Due to these similarities of EBV-associated lymphomas in huNSG mice and patients, the transcriptional characteristics of PTLD-like tumors of FK506-treated EBV-infected mice could be further explored for biomarkers of PTLD development in transplant patients, as shown for sCD30 and IL-6 in the current study. Here, IL6 is linked to post-transplant lymphoproliferative disease.