HIV and prior exposure to antiretroviral therapy alter tumour composition and tumour: T-cell associations in diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma worldwide, accounting for up to 40% of new non-Hodgkin Lymphoma (NHL) globally. People living with HIV are up to 17 times more likely to develop NHL, and as such, DLBCL is the leading cause of cancer death in this high-risk population. While histologically indistinguishable, HIV-associated (HIV+) and HIV-negative (HIV-) DLBCL are molecularly distinct, and biological differences may have implications for the development of future therapeutic interventions. Further, the impact of immunologic differences in people with HIV, including preceding ART, remains largely unknown. Here, we investigate the impact of HIV infection and ART exposure on the clinical features of DLBCL and T-cell immune response by performing imaging mass cytometry on our unique patient cohort in Malawi. In this cohort, HIV infection is positively prognostic, and HIV+/ART-naïve patients have the best outcomes. No established biomarkers other than Ki67 are associated with HIV or ART status, and the only tumour-intrinsic biomarkers that remain prognostic are MYC and MYC/BCL2 protein co-expression. Finally, TCR clonality is associated with distinct tumour-T cell interactions by HIV/ART status, indicating differential anti-tumour immune responses. We demonstrate previously undescribed HIV and ART-related differences in the DLBCL tumour microenvironment.

HIV infection and ART exposure affect tumor TCR repertoire of diffuse large B cell lymphoma.

The most common subtype of lymphoma globally, diffuse large B cell lymphoma (DLBCL), is a leading cause of cancer death in people with HIV. The restructuring of the T cell compartment because of HIV infection and antiretroviral therapy (ART) may have implications for modern treatment selection, but current understanding of these dynamic interactions is limited. Here, we investigated the T cell response to DLBCL by sequencing the T cell receptor (TCR) repertoire in a cohort of HIV-negative (HIV-), HIV+/ART-experienced, and HIV+/ART-naive patients with DLBCL. HIV+/ART-naive tumor TCR repertoires were more clonal and more distinct from each other than HIV- and HIV+/ART-experienced ones. Further, increased overlap between tumor and blood TCR repertoires was associated with improved survival and HIV/ART status. Our study describes TCR repertoire characteristics for the first time to our knowledge in an African DLBCL cohort and demonstrates contributions of HIV infection and ART exposure to the DLBCL TCR repertoire.

Comprehensive genomic profiling reveals molecular subsets of ASXL1-mutated myeloid neoplasms.

A large-scale genomic analysis of patients with ASXL1-mutated myeloid disease has not been performed to date. We reviewed comprehensive genomic profiling results from 6043 adults to characterize clinicopathologic features and co-mutation patterns by ASXL1 mutation status. ASXL1 mutations occurred in 1414 patients (23%). Mutation co-occurrence testing revealed strong co-occurrence (p < 0.01) between mutations in ASXL1 and nine genes (SRSF2, U2AF1, RUNX1, SETBP1, EZH2, STAG2, CUX1, CSF3R, CBL). Further analysis of patients with these co-mutations yielded several novel findings. Co-mutation patterns supported that ASXL1/SF3B1 co-mutation may be biologically distinct from ASXL1/non-SF3B1 spliceosome co-mutation. In AML, ASXL1/SRSF2 co-mutated patients frequently harbored STAG2 mutations (42%), which were dependent on the presence of both ASXL1 and SRSF2 mutation (p < 0.05). STAG2 and SETBP1 mutations were also exclusive in ASXL1/SRSF2 co-mutated patients and associated with divergent chronic myeloid phenotypes. Our findings support that certain multi-mutant genotypes may be biologically relevant in ASXL1-mutated myeloid disease.

The clinical significance of adenomatous polyposis coli (APC) and catenin Beta 1 (CTNNB1) genetic aberrations in patients with melanoma.

