Investigations on the RA FLS cells propose that LINE1 is associated with the aggressive phenotype of these cells through regulation of stress-activated protein kinase (SAPK) [p38 MAPK] signaling cascades, which is a part of a kinase pathway that leads to the production of cytokines including IL-8, IL-6 [115], and MMPs [116]. Here, CXCL8 is linked to rheumatoid arthritis.