Acute myeloid leukemia with mixed phenotype is characterized by stemness transcriptomic signatures and limited lineage plasticity.

Mixed phenotype (MP) in acute leukemias poses unique classification and management dilemmas and can be seen in entities other than de novo mixed phenotype acute leukemia (MPAL). Although WHO classification empirically recommends excluding AML with myelodysplasia related changes (AML-MRC) and therapy related AML (t-AML) with mixed phenotype (AML-MP) from MPAL, there is lack of studies investigating the clinical, genetic, and biologic features of AML-MP. We report the first cohort of AML-MRC and t-AML with MP integrating their clinical, immunophenotypic, genomic and transcriptomic features with comparison to MPAL and AML-MRC/t-AML without MP. Both AML cohorts with and without MP shared similar clinical features including adverse outcomes but were different from MPAL. The genomic landscape of AML-MP overlaps with AML without MP but differs from MPAL. AML-MP harbors more frequent RUNX1 mutations than AML without MP and MPAL. RUNX1 mutations did not impact the survival of patients with MPAL. Unsupervised hierarchal clustering based on immunophenotype identified biologically distinct clusters with phenotype/genotype correlation and outcome differences. Furthermore, transcriptomic analysis showed an enrichment for stemness signature in AML-MP and AML without MP as compared to MPAL. Lastly, MPAL but not AML-MP often switched to lymphoid only immunophenotype after treatment. Expression of transcription factors critical for lymphoid differentiation were upregulated only in MPAL, but not in AML-MP. Our study for the first time demonstrates that AML-MP clinically and biologically resembles its AML counterpart without MP and differs from MPAL, supporting the recommendation to exclude these patients from the diagnosis of MPAL. Future studies are needed to elucidate the molecular mechanism of mixed phenotype in AML. Key points: AML-MP clinically and biologically resembles AML but differs from MPAL. AML-MP shows RUNX1 mutations, stemness signatures and limited lymphoid lineage plasticity.

Outcomes with high dose cytarabine and mitoxantrone induction for adults with mixed phenotype acute leukemia.

The optimal induction strategy for mixed phenotype acute leukemia (MPAL) is unknown, though retrospective data has shown improved remission rates and overall survival with acute lymphoblastic leukemia (ALL)-based regimens. At Memorial Sloan Kettering Cancer Center (MSKCC), the most utilized induction regimen for MPAL is high dose cytarabine plus mitoxantrone ("ALL-2"), though outcomes with this regimen are not well described. In this study, outcomes to first-line induction chemotherapy in 24 patients at MSKCC with MPAL classified by 2016 World Health Organization criteria are reported. The overall response rate was 94 % (16 of 17) in patients receiving ALL-2, including 86 % (6 of 7) in patients with extramedullary disease. Thirteen patients who received ALL-2 induction proceeded to allogeneic hematopoietic cell transplant (allo-HCT). The most common toxicity associated with ALL-2 was febrile neutropenia, documented in 12 patients. With a median follow-up of 37 months, median overall survival was not reached in the ALL-2 cohort, and 3-year overall survival was 62 %. In multivariate analysis, age ≥ 60 years and MPAL with isolated extramedullary disease were associated with significantly worse overall survival (P = .009 and P = .01, respectively). These results support further prospective investigation of ALL-2 as a front-line induction regimen for adults with MPAL.

Quantitative Off-Target Detection of Epstein-Barr Virus-Derived DNA in Routine Molecular Profiling of Hematopoietic Neoplasms by Panel-Based Hybrid-Capture Next-Generation Sequencing.

