ABCG2 and non-small cell lung carcinoma: To examine the molecular mechanisms underlying the contribution of Shh signaling to EGFR-TKI resistance in NSCLC cells, we examined Snail, E-cadherin, and ABCG2 expression at 0, 24, and 48 h after treatment of PC9 cells with N-Shh (0.5 μg/mL) by Western blotting.