VTN and cancer: Moreover, staining of extracellular matrix molecules, vitronectin -main αv integrins receptor-, and laminin, shows that SRO-91, like RBV, does not act on the organization of the extracellular matrix and matrix microenvironment (S5 Fig) of cancer cells–an effect of RBV on several other cell models [7,24,32]—by its specific action on eIF4E.