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.

Safety, efficacy, and affordability of ABVD for Hodgkin lymphoma in Malawi: a prospective cohort study.

Background: ABVD (doxorubicin, bleomycin, vinblastine, and dexamethasone) is a proven, curative regimen for Hodgkin lymphoma (HL). Prospective data describing HL treatment in sub-Saharan Africa are limited. We aimed to fill this knowledge gap, using data from Malawi. Methods: We report a prospective observational cohort of HL (aged ≥ 15) from a single, tertiary referral centre in Malawi. We enrolled patients with pathologicially confirmed Hodgkin lymphoma between June 1, 2013, and Dec 31, 2021 with follow-up censored on May 31, 2022. Patients were treated with ABVD and concurrent antiretroviral therapy if HIV-positive and were followed up for 5 years. The primary outcome was overall survival; secondary outcomes included progression-free survival, response assessment, and adverse events. Microcosting of HL diagnosis, treatment, and follow-up was embedded. Findings: We enrolled 38 patients with a median age of 27 years (interquartile range 19-46); eleven (28%) were HIV-positive. Of 35 patients treated with ABVD, 24 (71%) had stage III/IV, nine (26%) unfavourable limited stage, and two (6%) favourable limited stage. Among HIV-infected individuals, mean CD4 count at HL diagnosis was 179 cells/uL and ten (91%) had HIV RNA < 400 copies/mL. Grade 3/4 neutropenia occurred in 24 (68%) patients and caused treatment delay in 16 (46%). Of ten deaths, seven were due to HL, two possible treatment-related toxicity, and one uncertain. 2-year overall survival was 82% (95% CI 70-96%) and 2-year progression-free survival was 64% (95% CI 50-83%). PFS appeared better for HIV-positive patients (HR 0.23 (95% CI 0.05-1.02)) after controlling for stage and performance status (p = 0.05). We estimated $2708 (2022 USD) for HL diagnosis, treatment, and follow-up in our cohort. Interpretation: Our findings suggest that treatment with ABVD is safe, efficacious, and affordable for HL in Malawi. Outcomes are worse than in high-income countries due to HL progression. Future studies are needed to understand outcome inequities and to assess efficacy of therapies for patients with relapsed or refractory HL in Malawi. Funding: National Institutes of Health, Lineberger Comprehensive Cancer Center.

Update on pathology laboratory development and research in advancing regional cancer care in Malawi.

The pathology laboratory at Kamuzu Central Hospital (KCH) in Lilongwe, Malawi was established in 2011. We published our initial experiences in laboratory development and telepathology in 2013 and 2016, respectively. The purpose of this paper is to provide an update on our work by highlighting the positive role laboratory development has played in improving regional cancer care and research. In addition, we provide a summary of the adult pathology data from specimens received between July 1, 2011, and May 31, 2019, with an emphasis on malignant diagnoses. We compare these summaries to estimates of cancer incidence in this region to identify gaps and future needs.

Breast Cancer Germline Genetic Counseling and Testing for Populations of African Heritage Globally: A Scoping Review on Research, Practice, and Bioethical Considerations.

PURPOSE: Despite the disproportionately high risk of breast cancer among women of African heritage, little is known about the facilitators and barriers to implementing germline genetic testing and counseling (GT/C). METHODS: This scoping review followed guidelines recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. Published manuscripts from database inception through 2021 were sourced from PubMed, Cumulative Index to Nursing and Allied Health Literature via EBSCO, Embase, Cochrane Library, and Scopus. Search terms were used to retrieve articles addressing (1) African heritage, (2) breast cancer, and (3) GT or GC. The screening involved abstract and title review and full-text review. Data were extracted for all articles meeting the inclusion criteria. RESULTS: A total of 154 studies were included. Most studies that took place were conducted in the United States (71.4%), and most first authors (76.9%) were from the United States. GT was conducted in 73 (49.7%) studies. BRCA1/BRCA2 were the most commonly studied genes for germline mutations. GC was conducted in 49 studies (33.3%), and perspectives on GC were evaluated in 43 (29.3%). The use of racial/ethnic categories varied broadly, although African American was most common (40.1%). Racism was mentioned in three studies (2.0%). CONCLUSION: There is a growing body of literature on GT/C for breast cancer in women of African heritage. Future studies on GT/C of African populations should consider increased clarity around racial/ethnic categorizations, continued community engagement, and intentional processes for informed consent.

