Kenneth G. Zierer, MD, is a board-certified gastroenterologist with expertise in digestive and liver health. Board certified in gastroenterology, internal medicine and pediatrics, Dr. Zierer’s clinical focus includes FibroScan®, a noninvasive technology used to assess liver health. He sees patients at GANJ’s Clifton and Rutherford locations.

Joseph A. Zangara, MD, is a gastroenterologist with North Jersey Gastroenterology, a division of Gastroenterology Associates of New Jersey. Dr. Zangara completed his medical training at UMDNJ and his residency and gastroenterology fellowship at the University of Maryland. He sees patients at GANJ’s Wayne location.

Ariy Volfson, MD, is a board-certified gastroenterologist with special expertise in inflammatory bowel disease and advanced endoscopic procedures. His clinical expertise includes colonoscopy, capsule endoscopy, upper endoscopy and other GI procedures. Dr. Volfson sees patients at GANJ’s Oakland and Woodland Park locations.

Mark Tanchel, MD, is a board-certified gastroenterologist and member of Hackensack Digestive Disease Associates, a division of Gastroenterology Associates of New Jersey. Affiliated with Hackensack University Medical Center, Dr. Tanchel has also participated in the education and training of gastroenterology fellows. He sees patients at GANJ’s Hackensack location.

Jose Ramon E. Suatengco, MD, is an experienced gastroenterologist and member of Ocean Family Gastroenterology, a division of Gastroenterology Associates of New Jersey. Practicing gastroenterology in Toms River for more than 25 years, Dr. Suatengco specializes in colonoscopy, endoscopy, anal manometry and capsule endoscopy.

Jonathon Stillman, MD, is a gastroenterologist and member of North Jersey Gastroenterology, a division of Gastroenterology Associates of New Jersey. Dr. Stillman completed his medical training at the University of Pennsylvania, followed by residency at Cornell Medical Center and fellowship training at Memorial Sloan Kettering Cancer Center. He sees patients at GANJ’s Wayne location.

John Sotiriadis, MD, PhD, AGAF, FACG, is board certified in gastroenterology and internal medicine and provides advanced, patient-centered digestive care. A fellow of both the American College of Gastroenterology and American Gastroenterological Association, Dr. Sotiriadis also serves as Section Chief at Palisades Medical Center. He sees patients at GANJ’s North Bergen and Hoboken locations.