In the present study, using stable lines of NIH-3T3 cells that contain overexpressed wild- type human NEU3 and/or EGFR, we found that NEU3 is required for the biological synergy with the receptor as well as its phosphorylation, and additionally, for the activation of cellular Src, which has also been shown to be overexpressed in many of these same cancers. This evidence concerns the gene EGFR and cancer.