In order to evaluate the role of E2A-encoded E47 protein as a potential tumor suppressor in murine T-ALL, we have introduced nondegradable mutant E47 by retroviral vector into intracellular domain of Notch1- (ICN1-) overexpressing tumors, and we found that overexpression of E47 led to suppression of tumor cell growth [98]. The gene discussed is NOTCH1; the disease is neoplasm.