Crossing Eμ-Myc mice with Rock1 NC or Rock1 WT mice revealed that the absence of caspase cleavage of ROCK1 resulted in a significant 45% increase in median survival, and a shift towards an increased incidence of thymic lymphomas in Eμ-Myc; Rock1 NC mice The prolonged survival of Eμ-Myc; Rock1 NC mice was associated with decreased bone marrow cellularity and altered cell cycle progression, although there were no significant effects on B cell differentiation. The gene discussed is MYC; the disease is thymus lymphoma.