Morel et al. [123] first showed that TRAIL induced RA-SF proliferation through activation of MAPK and PI3K/Akt since RA-SF proliferation could be inhibited by the ERK 1/2 SMI, PD98059, the p38 kinase SMI, SB203580 and the PI3K/Akt SMI, LY294002, respectively. This evidence concerns the gene AKT1 and rheumatoid arthritis.