JAK inhibitor I is a JAK1/2/3 inhibitor that decreased cell proliferation in breast cancer cells[146], increased apoptosis in esophageal squamous cell carcinoma cancer stem cells[147], inhibited STAT3 phosphorylation in HCC cells[148], and, in combination with cisplatin, decreased PD-L1 expression in prostate cancer cells[149]. This evidence concerns the gene JAK1 and breast cancer.