While tumor-draining lymph nodes play a major role in the initiation of tumor-targeting immunity12, many solid neoplasms contain so-called “tertiary lymphoid structures” (TLSs), which in their mature form are spatially organized clusters of CD8+ effector T (TEFF) cells, B lymphocytes, and CD21+CD23+ follicular dendritic cells (DCs), generally served by high-endothelial venules (HEVs)13–15. The gene discussed is FCER2; the disease is neoplasm.