Dr. El-Hashash is a fellow of the California Institute of Regenerative Medicine and New York University Medical School. Prof. El-Hashash worked as a senior biomedical research scientist at Mount Sinai School of Medicine of New York University and Children's Hospital Los Angeles. He was Assistant Professor and Principal Investigator of Stem Cell & Regenerative Medicine at Keck School of Medicine and Ostrow School of Dentistry of The University of Southern California. In 2016, Prof. El-Hashash joined The University of Edinburgh, Edinburgh Medical School-Zhejiang International Campus, as Tenure-Track Associate Professor and Senior Principal Investigator of Biomedicine, Stem Cell & Regenerative Medicine. Prof.

El-Hashash has several breakthrough discoveries in genes/enzymes that control stem cell behavior and regenerative medicine and has published more than 25 papers in international journals and serves as an editorial board member of repute. He is the editor or author of several books on stem cell and regenerative medicine.