Expressions of glucose transporter Types 1 and 3 and hexokinase-II in diffuse large B-cell lymphoma and other B-cell non-Hodgkin's lymphomas

Metabolic Reprogramming and Potential Therapeutic Targets in Lymphoma

Lymphoma is a heterogeneous group of diseases that often require their metabolism program to fulfill the demand of cell proliferation. Features of metabolism in lymphoma cells include high glucose uptake, deregulated expression of enzymes related to glycolysis, dual capacity for glycolytic and oxidative metabolism, elevated glutamine metabolism, and fatty acid synthesis. These aberrant metabolic changes lead to tumorigenesis, disease progression, and resistance to lymphoma chemotherapy. This metabolic reprogramming, including glucose, nucleic acid, fatty acid, and amino acid metabolism, is a dynamic process caused not only by genetic and epigenetic changes, but also by changes in the microenvironment affected by viral infections. Notably, some critical metabolic enzymes and metabolites may play vital roles in lymphomagenesis and progression. Recent studies have uncovered that metabolic pathways might have clinical impacts on the diagnosis, characterization, and treatment of lymphoma subtypes. However, determining the clinical relevance of biomarkers and therapeutic targets related to lymphoma metabolism is still challenging. In this review, we systematically summarize current studies on metabolism reprogramming in lymphoma, and we mainly focus on disorders of glucose, amino acids, and lipid metabolisms, as well as dysregulation of molecules in metabolic pathways, oncometabolites, and potential metabolic biomarkers. We then discuss strategies directly or indirectly for those potential therapeutic targets. Finally, we prospect the future directions of lymphoma treatment on metabolic reprogramming.

Plasma Metabolites Forecast Occurrence and Prognosis for Patients With Diffuse Large B-Cell Lymphoma

Background

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin’s lymphoma with considerable heterogeneity and different clinical prognosis. However, plasma metabomics used to forecast occurrence and prognosis of DLBCL are rarely addressed.

Method

A total of 65 volunteers including 22 healthy controls (Ctrl), 25 DLBCL patients newly diagnosed (ND), and 18 DLBCL patients achieving complete remission (CR) were enrolled. A gas chromatography mass spectrometry-based untargeted plasma metabolomics analysis was performed.

Results

Multivariate statistical analysis displayed distinct metabolic features among Crtl, ND, and CR groups. Surprisingly, metabolic profiles of newly diagnosed DLBCL patients undergoing different prognosis showed clear and distinctive clustering. Based on the candidate metabolic biomarkers (glucose and aspartate) and clinical indicators (lymphocyte, red blood count, and hemoglobin), a distinct diagnostic equation was established showing improved diagnostic performance with an area under curve of 0.936. The enrichment of citric acid cycle, deficiency of branched chain amino acid, methionine, and cysteine in newly diagnosed DLBCL patients was closely associated with poor prognosis. In addition, we found that malate and 2-hydroxy-2-methylbutyric acid were positively correlated with the baseline tumor metabolic parameters (metabolically active tumor volume and total lesion glycolysis), and the higher abundance of plasma malate, the poorer survival.

Conclusion

Our preliminary data suggested plasma metabolomics study was informative to characterize the metabolic phenotypes and forecast occurrence and prognosis of DLBCL. Malate was identified as an unfavorable metabolic biomarker for prognosis-prediction of DLBCL, which provided a new insight on risk-stratification and therapeutic targets of DLBCL. More studies to confirm these associations and investigate potential mechanisms are in the process.

B-cell Receptor Signaling Induced Metabolic Alterations in Chronic Lymphocytic Leukemia Can Be Partially Bypassed by TP53 Abnormalities

