Spearman correlations between protein expression and sensitivity to Plk1 inhibitors (BI2536, GSK461364, BRD-K70511574, and GW-843682X), based on data from the Cancer Therapeutics Response Portal v2 database and protein expression data derived from the MD Anderson Cell Line Project database (Li et al, 2017). Proteins with expression levels that correlate with area under the curve (AUC) values for at least two drugs are included in the graph. The color and size of the data point represent the direction and significance (p value) of the correlation. Red indicates a positive correlation with drug resistance and green a positive correlation with drug sensitivity (i.e., proteins in red are more highly expressed in resistant cell lines). 