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Purcell P, Joo BW, Hu JK, Tran PV, Calicchio ML, O'Connell DJ, Maas RL, Tabin CJ.Purcell P, et al. Among authors: maas rl.Proc Natl Acad Sci U S A. 2009 Oct 27;106(43):18297-302. doi: 10.1073/pnas.0908836106. Epub 2009 Oct 8.Proc Natl Acad Sci U S A. 2009.PMID: 19815519Free PMC article.