['Fibroblast activation protein-alpha (FAPα) is a type-II integral membrane serine protease and is expressed in most stromal fibroblasts. Recent studies showed that FAPα is also expressed in certain cancer cells but its role is still uncertain.', 'We analyzed the non-enzymatic activity of FAPα in breast cancer cells by introducing an enzymatic mutant FAPα (FAPS624A), in which the serine catalytic triad was destroyed. FAPα overexpression and knockdown cells were generated as controls.', 'Cellular growth and motility were markedly increased in MCF-7 cells overexpressing FAPα and enzymatic-mutant FAPS624A. This is consistent with observations in FAPα-silenced BT549 cells. Western blotting showed activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) and matrix metalloproteinase (MMP) 2/9 in both wild-type FAPα-overexpressing and enzymatic-mutant FAPS624A-overexpressing cells.'] Does promotion of Cellular Growth and Motility be Independent of Enzymatic Activity of Fibroblast Activation Protein-α?