9 research outputs found
Conditional Screening for Ultra-high Dimensional Covariates with Survival Outcomes
Identifying important biomarkers that are predictive for cancer patients'
prognosis is key in gaining better insights into the biological influences on
the disease and has become a critical component of precision medicine. The
emergence of large-scale biomedical survival studies, which typically involve
excessive number of biomarkers, has brought high demand in designing efficient
screening tools for selecting predictive biomarkers. The vast amount of
biomarkers defies any existing variable selection methods via regularization.
The recently developed variable screening methods, though powerful in many
practical setting, fail to incorporate prior information on the importance of
each biomarker and are less powerful in detecting marginally weak while jointly
important signals. We propose a new conditional screening method for survival
outcome data by computing the marginal contribution of each biomarker given
priorly known biological information. This is based on the premise that some
biomarkers are known to be associated with disease outcomes a priori. Our
method possesses sure screening properties and a vanishing false selection
rate. The utility of the proposal is further confirmed with extensive
simulation studies and analysis of a Diffuse large B-cell lymphoma (DLBCL)
dataset.Comment: 34 pages, 3 figure
Discussion of âPost selection shrinkage estimation for highâdimensional data analysisâ
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136472/1/asmb2216_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136472/2/asmb2216.pd
Quantile-adaptive model-free variable screening for high-dimensional heterogeneous data
We introduce a quantile-adaptive framework for nonlinear variable screening
with high-dimensional heterogeneous data. This framework has two distinctive
features: (1) it allows the set of active variables to vary across quantiles,
thus making it more flexible to accommodate heterogeneity; (2) it is model-free
and avoids the difficult task of specifying the form of a statistical model in
a high dimensional space. Our nonlinear independence screening procedure
employs spline approximations to model the marginal effects at a quantile level
of interest. Under appropriate conditions on the quantile functions without
requiring the existence of any moments, the new procedure is shown to enjoy the
sure screening property in ultra-high dimensions. Furthermore, the
quantile-adaptive framework can naturally handle censored data arising in
survival analysis. We prove that the sure screening property remains valid when
the response variable is subject to random right censoring. Numerical studies
confirm the fine performance of the proposed method for various semiparametric
models and its effectiveness to extract quantile-specific information from
heteroscedastic data.Comment: Published in at http://dx.doi.org/10.1214/13-AOS1087 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org