CCN2 and rheumatoid arthritis: Notably, in our multicenter validation cohort study, serum CTGF was an excellent diagnostic biomarker to predict RA, with sensitivity, specificity, positive likelihood, the negative likelihood, positive predictive value and negative predictive value of 0.82, 0.91, 5.74, 0.12, 0.85 and 0.90, respectively [16].