In this review, positive expression of Met (the stem cell marker and receptor for HGF) in PC bone metastases was demonstrated in two studies [38, 41]; another study reported significant overexpression of the Wnt/nuclear β-catenin pathway in bone metastases [48], and Notch expression was found to be significantly higher expression in bone metastasis tissues compared to primary PC tissues [54]. Here, HGF is linked to pachyonychia congenita.