Genotypic and Phenotypic Differences between Nodal and Extranodal Diffuse Large B-Cell Lymphomas

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of diseases that have diverse clinical, pathological, and biological features. Here, it is shown that primary nodal and extranodal DLBCLs differ genomically and phenotypically. Using conventional comparative genomic hybridization (CGH), the authors assessed the chromosomal aberrations in 18 nodal, 13 extranodal, and 5 mixed DLBCLs. The results demonstrate significantly distinct chromosomal aberrations exemplified by gains of chromosomal arms 1p, 7p, 12q24.21-12q24.31, and 22q and chromosome X and loss of chromosome 4, 6q, and 18q22.3-23 in extranodal compared with nodal DLBCLs. Nodal DLBCLs showed an increased tendency for 18q amplification and BCL2 protein overexpression compared with extranodal and mixed tumors. Using a panel of five antibodies against GCET1, MUM1, CD10, BCL6, and FOXP1 proteins to subclassify DLBCLs according to the recent Choi algorithm, the authors showed that the genomic profiles observed between the nodal and extranodal DLBCLs were not due to the different proportions of GCB vs ABC in the two groups. Further delineation of these genomic differences was illuminated by the use of high-resolution 21K BAC array CGH performed on 12 independent new cases of extranodal DLBCL. The authors demonstrated for the first time a novel genome and proteome-based signatures that may differentiate the two lymphoma types.     

A Unified 35-Gene Signature for both Subtype Classification and Survival Prediction in Diffuse Large B-Cell Lymphomas

Cancer subtype classification and survival prediction both relate directly to patients'' specific treatment plans, making them fundamental medical issues. Although the two factors are interrelated learning problems, most studies tackle each separately. In this paper, expression levels of genes are used for both cancer subtype classification and survival prediction. We considered 350 diffuse large B-cell lymphoma (DLBCL) subjects, taken from four groups of patients (activated B-cell-like subtype dead, activated B-cell-like subtype alive, germinal center B-cell-like subtype dead, and germinal center B-cell-like subtype alive). As classification features, we used 11,271 gene expression levels of each subject. The features were first ranked by mRMR (Maximum Relevance Minimum Redundancy) principle and further selected by IFS (Incremental Feature Selection) procedure. Thirty-five gene signatures were selected after the IFS procedure, and the patients were divided into the above mentioned four groups. These four groups were combined in different ways for subtype prediction and survival prediction, specifically, the activated versus the germinal center and the alive versus the dead. Subtype prediction accuracy of the 35-gene signature was 98.6%. We calculated cumulative survival time of high-risk group and low-risk groups by the Kaplan-Meier method. The log-rank test p-value was 5.98e-08. Our methodology provides a way to study subtype classification and survival prediction simultaneously. Our results suggest that for some diseases, especially cancer, subtype classification may be used to predict survival, and, conversely, survival prediction features may shed light on subtype features.     

Clinicopathologic Analysis of Localized Nasal/Paranasal Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) comprises 2 molecularly distinct subgroups of non-germinal center B-cell-like (non-GCB) and germinal center B-cell-like (GCB) DLBCLs, with the former showing relatively poor prognosis. In the present study, we analyzed the clinicopathological features of 39 patients with localized nasal/paranasal DLBCL. Immunohistochemistry-based subclassification revealed that 11 patients (28%) were of the GCB-type according to Hans’ algorithm and 11 (28%) were of the GCB-type according to Choi’s algorithm. According to both Hans’ and Choi’s algorithms, the non-GCB type was predominant. Nevertheless, prognosis was good. Overall survival did not differ significantly between the GCB and non-GCB subgroups (Hans’ algorithm: p = 0.57, Choi’s algorithm: p = 0.99). Furthermore, the prognosis of localized nasal/paranasal DLBCL was better than that of other localized extranodal DLBCLs. The prognosis of extranodal DLBCL is usually considered poorer than that of nodal DLBCL. However, in our study, no difference was noted between patients with localized nasal/paranasal DLBCL and patients with localized nodal DLBCL. In conclusion, although the non-GCB subtype is thought to show poor prognosis, in our study, the prognosis for localized nasal/paranasal DLBCL patients was good irrespective of subclassification.     

