Furthermore, all immune-related genes were classified into various categories according to fold changes as shown in Figure 2B. Given the previous reports demonstrating associations between the type I IFN pathway and endocrine resistance [28] and CDK4/6 inhibitor resistance [29] in the HR-positive breast cancer, a collection of type I IFN genes, such as STAT1, IRF9, and SP100, were analyzed in detail. Here, STAT1 is linked to breast cancer.