Dr. Emily J. Gallagher
Dr. Emily Jane Gallagher is Associate Professor of Medicine, Endocrinology, Diabetes and Bone Disease at the Icahn School of Medicine at Mount Sinai, NY. She earned her medical degree from the University College Dublin, Ireland, completed residency in internal medicine and two years of endocrinology fellowship in Dublin and a became a Member of the Royal College of Physicians of Ireland before moving to New York. She then completed residency and fellowship at Mount Sinai Hospital in New York, and embarked on a career as a physician-scientist studying the impact of the metabolic syndrome on cancer and obtained a PhD in Physiology and Medical Physics from the Royal College of Surgeons of Ireland. She is currently funded by an R37 MERIT award from the National Cancer Institute. Dr. Gallagher is also involved in physician-scientist training at Mount Sinai, is Director of the Physician-Scientist Training Program in the Internal Medicine Residency, and and is MPI on two R38 StARR Awards. As a physician, Dr. Gallagher has an oncoendocrinology clinical practice where she treats people with endocrine and metabolic complications of cancer, and its therapies.
Zijun He – Associate Researcher
Zijun earned her Bachelor of Science in Biological Sciences from the University of California, Irvine, and completed her Master of Science degree in Clinical Research at the Icahn School of Medicine at Mount Sinai. She conducted her master’s thesis research under the mentorship of Dr. Emily Gallagher, with whom she continues to work as an Associate researcher.
Zijun’s research focuses on understanding how hyperinsulinemia, insulin receptor (IR) isoform, and lipid peroxidation products contribute to the progression and metabolic regulation of triple negative breast cancer (TNBC). Under Dr. Gallagher’s guidance, she works on studies examining the effects of hyperinsulinemia on cancer cell signaling, including its impact on IR isoform switching. Her efforts support ongoing work to better define the mechanisms underlying IR regulation, signaling, and mitogenic activity in the context of hyperinsulinemia.
Zijun is also involved in research exploring the role of 7α-hydroxycholesterol (7αOHC), a lipid peroxidation product that was recently identified in the serum of women with breast cancer and was positively correlated with tumor size. She is working to understand its potential contribution to TNBC development and progression.
Saidhbh O’Callaghan – Associate Researcher
Saidhbh is an Associate Researcher in the Gallagher Lab. She earned a First Class Honors degree in Physiology from University College Dublin, Ireland. After graduating, she relocated to New York City and joined the Gallagher Lab in March 2025.
Her project focuses on how circulating lipids, particularly triglycerides and very low-density lipoproteins (VLDL), influence tumor growth and progression in Triple Negative Breast Cancer (TNBC). Elevated triglycerides are associated with higher TNBC mortality, but the mechanisms driving this link remain unclear. Saidhbh’s project focuses on determining how higher levels of VLDL affect TNBC biology and to identify metabolic pathways that may contribute to disease progression.
Richard Vica – MD
Richard is currently in his third year of Internal Medicine residency with an interest in specializing in onco-endocrinology and neuroendocrine tumors (NETs). His research focuses on exploring the effect of incretin mimetics, particularly glucagon-like peptide-1 receptor agonists, on NET progression. As part of his training, he has studied ways to optimize patients’ behavioral habits to improve health-related outcomes and has published a book chapter on routine changes in obesity and type 2 diabetes in Lifestyle Medicine.
He is passionate about medical education and was selected to participate in the 2025 Mount Sinai, Boston Children’s, and Harvard Macy Course for Future Academic Clinician-Educators. He will serve as a Chief Medical Resident in 2026–2027 before applying to endocrinology fellowship.
Fun fact about myself:
- Cat enthusiast
- Fan of Jules Verne’s and Dan Brown’s books
- The Oscar season is my favorite time of the year
Alexis Engel – Medical Student
Alexis is an MD student in the Gallagher lab. She grew up in NYC and completed her bachelor’s degree in Mathematics at Washington University in St. Louis. Alexis received the REGMS award from the Endocrine Society to investigate the role of the insulin receptor in mediating racial disparities in breast cancer outcomes. She is interested in understanding how hyperinsulinemia and metabolic syndrome contribute to the risk of cancer and other chronic diseases and hopes to apply these findings in clinical practice to improve patient care.