- High levels of p19/nm23 protein in neuroblastoma are associated with advanced stage disease and with N-myc gene amplification. Hailat, N., Keim, D.R., Melhem, R.F., Zhu, X.X., Eckerskorn, C., Brodeur, G.M., Reynolds, C.P., Seeger, R.C., Lottspeich, F., Strahler, J.R. J. Clin. Invest. (1991)