As shown in Fig. 2A, narazaciclib potently inhibited the proliferation of Ba/F3-CSF1R cells in the presence of CSF1 with an IC50 of ~ 3.54 nM, similar to a FDA-approved CSF1R inhibitor (CSF1Ri) for treating Tenosynovial giant cell tumors (TGCT), pexidartinib27 (or PLX-3397, IC50 ~ 3.88 nM) but 16 times more potent than another CSF1Ri, GW2580, with an IC50 of 59.46 nM. Here, CSF1R is linked to tenosynovial giant cell tumor.