Biostatistics Branch Fellows
Simina Boca - Postdoctoral Fellow
Simina Boca joined the Biostatistics Branch (BB) of the Division of Cancer Epidemiology (DCEG) in October 2011 as a postdoctoral fellow. Her mentors are Dr. Joshua Sampson and Dr. Nilanjan Chatterjee. Dr. Boca received her Ph.D. in Biostatistics from Johns Hopkins University in 2011, under the mentorship of Giovanni Parmigiani and Jeffrey T. Leek. Her doctoral work concerned the development of statistical methods for set-level inference in high-dimensional data, with her primary area of scientific interest being cancer genomics. She also conducted research in population genetics. For her postdoctoral fellowship, she is further pursuing her interest in the analysis of “omics” data, including metabolomics and genome-wide association studies.
Key Publications:
Arpita Ghosh - Postdoctoral Fellow
Dr. Arpita Ghosh joined the Biostatistics Branch (BB), Division of Cancer Epidemiology and Genetics (DCEG), in October 2009 as a visiting fellow. Her mentor is Dr. Sholom Wacholder, Senior Investigator, BB, DCEG. She received her doctoral degree in Biostatistics from the University of North Carolina, Chapel Hill. Her thesis focused on statistical problems for genome-wide association studies and genetic epidemiology, including winner’s curse, analysis of secondary phenotypes and variable selection in data mining.
While at NCI, Dr. Ghosh is collaborating on epidemiologic studies and related methodological problems. Her current research involves methodological issues related to design and analysis of datasets pooled across different studies and application of kin-cohort design to GWAS data with family history.
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Summer Han - Research Fellow
Summer S. Han joined the Biostatistics Branch in August of 2009 as a Research Fellow. Dr. Han received her Ph.D. from the Department of Statistics at Yale University, working on statistical methods for linkage analysis of complex disorders that incorporate data on multiple quantitative traits. Her primary mentor is Dr. Philip Rosenberg, Senior Investigator in Biostatistics Branch in the Division of Cancer Epidemiology and Genetics, and she’s also working with Dr. Nilanjan Chatterjee, Chief of Biostatistics Branch for developing methodologies for detecting gene-gene/ gene-environment interactions with biologically more plausible constraints to enhance power. For collaborations, she’s currently working with Dr. Lee Moore, Investigator in Occupational & Environmental Epidemiology Branch in the Division of Cancer Epidemiology and Genetics for several candidate gene studies for renal cell carcinoma. Dr. Han’s research interests include gene-gene/gene-environment interactions, genome-wide association studies, pathway analysis for candidate genes studies, likelihood ratio tests under nonstandard boundary conditions, and isotonic regression.
Key Publications:
- • Han SS, Chang JC. Reconsidering the asymptotic null distribution of likelihood ratio tests for genetic linkage in multivariate variance components models under complete pleiotropy. 2009 Biostatistics, 2010 11(2):226-41
- • Grigorenko EL, Han SS, Yrigollen CM, Leng L, McDonald C, Mizue Y, Anderson GM, Mulder EJ, de Bildt A, Minderaa RB, Volkmar FR, Chang JT, Bucala R. Macrophage Migration Inhibitory Factor and Autism Spectrum Disorders. Pediatrics 2008; 122(2):e438–e445.
- • Yrigollen CM, Han SS, Kochetkova A, Babitz T, Chang JT, Volkmar FR, Leckman JF, Grigorenko EL. Genes Controlling Affiliative Behavior as Candidate Genes for Autism. Biological Psychiatry 2008; 63(10): 911-916.
Stephanie Kovalchik - Postdoctoral Fellow
Stephanie Kovalchik joined the Biostatistics Branch in March 2011. Her mentors are Dr. Hormuzd Katki and Dr. Ruth Pfeiffer. Her dissertation research concerned statistical issues in estimating treatment and patient factor interactions with meta-analysis. Her dissertation adviser was Dr. William G. Cumberland, and her doctoral training was supported by an NIH training grant for Biostatistics of HIV/AIDS research. Dr. Kovalchik’s main research interests include subgroup analysis, hierarchical modeling, meta-analysis and comparative effectiveness research. She received a B.S. in Biology from the California Institute of Technology in 2003, a M.S. in Biostatistics in 2006 and Ph.D. in Biostatistics in 2010 from the University of California, Los Angeles.
