CD44 and cancer: Based on the reported expression of CD44, CD133 and EpCAM as cancer stem cell surface markers, H460, H1299 and SKMES-1 cells were screened to examine differences, if any, in their cell surface expression of these markers between matched PT and CisR cell lines (Supplementary Fig. 5). While there was significant increase in CD44 across all PT and CisR cell lines relative to their isotype controls, CD44+ populations were significantly higher in PT cells relative to their CisR counterparts.