JAK2 and systemic sclerosis: Our experiments showed that subcutaneous injection of bleomycin significantly increased the protein expression of JAK2, p-JAK2, TGF-β1, and TGF-β receptors in the lung tissue (Fig. 2D) and skin (Fig. 2E), which indicated that the JAK2 and TGF-β1 signaling pathways are extremely likely to be involved in the development and progression of SSc-ILD.