Current Lab Members

Principal Investigator
Phone: (650) 725 5901

Alejandro Sweet-Cordero
School of Medicine Profile
Academic Appointments

• Associate Professor, Pediatrics - Cancer Biology
• Member, Bio-X
• Member, Cancer Center

Clinical Focus

Pediatric Hematology-Oncology

Honors and Awards

• Scholar Award, Rita Allen Foundation (2008-2011)
• Clinical Scientist Development Award, Doris Duke Foundation (2007-2010)
• Sidney Kimmel Scholar, Sidney Kimmel Foundation (2006-2008)

Professional Education
Fellowship: Dana-Farber Cancer Institute MA (2002)
Residency: UCSF Medical Center CA (1998)
Internship: UCSF Medical Center CA (1996)
Medical Education: UCSF School of Medicine CA (1995)
B.A.: Stanford University, Anthropology (1989)
B.S. Stanford University, Biology (1989)

Phone: (650) 736 2753

Alyssa Ray Duran
Administrative Associate


Phone: (650) 736 2753
Leanne Sayles
Lab Manager

Leanne hails from the frigid climate of Western Canada.  She attended the University of Alberta in Edmonton (Alberta, Canada) where she obtained a Bachelor of Science in Molecular Genetics in 1999.
Leanne then went on to work as a Research Assistant in the Department of Biochemistry at the U of A.
She studied Gene Therapies for Mitochondrial Dysfunction in the Nematode C.elegans.  While this research was extremely fulfilling, the constant fears of being eaten by wild Polar Bears and the chance of being encased in a block of ice on the way to work instigated a move to a much warmer climate.

She and her family moved to the Bay area in 2005 when she accepted a position in Alejandro's laboratory.  Leanne currently spends quality time keeping those around her happy and studying Ras induced non-small cell lung cancer.  By using in vivo and in vitro methods, she is investigating the requirements for tumor initiation and chemotherapy response in a mouse model of Kras induced oncogenesis.
Phone: (650) 736 2753
Dana Gwinn
Postdoctoral Fellow

Dana hails from the gem of the Pacific Northwest, Seattle, WA, where she attended the same high school as music god Jimi Hendrix, as well as 2007 NBA Rookie of the Year, Brandon Roy. However, instead of becoming a rock star or professional athlete, Dana pursued her love of science at Colby College in Waterville, ME. From there, she began working with Dr. Reuben Shaw at Harvard, and jumped at the opportunity to move to sunny southern California to work with Dr. Shaw at the Salk Institute, where she joined the Ph.D. program at UCSD, and graduated in 2011.

Dana's work in the Sweet-Cordero lab focuses on determining how oncogenic Kras alters cellular metabolism, and how cells expressing oncogenic Kras differentially use fuel sources such as glucose and glutamine. Outside of lab...oh wait, there is no outside of lab!


Bethsaida Nieves
Phone: (650) 736 2753

Bethsaida Nieves
Postdoctoral Fellow

Bethsaida was born and raised in Brooklyn, NY and then moved with her family to Teaneck, NJ, a small town just outside of Manhattan.  She did her undergraduate studies at Pennsylvania State University in State College, PA where she not only became a huge football fan, but also developed a passion for research.  During that time, she joined Dr. Craig Cameron's lab in the Biochemistry department and later received her B.S. in Genetics and Development Biology.  From one cold state to another, she enrolled in the graduate studies program at Albany Medical College in Albany, NY, where she worked under the mentorship of Dr. Susan LaFlamme.  After receiving her PhD, she relocated to the sunny state of California and joined the Sweet-Cordero lab as a postdoctoral fellow where she is currently studying Ewing's sarcoma, a rare bone and soft tissue cancer found in children and adolescents.  Her research is focused on analyzing the consequence of EWS/FLI-1 expression in human mesenchymal stem cells in vitro and in vivo as well as identifying mechanisms responsible for resistance to chemotherapy in Ewing's sarcoma.


Phone: (650) 736 2753
David Simpson
Postdoctoral Fellow

David is a native of California, where he earned a B.S. in Genetics at UCDavis in 2004. He continued his studies at the Watson School of Biological Sciences in the Tansey laboratory, studying how oncogenic transcription factors regulate cancer progression. After a detour through the South to Vanderbilt University, he received his Ph.D. (2010, Cold Spring Harbor Laboratory), and discovered the meaning of life: bacon, bourbon, and barbecue.

In the Sweet-Cordero lab, David is discovering new therapeutic targets that will make lung cancers more susceptible to chemotherapy. He specializes in using next-generation sequencing and shRNA libraries as tools to find the genes cancer cells require to evade therapy. Outside of the lab, you can hear David play in the horn section of the Stanford Symphony Orchestra in their new Bing hall.