Lymphomas and Amyloid in the Gastrointestinal Tract.

Lymphoproliferative disorders are a heterogeneous group of neoplasms with varying clinical, morphologic, immunophenotypic, and genetic characteristics. A subset of lymphomas have a proclivity for the gastrointestinal tract, although this region may also be involved by systemic lymphomas. In addition, a number of indolent lymphoproliferative disorders of the gastrointestinal tract have been defined over the past decade, and it is important to accurately differentiate these neoplasms to ensure that patients receive the proper management. Here, the authors review lymphoid neoplasms that show frequent gastrointestinal involvement and provide updates from the recent hematolymphoid neoplasm classification systems.

Case report: Multicentric Castleman disease as a manifestation of immune reconstitution inflammatory syndrome in Malawi.

Introduction: Multicentric Castleman disease (MCD) is a lymphoproliferative disorder characterized by systemic inflammation, lymphadenopathy, and cytopenias. MCD caused by Kaposi sarcoma herpesvirus (MCD-KSHV) frequently arises in the context of HIV. It can be associated with immune reconstitution inflammatory syndrome (IRIS), but MCD-IRIS is rarely reported in sub-Saharan Africa (SSA) where HIV and KSHV infection are common. Case description: A 36-year-old woman in Malawi with HIV on antiretroviral therapy (ART) for nine years presented with fatigue, weight loss, and lymphadenopathy. Lymph node biopsy was consistent with HIV lymphadenitis without evident KSHV-MCD and HIV RNA was 4,244 copies/mL. She switched to second-line ART and returned four months later with worsening lymphadenopathy, fever, night sweats, weight loss, and anemia. A repeat lymph node biopsy demonstrated unequivocal KSHV-MCD features not present on the original biopsy. Her repeat HIV viral load was undetectable and she received chemotherapy with subsequent remission on continued ART for 24 months. Discussion: This is among the first reported cases of MCD-IRIS from SSA, which has implications for a region where HIV and KSHV are highly prevalent. MCD-IRIS may contribute to early mortality after ART initiation in SSA, and increased awareness alongside improved diagnostic and treatment capacity are needed.

The role of telepathology in improving cancer diagnostic and research capacity in sub-Saharan Africa.

Non-communicable disease (NCD), including cancer, disproportionately affect Low- and Middle-Income Countries (LMICs). This inequity is in part due to limitations of pathology services, both human and infrastructural. While significant improvements have been made to address these gaps, creative approaches that are mindful of regional priorities, cultural differences, and unique local challenges are needed. In this perspective, we will describe the implementation of telepathology services in sub-Saharan Africa (SSA) that serve as cornerstones for direct patient care, multi-disciplinary care coordination, research programs, and building human capacity through training. Models and challenges of system implementation, sustainability, and pathologist engagement will be discussed. Using disease and site-specific examples, we will suggest metrics for quality control and improvement initiatives that are critical for providing high-quality cancer registry data and necessary for future implementation of therapeutic and interventional clinical trials.

Comparison of baseline lymphoma and HIV characteristics in Malawi before and after implementation of universal antiretroviral therapy.

