The Metacore database was used to analyze protein-protein interactions among the members of the classifier and identified a highly significant interaction sub-network (P < 4.85⁻³⁶), which included 2 ANGPT1 signaling-related pathways (both part of MetaCore Curated Map 532). The key classifier node that linked both of these pathways was ANGPT1. Red circles represent genes up-regulated in nonresponders.