Peng Li - Postdoctoral Fellow
Peng Li joined the Biostatistics Branch, Division of Cancer Epidemiology and Genetics (DCEG) as a visiting post-doctoral fellow in September 2010. Dr. Li received his Ph.D. in statistics at the Nankai University in China. His primary mentor is Dr. Jianxin Shi, Principal Investigator in Biostatistics Branch in the Division of Cancer Epidemiology and Genetics. Dr. Li is working with Dr. Shi on calling copy number variations, testing association between copy number variantion and cancer risk, next generation resequencing studies and developing new statistical approaches to analyze rare genetic variants in cancer genetic studies.
Key Publications:
Paige Maas - Predoctoral Fellow
Paige Maas joined the Biostatistics Branch in the fall of 2009 as the first participant in the Biostatistics in Cancer Epidemiology Predoctoral Training Program, a partnership between the National Cancer Institute and Johns Hopkins School of Public Health. She received a degree in Applied Mathematics and minors in Biology and Psychology from Pomona College in 2009. Her research interests are still developing and include longitudinal data analysis, regression modeling, and survival analysis. She is currently a Ph.D. candidate at Johns Hopkins School of Public Health and will begin working on statistical research projects at the National Cancer Institute in the summer of 2010.
Ju-Hyun Park - Postdoctoral Fellow
Ju-Hyun Park, Ph.D., joined the Biostatistics Branch (BB), Division of Cancer Epidemiology and Genetics in September 2008 as a postdoctoral fellow after completing his doctorate in Biostatistics at the University of North Carolina at Chapel Hill in August. Prior to that, he was a predoctoral fellow at the National Institute of Environmental Health Sciences, National Institutes of Health, in Research Triangle Park, North Carolina. He is working under Dr. Nilanjan Chatterjee, to develop Bayesian statistical approaches for flexible design and analysis of modern epidemiologic studies. His research interests include: developing nonparametric Bayesian methodologies with a focus on density estimation and predictor-dependent clustering. Currently he is involved in developing a Bayesian approach to power calculations for genome-wide association studies. Dr. Park was awarded the Distinguished Student Paper Award at 2008 International Biometric Society Eastern North American Region (ENAR) meeting.
Key Publications:
- • Dunson, D.B. and Park, J.-H. (2008) Kernel stick-breaking processes, Biometrika 95, 307-323.
- • Dunson, D.B., Pillai, N., and Park, J.-H. (2007) Bayesian density regression, Journal of the Royal Statistical Society B 69, 163-183.
Yenny Webb-Vargas - Predoctoral Fellow
Yenny Webb-Vargas joined the Biostatistics Branch in the fall of 2010 as part of the joint program between the National Cancer Institute and Johns Hopkins School of Public Health, the Biostatistics in Cancer Epidemiology Predoctoral Training Program. Her interests are structural equations, survival, and longitudinal models. She is working under Dr. Ruth Pfeiffer on the ecologic analysis of breast cancer trends in relation to changes in risk factor distributions. She has a B.S. in Chemistry, Bacteriology and Parasitology from the Autonomous University of Nuevo Leon, an M.S. in Applied Statistics from the Monterrey Institute of Technology and Higher Education, and is a Biostatistics PhD candidate at the Johns Hopkins School of Public Health.
Key Publications:
Jincao Wu - Postdoctoral Fellow
Dr. Jincao Wu joined the Biostatistics Branch in September 2011 as a visiting fellow. Her mentors are Dr. Mitchell Gail and Dr. Ruth Pfeiffer. Dr. Wu received her Ph.D. in Biostatistics from the University of Michigan. Her thesis focuses on developing Bayesian models to predict patients’ clinical outcome or survival using high-dimensional brain imaging data. Currently, her research involves building risk prediction models based genotypic data in the genome-wide association studies, developing imputation methods to handle missing data in breast cancer case-control studies and developing methodologies for model selection and data de-noising in the study of mass spectrometry data.
Key Publications:
Han Zhang - Postdoctoral Fellow
Han Zhang joined the Biostatistics Branch, Division of Cancer Epidemiology and Genetics (DCEG) as a visiting fellow in August 2011. Dr. Zhang received Ph.D. degree in statistics from the University of Science and Technology of China (USTC). His Ph.D. thesis focused on developing algorithms for haplotype analysis under pooling and individual design. He is now working with Dr. Kai Yu on the statistical approaches for rare variants association analysis and gene-gene interaction analysis in case-control studies.
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