A study on the doxorubicin resistance of B cell lymphoma indicated that Btk participates in EBNA2‐induced drug resistance and that the Btk inhibitor ibrutinib can sensitize lymphoma cells to doxorubicin in vitro.30 Thus, Btk participates in all the development phases of EBV‐related lymphomas, from infection to tumorigenesis. The gene discussed is BTK; the disease is infection.