RAF1 and melanoma: Since caspase 9 is not cleaved in the presence of activated Raf-1, a stable interaction between caspase 9 and XIAP is not expected, however, overexpression of XIAP by inhibiting newly generated cleaved caspase 9 would prevent further autoprocessing of procaspase monomers In mammals, MAPK activation has been associated with the increase of XIAP expression in melanoma cells [51], monocytes [52] and Jurkat cells [53].