JAK2 and neoplasm: Numerous studies have tried to identify genetic predictors attributable to PD‐L1 expression in tumor cells.27, 31 To date, genetic alterations involving the PD‐L1 and PD‐L2 locus (9p24.1) as well as their induction via JAK2 signaling have been identified in a subset of PTLD.37 However, even in the latter studies the contribution of EBV was considered to be the main disease‐driving factor.