Phosphorylated VEGFR2/KDR receptors are widely expressed in B-cell non-Hodgkin's lymphomas and correlate with hypoxia inducible factor activation

Association of single nucleotide variants in VEGFA and KDR with the risk and angiogenic features of diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype and dependent on angiogenesis (AG), whose main effectors are VEGFA and VEGFR2. Functional single nucleotide variants (SNVs) are described in VEGFA and KDR genes. However, it still unknown whether VEGFA - 2578C/A, -2489C/T, -1154G/A, -634G/C, -460C/T and KDR-604T/C, -271G/A, +1192G/A and +1719A/T SNVs act on DLBCL risk and angiogenic features. Genomic DNA from 168 DLBCL patients and 205 controls was used for SNV genotyping. Angiogenesis was immunohistochemically assessed in tumor biopsies, with reactions for VEGFA, VEGFR2, and CD34. VEGFA -1154GG genotype were associated with 1.6-fold higher DLBCL risk. KDR + 1192GG plus KDR + 1719 TT and KDR + 1192GG plus VEGFA - 2578CC combined genotypes are associated with 2.19- and 2.04-fold higher risks of DLBCL, respectively. VEGFA - 634GG or GC genotypes are associated with increased microvessel density and VEGFA levels. No relationship was observed between SNVs and cell-of-origin classification of DLBCL, but higher VEGFA and VEGFR2 were seen in non-germinal center tumors.

One Omics Approach Does Not Rule Them All: The Metabolome and the Epigenome Join Forces in Haematological Malignancies

Aberrant DNA methylation, dysregulation of chromatin-modifying enzymes, and microRNAs (miRNAs) play a crucial role in haematological malignancies. These epimutations, with an impact on chromatin accessibility and transcriptional output, are often associated with genomic instability and the emergence of drug resistance, disease progression, and poor survival. In order to exert their functions, epigenetic enzymes utilize cellular metabolites as co-factors and are highly dependent on their availability. By affecting the expression of metabolic enzymes, epigenetic modifiers may aid the generation of metabolite signatures that could be utilized as targets and biomarkers in cancer. This interdependency remains often neglected and poorly represented in studies, despite well-established methods to study the cellular metabolome. This review critically summarizes the current knowledge in the field to provide an integral picture of the interplay between epigenomic alterations and the cellular metabolome in haematological malignancies. Our recent findings defining a distinct metabolic signature upon response to enhancer of zeste homolog 2 (EZH2) inhibition in multiple myeloma (MM) highlight how a shift of preferred metabolic pathways may potentiate novel treatments. The suggested link between the epigenome and the metabolome in haematopoietic tumours holds promise for the use of metabolic signatures as possible biomarkers of response to treatment.

New concepts in follicular lymphoma biology: From BCL2 to epigenetic regulators and non-coding RNAs

The molecular pathogenesis of follicular lymphoma (FL) was partially revealed 3 decades ago, with the discovery of the translocation that brings BCL2 under the influence of immunoglobulin heavy chain enhancers in a vast majority of cases. Despite the importance of this seminal observation, it has become increasingly clear that additional genetic alterations need to occur to trigger neoplastic transformation and disease progression. The evolution of FL involves developmental arrest and disruption of the normal function of one or more of epigenetic regulators including KMT2D/MLL2, EZH2, CBP/CREBBP, p300/EP300, and HIST1H1 in >95% of cases. B-cells "arrested" in germinal centers acquire dozens of additional genetic aberrations that influence key pathways controlling their physiological development including B Cell Receptor (BCR) signaling, PI3K/AKT, TLR, mTOR, NF-κB, JAK/STAT, MAPK, CD40/CD40L, chemokine, and interleukin signaling. Additionally, most cases of FL do not result from linear accumulation of genomic aberrations, but rather evolve from a common progenitor cell population by diverse evolution, creating multiple FL subclones in one patient. Moreover, one of the subclones might acquire a combination of aberrations involving genes controlling cell survival and proliferation including MDM2, CDKN2A/B, BCL6, MYC, TP53, β2M, FOXO1, MYD88, STAT3, or miR-17-92, and this can lead to the transformation of an initially indolent FL to an aggressive lymphoma (2%-3% risk per year). The complexity of the disease is also underscored by the importance of its interactions with the microenvironment that can substantially influence disease development and prognosis. Interpreting individual aberrations in relation to their impact on normal processes, their frequency, position in the disease evolution, and the consequences of their (co)occurrence, are the basis for understanding FL pathogenesis. This is necessary for the identification of patients with risk of early progression or transformation, for the development of novel targeted therapies, and for personalized treatment approaches. In this review, we summarize recent knowledge of molecular pathways and microenvironmental components involved in FL biology, and discuss them in the context of physiological B-cell development, FL evolution, and targeted therapies.

