Fig. 4

Co-culture spheroids exhibit leader–follower behavior. A Representative images of migration strands featuring leader–follower behavior in 1.5 and 4.5 mg mL⁻¹ collagen gels 24 h post-embedding. B Average number of leader cells per spheroid. C Relative percentage of leader cells for MDA⁺ and MDA⁻ cells in MDA^MIX spheroids in 1.5 and 4.5 mg mL⁻¹ collagen gels; **p < 0.01