Inhibition of Cyclin-dependent Kinase-2 Induces Apoptosis in Human Diffuse Large B-cell Lymphomas

Cyclin-dependent kinase (cdk) inhibitors have the potential to induce growth arrest and apoptosis in cancer cells. The genes encoding cdks involved in G1-S progression are often amplified in B-cell malignancies, including diffuse large B-cell lymphoma (DLBCL). Here, we evaluated the in vitro cytotoxic activity of the cdk2 inhibitor CVT-313 against several human DLBCL cells. Treatment of DLBCL cells with CVT-313 resulted in apoptosis. CVT-313 treatment reduced cdk2-mediated phosphorylation of the retinoblastoma gene product (Rb) on T821, but did not affect cyclin D-cdk4/6-mediated Rb phosphorylation on S807/811. Depletion of endogenous cdk2 by short interfering (si)RNA also resulted in apoptosis in human LY3, LY8 and LY18 DLBCL cells. Importantly, inhibition of cdk2 with CVT-313 or knockdown of endogenous cdk2 with siRNA resulted in down-regulation of the anti-apoptotic factor Myeloid cell leukemia-1 (Mcl-1), suggesting that decreased levels of cellular Mcl-1 contribute to apoptosis. In support of this, siRNA-mediated knockdown of Mcl-1 was sufficient to induce apoptosis in LY3 and LY18 DLBCL. Further, cdk2 inhibition led to decreased Mcl-1 mRNA levels, which was proceeded by reduced phosphorylation of serine 2 on the carboxyl terminal domain (CTD) of RNA polymerase II. Taken together, these data suggest that cdk2 activity is necessary for the survival of human DLBCL.     

Ran GTPase-Activating Protein 1 Is a Therapeutic Target in Diffuse Large B-Cell Lymphoma

Lymphoma-specific biomarkers contribute to therapeutic strategies and the study of tumorigenesis. Diffuse large B-cell lymphoma (DLBCL) is the most common type of malignant lymphoma. However, only 50% of patients experience long-term survival after current treatment; therefore, developing novel therapeutic strategies is warranted. Comparative proteomic analysis of two DLBCL lines with a B-lymphoblastoid cell line (LCL) showed differential expression of Ran GTPase-activating protein 1 (RanGAP1) between them, which was confirmed using immunoblotting. Immunostaining showed that the majority of DLBCLs (92%, 46/50) were RanGAP1⁺, while reactive lymphoid hyperplasia (n = 12) was RanGAP1⁺ predominantly in germinal centers. RanGAP1 was also highly expressed in other B-cell lymphomas (BCL, n = 180) with brisk mitotic activity (B-lymphoblastic lymphoma/leukemia: 93%, and Burkitt lymphoma: 95%) or cell-cycle dysregulation (mantle cell lymphoma: 83%, and Hodgkin’s lymphoma 91%). Interestingly, serum RanGAP1 level was higher in patients with high-grade BCL (1.71 ± 2.28 ng/mL, n = 62) than in low-grade BCL (0.75 ± 2.12 ng/mL, n = 52) and healthy controls (0.55 ± 1.58 ng/mL, n = 75) (high-grade BCL vs. low-grade BCL, p = 0.002; high-grade BCL vs. control, p < 0.001, Mann-Whitney U test). In vitro, RNA interference of RanGAP1 showed no effect on LCL but enhanced DLBCL cell death (41% vs. 60%; p = 0.035) and cell-cycle arrest (G0/G1: 39% vs. 49%, G2/M: 19.0% vs. 7.5%; p = 0.030) along with decreased expression of TPX2 and Aurora kinases, the central regulators of mitotic cell division. Furthermore, ON 01910.Na (Estybon), a multikinase inhibitor induced cell death, mitotic cell arrest, and hyperphosphorylation of RanGAP1 in DLBCL cell lines but no effects in normal B and T cells. Therefore, RanGAP1 is a promising marker and therapeutic target for aggressive B-cell lymphoma, especially DLBCL.     

