HRAS and pachyonychia congenita: We have shown that ZOL interferes with the p21ras/raf-1/MEK1/ERK and pKB/akt signalling cascades, as p21ras and Raf-1 contents were clearly reduced in PC cells, and the active phosphorylated species of ERK1-2-, and pKB/akt-mediated phosphorylation of GSKα/β were strongly downregulated in cells exposed to the drug.