FYN and breast cancer: WISP1’s EMT program requires both MIF-CD74/CD44v signaling and Lyn/Fyn activation; MIF maintains mesenchymal traits through pathways previously tied to CD44v-mediated metastasis [12,55,56], while Lyn/Fyn kinases—overexpressed in aggressive breast cancers [33,34,35,36,37,57]—orchestrate E-cadherin internalization and actin remodeling.