Access to antiretroviral therapy (ART) led to epidemiological changes in human immunodeficiency virus (HIV) associated lymphoma in high-income countries such as reductions in diffuse large B-cell lymphoma (DLBCL) and stable or increased Hodgkin lymphoma (HL) and Burkitt lymphoma (BL). In 2016, Malawi implemented a universal ART (UART) policy, expanding ART eligibility to all persons living with HIV (PLWH). We compare the distribution of lymphoma subtypes and baseline HIV and prognostic characteristics for lymphoma patients in Malawi before and after implementation of UART. We enrolled patients with pathologically confirmed incident lymphoproliferative disorders into a observational clinical cohort. At diagnosis, a comprehensive clinicopathological evaluation was performed. Of 412 participants, 156 (38%) were pre-UART (2013-June 2016) and 256 (62%) post-UART (July 2016-2020). HIV prevalence was 50% in both groups. The most common pre-UART diagnoses were DLBCL [75 (48%)], low-grade non-Hodgkin lymphoma (NHL) [19 (12%)], HL [17 (11%)] and, BL [13 (8%)]. For post-UART they were DLBCL [111 (43%)], NHL [28 (11%)], BL [27 11%)] and, HL [20 (8%)]. Among PLWH, 44 (57%) pre-UART initiated ART prior to lymphoma diagnosis compared to 99 (78%) post-UART (p = 0.02). HIV-ribonucleic acid was suppressed <1000 copies/mL in 56% (33/59) pre-UART and 71% (73/103) post-UART (p = 0.05). CD4 T-cell counts were similar for both groups. We observed similar findings in the subset of participants with DLBCL. Overall, there were no significant changes in incident lymphoma subtypes (p = 0.61) after implementation of UART, but HIV was better controlled. Emerging trends bear monitoring and may have implications for prognosis and health system priority setting. Trial registration: ClinicalTrials.gov identifier: NCT02835911.

Quantitative Imaging Analysis of the Spatial Relationship between Antiretrovirals, Reverse Transcriptase Simian-Human Immunodeficiency Virus RNA, and Fibrosis in the Spleens of Nonhuman Primates.

Although current antiretroviral therapy (ART) has increased life expectancy, a cure for human immunodeficiency virus (HIV) remains elusive due to the persistence of the virus in tissue reservoirs. In the present study, we sought to elucidate the relationship between antiretrovirals (ARVs) and viral expression in the spleen. We performed mass spectrometry imaging (MSI) of 6 different ARVs, RNAscope in situ hybridization of viral RNA, and immunohistochemistry of three different fibrosis markers in the spleens of 8 uninfected and 10 reverse transcriptase simian-human immunodeficiency virus (RT-SHIV)-infected rhesus macaques (infected for 6 weeks) that had been dosed for 10 days with combination ART. Using MATLAB, computational quantitative imaging analysis was performed to evaluate the spatial and pharmacological relationships between the 6 ARVs, viral RNA, and fibrotic deposition. In these spleens, >50% of the spleen tissue area was not covered by any detectable ARV response (any concentration above the limits of detection for individual ARVs). The median spatial ARV coverage across all tissues was driven by maraviroc followed by efavirenz. Yet >50% of RNA-positive cells were not exposed to any detectable ARV. Quantifiable maraviroc and efavirenz colocalization with RNA-positive cells was usually greater than the in vitro concentration inhibiting 50% replication (IC50). Fibrosis markers covered more than 50% of the spleen tissue area and had negative relationships with cumulative ARV coverages. Our findings suggest that a heterogeneous ARV spatial distribution must be considered when evaluating viral persistence in lymphoid tissue reservoirs.

Clinical Characteristics and Outcomes of Acute Lymphoblastic Leukemia in Adolescents and Young Adults in Malawi.