It has been unclear what role metabolism is playing in the pathophysiology of chronic lymphocytic leukemia (CLL). One reason is that the study of CLL metabolism is challenging due to the resting nature of circulating CLL cells. Also, it is not clear if any of the genomic aberrations observed in this disease have any impact on metabolism. Here, we demonstrate that CLL cells in proliferation centers exhibit upregulation of several molecules involved in glycolysis and mitochondrial metabolism. Comparison of CXCR4/CD5 intraclonal cell subpopulations showed that these changes are paralleled by increases in the metabolic activity of the CXCR4^lowCD5^high fraction that have recently egressed from the lymph nodes. Notably, anti-IgM stimulation of CLL cells recapitulates many of these metabolic alterations, including increased glucose uptake, increased lactate production, induction of glycolytic enzymes, and increased respiratory reserve. Treatment of CLL cells with inhibitors of B-cell receptor (BCR) signaling blocked these anti-IgM-induced changes in vitro, which was mirrored by decreases in hexokinase 2 expression in CLL cells from ibrutinib-treated patients in vivo. Interestingly, several samples from patients with 17p-deletion manifested increased spontaneous aerobic glycolysis in the unstimulated state suggestive of a BCR-independent metabolic phenotype. We conclude that the proliferative fraction of CLL cells found in lymphoid tissues or the peripheral blood of CLL patients exhibit increased metabolic activity when compared with the bulk CLL-cell population. Although this is due to microenvironmental stimulatory signals such as BCR-engagement in most cases, increases in resting metabolic activity can be observed in cases with 17p-deletion.

Hexokinase II expression as a prognostic marker in diffuse large B-cell lymphoma: pre- and post-rituximab era

We aimed to assess HKII expression and its prognostic significance in diffuse large B-cell lymphoma (DLBCL) patients. The HKII protein level was determined by immunohistochemistry in 159 newly diagnosed DLBCL patients, and its relationship with overall response rate, progression-free survival (PFS), and overall survival (OS) was analyzed. HKII was expressed in 95 DLBCL patients (59.7%). HKII-positive patients had poorer outcomes than negative patients for 5-y PFS (68% vs. 84%, p = 0.029) and 5-y OS (78% vs. 94%, p = 0.05). When only patients without no bulky disease, B symptoms, or extranodal involvement who had low IPI scores were considered, those with positive HKII had worse 5y-PFS and 5y-OS (p < 0.05). Multivariate analysis indicated that HKII status was an independent prognostic factor of OS. In subgroup analysis, HKII expression was associated with inferior OS in the CHOP group (p = 0.017). In CHOP group patients without bulky disease or extranodal involvement who had low LDH and low IPI scores (p < 0.05), positive HKII was associated with worse PFS and OS. No differences in PFS and OS, or any independent prognostic factors, were found in the RCHOP group. In DLBCL, HKII is valuable as a prognostic biomarker and may be useful as a tool for assessing disease risk.

Impact of anti-diabetic sodium-glucose cotransporter 2 inhibitors on tumor growth of intractable hematological malignancy in humans

Under the dysfunction of mitochondria, cancer cells preferentially utilize both glycolytic and pentose phosphate pathways rather than electron transport chains to desperately generate adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH), classically recognized as the Warburg effect. Based on this background, the present study tested the hypothesis that anti-diabetic sodium-glucose cotransporter 2 (SGLT2) inhibitors would exert a tumor-suppressive impact on intractable human hematological malignancies via the modulation of glucose metabolism within cells and cell cycles. The level of mRNA for SGLT2 was remarkably elevated in leukemic cells from patients with adult T-cell leukemia (ATL), one of the most intractable blood cancers in humans, and as well as in two kinds of ATL cell lines (MT-1 and MT-2). Two kinds of SGLT2 inhibitors, Luseogliflozin and Tofogliflozin substantially suppressed the proliferation of MT-1 and MT-2 cells in both adherent and anchorage-independent culture conditions. Such a suppressive effect on tumor cell growth was reproduced by Luseogliflozin in leukemic cells in peripheral blood from patients with ATL. In MT-2 cells, both of SGLT2 inhibitors considerably attenuated glucose uptake, intracellular ATP levels, and NADPH production, resultantly enhancing cell cycle arrest at the G0/G1 phase. From the standpoint of metabolic oncology, the present study suggests that SGLT2 inhibitors would be a promising adjunctive option for the treatment of the most intractable human hematological malignancies like ATL.

Expression of hypoxia-inducible factor 1α, glucose transporter 1, and hexokinase 2 in primary central nervous system lymphoma and the correlation with the biological behaviors

BACKGROUND

It has been indicated that abnormal glucose metabolism mediated by hypoxia-inducible factor 1α (HIF-1α) played an essential role in the development of solid tumor. However, there were rare studies about the role of them in primary central nervous system lymphoma (PCNSL).

