. .. Liste-des-abreviations,

. Femme,

. Elevé, /13 (30,8) 8/22 (36,4) 6/16 (37,5) 5/17 (29,4) Prise en charge initiale Palliative

. Chimiothérapie-+-rituximab-+/-radiothérapie-+/-corticothérapie,

, Distribution des paramètres cliniques et pathologiques en fonction de la densité de TAMS et de leur expression de PD-L1 Phénotype non-GC Oui, vol.7

P. Réarrangement and . Oui,

. Réarrangement-bcl6-positif-oui,

, IELSG: International Extranodal Lymphoma Study Group

*. , Comparaison des groupes IELSG faible+intermediaire versus élevé

. ***,

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, L'objectif de ce travail est de définir la composition du microenvironnement tumoral et de caractériser la voie PD-1/PD-L1 dans les LBDGC-SNC

, Matériel et méthodes : 57 cas de patients atteints de LBDGC-SNC avec du matériel tumoral exploitable ont été étudiés après recueil des données cliniques. Des examens immunohistochimiques ont été réalisés pour analyser les TAMs (CD68, CD163), les TILs (CD3, CD4, CD8, PD-1) et les cellules tumorales (double marquage PAX5/PD-L1, PD-L1). Le gène PD-L1 a été étudié par hybridation in situ en fluorescence (FISH)

, La translocation du gène PD-L1 était une altération cytogénétique récurrente dans les LBDGC-SNC (8/47, 17%) et était corrélée à une expression de PD-L1 par les cellules tumorales, Résultats : Le double marquage PAX5/PD-L1 a identifié une expression de PD-L1 par les cellules tumorales dans 17,5% des cas (10/57)

M. De-tams and C. De-tils, La majorité des TAMs exprimaient PD-L1 et la majorité des TILs exprimaient PD-1. La densité des TAMs et des TILs, ainsi que l'expression de PD-L1 par les cellules tumorales, n'étaient pas associée à la survie. En revanche, l'expression de PD-1 par les TILs et de PD-L1 par les TAMs, étaient corrélées à un meilleur pronostic. Conclusion : Ces résultats suggèrent que la composition du microenvironnement tumoral et la voie PD-1/PD-L1 jouent un rôle important dans la pathogenèse des LBDGC-SNC et apportent de nouvelles perspectives

, Mots clés : Lymphomes B diffus à grandes cellules, Système nerveux central, p.1