The impact of histological grade on outcomes in follicular lymphoma: An analysis of patients in the SEER database in the context of evolving disease classification and treatment

Currently, there is no convincing evidence that the grade of follicular lymphoma (FL) impacts patient outcome. We correlated grades in 33 925 patients with nodal FL during 1992-2018 in the SEER database with disease-specific survival (DSS) and overall survival (OS). Patients with FL grade 3 had lower DSS and OS as compared to FL grades 1-2. During 1992-2005, the 10-year DSS for patients with FL grades 3 and grades 1-2 were 68.6%, and 71.4%, respectively, and in 2006-2018, they were 77.7% and 82.6%, respectively. The 10-year OS estimates in 1992-2005 were 49.9% and 54.2% for grade 3 and grades 1-2 respectively, and in 2006-2018, they were 59.1% and 63.5% for grade 3 and grades 1-2, respectively. After adjustment for stage and age, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 during 1992-2005 were 1.09 (1.02-1.16) and 1.07 (1.02-1.12), respectively, compared to FL grades 1-2; and during 2006-2018, the hazard ratios for death due to FL and death from any cause for patients with FL grade 3 were 1.34 (1.22-1.45) and 1.16 (1.10-1.23), respectively compared to FL grades 1-2. The grade of FL is an important determinant of disease biology.

Naive T-Cell Depletion to Prevent Chronic Graft-Versus-Host Disease

PURPOSE

Graft-versus-host disease (GVHD) causes morbidity and mortality following allogeneic hematopoietic cell transplantation. Naive T cells (TN) cause severe GVHD in murine models. We evaluated chronic GVHD (cGVHD) and other outcomes in three phase II clinical trials of TN-depletion of peripheral blood stem-cell (PBSC) grafts.

METHODS

One hundred thirty-eight patients with acute leukemia received TN-depleted PBSC from HLA-matched related or unrelated donors following conditioning with high- or intermediate-dose total-body irradiation and chemotherapy. GVHD prophylaxis was with tacrolimus, with or without methotrexate or mycophenolate mofetil. Subjects received CD34-selected PBSC and a defined dose of memory T cells depleted of TN. Median follow-up was 4 years. The primary outcome of the analysis of cumulative data from the three trials was cGVHD.

RESULTS

cGVHD was very infrequent and mild (3-year cumulative incidence total, 7% [95% CI, 2 to 11]; moderate, 1% [95% CI, 0 to 2]; severe, 0%). Grade III and IV acute GVHD (aGVHD) occurred in 4% (95% CI, 1 to 8) and 0%, respectively. The cumulative incidence of grade II aGVHD, which was mostly stage 1 upper gastrointestinal GVHD, was 71% (95% CI, 64 to 79). Recipients of matched related donor and matched unrelated donor grafts had similar rates of grade III aGVHD (5% [95% CI, 0 to 9] and 4% [95% CI, 0 to 9]) and cGVHD (7% [95% CI, 2 to 13] and 6% [95% CI, 0 to 12]). Overall survival, cGVHD-free, relapse-free survival, relapse, and nonrelapse mortality were, respectively, 77% (95% CI, 71 to 85), 68% (95% CI, 61 to 76), 23% (95% CI, 16 to 30), and 8% (95% CI, 3 to 13) at 3 years.

CONCLUSION

Depletion of TN from PBSC allografts results in very low incidences of severe acute and any cGVHD, without apparent excess risks of relapse or nonrelapse mortality, distinguishing this novel graft engineering strategy from other hematopoietic cell transplantation approaches.

TMOD-30. NTRK2 SPLICE VARIANT, TRKB.T1, LINKS NEUROBIOLOGY, EMBRYONIC DEVELOPMENT, AND ONCOGENESIS

Temporally regulated alternative splicing choices are vital for proper development yet the wrong splice choice may be detrimental. Here we highlight a novel role for the neurotrophin receptor splice variant TrkB.T1 in neurodevelopment, embryogenesis, transformation, and oncogenesis across multiple tumor types in both humans and mice. TrkB.T1 is the predominant NTRK2 isoform across embryonic organogenesis and is highly expressed in a wide range of adult and pediatric tumors. Further, forced expression of TrkB.T1 causes multiple solid and non-solid tumors in mice in the context of tumor suppressor loss. These results highlight a unique role for the neurotrophin receptor splicing in development and oncogenesis and underscore the need for considering alternative splicing and transcript level data in neuroscience, developmental biology, and oncology research.

