Our Team

Principal Investigator



Dr. Andreana N. Holowatyj, PhD, MS

Assistant Professor of Medicine & Cancer Biology

Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Vanderbilt University School of Medicine




Dr. Holowatyj has passionately worked for over 9 years to understand cancer development--both in the clinic and in the laboratory settings. She earned her PhD in Medicine at the Wayne State University School of Medicine and Karmanos Cancer Institute in Detroit, Michigan. Dr. Holowatyj then became an NIH/NHGRI Fellow in Genomic Medicine as well as the Susan Cooper Jones Endowed Postdoctoral Fellow in Cancer Research at the University of Utah, where she also earned an MS in Clinical Investigation at the University of Utah School of Medicine in Salt Lake City, Utah.

At Vanderbilt, Dr. Holowatyj's team and laboratory continues to focus on the essential need to treat the whole patient for whom multiple life domains are impacted after a cancer diagnosis—specifically among individuals younger than age 50. She created and leads the Reproductive Health After Cancer Diagnosis and Treatment (REACT) Study which has identified key challenges that individuals within this population are facing across their cancer journey. These findings have contributed to the development of the PREFACE Study, where we are working to discover new ways to improve reproductive health and survivorship for patients diagnosed with colorectal cancer before age 50.

Dr. Holowatyj's team is also dedicated to closing the major ‘gap’ in our understanding of appendix cancer biology and epidemiology—in order to make much-needed advances in disease prevention, detection and outcomes. She has served on the Expert Panel for the American Joint Committee on Cancer (AJCC) Staging Manual: Ninth Edition on Cancers of the Appendix. Dr. Holowatyj is also a member of the Board of Directors for the Vanderbilt Young Adult Cancers Center.

Her research has led to the first studies of appendix cancer biology, epidemiology and outcomes for young patients—including the discovery that approximately 1 in every 3 individuals diagnosed with appendix cancer is younger than age 50. These findings have contributed to the development of the GAP Study, where Dr. Holowatyj and her team are working to discover how changes in genes may contribute to appendix cancer development.

Study Staff

Rebecca Shreffler, BA


Rebecca completed her undergraduate studies in Chemistry and Music at Wittenberg University in Springfield, Ohio. She is currently the clinical research coordinator for the GAP and PREFACE Studies at Vanderbilt University Medical Center and the Vanderbilt-Ingram Cancer Center, where she is responsible for patient recruitment/enrollment, study visits and follow-up, data and sample collection as well as regulatory compliance.

Contact Rebecca at (615) 936-6204.


Lisa Long, BS


Lisa is the Senior Administrative Assistant for the Holowatyj Team at Vanderbilt University Medical Center. Lisa has been with Vanderbilt University since 2004, and has supported numerous cancer studies at the Vanderbilt Epidemiology Center. She is excited to provide administrative support for the GAP and PREFACE Studies.





Samantha Keller


Sam is currently an undergraduate student at Vanderbilt University majoring in Medicine, Health and Society (MHS) with a minor in Psychology. She joined our team in January 2021, and received a 2021 Vanderbilt Undergraduate Summer Research Program Award supported by the Drs. Sidney and Becca Fleischer Undergraduate Summer Research Fund. Her research is focused on cancer survivorship among adolescents and young adults (AYAs), particularly in the REACT Study. Sam’s professional interests include women’s health, psychology, oncology, nutrition and fitness and as a result, is thrilled to also get the opportunity to work on the GAP and PREFACE Studies at Vanderbilt.



Hannah Seagle, BS

Hannah Seagle


Hannah is an incoming graduate student in the Interdisciplinary Graduate Program (IGP) in Biomedical and Biological Sciences at the Vanderbilt University School of Medicine. She completed her undergraduate studies in Biochemistry and Molecular Biology at Wake Forest University in 2021. Over the last year, she has also worked on several COVID-19 clinical studies as a study coordinator. Hannah's professional interests include health disparities and women's health. She is excited to join the team as a 2022 summer research intern with a primary focus on appendix cancer genetics. 



Timothy Gibbs, MS


Tim completed his undergraduate studies in Spanish at Weber State University in Utah and went on to complete a Master's of Science degree at Touro College of Osteopathic Medicine in Interdisciplinary Studies in Biological and Physical Sciences. He is currently a medical student at Meharry Medical College in Nashville and joined our team in May 2020. His research is focused on early-onset colorectal and appendiceal cancer disparities, and he is also excited to help support the GAP Study at Vanderbilt.