Epstein-Barr virus (EBV) is associated with hematologic and solid tumors. We utilized a hybridization capture-based next-generation sequencing (NGS) platform targeting 400 genes associated with hematological malignancies to detect and quantify nontargeted viral-derived EBV reads that aligned to the EBV reference contig (NC_007605). We evaluated 5234 samples from 3636 unique patients with hematological neoplasms and found that 100 samples (1.9%) in 93 unique patients had ≥6 EBV reads (range, 6 to 32,325; mean, 827.5; median, 54). Most (n = 73, 73%) represented known EBV-associated conditions, and the most common was post-transplant lymphoproliferative disorders (n = 21, 29%). Documented EBV viremia was found in 4 of 27 samples with a moderate quantity of EBV reads and conditions not known to be EBV associated, whereas suspected viremia or low-level activation was likely in the remaining 23 samples. A good correlation (Spearman r = 0.8; 95% CI, 0.74-0.85) was found between EBV reads by NGS and systematic semiquantitative EBV-encoded RNA in situ hybridization in 162 available samples, particularly at greater EBV involvement. An optimal threshold for significant morphologic EBV involvement was found to be ≥10 reads by the receiver operating characteristic analysis (area under the curve, 0.990; 95% CI, 0.9974%-1.000%). Thus, in addition to mutational analysis, hybrid-capture-based NGS panels can detect and quantitate off-target EBV-derived viral DNA, which correlates well with morphology.

Epstein-Barr Virus-negative Marginal Zone Lymphoma as an Uncommon Form of Monomorphic Posttransplant Lymphoproliferative Disorder.

Monomorphic posttransplant lymphoproliferative disorders have been defined as lymphoid or plasmacytic proliferations that fulfill criteria for one of the B-cell or T/NK-cell neoplasms recognized in immunocompetent hosts in the current WHO Classification. Low-grade B-cell neoplasms have historically been excluded from this category, although rare reports of marginal zone lymphoma (MZL) have been described. We report 9 cases of posttransplant Epstein-Barr virus-negative MZL, all arising in solid organ transplant recipients (4 renal, 3 liver, 1 cardiac, and 1 liver, pancreas, and small bowel). Seven were extranodal MZL of mucosa-associated lymphoid tissue type, all of which had gastrointestinal involvement (4 colon, 1 duodenum, 1 stomach, and 1 oropharynx/base of tongue). Notably, the preferential involvement of intestine distinguishes posttransplant extranodal MZL from sporadic cases. Immunoglobulin light-chain restriction was seen in all cases, with polymerase chain reaction showing a monoclonal pattern in 7 of 8 cases with successful amplification of polymerase chain reaction products. A clonally unrelated recurrence was seen in one case. Next-generation sequencing identified recurrent mutations previously reported in MZL in 3/5 cases. MZL was diagnosed at least 1 year after solid organ transplant (median time to presentation, 84 mo; range, 13 to 108 mo). The median age was 44 (range, 9 to 73 y); the male: female ratio was 5:4. The mean follow-up was 33.4 months, with an indolent clinical course observed. A subset responded to reduction in immunosuppression and anti-CD20 therapy alone. These data support the designation of Epstein-Barr virus-negative MZL as an uncommon form of monomorphic posttransplant lymphoproliferative disorders.

Tracheobronchial Tumors: Radiologic-Pathologic Correlation of Tumors and Mimics.

Tracheobronchial masses encompass a broad spectrum of entities, ranging from benign and malignant neoplasms to infectious and inflammatory processes. This article reviews the cross-sectional findings of tracheal tumors and tumor-like entities, correlates imaging findings with histologic pathology, and discusses pearls and pitfalls in accurately diagnosing and classifying tracheal tumors and mimics.

Distinct molecular profile of IRF4-rearranged large B-cell lymphoma.

Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma-related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.

Immunophenotyping of Acute Myeloid Leukemia.

Immunophenotyping by multiparameter flow cytometry is a rapid and efficient technique to simultaneously assess and correlate multiple individual cell properties like size and internal complexity along with antigen expression in a population of cells. This method is utilized for rapid characterization of the blasts and classification of acute myeloid leukemia (AML), in both the peripheral blood (PB) and bone marrow (BM). This technique is not only useful in the initial diagnosis but also in monitoring and determining prognosis of the disease through minimal residual disease (MRD) testing. This chapter provides an overview of procedures for specimen processing, staining, and immunophenotyping of AML and describes the principles of data analysis for AML classification and MRD testing.

