BAK1 and breast cancer: Several promising PPIs have been targeted by SDCs, such as AMAP1/cortactin for preventing breast cancer invasion and metastasis [9], B7.1/CD28 for modulating T-cell activation [10], BAK/BCL2 or BAK/BCL-XL for inducing apoptosis in tumor cells [11-14], β-catenin/Tcf4 for cancer treatment [15,16], IL2/IL2Rα for suppressing autoimmune diseases [17,18], LFA1/ICAM1 for modulating lymphocyte and immune system function [19-21], and NGF/p75NTR for blocking neuropathic and inflammatory pain [22].