IL13 and neoplasm: When RAW264.7 mouse macrophages were stimulated with IFN‐γ (stimulating an anti‐tumour M1‐like phenotype), IL‐4/IL‐13 (stimulating a pro‐tumour M2‐like phenotype), or left unstimulated (naïve) [50], NAD(P)H and FAD autofluorescence showed a time dependent difference between the IFN‐γ and the IL‐4/IL‐13 macrophages.