<h4>Objective</h4>We investigated the role of GLI3, a transcription factor highly expressed in the pathogenic THY1<sup>+</sup>CD34<sup>-</sup> sublining subset of rheumatoid arthritis synovial fibroblasts (RASFs), in regulating their pathogenic behavior.<h4>Methods</h4>GLI3 protein levels were quantified in freshly isolated RASF subsets by Western blotting. Here, GLI3 is linked to rheumatoid arthritis.