This RhoA activation in lipin-1-depleted cells could be related to the increased concentration of PA which can activate the sphingosine kinase-1 to produce sphingosine-1-phosphate [37], a lipid mediator able to enhance RhoA activity [38], and to inhibit migration of various tumor cells including PC-3 [36, 38]. This evidence concerns the gene LPIN1 and neoplasm.