In order to study whether hnRNPK promoted the metastasis of A549 cells depending on its binding partner MAP 1B-LC1, we detected the effect of knockdown of MAP 1B-LC1 on the metastatic capacity of lung cancer cells stably overexpressing hnRNP K. The results demonstrated that knockdown of MAP 1B-LC1 suppressed the metastasis of lung cancer cells, which suggested MAP 1B-LC1 was one regulator of microtubule cytoskeleton system and promoted the stability of microtubule system during TGF-β1-induced EMT. This evidence concerns the gene TGFB1 and lung cancer.