PECAM1 and cancer: Figure 3 shows that cancer cells (Zsgreen labeled) spread over capillary-like structures formed by ECs (CD31+, in red). Although our model lacks a basement membrane it clearly demonstrates that the direct interaction between capillary-like structures formed by ECs and cancer cells modifies cancer cell morphology. The study of the crosstalk between endothelial and cancer cells plays a crucial role in angiogenesis and metastasis [123]; our model recapitulates this interaction in a physiologically relevant context.