ELP1 and skin squamous cell carcinoma: Expression of FD in cSCC tumors in vivo was analyzed by IHC of TMAs containing tissue samples representing different stages of epidermal carcinogenesis including pre-malignant AK (n = 65), cSCCIS (n = 61), primary non-metastatic cSCC (n = 140), metastatic cSCC (n = 70) and cSCC metastases (n = 9) along with normal skin (n=80).