OBJECTIVE

To investigate the protein levels of HIF-1α, glucose transporter 1 (GLUT1), and hexokinase 2 (HK2) in PCNSL and whether their levels are associated with prognostic factors.

METHODS

Expression of HIF-1α, GLUT1, and HK2 in 39 tumor tissues was evaluated by immunohistochemical stainning. The correlation of the expression of HIF-1α with the protein level of GLUT1 and HK2 was investigated. In addition, the association between these protein expression levels and clinical parameters and prognosis was analyzed.

RESULTS

In the tumor specimens of PCNSL, positive stainings of HIF-1α, GLUT1, and HK2 were in 23 patients (58.97%), 25 patients (64.1%), and 26 patients (66.67%), respectively, which were associated with the expression level of lactic dehydrogenase (LDH), but not with age, gender, number of lesion, ECOG score, or deep structure. The expression of HIF-1α was positively correlated with the expression of GLUT1 (p < .01, r = .749) and HK2 (p < .01, r = .787). Univariate analysis showed that upregulated GLUT1 was unfavorable predictors of progression-free survival (PFS) in PCNSL. The results of Cox proportional hazards model showed GLUT1 was significantly associated with shorter PFS (hazard ration: 5.65; 95% confidence interval: 1.23-25.84; p = .026).

CONCLUSIONS

This study indicated that there was a hypoxic microenvironment and HIF-1α was involved in the regulation of glycolysis pathway in PCNSL. GLUT1 might be a potential marker for shorter PFS in PCNSL.

The potential role of glycogen metabolism in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a common and aggressive form of non-Hodgkin lymphoma that may become refractory to available standard therapies, resulting in the need for the development of novel therapeutic targets. Increased metabolic activity of DLBCL tumor cells associated with high expression of glycolysis related proteins, such as glucose transporters and hexokinases, have already been described and indicates a pivotal role for glucose and glycogen metabolism in the malignant progression of the disease. Moreover, several enzymes involved in glycolysis and glycogen metabolism, including hexokinases and glycogen synthase kinase-3, are key molecules in mediating cell survival signaling, indicating that glucose/glycogen metabolism is tightly linked to the cell survival and can potentially be targeted for therapeutic purposes in DLBCL. In this review, we provide a summary of glycogen and glucose metabolism and discuss their significance in the metabolic reprograming that leads to cell survival and proliferation in DLBCL.

Glycolytic enzyme hexokinase II is a putative therapeutic target in B-cell malignant lymphoma

Hexokinase II (HXKII) is a key regulator of glucose metabolism that converts glucose to glucose 6-phosphate. Furthermore, HXKII blocks mitochondria-dependent apoptosis by inhibiting the release of cytochrome c. HXKII overexpression is frequently observed in several types of cancer and confers chemoresistance to cancer cells. In the present study, we found that compared with cell lines generated from diffuse large-B-cell lymphoma (DLBCL) patients, cell lines with features of Burkitt lymphoma have higher levels of HXKII because of the activation of both c-MYC and HIF-1. Under normoxia, HXKII levels were correlated with the growth ability of each B-cell lymphoma cell line. HXKII levels were further enhanced when the B-cell lymphoma cells were cultured under hypoxia. The high levels of HXKII induced by hypoxia conferred cisplatin resistance in all tested B-cell lymphoma cell lines. The HDAC inhibitor panobinostat significantly suppressed HXKII expression under both normoxic and hypoxic conditions. Importantly, panobinostat reversed the anti-lymphoma action of cisplatin, and this effect was diminished by hypoxia. These data suggest that HXKII plays different roles, including in the regulation of glycolysis and inhibition of apoptosis, depending on its expression levels. Furthermore, inhibition of HXKII expression by panobinostat may represent a new and attractive strategy to overcome cisplatin resistance.

Correlation of pretreatment 18F-FDG uptake with clinicopathological factors and prognosis in patients with newly diagnosed diffuse large B-cell lymphoma

Supplemental Digital Content is available in the text.

Objectives

The aim of this study is to determine the correlation of pretreatment fluorine-18 fluorodeoxyglucose uptake with clinicopathological factors and its prognostic value in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL).

