Search

In collaboration with the American College of Veterinary Pathologists

Background Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is an RNA-binding protein that is aberrantly expressed in cancers. We and others have previously shown that reduced hnRNP K expression downmodulates tumor-suppressive programs. However, overexpression of hnRNP K is the more commonly observed clinical phenomenon, yet its functional consequences and clinical significance remain unknown. Methods Clinical implications of hnRNP K overexpression were examined through immunohistochemistry on samples from patients with diffuse large B-cell lymphoma who did not harbor MYC alterations (n = 75). A novel transgenic mouse model that overexpresses hnRNP K specifically in B cells was generated to directly examine the role of hnRNP K overexpression in mice (three transgenic lines). Molecular consequences of hnRNP K overexpression were determined through proteomics, formaldehyde-RNA-immunoprecipitation sequencing, and biochemical assays. Therapeutic response to BET-bromodomain inhibition in the context of hnRNP K overexpression was evaluated in vitro and in vivo (n = 3 per group). All statistical tests were two-sided. Results hnRNP K is overexpressed in diffuse large B-cell lymphoma patients without MYC genomic alterations. This overexpression is associated with dismal overall survival and progression-free survival (P Conclusion Our findings indicate that hnRNP K is a bona fide oncogene when overexpressed and represents a novel mechanism for c-Myc activation in the absence of MYC lesions.

The serine protease inhibitor, elafin, is a critical component of the epithelial barrier against neutrophil elastase (NE). Elafin is downregulated in the majority of breast cancer cell lines compared with normal human mammary epithelial cells (HMECs). Here, we evaluated the role of elafin and NE on proliferation and tumorigenesis. Elafin is induced in growth factor-deprived HMECs as they enter a quiescent (G0) state, suggesting that elafin is a counterbalance against the mitogenic effects of NE in G0 HMECs. Stable knockdown of elafin compromises the ability of HMECs to maintain G0 arrest during long-term growth factor deprivation; this effect can be reversed by re-expression of wild-type elafin but not elafin-M25G lacking protease inhibitory function. These results suggest that NE, which is largely contributed by activated neutrophils in the tumor microenvironment, may be negatively regulating the ability of elafin to arrest cells in G0. In fact when purified NE was added to elafin-knocked down HMECs, these cells demonstrated greater sensitivity to the growth-promoting effects of purified NE. Activation of ERK signaling, downstream of toll-like receptor 4, was essential to the mitogenic effect of NE on HMECs. These findings were next translated to patient samples. Immunohistochemical analysis of normal breast tissue revealed robust elafin expression in the mammary epithelium; however, elafin expression was dramatically downregulated in a significant proportion of human breast tumor specimens. The loss of elafin expression during breast cancer progression may promote tumor growth as a consequence of increased NE activity. To address the role of NE in mammary tumorigenesis, we next examined whether deregulated NE activity enhances mammary tumor growth. NE knockout in the C3(1)TAg mouse model of mammary tumorigenesis suppressed proliferation and reduced the kinetics of tumor growth. Overall, the imbalance between NE and its inhibitors, such as elafin, presents an important therapeutic target in breast cancer.

Mdm2, an E3 ubiquitin ligase, negatively regulates the tumour suppressor p53. In this study we utilized a conditional Mdm2 allele, Mdm2(FM) , and a CAG-CreER tamoxifen-inducible recombination system to examine the effects of global Mdm2 loss in adult mice. Two different tamoxifen injection regimens caused 100% lethality of Mdm2(FM) (/-) ;CAG-CreER mice; both radio-sensitive and radio-insensitive tissues were impaired. Strikingly, a large number of radio-insensitive tissues, including the kidney, liver, heart, retina and hippocampus, exhibited various pathological defects. Similar tamoxifen injections in older (16-18 month-old) Mdm2(FM) (/-) ;CAG-CreER mice yielded abnormalities only in the kidney. In addition, transcriptional activation of Cdkn1a (p21), Bbc3 (Puma) and multiple senescence markers in young (2-4 month-old) mice following loss of Mdm2 was dampened in older mice. All phenotypes were p53-dependent, as Mdm2(FM) (/-) ;Trp53(-/-) ;CAG-CreER mice subjected to the same tamoxifen regimens were normal. Our findings implicate numerous possible toxicities in many normal tissues upon use of cancer therapies that aim to inhibit Mdm2 in tumours with wild-type p53.

