(A) HNSCC cells (1483) were transfected with a DA c-Src construct (Upstate Biotechnology) followed by isolation of stable clones in G418-containing media (400 µg/ml). Expression of Tyr 418 phosphorylation and total c-Src were examined by immunoblotting with pY418 Src antibody (BioSource International, Camarillo, CA) and anti-c-Src antibody (Santa Cruz Biotechnology, Inc., Santa Cruz, CA). Actin is shown as a control for loading (Oncogene Research Products, Boston, MA). (B) Additional HA-tagged DA c-Src clones were generated in 1483 cells. A representative western blot showing increased expression of pY418 Src as well as total c-Src is shown, in conjunction with expression of the HA-tag. The experiment was repeated 3 times with similar results.