These differences were attributed to the inherent bioactivity of HA rather than the different mechanical stiffness of the matrices (non-mineralized scaffolds: 0.5 MPa, mineralized scaffolds: 1.1 MPa), as scaffolds with lower (50% HA) and higher HA content (200% HA) and thus lower (0.7 MPa) and higher elastic modulus (2.1 MPa) exhibited similar effects on breast cancer cell proliferation and IL-8 secretion (data not shown). This evidence concerns the gene CXCL8 and breast cancer.