PURPOSE: There are limited data on treatment and outcomes for acute lymphoblastic leukemia (ALL) among adolescents and young adults in sub-Saharan Africa. We describe a prospective observational cohort in Malawi. METHODS: Patients age 15-39 years with newly diagnosed ALL at Kamuzu Central Hospital, Malawi, were enrolled from 2013 to 2019; follow-up was censored on December 2020. ALL diagnosis was confirmed on-site using immunohistochemistry and telepathology consultation involving pathologists in Malawi and the United States. All but four patients were treated with a modified pediatric-inspired regimen (Cancer and Leukemia Group B 10403 protocol). Key modifications included omission of asparaginase and no dose escalation for methotrexate. RESULTS: Of 19 participants, the median age was 22 (range 15-36) years. Of the 15 patients who initiated treatment, 11 (73%) achieved remission after induction, one (7%) died during induction, two (13%) had refractory disease, and one (7%) absconded. No patients were lost to follow-up. Eventually, 10 of 11 patients (91%) with confirmed remission relapsed. The median duration of first remission was 10 (range 3-22) months. Twelve of 15 treated patients (80%) had died at the time of censoring. Among treated patients, the 12- and 24-month overall survival was 50% (95% CI, 23 to 72) and 17% (95% CI, 3 to 42), respectively. CNS involvement was associated with worse survival. CONCLUSION: It is possible to treat adolescents and young adults with ALL in low-resource settings using a low-cost, pediatric-inspired regimen; however, outcomes are poor. Both cost and limitations in supportive care infrastructure limit intensive cytotoxic approaches such as asparaginase. Patient-reported outcomes are needed to understand the quality of life and cost-effectiveness. Critically, innovative, leap-frog therapies, such as monoclonal or bispecific antibodies, and feasible economic models for resource-limited settings are urgently needed.

Spatial distribution of incident pediatric Burkitt lymphoma in central and northern Malawi and association with malaria prevalence.

BACKGROUND: Burkitt lymphoma (BL) accounts for 90% of pediatric lymphomas in sub-Saharan Africa. Plasmodium falciparum malaria is considered an etiological factor of BL. We describe the geographic distribution of pediatric BL in Malawi and association with P. falciparum malaria prevalence rate (PfPR). METHODS: We enrolled 220 pathologically confirmed incident pediatric BL cases (2013-2018) into an observational clinical cohort at Kamuzu Central Hospital (KCH) in Lilongwe district. KCH is the main tertiary cancer referral center serving the central and northern regions of Malawi. Using an ecological study design, we calculated district-level annual BL incidence rate using census population estimates. District-level PfPR was extracted from the National Malaria Control Program 2010 report. BL incidence and PfPR maps were constructed in QGIS. Moran's I  test was used to identify BL spatial clusters. Pearson's correlation and multiple linear regression analyses were used to statistically examine the relationship between PfPR and BL. RESULTS: BL incidence was higher in central region districts (8.2 cases per million) than northern districts (2.9 cases per million) and was elevated in lakeshore districts. Districts with elevated PfPR tended to have elevated BL incidence. A low-risk BL cluster was detected in the north. Statistically, BL incidence was positively correlated with PfPR (r = .77, p < .01). A 1% increase in PfPR predicted an increase in BL incidence of 0.2 cases per million (p = .03), when controlling for travel time from referral district hospital to KCH. CONCLUSION: Our study supports evidence for an association between P. falciparum and BL and highlights a need to improve geographic accessibility to tertiary cancer services in Malawi's northern region.

Acute Leukemia Classification Using Transcriptional Profiles From Low-Cost Nanopore mRNA Sequencing.

PURPOSE: Most cases of pediatric acute leukemia occur in low- and middle-income countries, where health centers lack the tools required for accurate diagnosis and disease classification. Recent research shows the robustness of using unbiased short-read RNA sequencing to classify genomic subtypes of acute leukemia. Compared with short-read sequencing, nanopore sequencing has low capital and consumable costs, making it suitable for use in locations with limited health infrastructure. MATERIALS AND METHODS: We show the feasibility of nanopore mRNA sequencing on 134 cryopreserved acute leukemia specimens (26 acute myeloid leukemia [AML], 73 B-lineage acute lymphoblastic leukemia [B-ALL], 34 T-lineage acute lymphoblastic leukemia, and one acute undifferentiated leukemia). Using multiple library preparation approaches, we generated long-read transcripts for each sample. We developed a novel composite classification approach to predict acute leukemia lineage and major B-ALL and AML molecular subtypes directly from gene expression profiles. RESULTS: We demonstrate accurate classification of acute leukemia samples into AML, B-ALL, or T-lineage acute lymphoblastic leukemia (96.2% of cases are classifiable with a probability of > 0.8, with 100% accuracy) and further classification into clinically actionable genomic subtypes using shallow RNA nanopore sequencing, with 96.2% accuracy for major AML subtypes and 94.1% accuracy for major B-lineage acute lymphoblastic leukemia subtypes. CONCLUSION: Transcriptional profiling of acute leukemia samples using nanopore technology for diagnostic classification is feasible and accurate, which has the potential to improve the accuracy of cancer diagnosis in low-resource settings.