Patients and methods

A cohort of 162 patients with newly diagnosed DLBCL who had undergone pretreatment PET/computed tomography was retrospectively reviewed. The relationship of pretreatment maximum standard uptake value (SUV_max) with clinical factors, molecular markers, and efficacy was evaluated. The value of SUV_max in predicting progression-free survival (PFS) and overall survival was analyzed.

Results

In all, 72.9% of the patients received R-CHOP treatment; the rest received CHOP chemotherapy. The median follow-up duration was 30 months (range, 4–124 months). The median SUV_max was 12.2 (range, 1.7–42.7). SUV_max between groups differed significantly with respect to each of International Prognostic Index (IPI) factors, except for age and performance status. High SUV_max was associated with high Ki-67 and Glut-3 protein expression, but not with Glut-1. Complete remission rate differed significantly between the low (SUV_max≤9.0) and the high SUV_max (SUV_max>9.0) groups (91.7 vs. 61.1%, P=0.000). Patients with low SUV_max showed favorable survival (3-year PFS: 92.2 vs. 63.6%, P=0.000; 3-year overall survival: 95.5 vs. 78.3%, P=0.003). On multivariate analyses, SUV_max predicted PFS independent of revised-IPI (SUV_max: P=0.011, hazard ratio 4.784; revised-IPI: P=0.004, hazard ratio 2.551).

Conclusion

Pretreatment SUV_max was associated with clinicopathological factors, efficacy, and survival outcome. A novel prognostic model on the basis of IPI score/pretreatment SUV_max might be useful for risk stratification of patients with newly diagnosed DLBCL Video abstract: http://links.lww.com/NMC/A55.

Dual time-point FDG PET/CT and FDG uptake and related enzymes in lymphadenopathies: preliminary results

PURPOSE

The purpose of this study was to determine the ability of dual time-point (DTP) PET/CT with (18)F-FDG to discriminate between malignant and benign lymphadenopathies. The relationship between DTP FDG uptake and glucose metabolism/hypoxia markers in lymphadenopathies was also assessed.

METHODS

Patients with suspected lymphoma or recently diagnosed treatment-naive lymphoma were prospectively enrolled for DTP FDG PET/CT (scans 60 min and 180 min after FDG administration). FDG-avid nodal lesions were segmented to yield volume and standardized uptake values (SUV), including SUVmax, SUVmean, cSUVmean (with partial volume correction), total lesion glycolysis (TLG) and cTLG (with partial volume correction). Expression of glucose transporter-1 (GLUT-1), hexokinase-II (HK-II), glucose-6-phosphatase (G6Pase) and hypoxia-inducible factor-1alpha (HIF-1alpha) were assessed with immunohistochemistry and enzyme activity was determined for HK and G6Pase.

RESULTS

FDG uptake was assessed in 203 lesions (146 malignant and 57 benign). Besides volume, there were significant increases over time for all parameters, with generally higher levels in the malignant lesions. The retention index (RI) was not able to discriminate between malignant and benign lesions. Volume, SUVmax, TLG and cTLG for both scans were able to discriminate between the two groups statistically, but without complete separation. Glucose metabolism/hypoxia markers were assessed in 15 lesions. TLG and cTLG were correlated with GLUT-1 expression on the 60-min scan. RI-max and RI-mean and SUVmax, SUVmean and cSUVmean on the 60-min scan were significantly correlated with HK-II expression.

CONCLUSION

RI was not able to discriminate between malignant and benign lesions, but some of the SUVs were able to discriminate on the 60-min and 180-min scans. Furthermore, FDG uptake was correlated with GLUT-1 and HK-II expression.

Clinicopathologic Features and Molecular Characteristics of Glucose Metabolism Contributing to ¹⁸F-fluorodeoxyglucose Uptake in Gastrointestinal Stromal Tumors

Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) is useful in the preoperative diagnosis of gastrointestinal stromal tumors (GISTs); however, the molecular characteristics of glucose metabolism of GIST are unknown. We evaluated 18F-FDG uptake on preoperative PET/CT of 40 patients and analyzed the expression of glycolytic enzymes in resected GIST tissues by qRT-PCR, western blotting, and immunohistochemistry. Results of receiver operating characteristic curve analysis showed that the maximum standardized uptake value (SUVmax) cut-off value of 4.99 had a sensitivity of 89.5%, specificity was 76.2%, and accuracy of 82.5% for identifying tumors with a high risk of malignancy. We found that 18F-FDG uptake correlated positively with tumor size, risk grade, and expression levels of glucose transporter 1 (GLUT1), hexokinase 1 (HK1), and lactate dehydrogenase A (LDHA). Elevated HK and LDH activity was found in high-risk tumors. Among the isoforms of GLUT and HK, GLUT1 and HK1 expression increased with higher tumor risk grade. In addition, overexpression of glycolytic enzymes M2 isoform of pyruvate kinase (PKM2) and LDHA was observed in GISTs, especially in high-risk tumors. These results suggest that upregulation of GLUT1, HK1, PKM2, and LDHA may play an important role in GIST tumorigenesis and may be useful in the preoperative prediction of malignant potential.

Current status of PET/CT in the diagnosis and follow up of lymphomas

Lymphomas are a heterogeneous group of malignancies that have a distinct biological behavior according to the subtype and degree of differentiation. Adequate staging, which has a direct impact on prognosis, is essential to properly plan therapy. Structural cross-sectional imaging, such as computed tomography, has been the standard imaging tool to stage and monitor patients with lymphoma. However, molecular imaging such as positron emission tomography has shown complementary diagnostic and prognostic values. This review discusses the current value of positron emission tomography imaging using 2-[fluorine-18]fluoro-2-deoxy-d-glucose in staging, restaging, monitoring and detecting relapse in Hodgkin's and non-Hodgkin lymphoma.

Relationship between 2-deoxy-2-[(18)F]-fluoro-d-glucose uptake and clinicopathological factors in patients with diffuse large B-cell lymphoma

The aim of this study was to investigate correlations between the standardized uptake value of the biopsy site (BSUVmax) and levels of glucose transporter (GLUT)-1, GLUT-3 and hexokinase-II (HK-II), between BSUVmax and the Ki-67 proliferation index (MIB-1), and between BSUVmax and clinicopathological factors. Sixty-eight patients with diffuse large B-cell lymphoma (DLBCL) were included in this study. BSUVmax was significantly correlated with GLUT-1, GLUT-3 and the International Prognostic Index (IPI) (GLUT-1: r = 0.584, IPI: r = 0.363, p < 0.001; GLUT-3: r = 0.369, p = 0.009; IPI: r = 0.363, p = 0.004), but not with MIB-1 and HK-II. A statistically significant correlation was observed between GLUT-3 expression and each of IPI and gene expression profiling (GEP) (IPI: p = 0.0186; GEP: p = 0.0179). 2-Deoxy-2-[(18)F]-fluoro-d-glucose (FDG) uptake was significantly correlated with the levels of GLUT-1 and GLUT-3 and with IPI. The results indicated that GLUT-3 expression is related to GEP and IPI, and that BSUVmax and GLUT-3 may have a relationship with the prognosis of DLBCL.

Regional PET/CT after water gastric inflation for evaluating loco-regional disease of gastric cancer

OBJECTIVE

We aimed to improve diagnostic accuracy of (18)F-fluoro-2-deoxyglucose (FDG) PET/CT for gastric cancer with water gastric inflation.

MATERIALS AND METHODS

44 gastric cancer patients (M:F=30:14, age ± std=62.1 ± 14.5 y) were enrolled before surgery. Fifty minutes after injection of FDG (0.14 mCi/kg body weight), whole body PET/CT was performed first and then regional PET/CT over gastric area was obtained 80 min post FDG injection after water gastric inflation. Diagnostic accuracies for loco-regional lesions were compared between whole body and regional PET/CT.

RESULTS

48 primary tumors (23 EGC and 25 AGC) and 348 LN stations (61 metastatic and 287 benign) in 44 patients were investigated. Primary tumor sensitivity of whole body PET/CT (50%=24/48) was significantly improved by regional PET/CT (75%=36/48, p<0.005). Sensitivity of whole body PET/CT (24.6%=15/61) for LN metastasis was also significantly improved by regional PET/CT (36.1%=22/61, p<0.01), whereas specificity of whole body PET/CT (99.3%=285/287) was not compromised by regional PET/CT (98.3%=282/287, p>0.05). Higher primary tumor FDG uptake in regional PET/CT indicated shorter progress-free survival (p=0.0003).

