Spearman correlations between protein expression and sensitivity to Plk1 inhibitors (BI2536 GSK461364 AUC values for two Plk1 inhibitors are compared with expression of selected proteins (cMet, E-cadherin, β-catenin, and Snail); each data point represents an individual non-small cell lung cancer cell line. E-cadherin, β catenin, and cMet protein expression correlated with drug resistance. 