancer: Pathological Diagnosis and Mechanism of Thrombus Formation

    by Hirotsugu Hashimoto, Genki Usui, Yuta Tsugeno, Keisuke Sugita, Gulanbar Amori, Teppei Morikawa, Kentaro Inamura

    Lung cancer is the leading cause of cancer-related deaths worldwide. Although molecular therapies have emerged as efficacious strategies for the treatment of lung cancer, surgical resection is still recommended as a radical therapeutic option. Currently, lobectomy is regarded as the most reliable radical treatment of primary lung cancer. Among the various complications after lobectomy, cerebral thromboembolism requires attention as a life-threatening complication during the early postoperative period. It occurs in 0.2–1.2% of surgical cases of lung cancer and typically develops following left upper lobectomy with a long pulmonary vein stump (PVS). PVS-associated thrombosis is known to cause cerebral thromboembolism after such procedures; however, distinguishing this specific complication from that caused by postoperative atrial fibrillation is challenging. We summarize herein the diagnostic pathology of thrombus formation in accordance with its thrombogenic mechanism. We focus on the potential utility of the pathological assessment of thrombectomy specimens. The morphological information obtained from these specimens enables the presumption of thrombogenic etiology and provides useful clues to both select an appropriate pharmacotherapy and determine a follow-up treatment for cerebral thromboembolism.