All 744 compounds, common in PC3, VCAP, A549, HT29, HEPG2, HCC515, HA1E, MCF7, and A375, classified according to the number of differentially expressed genes at 6 h of incubation. (A) Significance based on individual cell lines; (B) cumulative significance across all nine cell lines ordered by distance from the other cell lines based on all linear discriminant axes.