CASC15 and skin basal cell carcinoma: We successfully identified several differentially expressed genes that were associated with specific BCC risk loci and that were expressed only in BCC-IV epithelial cells, including BNC2, CUX1, ZBTB10, and CASC15, whereas other genes showed broader expression across cell types in both normal and tumor cells, such as LPP, PLIN2, HLA-B, and NEU1.