SFRP1 and rheumatoid arthritis: Since TNF-α is a proinflammatory cytokine that mainly influences osteoclastogenesis and SFRP-1 is a specific inhibitor of Wnt signaling that inhibits osteoblastogenesis, thus the correlation between TNF-α and SFRP-1 and bone turnover markers in premenopausal female patients with RA is examined.