Supplementary Material for: Pilot Study Using Proteomics to Identify Predictive Biomarkers of Necrotizing Enterocolitis from Buccal Swabs in Very Low Birth Weight Infants R.Murgas Torrazza N.Li C.Young F.Kobeissy M.Chow S.Chen V.Mai R.Sharma M.Hudak J.Shuster 2013 <b><i>Background:</i></b> Necrotizing enterocolitis (NEC) is a major cause of death and morbidity in very low birth weight infants. <b><i>Objective:</i></b> To identify biomarker(s) that would predict NEC using buccal swab samples utilizing a proteomic approach. <b><i>Methods:</i></b> Cumulative buccal swab samples derived from very low birth weight preterm infants (<32 weeks' gestational age and <1,250 g) at 1, 2 and 3 weeks prior to the development of NEC and matched controls were subjected to two-dimensional difference gel electrophoresis and LC-MS/MS analysis for proteomic protein discovery. After identification of 21 altered proteins, we chose 3 candidate proteins using a broad systems biologic analysis approach that suggested several altered cellular processes that could be associated with NEC. <b><i>Results:</i></b> Preliminary validation studies using Western blots on these samples and 10 additional NEC and 10 matched control buccal samples collected within 2 or 3 weeks before NEC diagnosis analysis showed lower interleukin-1 receptor antagonist. <b><i>Conclusion:</i></b> Our results suggest that interleukin-1 receptor antagonist is worthy of further studies to determine its utility in helping predict NEC.