Inherited thrombocytopenia and platelet disorders with germline predisposition to myeloid neoplasia.

Advances in molecular genetic sequencing techniques have contributed to the elucidation of previously unknown germline mutations responsible for inherited thrombocytopenia (IT). Regardless of age of presentation and severity of symptoms related to thrombocytopenia and/or platelet dysfunction, a subset of patients with IT are at increased risk of developing myeloid neoplasms during their life time, particularly those with germline autosomal dominant mutations in RUNX1, ANKRD26, and ETV6. Patients may present with isolated thrombocytopenia and megakaryocytic dysmorphia or atypia on baseline bone marrow evaluation, without constituting myelodysplasia (MDS). Bone marrow features may overlap with idiopathic thrombocytopenic purpura (ITP) or sporadic MDS leading to misdiagnosis. Progression to myelodysplastic syndrome/ acute myeloid leukemia (MDS/AML) may be accompanied by progressive bi- or pancytopenia, multilineage dysplasia, increased blasts, cytogenetic abnormalities, acquisition of bi-allelic mutations in the underlying gene with germline mutation, or additional somatic mutations in genes associated with myeloid malignancy. A subset of patients may present with MDS/AML at a young age, underscoring the growing concern for evaluating young patients with MDS/AML for germline mutations predisposing to myeloid neoplasm. Early recognition of germline mutation and predisposition to myeloid malignancy permits appropriate treatment, adequate monitoring for disease progression, proper donor selection for hematopoietic stem cell transplantation, as well as genetic counseling of the affected patients and their family members. Herein, we describe the clinical and diagnostic features of IT with germline mutations predisposing to myeloid neoplasms focusing on mutations involving RUNX1, ANKRD26, and ETV6.

The immune checkpoint molecules PD-1, PD-L1, TIM-3 and LAG-3 in diffuse large B-cell lymphoma.

Signaling through immune checkpoint receptors may lead to T-cell exhaustion and function as immune escape mechanisms in cancer. For diffuse large B-cell lymphoma (DLBCL), the mechanistic and prognostic importance of these markers on tumor cells and the tumor microenvironment remains unclear. We determined the immunohistochemical expression of PD-1, PD-L1, TIM-3, and LAG-3 on tumor cells and on tumor infiltrating lymphocytes (TILs) among 123 DLBCL patients. TIM-3 showed positive staining on tumor cells in 39% of DLBCL cases and PD-L1 expression was noted in 15% of cases. Both PD-1 and LAG-3 were positive on tumor cells in a minority of DLBCL cases (8.3% and 7.5%, respectively), but were more widely expressed on TILs in a correlated manner. With median follow-up of 44 months (n = 70, range 5-85), 4-year progression-free survival (PFS) and overall survival (OS) rates were significantly inferior among DLBCL patients with high vs low/negative TIM-3 expression (PFS: 23% [95% CI 7% to 46%] vs 60% [95% CI 43% to 74%], respectively, P = 0.008; OS: 30% [95% CI 10% to 53%] vs 74% [95% CI 58% to 85%], respectively, P = 0.006). Differences in OS remained significant when controlling for International Prognostic Index in Cox regression analyses (HR 3.49 [95% CI 1.40-6.15], P = 0.007). In addition, we observed that co-culture of DLBCL cell lines with primed T cells in the presence of anti-LAG-3 and anti-TIM-3 induced potent dose-dependent increases in in vitro cell death via AcellaTox and IL-2 ELISA assays, suggesting potent anti-tumor activity of these compounds.

The distribution of T-cell subsets and the expression of immune checkpoint receptors and ligands in patients with newly diagnosed and relapsed acute myeloid leukemia.

