THY1 and melanoma: Remarkably, integrins and syndecan 4 form a trimolecular complex with Thy-1, where two triads have been reported: α5β1/Thy-1/syndecan 4 in melanoma/endothelial cells and αvβ3/Thy-1/syndecan 4 in a neuron/astrocyte model (Fiore et al., 2014; Burgos-Bravo et al., 2020).