BACKGROUND: Melanoma-intrinsic activated ß-catenin pathway, the product of the catenin beta 1 (CTNNB1) gene, has been associated with low/absent tumor-infiltrating lymphocytes, accelerated tumor growth, metastases development, and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. Little is known about the association between the adenomatous polyposis coli (APC) and CTNNB1 gene mutations in stage IV melanoma with immunotherapy response and overall survival (OS). METHODS: We examined the prognostic significance of somatic APC/CTNNB1 mutations in the Cancer Genome Atlas Project for Skin Cutaneous Melanoma (TCGA-SKCM) database. We assessed APC/CTNNB1 mutations as predictors of response to immunotherapies in a clinicopathologically annotated metastatic patient cohort from three US melanoma centers. RESULTS: In the TCGA-SKCM patient cohort (n = 434) presence of a somatic APC/CTNNB1 mutation was associated with a worse outcome only in stage IV melanoma (n = 82, median OS of APC/CTNNB1 mutants vs. wild-type was 8.15 vs. 22.8 months; log-rank hazard ratio 4.20, p = 0.011). APC/CTNNB1 mutation did not significantly affect lymphocyte distribution and density. In the 3-melanoma institution cohort, tumor tissues underwent targeted panel sequencing using two standards of care assays. We identified 55 patients with stage IV melanoma and APC/CTNNB1 genetic aberrations (mut) and 169 patients without (wt). At a median follow-up of more than 25 months for both groups, mut compared with wt patients had slightly more frequent (44% vs. 39%) and earlier (66% vs. 45% within six months from original diagnosis of stage IV melanoma) development of brain metastases. Nevertheless, time-to-development of brain metastases was not significantly different between the two groups. Fortunately, mut patients had similar clinical benefits from PD-1 inhibitor-based treatments compared to wt patients (median OS 26.1 months vs. 29.9 months, respectively, log-rank p = 0.23). Less frequent mutations in the NF1, RAC1, and PTEN genes were seen in the mut compared with wt patients from the 3-melanoma institution cohort. Analysis of brain melanoma tumor tissues from a separate craniotomy patient cohort (n = 55) showed that melanoma-specific, activated ß-catenin (i.e., nuclear localization) was infrequent (n = 3, 6%) and not prognostic in established brain metastases. CONCLUSIONS: APC/CTNNB1 mutations are associated with a worse outcome in stage IV melanoma and early brain metastases independent of tumor-infiltrating lymphocyte density. However, PD1 inhibitor-based treatments provide comparable benefits to both mut and wt patients with stage IV melanoma.

Myeloid neoplasms in the setting of chronic lymphocytic leukaemia/chronic lymphocytic leukaemia-like disease: a clinicopathological study of 66 cases comparing cases with prior history of treatment to those without.

AIMS: Myeloid neoplasms occur in the setting of chronic lymphocytic leukaemia (CLL)/CLL-like disease. The underlying pathogenesis has not been elucidated. METHODS: Retrospectively analysed 66 cases of myeloid neoplasms in patients with CLL/CLL-like disease. RESULTS: Of these, 33 patients (group 1) had received treatment for CLL/CLL-like disease, while the other 33 patients (group 2) had either concurrent diagnoses or untreated CLL/CLL-like disease before identifying myeloid neoplasms. The two categories had distinct features in clinical presentation, spectrum of myeloid neoplasm, morphology, cytogenetic profile and clinical outcome. Compared with group 2, group 1 demonstrated a younger age at the diagnosis of myeloid neoplasm (median, 65 vs 71 years), a higher fraction of myelodysplastic syndrome (64% vs 36%; OR: 3.1; p<0.05), a higher rate of adverse unbalanced cytogenetic abnormalities, including complex changes, -5/5q- and/or -7/7q- (83% vs 28%; OR: 13.1; p<0.001) and a shorter overall survival (median, 12 vs 44 months; p<0.05). CONCLUSIONS: Myeloid neoplasm in the setting of CLL/CLL-like disease can be divided into two categories, one with prior treatment for CLL/CLL-like disease and the other without. CLL-type treatment may accelerate myeloid leukaemogenesis. The risk is estimated to be 13-fold higher in patients with treatment than those without. The causative agent could be attributed to fludarabine in combination with alkylators, based on the latency of myeloid leukaemogenesis and the cytogenetic profile.

Bilineal evolution of a U2AF1-mutated clone associated with acquisition of distinct secondary mutations.

Rare hematologic malignancies display evidence of both myeloid and lymphoid differentiation. Here, we describe such a novel bilineal event discovered in an adult woman with B-lymphoblastic leukemia (BLL). At the time of BLL diagnosis, the patient had a normal karyotype and a bulk sequencing panel identified pathogenic variants in BCOR, EZH2, RUNX1, and U2AF1, a genotype more typical of myeloid neoplasia. Additionally, the patient was noted to have 3-year history of cytopenias, and morphologic dyspoiesis was noted on post-treatment samples, raising the possibility of an antecedent hematologic disorder. To investigate the clonal architecture of her disease, we performed targeted sequencing on fractionated samples enriched for either B-lymphoblasts or circulating granulocytes. These studies revealed a truncal founder mutation in the spliceosome gene U2AF1 in both fractions, while distinct secondary mutations were present only in B-lymphoblasts (BCOR, NRAS) or myeloid cells (ASXL1, EZH2, RUNX1). These results indicate that both processes evolved from a common U2AF1-mutated precursor, which then acquired additional mutations during a process of divergent evolution and bilineal differentiation. Our findings highlight an atypical mechanism of BLL leukemogenesis and demonstrate the potential utility of fractionated sequencing in the characterization of acute leukemia.

