Descriptive analysis of genetic aberrations and cell of origin in Richter transformation.

Richter transformation (RT) is a progression from chronic lymphocytic leukemia (CLL) to a more aggressive lymphoma, most often diffuse large B-cell lymphoma (DLBCL). Due to the rarity of the disease, data regarding the molecular profile and cell of origin (COO) of RT is limited. We performed immunohistochemistry analysis for COO determination and next-generation sequencing for gene mutation analysis in 11 RT patients. Seventy-nine percent of our patients were classified as non-GCB phenotype. Of the 57 unique mutations identified, the three most commonly mutated genes were TP53, TET2, and CREBBP. Neither TET2 nor CREBBP has been previously described in RT. Our analysis provides additional information to help guide further investigation of both the diagnosis and treatment of this complex and heterogeneous disease.