Feldman, Andrew L

ABSTRACTBackgroundPrimary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis (LyP) are indolent CD30‐positive lymphoproliferative disorders that rarely express TCR‐γδ. However, primary cutaneous gamma‐delta T‐cell lymphoma (pcGDTCL), characterized by TCR‐γδ expression on neoplastic cells, is a rare, aggressive cutaneous T‐cell lymphoma with a poor prognosis. Accurate differentiation is essential due to distinct clinical behavior and treatment.MethodsWe identified 11 TCR‐γδ‐positive pcALCL cases from internal and consultation files, verified by two cutaneous lymphoma experts, with clinicopathologic data recorded.ResultsThe median age was 68 years (range 38–95). Most cases presented as a single dermal lesion on the upper extremities. All were ALK‐negative, CD30‐positive (> 90% tumor cells), TCR‐βF1‐negative, and diffusely TCR‐γδ‐positive. CD4−/CD8− (54.5%) and CD4+/CD8− (45.5%) immunophenotypes were observed. CD2 (63.6%) and CD3 (54.5%) were the most common T‐cell antigens. Ulceration, inflammation (both 45.5%), and necrosis (36.4%) were frequent. Angiotropism, angiocentricity, and myxoid stroma appeared in one case; epidermotropism in two. Four of ten tested were DUSP22‐rearranged, and TP63 was negative in all eight tested.ConclusionsMost ALK‐negative TCR‐γδ‐positive pcALCL were CD4−/CD8−, followed by CD4+/CD8−. DUSP22 rearrangement occurred in 40% of cases, similar to reports in typical pcALCL. Its prognosis and the role of DUSP22 are yet to be clarified.

Abstract Background: Diffuse large B-cell lymphoma (DLBCL) is clinically heterogeneous, and gene expression profiling has identified at least two biologically distinct DLBCL subtypes defined by their cell of origin (COO): germinal center B cell (GCB) and activate B cell (ABC) or non-GCB. We evaluated a variety of putative DLBCL risk factors for etiologic heterogeneity by the COO in a clinic-based study of newly diagnosed DLBCL cases (N = 638) and frequency-matched controls (N = 2,253). Methods: The COO was determined on formalin-fixed, paraffin-embedded tumor tissue, with DLBCL classified as GCB (N = 283), non-GCB (N = 188), or undetermined/missing (N = 167; mainly because of lack of tissue). Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Results: We identified heterogeneity by the COO for low socioeconomic status (SES), which was only associated with non-GCB DLBCL (OR = 1.88 for low vs. average SES; 95% CI, 1.08–3.27); alcohol use, which was only associated with GCB DLBCL (OR = 0.48 for former drinkers; 95% CI, 0.29–0.80 and OR = 0.47 for current drinkers; 95% CI, 0.32–0.71); and borderline heterogeneity for the regular use of regular/extra-strength aspirin, which was only associated with non-GCB DLBCL (OR = 0.36; 95% CI, 0.16–0.85). In contrast, there was no significant heterogeneity by the COO for family history, medical history, or other lifestyle factors. Conclusions: Although requiring confirmation, most risk factors for DLBCL did not show etiologic heterogeneity by the COO, with some notable exceptions including alcohol use, SES, and perhaps regular use of regular/extra-strength aspirin showing associations. Impact: Mechanistically, these findings suggest that most of the DLBCL risk factors evaluated here influence lymphomagenesis prior to differentiation into COO subtypes, with selected factors acting later.

Abstract Marginal zone lymphoma (MZL) includes extranodal MZL (EMZL), splenic MZL (SMZL), and nodal MZL (NMZL) subtypes. Histologic transformation (HT) to large B-cell lymphomas is well documented but with a large variability in published cumulative incidence rates. We report results from the Molecular Epidemiology Resource (MER) cohort on the cumulative incidence of HT (with death as competing risk) and the associated risk factors and outcomes. We also conducted a meta-analysis of available studies on the cumulative incidence of HT. From 2002 to 2015, 529 patients with MZL were enrolled in the MER study (69% EMZL, 16% SMZL, and 15% NMZL). The 10-year overall survival (OS) from diagnosis was 66%. HT occurred in 21 patients with a 5-year and 10-year cumulative incidence of 2.7% (95% confidence interval [CI], 0.02-0.05) and 3.6% (95% CI, 0.02-0.06), respectively. HT was associated with an increased risk for death (subdistribution hazard ratio [HR], 3.95; 95% CI, 2.06-7.55). Predictors of HT were ≥2 extranodal sites and mucosa-associated lymphoid tissue International Prognostic Index score ≥2. The OS was 79% at 5 years and 55% at 10 years after HT. In the meta-analysis of 12 studies (6161 patients), the 5- and 10-year cumulative incidence of HT across all subtypes were 5% (95% CI, 0.05-0.06) and 8% (95% CI, 0.07-0.09), respectively. These rates were lower in EMZL (3% and 5%) than in SMZL (7% and 13%) and NMZL (9% and 13%). Although HT is relatively uncommon in the first decade after MZL diagnosis, it is associated with an inferior outcome and needs new approaches for prevention and management.