Epstein-Barr virus mucocutaneous ulcer followed by Hodgkin lymphoma in multiple myeloma patient.

Epstein-Barr virus mucocutaneous ulcers (EBV MCU) are B-cell lymphoproliferative disorders associated with immunosuppression. We report EBV MCU in a multiple myeloma patient on lenalidomide maintenance after stem cell transplant that resolved with decreased immunosuppression. Furthermore, the subsequent development of classical Hodgkin lymphoma suggests an underlying predisposition to EBV-driven lymphoproliferative disorders.

Safety and efficacy of rituximab in patients with diffuse large B-cell lymphoma in Malawi: a prospective, single-arm, non-randomised phase 1/2 clinical trial.

BACKGROUND: There are no clinical trials involving patients with diffuse large B-cell lymphoma (DLBCL) in sub-Saharan Africa since antiretroviral therapy (ART) for HIV became widely available in this region. We aimed to establish the safety and efficacy of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with DLBCL in Malawi. METHODS: This prospective, single-arm, non-randomised phase 1/2 clinical trial was done at Kamuzu Central Hospital Cancer Clinic (Lilongwe, Malawi). Eligible patients were adults (aged 18-60 years) with newly diagnosed DLBCL, an Eastern Cooperative Oncology Group performance status of 0-2, a CD4 count of 100 cells per µL or higher (if HIV-positive), measurable disease by physical examination, an absolute neutrophil count of 1000 × 109 cells per L or higher, a platelet count of 100 × 109 platelets per L or higher, a serum creatinine concentration of 132·60 µmol/L or less, a total bilirubin concentration of 34·21 µmol/L or less, a negative urine pregnancy test in women of childbearing potential, and no previous cytotoxic therapy. Pregnant or breastfeeding women, and individuals with CNS involvement from DLBCL, chronic hepatitis B infection (unless they were receiving tenofovir plus lamivudine), or any other comorbidities that would compromise the protocol objectives were excluded. Eligible patients received intravenous rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, and vincristine 1·4 mg/m2 (maximum 2 mg/m2), and oral prednisone 100 mg or an equivalent drug every 21 days for up to six cycles. HIV-positive patients received concurrent ART. The primary outcome was the proportion of patients with National Cancer Institute Common Terminology Criteria for Adverse Events grade 3 or 4 non-haematological toxic effects or treatment-related deaths after six cycles of treatment. Secondary efficacy outcomes included the proportion of patients with a complete response after six cycles of treatment, and progression-free survival and overall survival at 12 months and 24 months. This trial is registered with ClinicalTrials.gov, NCT02660710. FINDINGS: Between Aug 1, 2016, and July 31, 2019, 76 patients were screened, of whom 37 were eligible for the study and received R-CHOP. The median age of patients was 44 years (IQR 39-49) and 16 (43%) were women. Of all 37 patients, 20 (54%) had stage III or IV DLBCL, and the age-adjusted international prognostic index was 2 or higher in 25 (68%) patients. 27 (73%) patients were HIV-positive, with a median CD4 count of 208 cells per µL (IQR 144-422), and 21 (78%) patients were receiving ART at enrolment. Patients completed a median of six cycles (IQR 4-6). Grade 3 or 4 non-haematological toxic effects were reported in 12 (32% [95% CI 19-49]) patients, the most common of which was infection (nine [24%] patients). Of 16 (43%) deaths, ten were due to progression of DLBCL, four were due to treatment-related complications, and two were due to other causes, yielding a treatment-related mortality of 11% (95% CI 4-26%). Grade 3 or 4 neutropenia was observed in 26 (70%) patients, and grade 3 or 4 anaemia was observed in 11 (29%) patients. A total of 22 (59%) patients had a complete response. Overall survival was 68% (95% CI 50-80) at 12 months and 55% (37-70) at 24 months, and progression-free survival was 59% (42-73) at 12 months and 53% (35-68) at 24 months. INTERPRETATION: R-CHOP could be feasible, safe, and efficacious in patients with DLBCL in Malawi. This is the first completed clinical trial on DLBCL focused on sub-Saharan African populations. Given the paucity of data on treatment of DLBCL from this region, these results could inform emerging cancer treatment programmes in sub-Saharan Africa. FUNDING: The University of North Carolina Lineberger Comprehensive Cancer Center.

