Since increased collagen and fibronectin deposition and increased tumor stiffness have been linked to tumor progression (Piersma et al., 2020; Fenner et al., 2014; Provenzano et al., 2008), we investigated the mechanical properties of MDA+ and MDA- tumors to assess whether altered tumor matrix mechanics may contribute to metastatic potential. This evidence concerns the gene FN1 and neoplasm.