In support of the concept that mast cells serve only as bystanders in melanomagenesis, Ghouse et al. [20] showed that absence of local mast cells did not affect inflammatory cell infiltrates including CD19+ B cells, CD3e+CD8a+ T cells, CD3e+CD4+ T cells, CD11c+ cells, and CD11b+F4/80+ cells in B16-F10 melanomas or K14-HPV16+ SCCs of c-Kit-expressing Mcpt5-Cre+ mice. The gene discussed is KIT; the disease is melanoma.