Post-transplantation lymphoproliferative disorders (PTLD) are a heterogenous group of abnormal lymphoid proliferations that occur after solid organ transplant (SOT) or hematopoietic transplantation. PTLDs consist of a disease spectrum ranging from hyperplasia to aggressive lymphomas with 60-70% being Epstein-Barr virus positive. The majority of cases are B-cell, although 10-15% are of T-cell origin or rarely Hodgkin lymphoma. Recent SOT series suggest PTLD occurs at a median of 36-40 months after transplant. Clinically, extra-nodal disease is common (up to 75-85%) including CNS involvement, which is seen in 10-15% of all cases. Since the first report over 40 years ago, PTLD has remained one of the most morbid complications associated with SOT. However, recent data suggests improved survival in the modern era, especially with the integration of early rituximab-based therapy. These studies utilized first line rituximab (+/- chemotherapy) together with reduced immune suppression (RI) for monomorphic and polymorphic PTLD. It will be critical in future studies to determine which PTLDs are most amenable to initial therapy with RI alone, versus RI/rituximab, versus RI/rituximab/chemotherapy. Additionally, novel therapeutics, such as adoptive immunotherapy, should continue to be explored.

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We performed a multicenter, International analysis of solid organ transplant (SOT)-related primary central nervous system (PCNS) posttransplant lymphoproli-ferative disease (PTLD). Among 84 PCNS PTLD patients, median time of SOT-to-PTLD was 54 months, 79% had kidney SOT, histology was monomorphic in 83% and tumor was EBVþ in 94%. Further, 33% had deep brain involvement, 10% had CSF involvement, while none had ocular disease. Immunosuppression was reduced in 93%; additional first-line therapy included high-dose methotrexate (48%), high-dose cytarabine (33%), brain radiation (24%) and/or ritux-imab (44%). The overall response rate was 60%, while treatment-related mortality was 13%. With 42-month median follow-up, three-year progression-free survival (PFS) and overall survival (OS) were 32% and 43%, respectively. There was a trend on univariable analysis for improved PFS for patients who received rituximab and/or high-dose cytarabine. On multivariable Cox regression, poor performance status predicted inferior PFS (HR 2.61, 95% CI 1.32-5.17, p ¼ 0.006), while increased LDH portended inferior OS (HR 4.16, 95% CI 1.29-13.46, p ¼ 0.02). Moreover, lack of response to first-line therapy was the most dominant prognostic factor on multivariable analysis (HR 8.70, 95% CI 2.56-29.57, p ¼ 0.0005). Altogether, PCNS PTLD appears to represent a distinct clinicopathologic entity within the PTLD spectrum that is associated with renal SOT, occurs late, is monomorphic and retains EBV positivity.

We performed a multicenter, International analysis of solid organ transplant (SOT)-related primary central nervous system (PCNS) posttransplant lymphoproliferative disease (PTLD). Among 84 PCNS PTLD patients, median time of SOT-to-PTLD was 54 months, 79% had kidney SOT, histology was monomorphic in 83% and tumor was EBVþ in 94%. Further, 33% had deep brain involvement, 10% had CSF involvement, while none had ocular disease. Immunosuppression was reduced in 93%; additional first-line therapy included high-dose methotrexate (48%), high-dose cytarabine (33%), brain radiation (24%) and/or rituximab (44%). The overall response rate was 60%, while treatment-related mortality was 13%. With 42-month median follow-up, three-year progression-free survival (PFS) and overall survival (OS) were 32% and 43%, respectively. There was a trend on univariable analysis for improved PFS for patients who received rituximab and/or high-dose cytarabine. On multivariable Cox regression, poor performance status predicted inferior PFS (HR 2.61, 95% CI 1.32-5.17, p ¼ 0.006), while increased LDH portended inferior OS (HR 4.16, 95% CI 1.29-13.46, p ¼ 0.02). Moreover, lack of response to first-line therapy was the most dominant prognostic factor on multivariable analysis (HR 8.70, 95% CI 2.56-29.57, p ¼ 0.0005). Altogether, PCNS PTLD appears to represent a distinct clinicopathologic entity within the PTLD spectrum that is associated with renal SOT, occurs late, is monomorphic and retains EBV positivity.

Background: HoxA10 target genes include CDX4 and FGF2, and HOXA10 is a Cdx4 target gene. Results: Transcription of newly identified, ␤-catenin-binding cis elements in the CDX4 and HOXA10 promoters is regulated by Fgf2-dependent activity of ␤-catenin. Conclusion: Positive feedback between CDX4 and HOXA10 involves ␤-catenin and Fgf2. Significance: Understanding cross-regulation between HoxA10, Cdx4, and ␤-catenin provides insights into leukemogenesis.