Whereas overexpression of Bcl-2 seems to be a main characteristic of leukemia cells, upregulation of Bcl-xl, Mcl-1, Bcl-w, and Bcl2A1 is preferentially found in solid tumors, including PC [7,9,10,11,12,13,14,15]. This evidence concerns the gene BCL2 and pachyonychia congenita.