Abstract Recent introduction of 2 different lymphoma classifications has raised concerns about consistency in diagnosis, management, and clinical trial enrollment. Data from a large cohort reflecting real-world clinical practice suggest that differences between the classifications will affect <1% of non-Hodgkin lymphomas.

Abstract Rearrangements that place the oncogenes MYC, BCL2, or BCL6 adjacent to superenhancers are common in mature B-cell lymphomas. Lymphomas with diffuse large B-cell lymphoma (DLBCL) or high-grade morphology with both MYC and BCL2 rearrangements are classified as high-grade B-cell lymphoma with MYC and BCL2 rearrangements (“double hit”; HGBCL-DH-BCL2) and are associated with aggressive disease and poor outcomes. Although it is established that MYC rearrangements involving immunoglobulin (IG) loci are associated with inferior outcomes relative to those involving other non-IG superenhancers, the frequency of and mechanisms driving IG vs non-IG MYC rearrangements have not been elucidated. Here, we used custom targeted capture and/or whole-genome sequencing to characterize oncogene rearrangements across 883 mature B-cell lymphomas including Burkitt lymphoma, follicular lymphoma, DLBCL, and HGBCL-DH-BCL2 tumors. We demonstrate that, although BCL2 rearrangement topology is consistent across entities, HGBCL-DH-BCL2 have distinct MYC rearrangement architecture relative to tumors with single MYC rearrangements or with both MYC and BCL6 rearrangements (HGBCL-DH-BCL6), including both a higher frequency of non-IG rearrangements and different architecture of MYC::IGH rearrangements. The distinct MYC rearrangement patterns in HGBCL-DH-BCL2 occur on the background of high levels of somatic hypermutation across MYC partner loci in HGBCL-DH-BCL2, creating more opportunity to form these rearrangements. Furthermore, because 1 IGH allele is already disrupted by the existing BCL2 rearrangement, the MYC rearrangement architecture in HGBCL-DH-BCL2 likely reflects selective pressure to preserve both BCL2 and B-cell receptor expression. These data provide new mechanistic explanations for the distinct patterns of MYC rearrangements observed across different lymphoma entities.

AbstractTo address the current and long‐term unmet health needs of the growing population of non‐Hodgkin lymphoma (NHL) patients, we established the Lymphoma Epidemiology of Outcomes (LEO) cohort study (NCT02736357; https://leocohort.org/). A total of 7735 newly diagnosed patients aged 18 years and older with NHL were prospectively enrolled from 7/1/2015 to 5/31/2020 at 8 academic centers in the United States. The median age at diagnosis was 62 years (range, 18–99). Participants came from 49 US states and included 538 Black/African‐Americans (AA), 822 Hispanics (regardless of race), 3386 women, 716 age <40 years, and 1513 rural residents. At study baseline, we abstracted clinical, pathology, and treatment data; banked serum/plasma (N = 5883, 76.0%) and germline DNA (N = 5465, 70.7%); constructed tissue microarrays for four major NHL subtypes (N = 1189); and collected quality of life (N = 5281, 68.3%) and epidemiologic risk factor (N = 4489, 58.0%) data. Through August 2022, there were 1492 deaths. Compared to population‐based SEER data (2015–2019), LEO participants had a similar distribution of gender, AA race, Hispanic ethnicity, and NHL subtype, while LEO was underrepresented for patients who were Asian and aged 80 years and above. Observed overall survival rates for LEO at 1 and 2 years were similar to population‐based SEER rates for indolent B‐cell (follicular and marginal zone) and T‐cell lymphomas, but were 10%–15% higher than SEER rates for aggressive B‐cell subtypes (diffuse large B‐cell and mantle cell). The LEO cohort is a robust and comprehensive national resource to address the role of clinical, tumor, host genetic, epidemiologic, and other biologic factors in NHL prognosis and survivorship.

Gene fusions involving tumor protein p63 gene (TP63) occur in multiple T and B cell lymphomas and portend a dismal prognosis for patients. The function and mechanisms of TP63 fusions remain unclear, and there is no target therapy for patients with lymphoma harboring TP63 fusions. Here, we show that TP63 fusions act as bona fide oncogenes and are essential for fusion-positive lymphomas. Transgenic mice expressing TBL1XR1::TP63, the most common TP63 fusion, develop diverse lymphomas that recapitulate multiple human T and B cell lymphomas. Here, we identify that TP63 fusions coordinate the recruitment of two epigenetic modifying complexes, the nuclear receptor corepressor (NCoR)—histone deacetylase 3 (HDAC3) by the N-terminal TP63 fusion partner and the lysine methyltransferase 2D (KMT2D) by the C-terminal TP63 component, which are both required for fusion-dependent survival. TBL1XR1::TP63 localization at enhancers drives a unique cell state that involves up-regulation of MYC and the polycomb repressor complex 2 (PRC2) components EED and EZH2. Inhibiting EZH2 with the therapeutic agent valemetostat is highly effective at treating transgenic lymphoma murine models, xenografts, and patient-derived xenografts harboring TP63 fusions. One patient with TP63 -rearranged lymphoma showed a rapid response to valemetostat treatment. In summary, TP63 fusions link partner components that, together, coordinate multiple epigenetic complexes, resulting in therapeutic vulnerability to EZH2 inhibition.