Such phenomenon was corroborated by qRT-PCR on primary NPC biopsies, showing higher expression of Treg lineage and activation markers, FOXP3, IL2RA and CTLA4 in CD70-high patients (Supplementary Fig. 2h), who was stratified by the above flow cytometry result (Fig. 2e). The gene discussed is CTLA4; the disease is nasopharyngeal carcinoma.