For example, Shiozawa et al. demonstrated that annexin A2, expressed on bone marrow cells, is involved in stem cell homing mechanisms necessary for prostate cancer cells to gain access to the niche 39; recently, it has been shown that annexin A2–CXCL12 interactions regulate metastatic prostate cancer cell targeting and their growth in the bone marrow 40. Here, CXCL12 is linked to prostate cancer.