This report describes a neoplasm involving the adrenal cortex of an aged female African clawed frog (Xenopus laevis). The animal was found to be in poor body condition and was subsequently...

hnRNP K is an RNA binding protein that controls a multitude of cellular processes and is aberrantly expressed in cancers. We have previously shown that hnRNP K functions as a haploinsufficient tumor suppressor in AML patients with 9q deletions. However, overexpression of hnRNP K is the more commonly observed clinical phenomenon. We have recently discovered that hnRNP K overexpression in patients with diffuse large B-cell lymphoma correlates with dismal outcomes and directly resulted in the development of lymphomas in transgenic mice. To understand the mechanistic basis for the oncogenicity of hnRNP K overexpression and to identify therapeutic vulnerabilities, we performed RNA-sequencing, RNA immunoprecipitation following by sequencing (RIP-Seq), mass spectrometry, and polysome assays. We observed that hnRNP K regulates both global transcription and translational processes within the cell via modulation of 7SK and translation initiation proteins (such as the eIFs and PABP), respectively. Consequently, we hypothesized that aberrant hnRNP K expression primarily perturbs oncogenes with short half-lives. Mechanistically, we identified that hnRNP K binds to the RNA and regulates the expression of a plethora of critical oncogenes and tumor suppressors involved in hematologic malignancies such as c-Myc, RUNX1, and Cyclin D1. As proof of concept for clinical applications, we have demonstrated that hnRNP K-driven c-Myc overexpression renders tumors susceptible to bromodomain inhibition. Given that hnRNP K directs global transcription and translation, it is likely that hnRNP K overexpressing tumors will also be sensitive to transcriptional and translational inhibitors such as CDK9 inhibitors and omacetaxine mepesuccinate, respectively. However, since hnRNP K also regulates a plethora of additional cellular processes that extend far beyond mRNA and protein synthesis, there is a need to develop hnRNP K-specific inhibitors that will only target these activities. Thus, we have recently begun to identify small molecule compounds that can directly inhibit hnRNP K-RNA binding function on specific targets using an in vitro fluorescent binding assay. Using this assay, we are currently screening a library of 70,000 small molecule compounds to identify agents that can prevent hnRNP K-RNA interactions. In summary, we have established that hnRNP K is a bona fide oncogene that drives lymphomagenesis. Global analyses have revealed therapeutic vulnerabilities of hnRNP K overexpressing tumors. Furthermore, using our in vitro RNA binding assays, we anticipate identification of novel hnRNP K-specific inhibitors. Disclosures No relevant conflicts of interest to declare.

Objective The objectives of this study were to evaluate tensile strength retention of polydioxanone as a function of time in a swine venous system and to assess the feasibility of an absorbable inferior vena cava (IVC) filter made from polydioxanone in a pilot swine study. Methods Twenty strands (60 cm each) of size 1 polydioxanone absorbable suture (Ethicon, Somerville, NJ) were placed in the central venous system of domestic swine. Strands were harvested at weekly intervals during 10 weeks for tensile strength testing. Results were compared with control samples obtained from an in vitro engineered circulation system containing sodium phosphate buffer solution. Three IVC filters braided from polydioxanone suture were also catheter deployed in three swine to assess absorbable IVC filter feasibility. Results Polydioxanone retained 82% tensile strength in vitro vs 79% in vivo at 35 days (P > .22), the desired prophylactic duration. For IVC filters made from polydioxanone, technical success of placement was achieved in all three filters deployed (100%). Autologous thrombus deployed inferior to the filter remained trapped in the filter until thrombus resorption, with no evidence of pulmonary emboli on follow-up computed tomography. There were no instances of caval penetration, filter-induced IVC thrombosis, filter migration, or tilt >15 degrees with imaging and clinical follow-up carried out to 32 weeks. Conclusions Strength retention of polydioxanone suture placed in the venous system of swine is similar to earlier in vitro studies out to 10 weeks (P > .06 for all weeks) and is more than sufficient (8.20 ± 0.37 kg mean load at break for size 1) to trap thrombus. Pilot animal study suggests that an absorbable polydioxanone IVC filter can be catheter deployed to capture and to hold iatrogenically administered autologous thrombus through resorption.

