Furthermore, we found a similar rate of H-ras mutations in both Ikkα+/− and WT skin tumors, while Ikkα+/− mice developed more skin tumors than WT mice, suggesting that, at the tumor initiation stage, IKKα reduction promotes H-Ras-targeted cell expansion following TPA treatment, which accelerates skin tumor formation. This evidence concerns the gene HRAS and skin neoplasm.