Prognostic Significance of PD1, PD-L1 Expression , Pathological Subtypes and Metabolic Activity on 18F-FDG PET/CT in Refractory /Relapsing Pediatric Hodgkin Lymphoma

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.4545-4545
• Main Authors: Khedr, Reham, Khorshed, Eman, Hassanein, Omneya, Abdelrahman, Hany, Elwakil, Madeeha, Zaghloul, Mohamed, Hamoda, Asmaa Mohammed
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-150262

Background: Hodgkin Lymphoma (HL) is a unique disease entity both in its pathology and the young patient population that it primarily affects. Several meta-analyses have demonstrated that high PD-L1 expression levels are correlated with adverse clinical and pathologic features. Objectives: The aim of this study is to evaluate the correlation between the expression of PD-L1 and clinicopathological features, as well as the prognostic significance of PD-L1 expression with regard to interim PET response in relapsing / refractory pediatric HL. Methods: We measured the expression of PD-1/PD-L1 in the baseline diagnostic samples of children with relapsing/ refractory classical HL. The results were correlated with the pathological subtypes as well as the clinical outcome. Results: Of the 88 included patients, 77% had advanced stage HL. PD-1 expression was detected in 50% of cases, whereas PD-L1 (membranous) was expressed by tumor cells in 60% of the cases, and strongly expressed in 16% of cases. Notably, PD-L1 (cytoplasmic) was detected in 55% of the cases. There was a significant differences in the expression levels of PDL-1 between the different pathological subtypes (p = 0.006). OS of patients with PD-L1expression (Cytoplasmic) was 83% vs 91% in patients with absent expression (P=0.001). There was no prognostic significance of PD-L1 expression with regard to PET response (p=0.31). Conclusion: Although PD-L1 expressions did not show statistically significance with well-established prognostic factors, our preliminary data indicate that pathological subtypes and cytoplasmic expression of PD-L1 may have a prognostic implication on survival in pediatric HL. [Display omitted] No relevant conflicts of interest to declare.