title: Along signal paths: an empirical gene set approach exploiting pathway topology.
abstract: Gene set analysis using biological pathways has become a widely used statistical approach for gene expression analysis. A biological pathway can be represented through a graph where genes and their interactions are, respectively, nodes and edges of the graph. From a biological point of view only some portions of a pathway are expected to be altered; however, few methods using pathway topology have been proposed and none of them tries to identify the signal paths, within a pathway, mostly involved in the biological problem. Here, we present a novel algorithm for pathway analysis clipper, that tries to fill in this gap. clipper implements a two-step empirical approach based on the exploitation of graph decomposition into a junction tree to reconstruct the most relevant signal path. In the first step clipper selects significant pathways according to statistical tests on the means and the concentration matrices of the graphs derived from pathway topologies. Then, it identifies within these pathways the signal paths having the greatest association with a specific phenotype. We test our approach on simulated and two real expression datasets. Our results demonstrate the efficacy of clipper in the identification of signal transduction paths totally coherent with the biological problem.
authors.affiliation: CRIBI Biotechnology Center, Department of Biology, University of Padova, via U Bassi 58/B, 35121 Padova, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Martini
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sales
authors.forename: M Sofia
authors.initials: MS
authors.lastname: Massa
authors.forename: Monica
authors.initials: M
authors.lastname: Chiogna
authors.forename: Chiara
authors.initials: C
authors.lastname: Romualdi
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism; D049288:Muscular Dystrophies, Limb-Girdle / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D059467:Transcriptome