SDC1 and post-transplant lymphoproliferative disease: Some PGs have also been studied in EBV-associated cancers and premalignant conditions: chondroitinsulfate proteoglycan CD44 is detected in EBV-associated NPC [27–29] and EBV-related gastric carcinoma [30]; syndecan-1 (CD138) has been suggested to play a role in EBV-related PTLD [31].