Genomic characteristics and prognostic significance of co-mutated ASXL1/SRSF2 acute myeloid leukemia.

The ASXL1 and SRSF2 mutations in AML are frequently found in patients with preexisting myeloid malignancies and are individually associated with poor outcomes. In this multi-institutional retrospective analysis, we assessed the genetic features and clinical outcomes of 43 patients with ASXL1mut SRSF2mut AML and compared outcomes to patients with either ASXL1 (n = 57) or SRSF2 (n = 70) mutations. Twenty-six (60%) had secondary-AML (s-AML). Variant allele fractions suggested that SRSF2 mutations preceded ASXL1 mutational events. Median overall survival (OS) was 7.0 months (95% CI:3.8,15.3) and was significantly longer in patients with de novo vs s-AML (15.3 vs 6.4 months, respectively; P = .04 on adjusted analysis). Compared to ASXL1mut SRSF2wt and ASXL1wt SRSF2mut , co-mutated patients had a 1.4 and 1.6 times increase in the probability of death, respectively (P = .049), with a trend towards inferior OS (median OS = 7.0 vs 11.5 vs 10.9 months, respectively; P = .10). Multivariable analysis suggests this difference in OS is attributable to the high proportion of s-AML patients in the co-mutated cohort (60% vs 32% and 23%, respectively). Although this study is limited by the retrospective data collection and the relatively small sample size, these data suggest that ASXL1mut SRSF2mut AML is a distinct subgroup of AML frequently associated with s-AML and differs from ASXL1mut SRSF2wt /ASXL1wt SRSF2mut with respect to etiology and leukemogenesis.

Identification of high-risk monomorphic post-transplant lymphoproliferative disorder following solid organ transplantation.

Monomorphic post-transplant lymphoproliferative disorder (M-PTLD) occurring after solid organ transplant histologically resembles aggressive non-Hodgkin lymphomas, with diffuse large B-cell lymphoma being the most common. In a cohort of 40 patients with DLBCL-type M-PTLD, inferior progression free survival (PFS) was observed for Revised International Prognostic Index (R-IPI) >2 (p = 0.01) and high-risk pathologic features (p = 0.02), defined by double expressor lymphoma, MYC rearrangement, or increased copy number of either MYC or BCL2. Overall survival (OS) was inferior in R-IPI >2 (p = 0.002) and high-risk pathologic features (p = 0.003). Combining both R-IPI >2 and high-risk pathologic features resulted in well-delineated good, intermediate, and poor risk groups of DLBCL-type M-PTLD with respect to both PFS and OS (p < 0.001). Our results demonstrate a prognostic role for both the R-IPI score and presence of high-risk pathologic features in DLBCL-type M-PTLD.

Myeloid sarcoma manifesting as generalized lymphadenopathy in a patient with myelofibrosis.

Immunophenotyping is critical to the diagnosis of MS, as it can be difficult to differentiate from other diagnoses including lymphoma using conventional light microscopy.

Epstein-Barr virus-negative diffuse large B cell lymphoma with aberrant expression of CD3 and other T cell-associated antigens: report of three cases with a review of the literature.

Expression of CD3 on a mature B cell neoplasm, such as diffuse large B cell lymphoma (DLBCL), is extremely rare. When it is present, it will cause diagnostic confusion since the classification of lymphoid neoplasms is largely based on immunophenotyping to determine the cell lineage. We report three cases of DLBCL with CD3 and other T cell-associated antigens. A literature search identifies 30 additional cases of DLBCL expressing CD3, with the majority (78.6 %) displaying cytoplasmic expression, while two of our cases demonstrate membranous staining. Additionally, expression of CD3 tends to be partial and weak in both our series and the reported cases. Of the 28 cases reported in the literature that were tested for Epstein Barr Virus (EBV), 16 (57.1 %) are positive, suggesting an important role of EBV in promoting lineage ambiguity/infidelity, whereas, all three cases in our series are negative for the virus. All three cases in our series show homogeneous expression of multiple B cell specific antigens, while the reported cases show variable expression with some having B cell antigens downregulated, particularly in those cases with EBV association or anaplastic morphology. A low threshold for testing EBV status is advocated in DLBCL with phenotypic ambiguity along with panels of immunohistochemical stains and B/T cell receptor gene rearrangement analysis.