In studies showing RACGAP1 overexpression in squamous cell carcinoma, it is indicated that RACGAP1 can activate Rac1, but inactivate RhoA, which results from the phosphorylation of RACGAP1 at Ser387 by aurora B kinase, to convert the RACGAP1 substrate preference from Rac to RhoA, although evidence of the activation of aurora B kinase is not given [76] (Figure 2b). This evidence concerns the gene RACGAP1 and squamous cell carcinoma.