Studies show that only 47% of metastatic disease in cSCC overexpress EGFR which leads to the hypothesis that the metastatic cell population that does not overexpress EGFR may originate from another clone, hypothesis supported by the fact that a study on the use of EGFR inhibitor (gefitinib) in patients with metastatic cSCC showed that the therapy had no results [136]. This evidence concerns the gene EGFR and skin squamous cell carcinoma.