Here, we report that polyethylene glycol (PEG)-coated copper(II) sulfide nanoparticles (PEG-CuS NPs) with their peak absorption tuned to 1064 nm could be used both as a contrast agent for photoacoustic tomographic imaging of mouse tumor vasculature and as a mediator for confined photothermolysis of tumor cells in an orthotopic syngeneic 4T1 breast tumor model. PEG-CuS NPs showed stronger photoacoustic signal than hollow gold nanospheres and single-wall carbon nanotubes at 1064 nm. MicroPET imaging of 4T1 tumor-bearing mice showed a gradual accumulation of the NPs in the tumor over time. About 6.5% of injected dose were taken up in each gram of tumor tissue at 24 h after intravenous injection of (64)Cu-labeled PEG-CuS NPs. For both photoacoustic imaging and therapeutic studies, nanosecond (ns)-pulsed laser was delivered with Q-switched Nd:YAG at a wavelength of 1064 nm. Unlike conventional photothermal ablation therapy mediated by continuous wave laser with which heat could spread to the surrounding normal tissue, interaction of CuS NPs with short pulsed laser deliver heat rapidly to the treatment volume keeping the thermal damage confined to the target tissues. Our data demonstrated that it is possible to use a single-compartment nanoplatform to achieve both photoacoustic tomography and highly selective tumor destruction at 1064 nm in small animals.

Deletion of the short-arm of chromosome 17 (17p-) is one of the most critical genetic alterations used in chronic lymphocytic leukemia (CLL) risk stratification. The tumor suppressor TP53 maps to this region, and its loss or mutation accelerates CLL progression, hampers response to chemotherapy and shortens survival. Although florescent in situ hybridization analyses for 17p deletions are routinely performed during clinical diagnoses, p53 mutational status is often unexamined. Given the limited clinical data that exists for frontline treatment of patients with CLL harboring TP53 mutations, there is a need to understand the biology of CLL with TP53 mutations and identify treatment strategies for this subset of patients. Herein, we used a CLL mouse model (Eμ-TCL1) harboring one of the most common TP53 hot-spot mutations observed in CLL (p53R172H, corresponding to p53R175H in humans) to evaluate its impact on disease progression, survival, response to therapy and loss of the remaining wild-type Trp53 allele following ibrutinib treatment. We show that ibrutinib was effective in increasing survival, activating cellular programs outside the p53 pathway and did not place selective pressure on the remaining wild-type Trp53 allele. These data provide evidence that ibrutinib acts as an effective treatment for aggressive forms of CLL with TP53 mutations.

Deletion of the 9q21.32 locus is observed in some patients with AML, suggesting an undescribed tumor suppressor resides in this region. HNRNPK is an attractive candidate, as it is one of six genes mapped to this region and is thought to drive AML progression when mutated. Mechanistically, hnRNP K functions as a DNA and RNA binding protein that transcriptionally and translationally governs gene expression. Together, these findings suggest hnRNP K may serve as a currently uncharacterized tumor suppressor and that its haploinsufficiency plays a pivotal role in AML progression. To interrogate a potential relationship between HNRNPK haploinsufficiency and AML, we performed fluorescence in situ hybridization (FISH) using bone marrow aspirates from newly diagnosed AML patients. These analyses revealed the HNRNPK gene is specifically lost in a subset of AML patients and results in a significant decrease in HNRNP K expression in CD34+ cells from patients harboring this deletion (Fig. 1A). To directly examine the potential tumor-suppressive activities of hnRNP K in vivo, we generated a haploinsufficient hnRNP K (hnRNP K+/-) mouse model. hnRNP K haploinsufficiency resulted in reduced survival and hematologic neoplasms with marked genomic instability (Fig. 1B). Critically, hnRNP K+/- hematopoietic stem progenitor cells (HSPCs) were transplantable and had the capacity to develop hematopoietic neoplasms in recipient mice. To examine the mechanism driving these tumor phenotypes, we analyzed the cytokine profile of hnRNP K+/- mice. This examination revealed that several critical pro-proliferation and myeloid differentiation cytokines were significantly overexpressed (e.g.; IL-3, IL-6, GM-CSF, and G-CSF), resulting in activation of the JAK-STAT pathway (Fig. 1C). Next, we analyzed the proliferation potential of hnRNP K+/- HSPCs and mouse embryo fibroblast (MEFs) using cell based studies. Here, we observed a significant increase in the number of colony forming units in HSPCs and proliferation potential in both HSPC and MEFs between cells from hnRNP K+/- and wild type mice. Critical to the proliferative advantaged observed in hnRNP K+/- cells, activation of the p53/p21 pathway was significantly reduced in hnRNP K+/- MEFs following exposure to ionizing radiation. To more fully explore the molecular mechanisms responsible for these phenotypes, we performed whole-transcriptome analyses. Pathway analysis revealed that hnRNP K haploinsufficiency resulted in the attenuation of critical p53- and C/EBP pathways (Fig. 1D). We next validated expression changes in critical genes known to govern tumorigenesis, myeloid differentiation, and proliferation. Here, we observed a significantly down regulation in C/EBPa, C/EBPβ, and p21 at both the transcript and protein level (Fig. 1E-F). To assess the relationship between hnRNP K expression and regulation of these genes, we performed Chromatin Immunoprecipitation (ChIP) and RNA immunoprecipitation (RIP) analyses. ChIP analysis revealed the transcriptional activities of hnRNP K through its direct interaction with the promoter of these genes. Critically, reduced hnRNP K expression significantly diminished these interactions, resulting in their reduced expression. Interestingly, RIP analyses revealed that hnRNP K may also specifically regulate the expression of the tumor suppressive p42 isoform of C/EBPα through its translation regulation of the C/EBPα transcript. Together, these results suggest hnRNP K is a bona fide tumor suppressor and that its loss contributes to the development of hematologic malignancies. Given its critical regulation of the p53 pathway, drug therapies targeting the p53 pathway may serve as efficacious treatment options for patients with 9q deletions. To address this, we are currently examining the efficacy of Mdm2-p53 antagonist (e.g.; Nutlin-3 and AMG-232) using primary patient samples and primary cells from hnRNP K+/- mice with hematologic malignancies. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

