Among the cell signaling pathways we have studied the activation of RANKL-RANK signaling was of particular interest because this signaling pathway was activated in both animal models and clinical PC specimens [8], [12], and targeting RANKL with an anti-RANKL antibody, denosumab, has been highly effective in blocking the lytic bone lesions associated with men treated with androgen deprivation therapy [13]. Here, TNFRSF11A is linked to pachyonychia congenita.