FYN and neoplasm: STAT3-Y705 phosphorylation has been shown to be regulated by SRC kinases in cultured tumor cells (Garcia et al., 2001; Ram and Iyengar, 2001; Silva, 2004), and Fyn is required for Stat3-PO activation in T-cell receptor signaling and T-cell differentiation (Qin et al., 2024).