Phone: (650) 736 2753
Victoria Sahakian
CIRM Intern

Victoria grew up in San Francisco where she enjoyed jogging in the fog on Ocean Beach. She attended the University of California, San Diego where she studied biology and conducted research on C. elegans, studying mutant worms for synaptic defects using pharmacological and behavioral assays and mapping these mutations to the genome. After graduation, Victoria worked as a research analyst in global health where she analyzed and structured worldwide outbreak data to predict and prevent the incidence of new disease threats. After developing an interest in stem cell research she started the SCILL (Stem Cell Internships in Laboratory-based Learning) program in 2012, supported by CIRM, in which she will be awarded a Master's degree upon completion of her internship here at Stanford.

Currently, she is studying how chromatin regulation in cancer stem cells influences response to chemotherapy in lung cancer. Outside the lab, Victoria enjoys dancing East & West Coast swing, salsa, and tango. She also loves to play basketball and run on the beach barefoot.


Phone: (650) 736 2753
Cassie Greene
Life Science Research Assistant

Cassie is originally from Westchester, New York. She attended Cornell University, where she got her first taste of research in Dr. Antje Baeumner's microfluidics lab and received her Bachelor's degree in Bioengineering in 2011. When her boyfriend was accepted to Stanford's applied physics PhD program, they gladly exchanged the unending cold of upstate NY for the enduring sunshine of Palo Alto.

Cassie's work in the Sweet-Cordero lab supports several projects, including the development of a pediatric solid tumor bank and next-generation sequencing of pediatric sarcomas for a translational medicine program at Stanford. In her spare time, Cassie enjoys cooking and baking as well as singing in various vocal ensembles and local community theater.


Phone: (650) 736 2753
Marcus Breese

Marcus was born in Ohio, but grew up in the Chicago suburbs and Northern Indiana. In 2000, he earned a B.S. in Biochemistry and Molecular Biology from Denison University in Granville, OH. While there he started working in bioinformatics by examining evolutionary co-mutation rates of amino acids in RNA polymerase under the guidance of Peter Kuhlman, Ph.D. During graduate school at the Indiana University School of Medicine, Marcus followed a dual wet lab/computational track under Matt Grow, Ph.D. and later under Howard Edenberg, Ph.D. At IU, he worked to help establish the Center for Medical Genomics microarray core facility, working on protocols and techniques for spotted cDNA microarray fabrication and analysis, Affymetrix GeneChip analysis, and creation of an in-house LIMS system. His thesis work involved identification of potential targets of the cardiogenic transcription factor Nkx2-5 in Xenopus laevis. This involved an equal amount of wet-lab and bioinformatics work to re-annotate the frog transcriptome using transcript similarity to other (better annotated) organisms. Prior to receiving his Ph.D., Marcus started to focus on bioinformatics by collaborating with Yunlong Liu, Ph.D. in the Center for Computational Biology and Bioinformatics at IU. Here he started working with next-generation sequencing (NGS) data analysis. After defending his thesis in 2011, this work continued in Dr. Liu's lab where Marcus developed NGS analysis tools and pipelines for HPC clusters for SOLiD and Illumina data. Starting in the winter of 2012, Marcus had a brief postdoc fellowship in the lab of Sean Mooney, Ph.D. at the Buck Institute for Research on Aging in Novato, CA. His main role there was to revamp the research computing infrastructure for the institute and perform data analysis for collaborators. Marcus was excited to join the Sweet-Cordero lab in 2013 to work on a pediatric cancer genome sequencing initiative.


Phone: (650) 736 2753
Dedeepya Vaka
Data Analyst

I grew up southern part of India. After completing my bachelors in Biotechnology in 2007, I wanted to pursue my higher education in U.S. I received my graduation in Bioinformatics from University of Texas El Paso in 2009 and started working as a Bioinformatician.

Before moving to Stanford I worked as an intern in University of Illinois Urbana Champaign on developing Next-Gen sequencing pipeline for Illumina reads. Later I worked as a full-time Bioinformatics Systems Engineer for FGSR (Functional Genomics Shared Resource) Vanderbilt University, where I used to provide Bioinformatics support mainly focusing on experimental design, statistical methods and advance bioinformatics analysis for multiple PI's.

Currently I am providing Bioinformatics support (both in microarrays and deep-sequencing) for Dr. Sweet-Cordero, Dr. Sage and Dr. Celery labs.

Sweet-Cordero Lab Alumni

Ron Chen
Sustainability Program Lead, Nepal Education Initiative Organization





Michelle Marques Howarth
Postdoctoral Fellow, Celgene





Diego Jaitin
Senior Intern, Weizmann Institute of Science





Shuang Niu
Pathology Resident, UTSW





Silve Vicent
Investigator, University of Navarra CIMA





Yanyan Zheng
Staff Scientist, Merck