While the landmark paper by Pajtler et al. did not find any copy number loss or gain, there was over 50% copy number loss in chromosome 19p and 19q in the 24 PF-SE patients studied by Witt et al. Based on examination of the transcription profiles of PF-SE tumors, its tumorigenesis appears to be related to fatty acid metabolism, mast cell and leukocyte processes (KIT), signal transduction pathways (specifically STAT), as well as, chemotaxis [40]. Here, KIT is linked to pemphigus foliaceus.