Dissecting the pathogenesis of classical Hodgkin lymphoma (cHL), a common cancer in young adults, remains challenging because of the rarity of tumor cells in involved tissues (usually <5%). Here, we analyzed the coding genome of cHL by microdissecting tumor and normal cells from 34 patient biopsies for a total of ∼50 000 singly isolated lymphoma cells. We uncovered several recurrently mutated genes, namely, (32% of cases), (24%), (18%), and (16%), and document the functional role of mutant STAT6 in sustaining tumor cell viability. Mutations of genetically and functionally cooperated with disruption of, a JAK-STAT pathway inhibitor, to promote cHL growth. Overall, 87% of cases showed dysregulation of the JAK-STAT pathway by genetic alterations in multiple genes (also including ,, ,, and ), attesting to the pivotal role of this pathway in cHL pathogenesis and highlighting its potential as a new therapeutic target in this disease.

Purpose: Few biological prognosticators are useful for prediction of Richter syndrome (RS), representing the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma. Stereotyped B-cell receptors (BCR) may have prognostic effect in CLL progression. We tested the prognostic effect of stereotyped BCR for predicting RS transformation. Experimental Design: The prevalence of stereotyped BCR was compared in RS (n = 69) versus nontransformed CLL (n = 714) by a case-control analysis. Subsequently, the effect of stereotyped BCR at CLL diagnosis on risk of RS transformation was actuarially assessed in a consecutive CLL series (n = 753).Results: RS (n = 69) displayed a higher prevalence of stereotyped BCR (P < 0.001) compared with nontransformed CLL. The actuarial risk of RS transformation was significantly higher in CLL carrying stereotyped BCR (P < 0.001). Among BCR subsets most represented in CLL, subset 8 using IGHV4-39/IGHD6-13/IGHJ5 carried the highest risk of RS transformation [hazard ratio (HR), 24.50; P < 0.001]. Multivariate analysis selected stereotyped BCR (HR, 3.33; P = 0.001) and IGHV4-39 usage (HR, 4.03; P = 0.004) as independent predictors of RS transformation.The combination of IGHV4-39 usage and stereotyped BCR in the same patient identified CLL with a very high risk of RS transformation (5-year risk, 68.7%). The risk carried by stereotyped BCR and IGHV4-39 usage was specific for RS transformation and had no effect on CLL progression without transformation. Conclusions: Analysis of BCR features may help identify CLL patients at risk of RS. A close monitoring and a careful biopsy policy may help early recognition of RS in CLL patients using stereotyped BCR, particularly if combined with IGHV4-39.

Increasing evidence argues that the success of an anticancer treatment may rely on immunoadjuvant side effects including the induction of immunogenic tumor cell death. Based on the assumption that this death mechanism is a similar prerequisite for the efficacy of an active immunotherapy using killed tumor cells, we examined a vaccination strategy using dendritic cells (DC) loaded with apoptotic and necrotic cell bodies derived from autologous tumors. Using this approach, clinical and immunologic responses were achieved in 6 of 18 patients with relapsed indolent non-Hodgkin's lymphoma (NHL). The present report illustrates an impaired ability of the neoplastic cells used to vaccinate nonresponders to undergo immunogenic death on exposure to a cell death protocol based on heat shock, γ-ray, and UVC ray. Interestingly, when compared with doxorubicin, this treatment increased surface translocation of calreticulin and cellular release of high-mobility group box 1 and ATP in histologically distinct NHL cell lines. In contrast, treated lymphoma cells from responders displayed higher amounts of calreticulin and heat shock protein 90 (HSP90) compared with those from nonresponders and boosted the production of specific antibodies when loaded into DCs for vaccination. Accordingly, the extent of calreticulin and HSP90 surface expression in the DC antigenic cargo was significantly associated with the clinical and immunologic responses achieved. Our results indicate that a positive clinical effect is obtained when immunogenically killed autologous neoplastic cells are used for the generation of a DC-based vaccine. Therapeutic improvements may thus be accomplished by circumventing the tumor-impaired ability to undergo immunogenic death and prime the antitumor immune response. Cancer Res; 70(22); 9062-72. ©2010 AACR.

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