STAT3 and lung cancer: Given the importance of the ERK [9], p38 [10], AKT [11,12] and STAT3 [13,14,15] pathways in the regulation of cell proliferation, migration and invasion and the initiation and progression of lung cancer, we examined the effects of KDF1 overexpression on these pathways by detecting the expression level of AKT, p-AKT, ERK, p-ERK, p38, p-p38, STAT3 and p-STAT3 in A549 cells overexpressing KDF1.