Lab Members

John Witte

Professor, 415-502-6882

John is Professor of Epidemiology and Biostatistics, and Urology, Head of the Division of Genetic and Cancer Epidemiology, Associate Director of the Institute for Human Genetics, and co-Leader of the Cancer Genetics Program at UCSF. He obtained a BS in Mathematical Sciences, a MS in Industrial Engineering and Operations Research, and a PhD in Epidemiology (with Sander Greenland at UCLA). Before joining the faculty at UCSF in 2003, he did a post-doc in Biostatistics and spent eight years on the faculty at Case Western Reserve University. In addition to work, he enjoys spending time with his family and friends, outdoors, and in the swimming pool!

Emmalyn Chen

Doctoral Student

Emmalyn is a PhD student in the Pharmaceutical Sciences and Pharmacogenomics (PSPG) program at UCSF. In 2014, she obtained a BS in Bioengineering from UC Berkeley. She is generally interested in using genomic data to better understand disease risk and progression. Specifically, she wants to investigate genetic variants that are driving a multiple cancer phenotype. Outside of the office, you will find her watching nature documentaries, top-rope/bouldering, eating seafood, and hanging out with her cats.

Jean Costello

Doctoral Student

Jean Costello is a PhD student in the Bioinformatics program. She received her BA in Mathematics from the University of Minnesota in 2014 and worked as a software developer for three years before enrolling in graduate school. She is interested in exploring the relationship between environmental exposures and preterm birth. When not at work, she enjoys making origami, playing piano, and hiking.

Linda Kachuri


Linda Kachuri joined the Witte lab in February 2018, shortly after completing her PhD in Epidemiology at the University of Toronto under the supervision of Dr. Rayjean Hung. She received an MPH in Epidemiology, also from the University of Toronto in 2012, and a BSc in Psychology from McGill University in 2010. Linda's doctoral research explored the role of rare variants in chromosome 5p15 and telomere length in lung cancer risk and progression. In addition to genetic epidemiology, she is also interested in environmental and occupational cancer risk factors. As a postdoc, Linda is looking forward to working on collaborative projects in prostate cancer, and leveraging genetic and molecular data to gain insight into the mechanisms of cancer etiology and progression. Outside of work Linda enjoys travelling, photography, and exploring the local food scene.

Taylor Cavazos

Doctoral Student

Taylor is a PhD student in the Biological and Medical Informatics (BMI) program at UCSF. She received her BS in Bioengineering: Bioinformatics at UCSD in 2017. She is currently researching the genetic implications of disease progression in low-risk prostate cancer. In general, Taylor is interested in developing computational tools that integrate multi-omic datasets to advance the treatment and understanding of cancer. Her favorite activities are hiking, wakeboarding, and spending time at the beach.

Travis Meyers


Travis completed his MPH and PhD in epidemiology at the UCLA Fielding School of Public Health and joined the Witte Lab in 2017. He earned a BA in biology from Whitman College in Walla Walla, Washington. Dr. Zuo-Feng Zhang supervised Travis’s doctoral research on cumulative cigarette tar exposure, genetic variants, and their interactions on susceptibility and survival of lung and upper aerodigestive tract cancers. Travis is interested in genome-wide association studies as well as gene-environment interaction for cancer risk and progression. A Sacramento native, he enjoys running, tennis, hiking, and spending time with friends and family.


Former Lab Members (& Current Employer)