NPM1 mutations are one of the most common alterations observed in acute myeloid leukemia (AML). When coupled with wild type FLT3 status in cytogenetically normal (CN) patients, NPM1 mutations confer favorable prognoses compared with other alterations. However, a subset of CN NPM1Mut :FLT3Wt patients with AML have dismal outcomes, suggesting that uncharacterized alterations influence the outcomes in these patients. To address this, we performed reverse phase protein array (RPPA) analysis on CD34+ bone marrow cells isolated from 43 de novo CN NPM1Mut :FLT3Wt AML patient as well as healthy donor controls. Through these analyses, we observed that overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K) associated with extremely poor outcomes within this a priori favorable prognostic group, as almost 90% of patients with increased hnRNP K expression died within 12 months of diagnosis while nearly 40% of individuals with normal hnRNP K expression survived seven years (Figure 1A). hnRNP K is a multifunctional RNA and DNA binding protein whose expression is often altered in cancers. To directly examine the functional relationship between hnRNP K overexpression and mutant NPM1 in hematologic malignancies, we generated tissue-specific transgenic mouse models with the ability to overexpress hnRNP K (hnRNP KTg) in the presence or absence of mutant Npm1 (Npm1Tg). By crossing these mice with Vav-Cre expressing mice, we specifically activated hnRNP K overexpression and mutant NPM1 expression in the hematological compartment. Using Lin-CD117+ hematopoietic stem cells (HSCs) from hnRNP KTg, Npm1Tg, and hnRNP KTg;Npm1Tg mice, we observed significant changes in differentiation and proliferation potential in colony formation assays. Overexpression of hnRNP K alone significantly increased the number of colonies compared to wild type and Npm1Tg HSCs while expression of mutant Npm1Tg resulted in increased numbers of cells compared to wild type and hnRNP KTg HSCs. Importantly, the combination of hnRNP K overexpression and mutant Npm1 resulted in a cumulative increase in both the number of colonies and number of cells, indicating that hnRNP K and mutant NPM1 cooperate to dictate differentiation and proliferation potential in HSCs (Figure 1B). Next, we examined the in vivo impact of hnRNP K overexpression and mutant Npm1 expression by analyzing the bone marrows of Npm Tg, hnRNP KTg, and Npm1Tg;hnRNP KTg mice. Within the first six months of life, these mice rapidly developed significant myeloid hyperplasias as determined by flow cytometry and pathologic analyses (Figure 1C). Together, our findings reveal that mutant Npm1 and hnRNP K overexpression result in similar myeloid phenotypes. However, these genetic alterations are also cooperative, suggesting both increased hnRNP K expression and mutant NPM1 synergize to impact hematopoietic phenotypes and drive AML progression through similar pathways but potentially via unique molecular processes. Currently, we are investigating the direct interaction and global relationship between hnRNP K and mutant Npm1 in regulating tumor suppressor and oncogenic programs (e.g.; p53- and c-Myc pathways). Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

