New Weinberg lab research, published in PNAS, reveals how cancer cells reawaken from dormancy. They showed this mechanism is sparked by inflammation in surrounding tissue, then driven by M2 macrophages that secrete EGFR ligands signaling dormant cancer cells to rapidly multiply. Moreover, cells develop ‘awakening memory,’ no longer requiring inflammatory signals to stay active. Understanding these mechanisms could enable more effective strategies against metastatic cancer. This work was supported in part by the MIT Stem Cell Initiative.