CONCLUSION

Diagnostic accuracy of whole body PET/CT for loco-regional disease of gastric cancer could be significantly improved by regional PET/CT after water gastric inflation and prognosis could be effectively predicted by primary tumor FDG uptake in regional PET/CT.

GLUT1 expression patterns in different Hodgkin lymphoma subtypes and progressively transformed germinal centers

Background

Increased glycolytic activity is a hallmark of cancer, allowing staging and restaging with ¹⁸F-fluorodeoxyglucose-positron-emission-tomography (PET). Since interim-PET is an important prognostic tool in Hodgkin lymphoma (HL), the aim of this study was to investigate the expression of proteins involved in the regulation of glucose metabolism in the different HL subtypes and their impact on clinical outcome.

Methods

Lymph node biopsies from 54 HL cases and reactive lymphoid tissue were stained for glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA) and lactate exporter proteins MCT1 and MCT4. In a second series, samples from additional 153 HL cases with available clinical data were stained for GLUT1 and LDHA.

Results

Membrane bound GLUT1 expression was frequently observed in the tumor cells of HL (49% of all cases) but showed a broad variety between the different Hodgkin lymphoma subtypes: Nodular sclerosing HL subtype displayed a membrane bound GLUT1 expression in the Hodgkin-and Reed-Sternberg cells in 56% of the cases. However, membrane bound GLUT1 expression was more rarely observed in tumor cells of lymphocyte rich classical HL subtype (30%) or nodular lymphocyte predominant HL subtype (15%). Interestingly, in both of these lymphocyte rich HL subtypes as well as in progressively transformed germinal centers, reactive B cells displayed strong expression of GLUT1. LDHA, acting downstream of glycolysis, was also expressed in 44% of all cases. We evaluated the prognostic value of different GLUT1 and LDHA expression patterns; however, no significant differences in progression free or overall survival were found between patients exhibiting different GLUT1 or LDHA expression patterns. There was no correlation between GLUT1 expression in HRS cells and PET standard uptake values.

Conclusions

In a large number of cases, HRS cells in classical HL express high levels of GLUT1 and LDHA indicating glycolytic activity in the tumor cells. Although interim-PET is an important prognostic tool, a predictive value of GLUT1 or LDHA staining of the primary diagnostic biopsy could not be demonstrated. However, we observed GLUT1 expression in progressively transformed germinal centers and hyperplastic follicles, explaining false positive results in PET. Therefore, PET findings suggestive of HL relapse should always be confirmed by histology.

Overexpression of hexokinase-2 in giant cell tumor of bone is associated with false positive in bone tumor on FDG-PET/CT

INTRODUCTION

The aim of the current study was to evaluate the usefulness of maximum standardized uptake value (SUV(max)) in 2-deoxy-2-F(18)-fluoro-D-glucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) for preoperative differential diagnosis between benign and malignant bone tumors.

MATERIALS AND METHODS

Seventy-nine patients with bone tumors were examined by FDG-PET prior to histopathological diagnosis. The SUV(max) was calculated and compared between benign and malignant lesions, and among different histopathological subgroups, to identify false-positive histological subtypes.

RESULTS

There was a statistically significant difference in the SUV(max) of benign (3.7 ± 3.3; n = 17) and malignant (5.3 ± 3.3; n = 62) bone tumors. However, receiver operating characteristic curve analysis revealed the poor accuracy of this distinction. The cut-off value was determined to be 2.6, while the value of sensitivity and specificity was calculated to be 74.2 and 64.7 %, respectively. Giant cell tumor of bone (9.0 ± 2.0; n = 5) displayed a higher SUV(max) than osteosarcoma (4.2 ± 2.3; n = 18). Immunohistochemical analysis demonstrated that markers of these cancers, hexokinase-2 (HK-2) and glucose transporter type 1 (GLUT-1), supported our findings.

CONCLUSION

The poor accuracy of SUV(max) in 18F-FDG-PET/CT in distinguishing malignant from benign bone tumors was confirmed; some benign bone tumors showed high FDG uptake. Giant cell tumor of bone was a major false-positive histopathological subtype of bone tumors, showing high FDG accumulation. HK-2 contributed significantly to FDG uptake, whereas GLUT-1 appeared to play no role in FDG uptake in giant cell tumor of bone.

