Our previous study demonstrated that cancer cells undergo a change in their mechanical phenotype that includes cell softening and loss of stiffness sensing.Caveolin-1 (Cavl) , which is suppressed in many tumor cells and in oncogene-transformed cells, is linked to regulate the mechanical phenotype.Cav 1-upregulated RhoA activity and Y397FAK phosphorylation direct actin cap formation, which is positively correlated with cell elasticity and stiffness sensing in fibroblast.Ha-RasV12-induced transformation and changes in the mechanical phenotypes were reversed by re-expression of caveolin-1 and mimicked by the suppression of Cav1 in normal fibroblasts.