Effect of hypoxia-inducible factors in normal and leukemic stem cell regulation and their potential therapeutic impact

INTRODUCTION

Hypoxia inducible factors (HIF-1α and HIF-2α) are the main mediators of hypoxic responses that operate in both normal and pathological conditions. Recent evidence indicates that HIF-1α and HIF-2α could have overlapping, unique and even sometimes opposing activities in both normal physiology and disease. Despite an increase in our understanding of the different pathways regulated by HIF-1α and HIF-2α, the role played by each factor in HSC maintenance and leukemogenesis is still controversial.

AREAS COVERED

This review summarizes our current understanding of HIF-1α and HIF-2α activities and discusses the implications and challenges of using HIF inhibitors therapeutically in blood malignancies.

EXPERT OPINION

As HIF inhibitors are currently under clinical evaluation in different cancers, including hematological malignancies, a more thorough understanding of the unique roles performed by HIF-1α and HIF-2α in human neoplasia is warranted.

Glycolytic inhibitor 2-deoxy-d-glucose suppresses cell proliferation and enhances methylprednisolone sensitivity in non-Hodgkin lymphoma cells through down-regulation of HIF-1α and c-MYC

Metabolic reprogramming is linked to tumorigenesis, disease progression, clinical outcome and resistance to chemotherapy. However, the significance of glycolytic metabolism in non-Hodgkin lymphoma (NHL) remains unclear. Here we report that both NHL patient-samples and cell lines exhibited significant up-regulation of glycolytic metabolism. The glycolytic inhibitor 2-deoxy-d-glucose (2-DG) inhibited glucose consumption, lactic acid generation and cell proliferation and induced cell cycle arrest in NHL cell lines under both normoxia and hypoxia, and hypoxia could even enhance the inhibitory effects of 2-DG. Furthermore, 2-DG combined with methylprednisolone synergistically inhibited cell proliferation, induced cell apoptosis and cell cycle arrest, and thus increased the sensitivity of NHL cells to methylprednisolone via down-regulation of HIF-1α and c-MYC. In conclusion, these results present a novel insight into critical roles of glycolytic pathway activation in NHL progression and glucocorticoid resistance. Inhibition of the glycolytic pathway may provide a new therapeutic strategy for the treatment of NHL.

Hypoxia inducible factor-1α induces chemoresistance phenotype in non-Hodgkin lymphoma cell line via up-regulation of Bcl-xL

