Matsumura et al. have demonstrated that carcinoma-associated fibroblasts (CAFs) in tumor stroma drive the formation of tumor cell clusters composed of two distinct cancer cell populations: one highly epithelial state (showing high E-cadherin and low/negative ZEB1 expression), and one in a hybrid epithelial/mesenchymal state (showing low E-cadherin, high ZEB1 expression). The gene discussed is CDH1; the disease is carcinoma.