We reported previously that β2-microglobulin (β2-M), a major histocompatibility protein co-receptor, promotes PCa cell osteomimicry by inducing RANKL and non-collagenous bone matrix proteins (Huang et al. 2006, Odero-Marah et al. 2008). The gene discussed is TNFSF11; the disease is posterior cortical atrophy.