MYC Protein Expression in Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System

Primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) is a rare, aggressive subtype of DLBCL, the biology of which is poorly understood. Recent studies have suggested a prognostic role of MYC protein expression in systemic DLBCL, but little is known about the frequency and significance of MYC protein expression in CNS DLBCL. Hence, we investigated MYC protein expression profiles of CNS DLBCL and assessed the relationship between MYC expression and a variety of histopathologic, immunophenotypic, genetic, and clinical features. Fifty-nine CNS DLBCL diagnosed at our institution over the past 13 years were evaluated. The majority of cases (80%) showed centroblastic morphology, and 12 (20%) displayed a perivascular pattern of infiltration. According to the Hans criteria, 41 (69%) cases had a non-germinal center B-cell and 18 (31%) had a germinal center B-cell cell-of-origin (COO) phenotype. Mean MYC protein expression was 50% (median: 50%, range: 10-80%). Forty-three cases (73%) showed MYC overexpression (≥40%), and 35 (60%) showed MYC/BCL2 coexpression. MYC overexpression was seen in the single case harboring MYC translocation and in the cases showing increased copies of MYC (27%); however, no significant difference in mean MYC expression was seen between groups harboring or lacking MYC aberrations. In our series, age was associated with a significantly increased risk of death, and the perivascular pattern of infiltration was associated with a significantly increased risk of disease progression. Neither MYC expression (with or without BCL2 coexpression) nor other variables, including COO subtype were predictive of clinical outcome. Our findings indicate that the proportion of CNS DLBCL overexpressing MYC is higher compared to systemic DLBCL, and MYC overexpression appears to be independent of genetic MYC abnormalities. Thus, MYC expression and other immunophenotypic markers used for prognostication of systemic DLBCL might not apply to CNS DLBCL due to differences in disease biology.     

Blood Lymphocyte-to-Monocyte Ratio Identifies High-Risk Patients in Diffuse Large B-Cell Lymphoma Treated with R-CHOP

Background

Recent research has shown a correlation between immune microenvironment and lymphoma biology. This study aims to investigate the prognostic significance of the immunologically relevant lymphocyte-to-monocyte ratio (LMR), in diffuse large B-cell lymphoma (DLBCL) in the rituximab era.

Methodology/Principal Findings

We analyzed retrospective data from 438 newly diagnosed DLBCL patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy. We randomly selected 200 patients (training set) to generate a cutoff value for LMR by receiver operating characteristic (ROC) curve analysis. LMR was then analyzed in a testing set (n = 238) and in all patients (n = 438) for validation. The LMR cutoff value for survival analysis determined by ROC curve in the training set was 2.6. Patients with low LMR tended to have more adverse clinical characteristics. Low LMR at diagnosis was associated with worse survival in DLBCL, and could also identify high-risk patients in the low-risk IPI category. Multivariate analysis identified LMR as an independent prognostic factor of survival in the testing set and in all patients.

Conclusions/Significance

Baseline LMR, a surrogate biomarker of the immune microenvironment, is an effective prognostic factor in DLBCL patients treated with R-CHOP therapy. Future prospective studies are required to confirm our findings.     

Clinical Significance of sIL-2R Levels in B-Cell Lymphomas

Elevated soluble interleukin-2 receptor (sIL-2R) in sera is observed in patients with malignant lymphoma (ML). Therefore, sIL-2R is commonly used as a diagnostic and prognostic marker for ML, but the mechanisms responsible for the increase in sIL-2R levels in patients with B-cell lymphomas have not yet been elucidated. We first hypothesized that lymphoma cells expressing IL-2R and some proteinases such as matrix metalloproteinases (MMPs) in the tumor microenvironment can give rise to increased sIL-2R in sera. However, flow cytometric studies revealed that few lymphoma cells expressed IL-2R α chain (CD25) in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL), and most CD25-expressing cells in the tumor were T-cells. Distinct correlations between CD25 expression on B-lymphoma cells and sIL-2R levels were not observed. We then confirmed that MMP-9 plays an important role in producing sIL-2R in functional studies. Immunohistochemical (IHC) analysis also revealed that MMP-9 is mainly derived from tumor-associated macrophages (TAMs). We therefore evaluated the number of CD68 and CD163 positive macrophages in the tumor microenvironment using IHC analysis. A positive correlation between the levels of sIL-2R in sera and the numbers of CD68 positive macrophages in the tumor microenvironment was confirmed in FL and extranodal DLBCL. These results may be useful in understanding the pathophysiology of B-cell lymphomas.     

