Caveolin-1- and cavin-1-containing structures appeared close to the plasma membrane around the rear of cells moving in 3D and on 2D rigidity gradients (Figures 2A–2C and S2D–S2H) and in cancer cells escaping spheroids in 3D matrix (which share the elongated morphology of cells moving in 3D CDM; Figures 2D–2F). The gene discussed is CAV1; the disease is cancer.