The cancer cells were analyzed after 24 h of embedding into the PSF for the protein expression and, as shown in Fig. 8A, a down-regulation of the expression of the cyclin D1 was observed in a stiffness-dependent manner, indicating that the expression of this protein and, consequently, the invasiveness of the cancer cells in these systems is linked to the stiffness of the tumoroid. This evidence concerns the gene CCND1 and cancer.