A20 Mutation Is Not a Prognostic Marker for Activated B-Cell-Like Diffuse Large B-Cell Lymphoma

Background

Constitutive activation of nuclear factor κB (NF-κB) is a hallmark of activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL). Mutations in the A20 gene activate NF-κB, but the prognostic value of A20 mutations in ABC-DLBLC is unclear.

Purpose

To investigate the prognostic value of A20 mutation in ABC-DLBCL patients.

Methods

The somatic mutation of A20 was investigated in 68 de novo ABC-DLBCLs by PCR/sequencing. The Kaplan-Meier method was used to estimate median overall survival (OS) and progression-free survival (PFS).

Results

The A20 mutation rate in ABC-DLBCL patients was 29.4%. Complete remission rates were 35% and 45.8% in patients with and without A20 mutations, respectively (P = 0.410). In patients with and without A20 mutations, the median OS was 24.0 and 30.6 months, respectively (P = 0.58), and the median PFS was 15 and 17.4 months, respectively (P = 0.52). None of the differences between the patient groups were significant.

Conclusions

Our findings suggested that the A20 mutation is a frequent event in ABC-DLBCLs. However, there was no significant difference in PFS and OS in patients with or without A20 mutations. Further study is required to completely exclude A20 somatic mutation as a prognostic marker in the ABC subtype of DLBLC.     

Quercetin Potentiates the Antitumor Activity of Rituximab in Diffuse Large B-Cell Lymphoma by Inhibiting STAT3 Pathway

STAT3 pathway plays an important role in the growth of diffuse large B-cell lymphoma (DLBCL) cells. Here we investigated the antitumor activity of Quercetin, a flavonoid compound, in combination with rituximab in DLBCL cell lines in vitro. We found that Quercetin synergistically enhanced rituximab-induced growth inhibition and apoptosis in DLBCL cell lines. Moreover, we found Quercetin exerted inhibitory activity against STAT3 pathway and downregulated the expression of survival genes. These results suggest that combining the Quercetin with rituximab may present an attractive and potentially effective way for the treatment of DLBCL.     

EB病毒诱发人B细胞淋巴瘤的分子病理特性

EB病毒 (EBV ,Epstein Barrvirus)与人类多种肿瘤有关 ,尤其是与鼻咽癌和淋巴瘤的关系密切。为此研究了EB病毒在huPBL SCID嵌合体小鼠体内诱发人B细胞淋巴瘤的分子特性及肿瘤发生机制。从健康成人外周血分离出淋巴细胞 ,将之移植到SCID小鼠腹腔内 ,实验感染EBV ,观察肿瘤的形成 ;采用单向免疫扩散法连续监测小鼠血清中人IgG的含量。分别用PCR方法检测肿瘤组织中是否存在人Alu序列 ,原位杂交检测肿瘤组织中EB病毒小RNA分子EBER 1;免疫组织化学方法检测人白细胞分化抗原 (CD4 5、CD2 0、CD4 5RO、CD3) ,病毒基因(LMP1、EBNA2、BZLF1)的表达 ,以及细胞瘤基因蛋白 (p5 3、C myc、Bcl 2、Bax)在诱发肿瘤中的表达情况。结果发现 ,实验中 34只感染EBV的huPBL SCID小鼠有 2 4只诱发出肿瘤 ,根据病理形态学特征、Alu PCR和免疫标志均证实诱发瘤是人源性B淋巴细胞肿瘤。原位分子杂交显示肿瘤细胞核内存在EBER 1,少数瘤细胞表达EB病毒BZLF1蛋白阳性 ,部分瘤细胞表达LMP1和EBNA2蛋白阳性。连续监测 12只huPBL SCID小鼠血清中人IgG含量 ,发现IgG水平随诱瘤时间延长和肿瘤生长有逐渐增高趋势。免疫组化显示诱发的 2 4例淋巴瘤组织p5 3、C myc、Bcl 2和Bax蛋白表达阳性率分别为 83.33%、10 0 %、95 .83%、91.6 7%。结果     

Differential Impact of Relative Dose-Intensity Reductions in Diffuse Large B-Cell Lymphoma Treated with R-CHOP21 or R-CHOP14

