ICOS and neoplasm: Tumor associated CD4/CD8 double positive T (DPT) cells were found to be rich in L region, with co-expression of PD-1/HLA-DR/ICOS/CD45RO, and showed high levels of IFN-, TNF- and -1 after PD stimulation. Enrichment of DPT and PD-1DPT in L region indicated a good prognosis.