G9a/GLP-dependent histone H3K9me2 patterning during human hematopoietic stem cell lineage commitment

G9a and GLP are conserved protein methyltransferases that play key roles during mammalian development through mono- and dimethylation of histone H3 Lys 9 (H3K9me1/2), modifications associated with transcriptional repression. During embryogenesis, large H3K9me2 chromatin territories arise that have been proposed to reinforce lineage choice by affecting high-order chromatin structure. Here we report that in adult human hematopoietic stem and progenitor cells (HSPCs), H3K9me2 chromatin territories are absent in primitive cells and are formed de novo during lineage commitment. In committed HSPCs, G9a/GLP activity nucleates H3K9me2 marks at CpG islands and other genomic sites within genic regions, which then spread across most genic regions during differentiation. Immunofluorescence assays revealed the emergence of H3K9me2 nuclear speckles in committed HSPCs, consistent with progressive marking. Moreover, gene expression analysis indicated that G9a/GLP activity suppresses promiscuous transcription of lineage-affiliated genes and certain gene clusters, suggestive of regulation of HSPC chromatin structure. Remarkably, HSPCs continuously treated with UNC0638, a G9a/GLP small molecular inhibitor, better retain stem cell-like phenotypes and function during in vitro expansion. These results suggest that G9a/GLP activity promotes progressive H3K9me2 patterning during HSPC lineage specification and that its inhibition delays HSPC lineage commitment. They also inform clinical manipulation of donor-derived HSPCs.

Cyclin-A1 expression in acute myeloid leukemia stem cells and its representation as an immunogenic antigen that can be targeted by cytotoxic T cells

2523

Background: Targeted T-cell therapy represents a more specific and less toxic alternative to allogeneic stem cell transplantation for providing a cytotoxic anti-leukemic response to eliminate the leukemic stem cell (LSC) compartment in acute myeloid leukemia (AML). The aim of this study was to identify a leukemia-associated antigen that is both immunogenic and exhibits selective high expression in AML LSCs. Methods: Expression microarrays of leukemic and normal cells were used to identify suitable candidate genes. Cyclin-A1 appeared to be differentially expressed, and was further analyzed by quantitative RT-PCR, intracellular FACS staining, and immunofluorescence microscopy. T-cell clones specific for cyclin-A1 were generated by stimulation in vitro with an overlapping peptide library, followed by cloning of responding cells. Specificity of the clones was documented by intracellular IFNg and tetramer staining. Cytotoxicity was determined by chromium release and caspase-3 cleavage assays. Results: To identify target candidates with a suitable expression pattern, microarray data from LSCs, hematopoietic cells and healthy tissues were compared. Cyclin-A1 was found to be selectively expressed in LSCs of >50% of AML patients, but minimally expressed in normal tissues with exception of testis. Using dendritic cells and monocytes pulsed with a cyclin-A1 peptide library, T-cells were generated against eight cyclin-A1 oligopeptides. Two HLA A2-restricted epitopes were further characterized, and specific T-cell clones recognized both peptide-pulsed target cells and the HLA A2-positive AML line THP-1. Furthermore, cyclin-A1-specific CD8 T-cells lysed primary AML cells. Conclusions: Cyclin-A1, known to be important in meiosis, is expressed in AML LSCs and testis and can be targeted by T-cells. Thus, cyclin-A1 is the first prototypic LSC-associated leukemia-testis-antigen. Cyclin-A1 already has been shown to be leukemogenic in mice and to promote proliferation and survival in AML blasts. This pro-oncogenic activity, together with high expression levels and a multitude of immunogenic epitopes, make it a promising target for T-cell based therapy approaches.

Localization of erythropoietin receptor mRNA in primary breast tumors by laser capture microdissection