BACKGROUND: Phenotypic characterization of immune cells in the bone marrow (BM) of patients with acute myeloid leukemia (AML) is lacking. METHODS: T-cell infiltration was quantified on BM biopsies from 13 patients with AML, and flow cytometry was performed on BM aspirates (BMAs) from 107 patients with AML who received treatment at The University of Texas MD Anderson Cancer Center. The authors evaluated the expression of inhibitory receptors (programmed cell death protein 1 [PD1], cytotoxic T-lymphocyte antigen 4 [CTLA4], lymphocyte-activation gene 3 [LAG3], T-cell immunoglobulin and mucin-domain containing-3 [TIM3]) and stimulatory receptors (glucocorticoid-induced tumor necrosis factor receptor-related protein [GITR], OX40, 41BB [a type 2 transmembrane glycoprotein receptor], inducible T-cell costimulatory [ICOS]) on T-cell subsets and the expression of their ligands (41BBL, B7-1, B7-2, ICOSL, PD-L1, PD-L2, and OX40L) on AML blasts. Expression of these markers was correlated with patient age, karyotype, baseline next-generation sequencing for 28 myeloid-associated genes (including P53), and DNA methylation proteins (DNA methyltransferase 3α, isocitrate dehydrogenase 1[IDH1], IDH2, Tet methylcytosine dioxygenase 2 [TET2], and Fms-related tyrosine kinase 3 [FLT3]). RESULTS: On histochemistry evaluation, the T-cell population in BM appeared to be preserved in patients who had AML compared with healthy donors. The proportion of T-regulatory cells (Tregs) in BMAs was higher in patients with AML than in healthy donors. PD1-positive/OX40-positive T cells were more frequent in AML BMAs, and a higher frequency of PD1-positive/cluster of differentiation 8 (CD8)-positive T cells coexpressed TIM3 or LAG3. PD1-positive/CD8-positive T cells were more frequent in BMAs from patients who had multiply relapsed AML than in BMAs from those who had first relapsed or newly diagnosed AML. Blasts in BMAs from patients who had TP53-mutated AML were more frequently positive for PD-L1. CONCLUSIONS: The preserved T-cell population, the increased frequency of regulatory T cells, and the expression of targetable immune receptors in AML BMAs suggest a role for T-cell-harnessing therapies in AML.

Mantle Cell Lymphoma in the Thyroid: A Rare Presentation.

BACKGROUND: While 2% of all extranodal Non-Hodgkin Lymphomas present in the thyroid, there exists insufficient data to describe the incidence of mantle cell lymphoma in the thyroid. A case series of 1400 patients revealed that <1% of thyroid lymphomas may be MCL; hence better understanding of the disease course is essential. PATIENT FINDINGS: A 65-year-old female was referred for a multinodular goiter. Multiple fine needle aspirations from the dominant right nodule were consistent with Hashimoto's thyroiditis and flow cytometry was negative. Due to progressing dysphagia, she underwent total thyroidectomy. SUMMARY: Pathology revealed MCL with mantle zone growth pattern in the right thyroid. Flow cytometry showed monoclonal B cells comprising 9% of total cells. The Ki-67 index was 10%. She was diagnosed as having stage IIE MCL and offered conservative management by medical oncology, given that she had no B symptoms. CONCLUSION: Though chemotherapy is the treatment of choice in MCL, a subset of patients with low-grade disease may be observed. As in our patient, mantle zone growth pattern and a Ki-67 index < 10% suggest a favorable prognosis. A diagnosis of primary MCL in the thyroid remains rare and staging modalities as well as treatment options continue to evolve.

Diagnosis of Metaplastic Breast Carcinoma: Keratin OSCAR Versus Other Cytokeratins.

