Massachusetts General Hospital Cancer Center (A.T.S., L.F., J.F.G., L.D., R.L.F., K.R.S., J.L., G.G., J.A.E.) and the Department of Pathology (A.J.I., L.L., G.G.), Massachusetts General Hospital, Boston, and the Broad Institute of the Massachusetts Institute of Technology and Harvard, Cambridge (I.L., G.G.) - all in Massachusetts; Pfizer Worldwide Research and Development, La Jolla, CA (S.B., A.B., B.J.B., Y.-L.D., W.L., L.P.J., T.S., S.T., M.M., T.W.J.); and the Japanese Foundation for Cancer Research, Tokyo (R.K.).