In this context, the observation that subsets of Rho GEFs are differentially regulated in normal skin, papilloma, and cSCCs suggests the specific engagement of physiological- and tumor-stage-specific Rac1-, RhoA, and Cdc42 (ID number: 12540)-dependent programs that may contribute to both skin homeostasis and pathophysiology. This evidence concerns the gene RAC1 and papilloma.