FAP and skin basal cell carcinoma: AR, androgen receptor; CEA, carcinoembryonic antigen; basal cell carcinoma, BCC; CK, cytokeratin; DTE, desmoplastic trichoepithelioma; EGFR, epidermal growth factor receptor; EMA, epithelial membrane antigen; FAP, fibroblast activation protein; MAC, microcystic adnexal carcinoma; MBCC, morphea basal cell carcinoma; PHLDA1, pleckstrin homology-like domain family A member 1; PKK1, pan-cytokeratin.