FOS and post-transplant lymphoproliferative disease: Vaysberg et al, from a panel of five EBV+ B cell lymphomas, identified three distinct and different variants of LMP1, with 2 gain of function mutations, which induced sustained MAP kinase activation and c‐Fos induction.28 Notably, we detected one of these gain of function mutations, S366T, in three of our polymorphic PTLD samples.