President

Family Medicine

Dr. Adam Paley has been an MPMG Board member since 2016, has served as President since 2018 and participates on the Executive Committee and Mills-Peninsula Network Committee. Dr. Paley earned his degree from Cornell University Medical College.

Vice President

Internal Medicine, Critical Care Medicine, Pulmonary Disease

Dr. Bernard Steyer graduated from Temple University School of Medicine in Philadelphia in 1978. He completed his residency in internal medicine and fellowship in pulmonary disease at the University of Arizona Medical Center and has been in independent group practice with his current group, Pulmonary Associates, since 1984. He is board certified in internal medicine, pulmonary disease and critical care and continues to be in full-time practice. He served as a director on the MPMG Board for many years before becoming President and Chairman of the Board in 2010, and now serves as Vice=President. He is married and has two adult children.

Secretary/Treasurer

Emergency Medicine

Dr. Allan Brody has been an MPMG Board member since 2010, serves as Secretary/Treasurer, participates on the MPMG Executive Committee and chairs the Mills-Peninsula Network Finance Committee. He has served as chief of staff and medical director of the Emergency Department at Mills-Peninsula Medical Center. Dr. Brody earned his medical degree from the University of California at Davis and did his residency in Emergency Medicine at Stanford University.

CEO

Dr. Keith Duncan was a staff pathologist, former Chief of Staff and Department Chair at Mills-Peninsula Medical Center for 35 years, having retired in 2021 He received his B.S in Biological Sciences, Ph.D. in Experimental Pathology and M.D. from the University of Southern California. Dr. Duncan took over the reins as CEO in April 2022, filling the large shoes of the long serving predecessor, Robert Hortop. Keith has a passion for music and gardening; he is married and has one son.

Performance Improvement Director

Family Medicine

Jill Pavliscak has been an MPMG Board member since 2018, is active on the MPMG Executive Committee and chairs the Mills-Peninsula Network Quality Committee and serves as Performance Improvement Director for MPMG. Dr. Pavliscak earned her medical degree from Oregon Health Sciences University and received her internship and residency training from the Swedish Cherry Hill Family Medicine Residency Program in Seattle. She enjoys spending time outside with her three children and husband, who practices medicine with her in Half Moon Bay.

Internal Medicine

Andra Batlin has been an MPMG Board member since 2017, has been part of the MPMG HCC/RAF Team, previously served on the Medical Policy and Credentialing Committees and is currently on the Quality Improvement Committee. Dr. Batlin earned her medical degree from St. George's University School of Medicine and received her residency training from the University of Massachusetts Internal Medicine Program. She is in private practice with her husband and works as an assistant professor for St. George's University School of Medicine. She is currently serving the position of the Vice Chair of the department of Internal Medicine at Peninsula Hospital. She enjoys spending time with her two daughters, family and friends.

Orthopedic Surgery

Dr. Dirk Diefendorf is a Fellowship Trained Specialist in Sports Medicine, Arthroscopic Surgery and Reconstructive Orthopedic Surgery. He is Board Certified in both Orthopedic Surgery and Sports Medicine by the American Board of Orthopedic Surgery. He has served as the Team Orthopedic Surgeon for Serra High School in San Mateo since 1992 and routinely cares for athletes of all ages. He has been an MPMG Board member since 2014 and has been a member of the MPMG Finance Committee since 2011. He has also served as Chairman of the Department of Orthopedic Surgery at Peninsula Hospital. Dr. Diefendorf earned his MD degree from Northwestern University and completed his Sports Medicine Fellowship at the Southern California Orthopedic Institute.

Internal Medicine

Dr. John Chow has been an MPMG Board member since 2006. Dr. Chow is a current member of the Credentialing Committee, previously served on the Finance Committee and received his medical degree from Albany Medical College of Union University in Albany, New York.

Dr. Joseph Fenerty has been an MPMG Board member since 2018. Dr. Fenerty earned his medical degree from Stanford University School of Medicine, received his internship and residency training from Santa Clara Valley Medical Center and University of California, San Francisco, respectively and completed a fellowship at Brigham and Women's Hospital, Boston.

Nephrology

Dr. Randy Chen has served as a member of the board of directors of MPMG since 2021 and the MPMG finance committee since 2019. He has been in independent practice as a nephrologist in the Peninsula area for 17 years. The majority of his medical training was done at UCLA from 2000-2006. In order to stay well-rounded as a physician, he also serves in medical director, medical consultant and board of director roles in different organizations which has helped him to understand the complexities of healthcare systems and care delivery. His interests outside of medicine include a love of animals (having several pug dogs), nature photography, cooking barbeque, and golf.

Dr. Jacqueline Koo joined the MPMG Board in 2025 and has served on the Mills Peninsula Network Quality Improvement Committee since 2024, spearheading the Diabetic Eye Exam Initiative. She has been in independent ophthalmology practice for over 17 years on the Peninsula. Jacqueline grew up in the South Bay (she remembers when 280 had no traffic) and graduated from Gunn High School in Palo Alto. She completed her undergraduate degree at Johns Hopkins University, her masters of public health degree at UC Berkeley, her medical school degree and ophthalmology residency at Boston University, and her cornea fellowship with Dr. Richard Lindstrom in Minnesota. 

Jacqueline is married to Dr. Edward Sun, an MPMG orthopedic spine surgeon. Their two high school age sons play varsity water polo and baseball. During the sports season, you will often find her and Ed supporting the boys at those games.  In their spare time, the family enjoys biking, skiing, and traveling together.

Dr. Serena Shi joined the MPMG Board in 2025.  After graduating from her endocrinology fellowship at UCLA in 2015, Serena went into independent practice in Burlingame. The office provides care in all aspects of general endocrinology, including nutrition counseling and diabetes education. 

Dr. Shi has served on the Mills-Peninsula Network Finance Committee since 2024.

Bob Hortop received his B.A. from the University of Michigan and J.D. from Santa Clara University School of Law. He is a member of the California State Bar. As a former hospital administrator at Mills Peninsula Medical Center, he assisted the medical community leadership to form MPMG. He worked for Sutter Health as Vice President for system wide Managed Care Contracting. Following his employment at Sutter Health he joined MPMG where he served as CEO until his retirement in 2023. As a member of the Board of MPMG, he serves as internal counsel.