Quantitative Imaging Analysis of the Spatial Relationship between Antiretrovirals, Reverse Transcriptase Simian-Human Immunodeficiency Virus RNA, and Collagen in the Mesenteric Lymph Nodes of Nonhuman Primates.

Human immunodeficiency virus (HIV) persistence in tissue reservoirs is a major barrier to HIV cure. While antiretrovirals (ARVs) suppress viral replication, antiretroviral therapy (ART) interruption results in rapid rebound viremia that may originate from lymphoid tissues. To understand the relationship between anatomic distribution of ARV exposure and viral expression in lymph nodes, we performed mass spectrometry imaging (MSI) of 6 ARVs, RNAscope in situ hybridization for viral RNA (vRNA), and immunohistochemistry of collagen in mesenteric lymph nodes from 8 uninfected and 10 reverse transcriptase simian/human immunodeficiency virus (RT-SHIV)-infected rhesus macaques dosed to steady state with combination ART. MATLAB-based quantitative imaging analysis was used to evaluate spatial and pharmacological relationships between these ARVs, viral RNA (both vRNA+ cells and follicular dendritic cell [FDC]-bound virions), and collagen deposition. Using MSI, 31% of mesenteric lymph node tissue area was found to be not covered by any ARV. Additionally, 28% of FDC-trapped virions and 21% of infected cells were not exposed to any detected ARV. Of the 69% of tissue area that was covered by cumulative ART exposure, nearly 100% of concentrations were greater than in vitro 50% inhibitory concentration (IC50) values; however, 52% of total tissue coverage was from only one ARV, primarily maraviroc. Collagen covered ∼35% of tissue area but did not influence ARV distribution heterogeneity. Our findings are consistent with our hypothesis that ARV distribution, in addition to total-tissue drug concentration, must be considered when evaluating viral persistence in lymph nodes and other reservoir tissues.

Clinical, immunophenotypic and genomic findings of NK lymphoblastic leukemia: a study from the Bone Marrow Pathology Group.

Natural killer (NK) cells are lymphocytes of the native immune system that play a pivotal role in host defense and immune surveillance. While the conceptual view of NK-neoplasms is evolving, little is known about the rare NK lymphoblastic leukemia (NK-LL), which remains as a provisional entity in the 2016 WHO Classification. The goal of this study is to characterize NK-LL cases and compare with other CD56 co-expressing acute leukemias. We identified 105 cases, diagnosed as NK-LL (6), CD56+ acute undifferentiated leukemia (AUL) (6), CD56+ T-lymphoblastic leukemia (T-LL) (51), and CD56+ acute myeloid leukemia (AML) (42). Compared to AUL patients, NK-LL patients were significantly younger (p = 0.021) and presented with higher white blood cell (WBC) (p = 0.037) and platelet counts (p = 0.041). Flow cytometry showed more frequent expression of cytoplasmic CD3 (cCD3, p = 0.064) and CD33, (p = 0.065), while HLA-DR was significantly absent from NK-LL (p = 0.035) compared to AUL. Compared to T-ALL, NK-LL cases showed less frequent cCD3 (p = 0.002), CD4 (p = 0.051), and CD10 expression (p = 0.06). The frequency of abnormal karyotypes was similar between NK-LL, AUL, and T-ALL. The mutational profile differed in four leukemia groups, with a significance enrichment of NOTCH1 (p = 0.002), ETV6 (p = 0.002) and JAK3 (p = 0.02) mutations in NK-LL as compared to AML. As compared to T-ALL, NK-LL cases showed a higher number of total mutations (p = 0.04) and significantly more frequent ETV6 mutations (p = 0.004). Clinical outcome data showed differences in overall survival between all four groups (p = 0.0175), but no difference in event free survival (p = 0.246). In this largest study to date, we find that that NK-LL shows clinical presentation, immunophenotypic and molecular characteristics distinct from AUL, T-ALL, and AML. Our findings suggest NK-LL is a distinct acute leukemia entity and should be considered in the clinical diagnosis of acute leukemias of ambiguous lineage.

