1) hypoxia induced MIF expression and secretion in PC cell lines in a HIF-1α–dependent manner; 2) MIF was required for maximal hypoxia-induced HIF-1α stabilization in PC cell lines; 3) MIF bound to CSN5 in PC cell lines and MIF depletion resulted in a loss of CSN5 binding and stabilization of HIF-1α. This evidence concerns the gene HIF1A and pachyonychia congenita.