Other (non-specific) biomarkers for RA include tumor necrosis factor (TNFα), interleukin 6 (IL-6), osteopontin, osteocalcin, amino-terminal telopeptide of type 1 collagen (NTX), carboxyl-terminal telopeptide of type 1 collagen (CTX), matrix Metalloproteinase 3 (MPP)-3 and so on [64]. Here, TNF is linked to rheumatoid arthritis.