STAT3 and cancer: In the cross-pathway integration of immune signals, individual subunits ensure the order and efficiency of signal transmission through diverse mechanisms: ACTR3 acts as a “signaling hub”: On one hand, it is activated by IL-6 and IL-8 secreted by cancer cells, which engage the histone methyltransferase MLL1/Menin-ACTR3 or IL-6/P-STAT3-ACTR3 pathways (Figure 2) to regulate actin dynamics and influence T cell migration and infiltration (Nair et al., 2024).