Metaplastic breast carcinoma (MBC) is a heterogenous group of tumors that diverge from conventional glandular differentiation. The metaplastic component can be focal or may be present purely posing diagnostic challenges. Since MBC may show focal immunostaining or may even be negative for some cytokeratins (CK), different CKs are often needed to prove their epithelial origin. OSCAR is a relatively new broad-spectrum anti-CK antibody. Thirty MBC cases diagnosed at our institution were retrieved, including 7 spindle cell carcinomas. Representative slides were immunostained for CK-OSCAR, CK-AE1/AE3, CAM5.2, CK-903, and CK5/6. Nineteen spindle cell lesions were used as controls, including 6 malignant and 10 borderline phyllodes tumor, 1 inflammatory pseudotumor, 1 solitary fibrous tumor, and 1 nodular fasciitis case. All 30 cases (100%) of metaplastic carcinomas were positive for CK-OSCAR, compared with 27/30 (90%, P=0.076) for CK-AE1/AE3, 21/30 (70%, P≤0.01) for CK-903, 19/30 (63.3%, P≤0.01) for CAM5.2, and 15/30 (50%, P≤0.01) for CK5/6. All control cases were negative for CK-OSCAR. All 7 spindle cell carcinomas were also positive for CK-OSCAR (100%) compared with 6/7 (85.7%) for CK-AE1/AE3, 4/7 (57%) for CK-903, 3/7 (42.8%) for CAM5.2, and 2/7 (28.5%) for CK5/6. Our data show that CK-OSCAR is more sensitive than other individual CKs in diagnosing MBC. Coupled with high specificity, CK-OSCAR may potentially be used in lieu of a panel of CKs to identify the epithelial origin of these tumors, especially in spindle cell tumors. This is particularly useful in limited core biopsy specimens, to help guide treatment and simultaneously lower testing costs.

Physiological measurements corroborate symptomatic improvement after therapeutic leukapheresis in a pregnant woman with chronic myelogenous leukemia.

Therapeutic leukapheresis can control the white blood cell count (WBC) of pregnant women with chronic myelogenous leukemia (CML) who have hyperleukocytosis without leukostasis. The medical justification for this treatment has not been objectively documented. We report a 27-year-old woman, diagnosed with CML at 10-week gestation, who developed severe dyspnea on exertion. A workup that included chest CT and echocardiography with a bubble study detected no cardiopulmonary pathology to explain her symptoms, and thus she was referred for leukapheresis. Prior to her first leukapheresis, which lowered her WBC from 154 × 10(3) /µL to 133 × 10(3) /µL, her oxygen saturation (SpO2 ) on room air decreased from 98 to 93% during 100 feet of slow ambulation and she was dyspneic. Just after the leukapheresis, her dyspnea on exertion was much improved and her SpO2 remained at 98% with repeat ambulation. Spirometry and lung volume studies obtained before and after her first leukapheresis demonstrated 32 and 31% improvements in forced vital capacity and forced expiratory volume in 1 s respectively, a 25% increase in functional residual capacity, and a 142% improvement in expiratory reserve volume. Residual volume decreased by almost 20%. Three times in a week, leukapheresis was continued until her WBC was controlled with interferon α-2b approximately 4 weeks later. Her dyspnea had completely resolved. She gave birth by elective caesarean section to a healthy boy at 32 weeks. Corroboration of symptom relief by leukapheresis with physiological data may justify such treatment in pregnant patients with CML. J. Clin. Apheresis 31:393-397, 2016. © 2015 Wiley Periodicals, Inc.

Automated red blood cell exchange for acute drug removal in a patient with sirolimus toxicity.

Sirolimus is an immunosuppressant used to prevent graft versus host disease in allogeneic hematopoietic stem cell transplant recipients. It has a large volume of distribution (12 ± 7.5 l/kg) and within the intravascular space ∼95% of it is bound to red blood cells. Because of potential toxic effects at high trough levels, therapeutic drug monitoring is recommended for sirolimus. We present a case of severe hepatic dysfunction due to Hepatitis B and sirolimus toxicity, in a 51-year-old male stem cell transplant recipient. An automated red cell exchange decreased his blood sirolimus level from 22.6 to 10.3 ng/ml (55% reduction) and improved his liver enzymes. Re-equilibration of sirolimus from other compartments to the blood necessitated a series of four red cell exchanges, after which the sirolimus level was 4.7 ng/ml. Although the patient ultimately succumbed to multiorgan failure, red cell exchange may be considered for acute removal of sirolimus in selected patients.