Mizukami Y, et al. – An analysis was performed of the mechanism of sorafenib–induced cutaneous adverse effects, with emphasis on mast cells (MCs) in situ. The results assisted in an improved comprehension of the mechanism by which sorafenib induced adverse cutaneous reactions via activation of skin–type MC degranulation and maturation. This activation was possibly associated with phosphoinositide 3–kinase (PI3K) signaling and stem cell factor (SCF) production. This could serve as a new target for treating sorafenib–induced adverse reactions.