A: A549 cells have high Src-ptyr418 levels. QU-DB (lanes 5-8) or A549 (lanes 1-4) cells were grown to different densities as indicated and extracts probed for Src-ptyr418, Stat3-ptyr705 or total Src. Note the low levels of Src-ptyr418 in QU-DB cells. B: Src-ptyr418 and Stat3-ptyr705 in NSCLC lines. The indicated cell lines were grown to 50% confluence and extracts probed for Src-ptyr418, Stat3-ptyr705, total Src or GAPDH as a loading control. C: Dasatinib reduces Stat3-ptyr705 levels in A459 cells: A549 or SK-LuCi6-Src cells were grown to subconfluence and treated with the Src-selective inhibitor, Dasatinib (1μM) or the DMSO carrier alone and cell extracts probed for Src-ptyr418, Stat3-ptyr705 or GAPDH as a loading control, as indicated.