Rad18 mediates specific mutational signatures and shapes the genomic landscape of carcinogen-induced tumors in vivo.

The E3 ubiquitin ligase Rad18 promotes a damage-tolerant and error-prone mode of DNA replication termed trans-lesion synthesis that is pathologically activated in cancer. However, the impact of vertebrate Rad18 on cancer genomes is not known. To determine how Rad18 affects mutagenesis in vivo, we have developed and implemented a novel computational pipeline to analyze genomes of carcinogen (7, 12-Dimethylbenz[a]anthracene, DMBA)-induced skin tumors from Rad18+/+ and Rad18- / - mice. We show that Rad18 mediates specific mutational signatures characterized by high levels of A(T)>T(A) single nucleotide variations (SNVs). In Rad18- /- tumors, an alternative mutation pattern arises, which is characterized by increased numbers of deletions >4 bp. Comparison with annotated human mutational signatures shows that COSMIC signature 22 predominates in Rad18+/+ tumors whereas Rad18- / - tumors are characterized by increased contribution of COSMIC signature 3 (a hallmark of BRCA-mutant tumors). Analysis of The Cancer Genome Atlas shows that RAD18 expression is strongly associated with high SNV burdens, suggesting RAD18 also promotes mutagenesis in human cancers. Taken together, our results show Rad18 promotes mutagenesis in vivo, modulates DNA repair pathway choice in neoplastic cells, and mediates specific mutational signatures that are present in human tumors.

Rosai-Dorfman Disease and Exocrine Pancreatic Insufficiency in a Patient With a Germline SLC29A3 Mutation.

Rosai-Dorfman disease (RDD) typically presents as bulky lymphadenopathy. Somatic mutations in RAS/MAP kinase pathway genes are common but germline mutations are rare. A patient with RDD and exocrine pancreatic insufficiency was found to have a homozygous germline mutation in SLC29A3, which has been associated with the Histiocytosis/Lymphadenopathy Plus Syndrome. His RDD also was positive for a somatic mutation in lymphoid enhancer binding factor 1 (LEF1). The concurrence of RDD and pancreatic insufficiency should raise consideration of SLC29A3 mutations. Other cases will be needed to confirm this observation and a possible contribution of LEF1 to the development of RDD.

Epidemiology of haematological malignancies in people living with HIV.

People living with HIV or AIDS are at increased risk of Hodgkin and non-Hodgkin lymphoma compared with HIV-negative individuals. Data on the risk of multiple myeloma or leukaemia are inconsistent and of low quality but the risk does not seem to be increased. Specific haematological malignancies occur in different contexts of age, CD4 cell count, HIV control, viral co-infections, or chronic inflammation, and the expansion of combination antiretroviral therapy has led to varied demographic and epidemiological shifts among people with HIV. Increased use of combination antiretroviral therapy has substantially reduced the risks of diffuse large B-cell lymphoma, Burkitt lymphoma, and primary CNS lymphoma, and to a lesser extent, Hodgkin lymphoma. There is no effect of combination antiretroviral therapy use on multiple myeloma or leukaemia. Although many cases of HIV are in low-income and middle-income countries, high-quality epidemiological data for haematological malignancies from these regions are scarce. Closing this gap is an essential first step in decreasing mortality from HIV-associated haematological malignancies worldwide. Finally, although multicentric Castleman disease is not a neoplastic condition, it is an emerging precursor to neoplastic high-grade B-cell lymphoproliferation among people with HIV, especially for individuals on long-term combination antiretroviral therapy with well controlled HIV.