PEBP1 and pachyonychia congenita: The notion of RKIP as suppressor of metastasis is supported by (1) its actions in inhibiting cancer cell migration and invasion but not proliferation in vitro [86,88,117], (2) its ability in suppressing PC metastasis in xenograft models [88] and transgenic mice [97], as well as (3) its significant downregulation in mPC [88].