Non-Hodgkin lymphoma (NHL) is one of the most common cancers in childhood. The development of chemoresistance in tumor cells is one of the principal causes of treatment failure. This resistance has been associated with different mechanisms, one being the overexpression of anti-apoptotic proteins such as Bcl-xL. It has been shown that this protein is regulated by the transcription factor hypoxia inducible factor-1α (HIF-1α), which is overexpressed in several tumors including NHL, and the overexpression of both proteins may result in resistance to chemotherapy. We investigated the role of HIF-1α in resistance to chemotherapy via the induction of Bcl-xL expression in NHL cell lines, using a pharmacological modulation of HIF-1α. Our data showed that treating Ramos cells with ethyl 3,4-dihydroxybenzoate, an inhibitor of prolyl hydroxylase, induces accumulation of HIF-1α and this correlates with an increase of Bcl-xL as well as resistance to apoptosis after exposure to chemotherapeutics drugs. In contrast, the treatment of Ramos cells with 2-methoxyestradiol, an inhibitor of HIF-1α activity, induced down-regulation of Bcl-xL expression, and this correlated with the sensitization of tumor cells to chemotherapeutic drugs. These data demonstrate that up-regulation of the anti-apoptotic protein Bcl-xL in NHL cells correlates with HIF-1α expression and activity, through which a phenotype of chemoresistance is induced.

In-vivo investigation of laser-induced choroidal neovascularization in rat using spectral-domain optical coherence tomography (SD-OCT)

PURPOSE

This study investigated the in-vivo formation process of laser-induced choroidal neovascularization (CNV) in rat using high-resolution spectral-domain optical coherence tomography (SD-OCT), and compared the results to histological methods.

METHODS

Brown Norway rats (n = 60, 6-8 weeks of age) received 532-nm diode laser photocoagulation. SD-OCT and fluorescein angiography (FA) were performed in vivo 2, 5, 7, 14, and 21 days post-laser application. Haematoxylin and eosin (H&E) staining and immunohistochemistry for CD31, phosphorylated vascular endothelial factor receptor 2 (pVEGFR2) were conducted at each time point to observe the CNV in vitro. Choroidal flatmount preparations were observed using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM).

RESULTS

SD-OCT monitored the longitudinal morphological changes of laser-induced CNV. CNV reached its maximal size on day 7, and began a gradual reduction on day 14. FA revealed similar dynamic changes in leakage. CNV thickness, as assessed by SD-OCT, was consistent with H&E-stained sections at each time point. CLSM and SEM revealed the details of the fibrovascular membrane. CD31 and pVEGFR2 expression supported the results of SD-OCT and histology.

CONCLUSIONS

SD-OCT was a convenient and reliable tool for the imaging of the CNV formation process and quantification of the lesion size in vivo.

Prognostic significance of hypoxia inducible factor-1α and vascular endothelial growth factor expression in patients with diffuse large B-cell lymphoma treated with rituximab

We evaluated hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression and their prognostic significance in diffuse large B-cell lymphoma (DLBCL). Expression of HIF-1α and VEGF was studied in 78 patients and results correlated with clinicopathological and prognostic data. HIF-1α and VEGF were expressed in 67% and 84% of patients, respectively, and a significant correlation was demonstrated between them (p < 0.001). Outcome was analyzed according to treatment. HIF-1α positive patients given rituximab demonstrated improved outcome, with 5-year overall survival of 72% for those receiving rituximab versus 65% for those not receiving rituximab, and 5-year progression-free survival (PFS) 76% versus 57%. No correlation was demonstrated between HIF-1α and other prognostic biomarkers including BCL6, CD10 and MUM-1. We demonstrated significantly improved PFS (p = 0.003) in patients receiving rituximab and showing BCL6 overexpression. The results confirm the significant association between HIF-1α and VEGF expression and suggest that HIF-1α expression is a favorable prognostic factor in patients with DLBCL treated with rituximab.

