Acute Myc de-activation in established KM adenocarcinomas triggered rapid and synchronous regression of all tumors, characterized by a direct reversal of all Myc-induced stromal changes: macrophages rapidly exited the tumor masses; tumor vasculature reformed into discrete vessels (“vascular re-normalization”) and widespread hypoxia reappeared; T, B, and NK cells rapidly repopulated the tumors and their environs; and tumor cell apoptosis and tumor regression rapidly ensued. The gene discussed is MYC; the disease is neoplasm.