TNF and erythema multiforme: SZD can reduce the expression of tumor necrosis factor (TNF-α), IL-6, and interleukin-8 (IL-8); the mRNA expression of extracellular regulated protein kinases (ERK), vascular endothelial growth factor (VEGF), and matrix metalloprotein-9 (MMP-9); and the protein expression of nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and MAPK-ERK kinase (MEK), thus influencing the MAPK/ERK signaling pathway as a way to treat EM [21].