VEGFA and VEGFR2 genetic polymorphisms and survival in patients with diffuse large B cell lymphoma

We evaluated the impact of functional polymorphisms in the vascular endothelial growth factor A (VEGFA) and vascular endothelial growth factor 2 (VEGFR2) genes on the survival of patients with diffuse large B cell lymphoma (DLBCL). Five potentially functional polymorphisms in the VEGFA (rs699947, rs2010963 and rs3025039) and VEGFR2 (rs1870377 and rs2305948) genes were assessed in 494 DLBCL patients treated with rituximab plus CHOP chemotherapy. The associations of genotype and haplotype with overall survival (OS) and progression-free survival (PFS) were analyzed. Of the five polymorphisms, VEGFR2 rs1870377T>A was significantly associated with both OS and PFS; in the dominant model, patients with the AA + TA genotypes had significantly better OS (P = 0.002) and PFS (P = 0.004) than those with the TT genotype. The association between significantly better OS and the AA + TA genotypes was observed separately in patients with low (0-2; P = 0.035) and high (3-5; P = 0.043) International Prognostic Index scores. Multivariate analysis showed that, relative to the AA + TA genotypes, the TT genotype was an independent prognostic factor for poor OS (HR, 1.71; 95% CI, 1.21-2.43; P = 0.002) and PFS (HR, 1.57; 1.13-2.17; P = 0.004). Other independent significant predictors of survival in patients with DLBCL were International Prognostic Index score, age > 60 years, lactate dehydrogenase concentration >normal, extranodal disease >1 and presence of B symptoms. The VEGFR2 rs1870377 polymorphism might affect survival in patients with DLBCL, suggesting that angiogenesis might be related to poor survival in these patients.

Angiogenesis and host immune response contribute to the aggressive character of non-melanoma skin cancers in renal transplant recipients

AIMS

The aim of this study was to determine the contribution of tumour angiogenesis to the aggressive growth of non-melanoma skin cancers (NMSCs) in renal transplant recipients (RTRs).

METHODS AND RESULTS

The study cohort included RTRs (n = 38) with formalin-fixed paraffin-embedded tumour samples available from first post-transplant NMSC (NMSC1) surgically excised at Christchurch Hospital, New Zealand, from 1997 to 2007. Comparable samples excised from immunocompetent individuals (ICIs) (n = 36) were selected to accommodate confounding factors. Markers of tumour angiogenesis were evaluated by immunohistochemistry, and analysed for associations with clinicopathological variables. As compared with ICIs, RTRs had a higher proportion of tumours with high microvessel density (P = 0.008), high proliferating capillary index (P < 0.0001) and low microvessel pericyte coverage index (P < 0.0001), and RTRs had a shorter cumulative second NMSC (NMSC2)-free interval (P < 0.0001). ICIs had a higher proportion of tumours with a 'marked' number of vascular endothelial growth factor (VEGF)-A-positive leukocytes than RTRs (P = 0.04), and RTRs with a 'moderate/marked' number of VEGF-A-positive leukocytes had longer cumulative NMSC2-free intervals than those with a 'minimum' number (P = 0.02).

CONCLUSIONS

This study demonstrates increased tumour angiogenesis in NMSC in RTRs, and suggests a role for VEGF-A-positive peritumoural leukocytes in suppressing NMSC development.

The emerging role of hypoxia, HIF-1 and HIF-2 in multiple myeloma

Hypoxia is an imbalance between oxygen supply and demand, which deprives cells or tissues of sufficient oxygen. It is well-established that hypoxia triggers adaptive responses, which contribute to short- and long-term pathologies such as inflammation, cardiovascular disease and cancer. Induced by both microenvironmental hypoxia and genetic mutations, the elevated expression of the hypoxia-inducible transcription factor-1 (HIF-1) and HIF-2 is a key feature of many human cancers and has been shown to promote cellular processes, which facilitate tumor progression. In this review, we discuss the emerging role of hypoxia and the HIFs in the pathogenesis of multiple myeloma (MM), an incurable hematological malignancy of BM PCs, which reside within the hypoxic BM microenvironment. The need for current and future therapeutic interventions to target HIF-1 and HIF-2 in myeloma will also be discussed.

Hypoxia-associated protein expression in primary central nervous system diffuse large B-cell lymphoma: does it predict prognosis?

