Because of the variable numbers of infiltrating CD4+ or IL‐17+ cells per patient`s biopsies and the high plasticity of the CD4+ T cell or IL‐17+ cell compartment, evaluation of the proportions of Th17 cells per infiltrating CD4+ or IL‐17+ cells can clarify their distributions within the individually present CD4+ or IL‐17+ cells in cancer tissues. The gene discussed is CD4; the disease is cancer.