STK11 and esophageal squamous cell carcinoma: Meanwhile, immunochemistry staining and immunoblot assays both proved that the protein level of LKB1 and the phosphorylation of AMPK was reduced in xenografts derived from RBM4-overexpressing ESCC cells (Fig. 7m and Supplementary Fig. 6g, h), which showed a greater sensitivity to glutaminase inhibitor, CB-839, suggesting that RBM4-LKB1-AMPK axis is involved in the glutamine dependency of ESCC cells.