In addition, it has been also proposed that FGF7/KGF treatment may induce endogenous synthesis of the EGFR ligand TGFα.51 In any case, these results are in agreement with the widely described role of PKCδ as tumor suppressor, which is down-regulated in squamous cell carcinomas (SCCs)52,53. Here, EGFR is linked to squamous cell carcinoma.