PLCH2 and arthritic joint disease: Based on our in vitro (Fig. 4 and Supplementary Fig. 1) and in vivo data (Fig. 5) showing that PLCη2 and PLCη2_C2 dramatically inhibited the inflammatory and tumor-like behaviors of RA FLSs, we next assessed the possible therapeutic effects of PLCη2 and PLCη2_C2 on arthritis progression.