In acute myeloid leukemia (AML), numerous genetic and epigenetic changes have been identified that result in loss of differentiation, apoptosis, and cell cycle arrest. In contrast, changes in protein expression are not as well characterized. To address these deficiencies, we performed RPPA analysis on 415 de novo AML patient samples and identified increased expression of heterogeneous nuclear ribonucleoprotein K (hnRNP K) as a predictor of poor outcome. These elevated hnRNP K levels were most predictive in AML patients who also harbored mutant NPM1 and wild type FLT3. While NPM1MUT/FLT3WT status typically confers favorable prognoses, increased hnRNP K expression negated this effect, as greater than 90% of NPM1MUT/FLT3WTindividuals with elevated hnRNP K expression died within 12 months. hnRNP K is a multifunctional protein that controls basic cellular functions through RNA, DNA, and protein-protein interactions (e.g.; p53) and whose expression is often altered in cancer. To examine the biological role of hnRNP K in vivo, we generated mouse models that either increase or decrease hnRNP K expression. Biallelic hnRNP K deletion results in embryonic lethality, while haploinsufficiency (hnRNP K+/-) results in a partial neonatal lethal phenotype. Surviving hnRNP K+/- mice have reduced survival and are more tumor prone than wild type mice (Fig. 1A and B). Analysis of hnRNP K+/- peripheral blood and bone marrow revealed significant hematologic neoplasms, including myeloid hyperplasias. The myeloid expansion appears to be a consequence of defects in proliferation (decreased p21) and differentiation (increased C/EBPβ and ε expression and activation of Stat3) pathways (Fig. 1C). In vitro studies using hnRNP K+/- hematopoietic stem cells (HSC) and mouse embryo fibroblast (MEFs) likewise revealed defects in differentiation and proliferation potential. HSC were used in burst formation unit erythroid colony assays (BFU-E). In these experiments, we observed a significant increase in the number of hnRNP K+/- cells and immature cells as compared to wild type BFU-E (Fig. 2A and B). RT-PCR analysis of BFU-Es revealed deregulation of p53/p21 and TGFβ- pathway genes (Fig. 2C). Similarly, hnRNP K+/- MEFs failed to properly activate the p53/p21 pathway following exposure to ionizing radiation (Fig. 2D). In contrast to diminished hnRNP K expression, overexpression results in activation of pro-growth and self-renewal pathway proteins in both humans and mice. RPPA analysis of AML patient samples that overexpress hnRNP K, as well as transient overexpression of hnRNP K in cell lines, results in increased expression of c-Myc. To directly examine the impact of hnRNP K overexpression in vivo, we generated transgenic mouse models. hnRNPK-transgenic mice express elevated levels of hnRNP K and are tumor prone. While it is tempting to classify hnRNP K as either an oncogene or a tumor suppressor, our haploinsufficiency and overexpression data seem to indicate that abnormal expression in either direction has a significant impact on tumor predisposition. Mechanistically, hnRNP Kappears to be an influential regulator involved in proliferation, self-renewal, and differential programs. The functional consequences reduced and overexpression of hnRNP K is currently under investigation. Given the clinical relationship between hnRNP K expression and NPM1 status, it is our next priority to evaluate the synergistic relationship between hnRNPK and NPM1 in regulating hematopoiesis and AML progression. To this end, we have taken two approaches. The first is to identify the biological relationship between these two proteins. To do this, we are attempting to generate double heterozygous NPM1+/- and hnRNP K+/- mice. However, thus far, double haploinsufficiency (NPM1+/-hnRNP K+/-) appears to result in a synthetic lethal phenotype. This surprising result highlights the unique in vivo relationship between these proteins. In the second approach, we have generated hnRNP K-transgenic (hnRNP KTG) mice on a mutant NPM1 (NPM1Mut) background. This hnRNPKTG: NPM1Mut mouse model specifically recapitulates the genetic alterations observed in the AML human patients who have reduction in survival. Together, these models will allow us to determine the relationship between these two proteins and examine how they impact leukemogenesis. Disclosures: No relevant conflicts of interest to declare.

