Then different conditioned media from MCF-7 cells, which showed a low level of endogenous ADAMTS-5 expression among the three breast cancer cell lines employed in this work (Supplementary Figure 3), were added to normal mammary fibroblasts spheroids embedded in 3D collagen matrix (Figure 3A and 3B, and Supplementary Videos 1 to 5). This evidence concerns the gene ADAMTS5 and breast cancer.