CD4 and nasopharyngeal carcinoma: Given that CD20+ B-cell follicle juxtaposing to a CD3+ T cell aggregation is the hallmark of TLS in multiple cancers4, we performed multiplex immunohistochemistry (IHC) staining assays and revealed prominent TLSs comprising B cells (CD20 as the signature maker), CD4+ T cells (CD3, CD4), CD8+ T cells (CD3, CD8), and fibroblasts (FAP-α) in NPC biopsies (Fig. 1a and Supplementary Fig. 1a).