SummaryhnRNP K regulates cellular programs, and changes in its expression and mutational status have been implicated in neoplastic malignancies. To directly examine its role in tumorigenesis, we generated a mouse model harboring an Hnrnpk knockout allele (Hnrnpk+/−). Hnrnpk haploinsufficiency resulted in reduced survival, increased tumor formation, genomic instability, and the development of transplantable hematopoietic neoplasms with myeloproliferation. Reduced hnRNP K expression attenuated p21 activation, downregulated C/EBP levels, and activated STAT3 signaling. Additionally, analysis of samples from primary acute myeloid leukemia patients harboring a partial deletion of chromosome 9 revealed a significant decrease in HNRNPK expression. Together, these data implicate hnRNP K in the development of hematological disorders and suggest hnRNP K acts as a tumor suppressor.

Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is an RNA and DNA binding protein that regulates critical pathways controlling differentiation and proliferation programs. While alterations in hnRNP K expression are associated with neoplastic malignancies, we currently do not understand how changes in hnRNP K expression contribute to tumor phenotypes in vivo. Previous biochemical and cell line studies demonstrate that hnRNP K transcriptionally regulates p53-dependent activities, suggesting it functions as a potential tumor suppressor. However, hnRNP K has also been shown to positively regulate c-Myc expression, indicating it may behave as an oncogene. The HNRNP K gene maps to a region of chromosome 9 (9q21.32), which is lost in a subset of patients with acute myeloid leukemia (AML). RNA expression analyses of patient samples with AML that harbor 9q21.32 deletions revealed a significant reduction in HNRNP K expression compared to wild type control samples, supporting the notion that hnRNP K acts as a tumor suppressor (Figure 1A). However, patients with AML who do not harbor a 9q21.32 deletion displayed a significant increase in hnRNP K expression (Figure 1A). Thus, to examine the association between altered hnRNP K expression and disease status in patients with AML, we performed reverse phase protein array (RPPA) analysis on CD34+ bone marrow cells from 415 de novo AML patient as well as healthy donor controls. Interestingly, we observed a significant correlation between elevated hnRNP K levels and poor outcomes, which supports the idea that hnRNP K has oncogenic potential (Figure 1A). Together, these observations indicate that any change in hnRNP K expression may contribute to the etiology of AML and supports the idea that hnRNP K may potentially act as either a haploinsufficient tumor suppressor or oncogene in AML. To directly interrogate these possibilities in vivo, we generated mouse models that either harbor a deletion of one hnRNP K allele (hnRNP K+/-) or overexpressed hnRNP K (hnRNP KTg) in the hematological compartment. Western blot analyses demonstrated that hnRNP K haploinsufficiency results in a significant reduction in hnRNP K expression while tissue-specific activation of hnRNP K resulted in overexpression of hnRNP K. Similar to our observation in AML patients, either hnRNP K haploinsufficiency or overexpression resulted in similar phenotypes in vitro and in vivo. Lin-CD117+ hematopoietic stem cells (HSCs) from hnRNP K+/- and hnRNP KTg mice had significant increases in differentiation and proliferation potential as determined by colony formation assays. In these experiments, we observed a significant increase in the number of total colonies and number of cells per colony in both hnRNP K+/- and hnRNP KTg HSCs as compared to wild type HSCs (Figure 1B). In vivo analyses of the hnRNP K+/- and hnRNP KTg mice revealed a significant increase in myeloid hyperplasia in the peripheral blood and bone marrow, increased tumor formation, genomic instability, and decreased survival compared to wild type mice (Figure 1C). Interestingly, both increased and decreased hnRNP K expression resulted in alterations in similar pathways that regulate differentiation and proliferations potential (e.g.; p53 and c-Myc pathways and alterations in C/EBP expression). Together, these clinical and animal model studies illustrate that either over-expression or under-expression of hnRNP K lead to strikingly similar phenotypes that directly impact the etiology of AML. Furthermore, these data not only implicate that hnRNP K behaves as both a tumor suppressor and oncogene, but also suggest that it functions as a master toggle that dictates the proliferation and differentiation potential of HSCs. We are currently using Whole Transcriptome Shotgun Sequencing (RNA-Seq) and ChIP-Seq to evaluate the mechanisms by which increased and decreased hnRNP K expression impact hematologic malignancies. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.