Hypoxia-associated proteins are commonly expressed as a consequence of disturbances in microcirculation. However, the clinical relevance of the proteins has never been studied in primary central nervous system lymphoma (PCNSL). The expression of hypoxia-inducible factor 1α (HIF-1α) and its downstream proteins, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1), were evaluated in a central nervous system (CNS) lymphoma xenograft model and in human PCNSL tissue. In the CNS lymphoma xenograft model, the expression of HIF-1α, VEGF, and GLUT-1 co-localized in subsets of lymphoma cells adjacent to necrosis. In tumor specimens from 51 patients with PCNSL, positive HIF-1α staining was found in 26 patients (51.0%), positive VEGF in 30 (58.8%), and positive GLUT-1 in 17 (33.3%), and HIF-1α showed a significant correlation with VEGF (p < 0.05). However, no significant association was seen between hypoxia-associated protein positivity and unfavorable clinical characteristics. Thus, the results failed to show an association with shorter overall survival or time to progression, except that the percentage of lymphoma cells positive for GLUT-1 (>20%) was significantly associated with worse survival. In conclusion, hypoxia-associated proteins were expressed in PCNSL, suggesting a hypoxic microenvironment. However, the prognostic relevance of these proteins for PCNSL was not demonstrated in this study.

Serum VEGF levels and tissue activation of VEGFR2/KDR receptors in patients with breast and gynecologic cancer

OBJECTIVES

Vascular endothelial cell growth factor (VEGF) plays an important role in the biology of gynecological cancer, usually linked with aggressive tumour behaviour and a poor postoperative outcome. Yet, its role in benign breast/gynecological conditions is less clear.

METHODS

Serum VEGF was analysed in a series of 49 patients with gynecological cancer and 61 patients with benign disease and compared to those of 12 normal female subjects. In addition, the activation status of VEGFR2/KDR receptors was investigated in formalin-fixed paraffin embedded tissues and related to VEGF.

RESULTS

Mean serum levels of VEGF were significantly higher in patients with breast, endometrial and ovarian cancer compared to healthy controls and those with benign breast/gynecologic disease in the respective organs. A similar trend was noted in some cases of simple endometrial hyperplasia, fibroadenoma and fibrocystic disease of the breast. The expression of phosphorylated VEGFR2/KDR receptors was higher in breast, endometrial, ovarian cancer in patients with high VEGF serum levels and this reached a level of statistical significance when all malignancies were combined.

CONCLUSIONS

Serum VEGF levels are increased in patients with breast and gynecological malignancies, but this can not be considered pathognomonic for cancer as it is also increased in certain benign conditions, including cases of fibroadenoma, fibrocystic disease of breast and simple endometrial hyperplasia. Furthermore, high serum VEGF levels are closely related to the activation status of the VEGFR2/KDR receptor in cancer cells, indicating a stimulatory effect of serum VEGF on the VEGF pathway contributing to tumor progression.

Oncogenic kinase NPM/ALK induces expression of HIF1α mRNA

The mechanisms of malignant cell transformation mediated by the oncogenic anaplastic lymphoma kinase (ALK) tyrosine kinase remain only partially understood. In this study, we report that T-cell lymphoma (TCL) cells carrying the nucleophosmin (NPM)/ALK fusion protein (ALK+ TCL) strongly express hypoxia-induced factor 1α (HIF1α) mRNA, even under normoxic conditions, and markedly upregulate HIF1α protein expression under hypoxia. HIF1α expression is strictly dependent on the expression and enzymatic activity of NPM/ALK, as shown in BaF3 cells transfected with wild-type NPM/ALK and kinase-inactive NPM/ALK K210R mutant and by the inhibition of the NPM/ALK function in ALK+ TCL cells by a small-molecule ALK inhibitor. NPM/ALK induces HIF1α expression by upregulating its gene transcription through its key signal transmitter signal transducer and activator of transcription 3 (STAT3), which binds to the HIF1α gene promoter as shown by the chromatin immunoprecipitation assay and is required for HIF1α gene expression as demonstrated by its small interfering RNA-mediated depletion. In turn, depletion of HIF1α increases mammalian target of rapamycin complex 1 activation, cell growth and proliferation and decreases vascular endothelial growth factor synthesis. These results identify a novel cell-transforming property of NPM/ALK, namely its ability to induce the expression of HIF1α, a protein with an important role in carcinogenesis. These results also provide another rationale to therapeutically target NPM/ALK and STAT3 in ALK+ TCL.

