RHOA and cancer: Ras homolog gene family member A (RhoA) can facilitate the invasion and metastasis of cancer cells by regulating cell matrix adhesion and cytoskeleton reorganization [115,116], while the overexpression of sphingosine-1-phosphate (S1P) 2 leads to the activation of RhoA guanosine triphosphatase (GTPase), thus promoting cell migration [105].