e22036

Background: Adverse effects of erythropoiesis stimulating agents on tumor progression and/or survival were observed in recent Phase III clinical trials, however, mechanisms are not understood. Whether tumor erythropoietin receptor (EpoR) expression is associated with erythropoietin-dependent tumor progression remains unclear, owing in part to the lack of specificity of commercial antibodies for protein detection. To overcome issues of protein detection, we previously optimized a quantitative RTPCR approach for reliable measurements of low level EpoR mRNA in primary tumor samples, and observed a 30-fold range of EpoR expression among panels of both breast and head and neck cancer samples. Methods: To test whether EpoR mRNA is expressed in tumor epithelial cells, we performed laser capture microdissection to fractionate 3 breast tumors into tumor epithelial enriched vs. depleted fractions. In each fraction, lineage marker and EpoR mRNA expression was normalized to 3 endogenous control genes. Results: Vascular endothelial markers in tumor epithelial-enriched fractions were reduced by an average of 15.3-fold (vascular endothelial cadherin) and 18.5-fold (platelet cell adhesion molecule 1) while the stromal marker vimentin was reduced by 14.7-fold. EpoR expression was enriched by 4.9-, 7.2-, and 1.1-fold in epithelial enriched fractions. Conclusions: Despite the depletion of endothelial cells, EpoR mRNA was at the same level or enriched in tumor epithelial fractions. These results demonstrate that malignant epithelial cells are a major source of EpoR mRNA in primary tumors. Applying this approach to additional breast cancer specimens as well as other cancer types will improve our understanding of erythropoietin-associated tumor progression.

[Table: see text]

Classification of child and adolescent eating disturbances. Workgroup for Classification of Eating Disorders in Children and Adolescents (WCEDCA)

OBJECTIVE

: The purpose of this article is to summarize major conceptual and clinical variables related to age-appropriate and developmentally appropriate classification of eating problems and disorders in children and adolescents.

METHOD

A review of current classifications and related literature in child development is provided. Problems with current classification schemes are identified and discussed.

RESULTS

Current classifications are inadequate to address the clinical and research needs of children and adolescents with eating disturbances and disorders.

CONCLUSION

A range of possible changes in classification strategies for eating disorders in children and adolescents are described.

Long-term and therapeutic-level hepatic gene expression of human factor IX after naked plasmid transfer in vivo

Naked DNA transfer of a high-expressing human factor IX (hFIX) plasmid yielded long-term (over 1 1/2 years) and therapeutic-level (0.5-2 microg/ml) gene expression of hFIX from mouse livers. The expression cassette contained a hepatic locus control region from the ApoE gene locus, an alpha1-anti-trypsin promoter, hFIX cDNA, a portion of the hFIX first intron, and a bovine growth hormone polyadenylation signal. In contrast, a hFIX plasmid containing the expression cassette without effective regulatory elements produced initially low-level gene expression that rapidly declined to undetectable levels. Southern analyses of the cellular DNA indicated that the majority of the input genome from either vector persisted as episomal forms of the original plasmids. Together with RT-PCR analyses of the transcripts, these data indicated that at least two processes are critical for sustained gene expression: persistence of vector DNA and transcriptional/posttranscriptional activation. Liver regeneration after partial hepatectomy resulted in a significant decline in transgene expression, further suggestive of decreased episomal plasmid maintenance rather than transgene integration. Transaminase levels and liver histology showed that rapid intravenous plasmid injection into mice induced transient focal acute liver damage (< 5% of hepatocytes), which was rapidly repaired within 3 to 10 days and resulted thereafter in histologically normal tissue. No significant differences were observed between rapid injection of plasmid and saline control solutions. Transient, very low level antibodies directed against hFIX did not prevent the circulation of therapeutic levels of the protein. Gene transfer of hFIX plasmid DNA into liver elicited neither transgene-specific cytotoxic effect nor long-term toxicity. These results demonstrate that long-term expression of hFIX can be achieved by nonviral plasmid transfer and suggest that this occurs independent of integration.

Immunohistochemical localization of ubiquitin cross-reactive protein in human tissues

Ubiquitin cross-reactive protein (UCRP) is an interferon-inducible ubiquitin homologue which is constitutively present in cells and can be conjugated to other proteins. Using a characterized polyclonal antiserum to UCRP, immunohistochemical localization of UCRP was performed on paraffin-processed normal human tissues and in human tissues known to contain ubiquitinated intracellular inclusions. The antibody to UCRP immunostained lymphoid cells, striated and smooth muscle, several epithelia, and neurons. The level of staining varied greatly between tissues but was in a consistent punctate pattern. Localization to neuromuscular junctions and striations is similar to that described for antisera to ubiquitin-protein conjugates. Inclusion bodies characterized by immunoreactivity to anti-ubiquitin were not detected by the antibody to UCRP. Importantly, because UCRP may also be detected by antisera to conjugated ubiquitin, future studies on the distribution of ubiquitin in tissue sections must now take account of possible cross-reactivity with UCRP.