Dr. Yasushi Hamaya is an Assistant Professor, School of Medicine, Faculty of Medicine, Internal Medicine 1(Divisions of Gastroenterology and Nephrology), Hamamatsu University School of Medicine (Concurrent). My clinical specialty is general gastroenterology, excluding hepatology. I specialize in chemotherapy for gastrointestinal, pancreatic and biliary cancers, as well as the endoscopic treatment of malignant gastrointestinal tumors. Many of the doctors in my department are engaged in clinical and basic research into inflammatory bowel disease, so I am very knowledgeable about the field. As I have little experience of surgical treatment or postoperative chemotherapy, my knowledge is often limited to what I have read in textbooks. As I provide both outpatient and inpatient care, I read a lot of case reports. I am also able to peer review them. My dissertation examined fecal RNA and clinicopathological factors in colorectal cancer (Factors that contribute to faecal cyclooxygenase-2 mRNA expression in subjects with colorectal cancer. Y Hamaya, K Yoshida, T Takai, M Ikuma, A Hishida, S Kanaoka Br J Cancer. 2010 Mar 2;102(5):916-21. doi: 10.1038/sj.bjc.6605564). I am also a peer-reviewed author of a paper on biomarkers for gastrointestinal cancers (Phosphatidylcholine in bile-derived small extracellular vesicles as a novel biomarker of cholangiocarcinoma. Cancer Med. 2023 Jun;12(12):13007-13018. doi: 10.1002/cam4.5973. Epub 2023 Apr 25). I am also conducting research on microsatellite instability (MBD4 frameshift mutation caused by DNA mismatch repair deficiency enhances cytotoxicity by trifluridine, an active antitumor agent of TAS-102, in colorectal cancer cells. Oncotarget. 2017 Nov 15;9(14):11477-11488. doi: 10.18632/oncotarget.22484. Efficacy of Adjuvant 5-Fluorouracil Therapy for Patients with EMAST-Positive Stage II/III Colorectal Cancer. PLoS One. 2015 May 21;10(5):e0127591. doi: 10.1371/journal.pone.0127591. eCollection 2015. Interleukin 6 alters localization of hMSH3, leading to DNA mismatch repair defects in colorectal cancer cells. Gastroenterology. 2015 Mar;148(3):579-89. doi: 10.1053/j.gastro.2014.11.027. Epub 2014 Nov 20). I have recently been studying tissue sampling and drainage techniques involving endoscopic ultrasound.