Immunohistochemistry (IHC) demonstrates tumor cell positivity for Factor XIIIa (RRID: AB_2881706) (Figure 3C) but negativity for CD34 (RRID: AB_10733337) (Figure 3D), with infiltrating mast cells exhibiting membranocytoplasmic CD117 (RRID: AB_2249558) immunoreactivity (Figure 3E) and scattered intratumoral lymphocytes showing occasional nuclear GATA3 (RRID: AB_2881774) expression (Figure 3F). The gene discussed is F13A1; the disease is neoplasm.