STAT3 and neoplasm: Notably, strong colocalization was observed in tumour tissue from the control group, whereas sanguinarine treatment significantly altered the subcellular localization of p‐STAT3‐Tyr and especially p‐STAT3‐Ser (Figure 2D), and potently inhibited the colocalization of HIF‐1α/p‐STAT3‐Tyr and HIF‐1α/p‐STAT3‐Ser (Figure 2E, 2F).