|Title||Flow sorting and exome sequencing reveal the oncogenome of primary Hodgkin and Reed-Sternberg cells.|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Reichel J, Chadburn A, Rubinstein PG, Giulino-Roth L, Tam W, Liu Y, Gaiolla R, Eng K, Brody J, Inghirami G, Carlo-Stella C, Santoro A, Rahal D, Totonchy J, Elemento O, Cesarman E, Roshal M|
|Date Published||2015 Feb 12|
|Keywords||Adolescent, Adult, Aged, Aged, 80 and over, Cell Line, Tumor, Cell Separation, Child, Cohort Studies, Exome, Female, Flow Cytometry, Genes, Neoplasm, Genome, Human, High-Throughput Nucleotide Sequencing, Hodgkin Disease, Humans, Male, Middle Aged, Reed-Sternberg Cells, Young Adult|
Classical Hodgkin lymphoma (cHL) is characterized by sparsely distributed Hodgkin and Reed-Sternberg (HRS) cells amid reactive host background, complicating the acquisition of neoplastic DNA without extensive background contamination. We overcame this limitation by using flow-sorted HRS and intratumor T cells and optimized low-input exome sequencing of 10 patient samples to reveal alterations in genes involved in antigen presentation, chromosome integrity, transcriptional regulation, and ubiquitination. β-2-microglobulin (B2M) is the most commonly altered gene in HRS cells, with 7 of 10 cases having inactivating mutations that lead to loss of major histocompatibility complex class I (MHC-I) expression. Enforced wild-type B2M expression in a cHL cell line restored MHC-I expression. In an extended cohort of 145 patients, the absence of B2M protein in the HRS cells was associated with lower stage of disease, younger age at diagnosis, and better overall and progression-free survival. B2M-deficient cases encompassed most of the nodular sclerosis subtype cases and only a minority of mixed cellularity cases, suggesting that B2M deficiency determines the tumor microenvironment and may define a major subset of cHL that has more uniform clinical and morphologic features. In addition, we report previously unknown genetic alterations that may render selected patients sensitive to specific targeted therapies.