Temsirolimus in the treatment of relapsed and/or refractory mantle cell lymphoma

Patients with mantle cell lymphoma (MCL) have a poor prognosis; consequently, new therapeutic approaches, such as rapamycin and its derivates, mammalian target of rapamycin (mTOR) inhibitors, are warranted. Temsirolimus (also known as CCI-779), a dihydroester of rapamycin, in MCL cell lines inhibited mTOR, downregulated p21 and v-Raf, and induced autophagy. The first clinical trial in MCL patients was performed using 250 mg of temsirolimus weekly for 6-12 cycles. The overall response rate was 38%; the median time to progression was 6.5 months, median overall survival was 12 months, and the median duration of response was 6.9 months. At lower dose (25 mg/week), the overall response rate was 41%, median overall survival was 14 months, and time to progression was 6 months. In another trial, 162 patients were randomly assigned to receive temsirolimus at 2 different doses (175 mg/week for 3 weeks, then 75 mg or 25 mg/week) or a treatment chosen by the investigator among the most frequently adopted single agents for treatment of relapsed MCL. Patients treated with 175/75 mg of temsirolimus had significantly higher response rates and longer progression-free survival than those treated with investigator's choice therapy. These data support the use of mTOR inhibitors for the treatment of MCL, probably in combination with other agents, such as antiangiogenic drugs or histone acetylase inhibitors.

Vascular endothelial growth factor stimulates protein kinase CbetaII expression in chronic lymphocytic leukemia cells

Chronic lymphocytic leukemia (CLL) is a malignant disease of mature B lymphocytes. We have previously shown that a characteristic feature of CLL cells are high levels of expression and activity of protein kinase CbetaII (PKCbetaII), and that this might influence disease progression by modulating signaling in response to B-cell receptor engagement. The aim of the present work was to investigate the factors involved in stimulating PKCbetaII expression in CLL cells. Here we show that the activation of PKCbetaII in CLL cells stimulated with vascular endothelial growth factor (VEGF) can drive expression of the gene for PKCbeta, PRKCB1. We found that this effect of VEGF on PRKCB1 transcription is paralleled by high expression of PKCbetaII protein and therefore probably contributes to the malignant phenotype of CLL cells. Taken together, the data presented in this study demonstrate that VEGF, in addition to its role in providing prosurvival signals, also plays a role in overexpression of PKCbetaII, an enzyme with a specific pathophysiologic role in CLL.

Insertional mutagenesis in mice deficient for p15Ink4b, p16Ink4a, p21Cip1, and p27Kip1 reveals cancer gene interactions and correlations with tumor phenotypes

The cyclin dependent kinase (CDK) inhibitors p15, p16, p21, and p27 are frequently deleted, silenced, or downregulated in many malignancies. Inactivation of CDK inhibitors predisposes mice to tumor development, showing that these genes function as tumor suppressors. Here, we describe high-throughput murine leukemia virus insertional mutagenesis screens in mice that are deficient for one or two CDK inhibitors. We retrieved 9,117 retroviral insertions from 476 lymphomas to define hundreds of loci that are mutated more frequently than expected by chance. Many of these loci are skewed toward a specific genetic context of predisposing germline and somatic mutations. We also found associations between these loci with gender, age of tumor onset, and lymphocyte lineage (B or T cell). Comparison of retroviral insertion sites with single nucleotide polymorphisms associated with chronic lymphocytic leukemia revealed a significant overlap between the datasets. Together, our findings highlight the importance of genetic context within large-scale mutation detection studies, and they show a novel use for insertional mutagenesis data in prioritizing disease-associated genes that emerge from genome-wide association studies.

