Dr. Santiago currently serves as Assistant Professor of Hematology at the University of Texas Health Science Center at San Antonio. During his fellowship at Duke University Medical Center, Dr. Santiago received funding from the National Institute of Health and the American Heart Association for research in biochemistry, cell biology and specifically, to study blood clotting factors.  In addition, at the University of Texas Health Science Center in San Antonio, he has participated in research studying the use of novel anticoagulants. 

Dr. Santiago is on staff at the following hospitals:  St. Luke's Baptist, Methodist, Methodist Specialty and Transplant, Kindred, LifeCare, Methodist Texsan, Christus Santa Rosa and Uvalde Memorial.  He is a member of the Bexar County Medical Society, Texas Medical Association, the Mexican American and Hispanic Physicians Association in San Antonio, the American Society of Clinical Oncology and the American Society of Hematology.

For the past 13 years, Dr. Santiago has been devoted to the care and treatment of patients with cancer, and malignant and non-malignant hematological disorders.  During this time he has also participated in clinical research studies involving new investigational drugs for cancer and hematological disorders.

Personally, Dr. Santiago devotes his free time to his family and his church.  His hobby is sailing on Lake Medina and he is a member of the Woodlawn Sailing Club.