TP53 Mutations, the Most Frequent Genetic Lesion in Richter Syndrome, Represent An Independent Predictor of Survival Post Transformation

Abstract 670 Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Knowledge of the genetic lesions associated with RS is scant and represents the aim of this study. The study was based on 47 RS cases (all DLBCL). In 32 cases, paired CLL/RS samples were available (28 clonally related and 4 clonally unrelated). In 15 cases, the sole RS sample was analysed. According to CD10/BCL6/MUM1 immunohistochemistry expression pattern, 43/47 (91.5%) RS were classified as non-germinal center DLBCL. At diagnosis, 37.8% RS showed ECOG PS >1, 77.8% Binet stage B-C, 95.7% Ann Arbor stage III-IV, 44.4% B symptoms, 45.7% tumor size >5 cm, 32.6% involvement of >1 extranodal site, 66.7% LDH elevation, and 28.9% platelets Disclosures: No relevant conflicts of interest to declare.