DLBCL is an aggressive lymphoma treated with R-CHOP. Recently, attempts have been made to improve the outcome by increasing both dose-density and intensity but there have been no benefits in terms of survival. When treating malignancies RDI is important to consider but there is little published information on DLBCL. The purpose of this study was to analyze the differential prognostic impact of RDI in two cohorts of DLBCL patients treated with R-CHOP21 or R-CHOP14. From January 2001 to August 2013 we included DLBCL patients homogenously treated with R-CHOP21 or R-CHOP14, with or without radiotherapy, at University Hospital Son Espases, Hospital Son Llatzer of Palma and Hospital del Mar of Barcelona (N = 157). In order to avoid selection bias the patients were retrospectively identified from the Pathology Department and Pharmacy registries. Median follow-up was 68 months. There was no difference in the response or survival between the two cohorts. In the R-CHOP21 group, both a reduction higher than 15% in RDI (RR 7.41) and R-IPI (RR 2.99) were independently associated with OS. However, a reduction higher than 15% in RDI (RR 4.41) was only noted for PFS. In the R-CHOP14 group, NCCN-IPI (RR 7.09) and B-symptoms (RR 5.37) for OS; AA stage III-IV (RR 6.26) and bulky disease (RR 4.05) for PFS. There was a trend towards a higher rate of RDI reduction observed in the R-CHOP14 group but it only made an impact in the R-CHOP21 group. We conclude that R-CHOP21 and R-CHOP14 are equivalent regimens in terms of response and survival, but only if RDI reductions are avoided. For patients receiving R-CHOP21 we recommend using clinical and support measures in order to avoid RDI reductions.     

The Expression of CD30 Based on Immunohistochemistry Predicts Inferior Outcome in Patients with Diffuse Large B-Cell Lymphoma

The prognostic value of CD30 expression indiffuse large B-cell lymphoma (DLBCL)remains controversial. Herein, we performed this retrospective study to investigate the clinical and prognostic significance of CD30 expression in patients with DLBCL.Among all the 146 patients, the expression of CD30 was observed in 23 cases (15.7%).The DLBCL patients with CD30 expression showed more likely to present B symptoms, bone marrow involvement, non-germinal centre B-cell-like (Non-GCB) DLBCL, BCL-2 and Ki-67overexpression(p<0.05). Patients with CD30 expression showed significantly poor overall and event-free survivalcompared with CD30 negative patients(p = 0.031 and 0.041, respectively), especially those with the high intermediate/high-risk international prognostic index (IPI)(p = 0.001 and 0.007, respectively). The prognostic value of CD30expression retained in DLBCL patients treated with eitherCHOP (cyclophosphamide, doxorubicin, vincristine,prednisone) or R-CHOP(rituximab+CHOP). The multivariate analysisrevealed that the expression of CD30 remained an unfavorable factor for both overall and event-free survival (p = 0.001 and 0.002, respectively).In conclusion, these data suggest that CD30 is expressed predominantly in Non-GCBDLBCL. The expression of CD30 implied poor outcomein DLBCL patientstreated with either CHOP or R-CHOP, especially those with the high intermediate/high-risk IPI, possibly indicating that anti-CD30 monoclonal antibody could be of clinical interest.     

Increased Expression of Several Mitochondrial Genes in Human and Monkey B-Cell Non-Hodgkin Lymphomas

Mitochondrial genes overexpressed in human and monkey B-cell non-Hodgkin lymphomas (B-NHLs) were sought via subtraction hybridization, cloning, and differential screening of the resulting cDNA libraries. The cDNAs of mitochondrial genes constituted an appreciable proportion of all lymphoma-specific cDNAs. Lymphomogenesis was associated with upregulation of a set of mitochondrial genes, which varied with lymphoma type but always included NADHIV. A possible association between upregulation of certain mitochondrial genes and cell malignant transformation is discussed.     

