To further demonstrate the functional consequences of mutant FGFR2, we performed colony formation assays and found that the overexpression of the FGFR2‐mutants in EMFGFR2−/− cells supports anchorage‐independent growth and potentially drives transformation and oncogenic growth of EM cells (Figure S5C). This evidence concerns the gene FGFR2 and erythema multiforme.