Hypoxia-inducible factor-1 {alpha} expression predicts superior survival in patients with diffuse large B-cell lymphoma treated with R-CHOP

PURPOSE Hypoxia-inducible factor (HIF) controls the expression of genes in response to hypoxia, as well as a wide range of other cellular processes. We previously showed constitutive stabilization of HIF-1alpha in the majority of patients with diffuse large B-cell lymphoma (DLBCL). To our knowledge, the prognostic significance of HIF in lymphoma has never been investigated. PATIENTS AND METHODS We studied the immunohistochemical protein expression of HIF-1alpha on tissue microarrays from 153 patients with DLBCL treated in sequential cohorts with cyclophosphamide, doxorubicin, oncovin, and prednisone (CHOP) or rituximab-CHOP (R-CHOP) from 1999 to 2002. Results were correlated with patient outcome. Results Median follow-up for all patients was 80 months. Among all patients, HIF-1alpha was expressed in 62% of germinal center and 59% of non-germinal center patients. With HIF-1alpha analyzed as a dependent variable, there were no survival differences in CHOP-treated patients. In the R-CHOP group, however, HIF-1alpha protein expression correlated with significantly improved progression-free survival (PFS) and overall survival (OS). Five-year PFS for HIF-1alpha-positive patients was 71% v 43% for HIF-1alpha-negative patients (P = .0187), whereas 5-year OS was 75% and 54%, respectively (P = .025). In multivariate analysis with International Prognostic Index criteria, HIF-1alpha remained a significant predictor for PFS (P = .026) and OS (P = .043). Compared with other biomarkers, HIF-1alpha correlated only with BCL6 (P = .004). In terms of gene expression, we found several common gene associations of HIF-1alpha and the stromal-1 signature with genes predominantly involved in regulation of the extracellular matrix (eg, BGN, COL1A2, COL5A1, and PLOD2). CONCLUSION The expression of HIF-1alpha protein is an important independent favorable prognostic factor for survival in patients with DLBCL treated with R-CHOP.

Lymphoma cell VEGFR2 expression detected by immunohistochemistry predicts poor overall survival in diffuse large B cell lymphoma treated with immunochemotherapy (R-CHOP)

Diffuse large B cell lymphoma (DLBCL) is clinically and biologically heterogeneous. In most cases of DLBCL, lymphoma cells co-express vascular endothelial growth factor (VEGF) and its receptors VEGFR1 and VEGFR2, suggesting autocrine in addition to angiogenic effects. We enumerated microvessel density and scored lymphoma cell expression of VEGF, VEGFR1, VEGFR2 and phosphorylated VEGFR2 in 162 de novo DLBCL patients treated with R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin and prednisone)-like regimens. VEGFR2 expression correlated with shorter overall survival (OS) independent of International Prognostic Index (IPI) (P = 0.0028). Phosphorylated VEGFR2 (detected in 13% of cases) correlated with shorter progression-free survival (PFS, P = 0.044) and trended toward shorter OS on univariate analysis. VEGFR1 was not predictive of survival on univariate analysis, but it did correlate with better OS on multivariate analysis with VEGF, VEGFR2 and IPI (P = 0.036); in patients with weak VEGFR2, lack of VEGFR1 coexpression was significantly correlated with poor OS independent of IPI (P = 0.01). These results are concordant with our prior finding of an association of VEGFR1 with longer OS in DLBCL treated with chemotherapy alone. We postulate that VEGFR1 may oppose autocrine VEGFR2 signalling in DLBCL by competing for VEGF binding. In contrast to our prior results with chemotherapy alone, microvessel density was not prognostic of PFS or OS with R-CHOP-like therapy.