The adhesion molecule P-selectin, expressed by the bone endothelial cells, and sialyl-Lewisx carbohydrate, available on the prostate cancer cell surface, play a crucial role in the association (Martensson et al., 1995[87]; Mazo and von Andrian, 1999[88]), while integrin molecules mediate the subsequent locking process (Romanov and Goligorsky, 1999[110]). The gene discussed is SELP; the disease is prostate cancer.