PD-1 Blockade Can Restore Functions of T-Cells in Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma In Vitro

Epstein–Barr virus-positive diffuse large B-cell lymphoma (EBV+DLBCL) is an aggressive malignancy that is largely resistant to current therapeutic regimens, and is an attractive target for immune-based therapies. Anti-programmed death-1 (PD-1) antibodies showed encouraging anti-tumor effects in both preclinical models and advanced solid and hematological malignancies, but its efficacy against EBV+DLBCL is unknown. Herein, we performed experiments using co-culture system with T cells and lymphoma cell lines including EBV+DLBCL and EBV-DLBCL [including germinal center B-cell like (GCB)-DLBCL and non-GCB-DLBCL] in vitro. We show that lymphoma cells augmented the expression of PD-1 on T cells, decreased the proliferation of T cells, and altered the secretion of multiple cytokines. However, through PD-1 blockade, these functions could be largely restored. Notbaly, the effect of PD-1 blockade on antitumor immunity was more effective in EBV+DLBCL than that in EBV-DLBCL in vitro. These results suggest that T-cell exhaustion and immune escape in microenvironment is one of the mechanisms underlying DLBCL; and PD-1 blockade could present as a efficacious immunotherapeutic treatment for EBV+DLBCL.     

Array-Based Comparative Genomic Hybridization Analysis Reveals Chromosomal Copy Number Aberrations Associated with Clinical Outcome in Canine Diffuse Large B-Cell Lymphoma

Canine Diffuse Large B-cell Lymphoma (cDLBCL) is an aggressive cancer with variable clinical response. Despite recent attempts by gene expression profiling to identify the dog as a potential animal model for human DLBCL, this tumor remains biologically heterogeneous with no prognostic biomarkers to predict prognosis. The aim of this work was to identify copy number aberrations (CNAs) by high-resolution array comparative genomic hybridization (aCGH) in 12 dogs with newly diagnosed DLBCL. In a subset of these dogs, the genetic profiles at the end of therapy and at relapse were also assessed. In primary DLBCLs, 90 different genomic imbalances were counted, consisting of 46 gains and 44 losses. Two gains in chr13 were significantly correlated with clinical stage. In addition, specific regions of gains and losses were significantly associated to duration of remission. In primary DLBCLs, individual variability was found, however 14 recurrent CNAs (>30%) were identified. Losses involving IGK, IGL and IGH were always found, and gains along the length of chr13 and chr31 were often observed (>41%). In these segments, MYC, LDHB, HSF1, KIT and PDGFRα are annotated. At the end of therapy, dogs in remission showed four new CNAs, whereas three new CNAs were observed in dogs at relapse compared with the previous profiles. One ex novo CNA, involving TCR, was present in dogs in remission after therapy, possibly induced by the autologous vaccine. Overall, aCGH identified small CNAs associated with outcome, which, along with future expression studies, may reveal target genes relevant to cDLBCL.     

NIAM-Deficient Mice Are Predisposed to the Development of Proliferative Lesions including B-Cell Lymphomas

Nuclear Interactor of ARF and Mdm2 (NIAM, gene designation Tbrg1) is a largely unstudied inhibitor of cell proliferation that helps maintain chromosomal stability. It is a novel activator of the ARF-Mdm2-Tip60-p53 tumor suppressor pathway as well as other undefined pathways important for genome maintenance. To examine its predicted role as a tumor suppressor, we generated NIAM mutant (NIAM^m/m) mice homozygous for a β-galactosidase expressing gene-trap cassette in the endogenous gene. The mutant mice expressed significantly lower levels of NIAM protein in tissues compared to wild-type animals. Fifty percent of aged NIAM deficient mice (14 to 21 months) developed proliferative lesions, including a uterine hemangioma, pulmonary papillary adenoma, and a Harderian gland adenoma. No age-matched wild-type or NIAM^+/m heterozygous animals developed lesions. In the spleen, NIAM^m/m mice had prominent white pulp expansion which correlated with enhanced increased reactive lymphoid hyperplasia and evidence of systemic inflammation. Notably, 17% of NIAM mutant mice had splenic white pulp features indicating early B-cell lymphoma. This correlated with selective expansion of marginal zone B cells in the spleens of younger, tumor-free NIAM-deficient mice. Unexpectedly, basal p53 expression and activity was largely unaffected by NIAM loss in isolated splenic B cells. In sum, NIAM down-regulation in vivo results in a significant predisposition to developing benign tumors or early stage cancers. These mice represent an outstanding platform for dissecting NIAM''s role in tumorigenesis and various anti-cancer pathways, including p53 signaling.