Interim positron emission tomography scan associated with international prognostic index and germinal center B cell-like signature as prognostic index in diffuse large B-cell lymphoma

[(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is essential to optimize the initial staging and to predict the prognosis of diffuse large B-cell lymphoma (DLBCL). To assess the relationship between the germinal center B cell-like/activated B cell-like (GCB/ABC) classification and PET scan features in DLBCL, 57 cases treated with rituximab and a cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP)/CHOP-like regimen were analyzed. The expression profile of 18 GCB/ABC related genes and five genes coding for glucose transporters (GLUTs) was determined from frozen tissues using DASL (cDNA-mediated Annealing, Selection, Ligation and extension) technology. According to the gene expression profile (GEP), 30 cases of DLBCL were classified as GCB subtype (2-year progression-free survival [PFS] 76%) and 27 cases as ABC subtype (2-year PFS 51%, p = 0.03). Using a semiquantitative assessment of the decrease in standard uptake value (SUV) at interim PET performed after 3-4 cycles of chemotherapy, we defined fast (n = 36) and slow (n = 9) metabolic responders. In multivariate analysis, GCB/ABC subtype, age-adjusted international prognostic index (aaIPI) and slow/fast metabolic response were independent variables that predicted outcome. A score incorporating aaIPI, fast/slow metabolic response and GCB/ABC classification was used to define two groups with highly significantly distinct outcomes. Our study suggests that the combination of GEP, aaIPI and interim PET more accurately predicts DLBCL prognosis and is therefore suitable for tailoring therapeutic strategies.

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.

Expression of glucose transporter-1, hypoxia-inducible factor-1α, phosphatidylinositol 3-kinase and protein kinase B (Akt) in relation to [(18)F]fluorodeoxyglucose uptake in nasopharyngeal diffuse large B-cell lymphoma: a case report and literature review

This report presents a case of nasopharyngeal diffuse large B-cell lymphoma and a literature review concerning the use of [(18)F]fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). A 37-year old man was admitted to hospital complaining of nasal secretions with minor epistaxis and a 20-year history of snoring. Nasal endoscopy found diffuse swelling in the nasopharynx and a biopsy was performed. Prior to chemotherapy, FDG-PET/CT showed soft tissue diffuse thickening and FDG accumulation in the nasopharynx and bilateral cervical lymph nodes; FDG did not accumulate elsewhere. After four cycles of chemotherapy (rituximab, cyclo phosphamide, doxorubicin, vincristine) and prednisone treatment, FDG-PET/CT showed that FDG still accumulated in the nasopharynx and bilateral cervical lymph nodes, therefore radiotherapy was initiated. At 1 year, FDG-PET/CT showed no FDG accumulation. Immunohistochemical analysis revealed that the tumour was positive for phosphorylated protein kinase B (Akt), suggesting that FDG uptake may be associated with factors activated by the phosphatidylinositol 3-kinase/Akt signalling pathway.

Reduced survival of patients with hepatocellular carcinoma expressing hexokinase II

Hexokinase II is a key enzyme in the glycolytic pathway and possesses anti-apoptotic properties in tumor cells. The present study aimed to analyze the expression of hexokinase II and its clinical correlation with clinical factors in patients with hepatocellular carcinoma who treated surgically in China. Reverse transcription-polymerase chain reaction and real-time quantitative polymerase chain reaction were performed to determine hexokinase II mRNA expression in cancer tissues. Protein expression of hexokinase II was evaluated immunohistochemically. Correlation of hexokinase II expression with clinical data was analyzed by the χ(2) or Fisher exact test. Survival was estimated by the Kaplan-Meier method, compared by log-rank test and Cox regression model. A total of 97 specimens were analyzed. Fifty-four tumors showed strong expression of hexokinase II (55.67% expression rate). There were no statistical associations between hexokinase II expression and age, gender, tumor size, TNM stage, serum AFP level, and hepatitis virus infection. Kaplan-Meier curves showed an association between positive Hexokinase II expression and worse overall survival (P value = 0.043). Furthermore, patients expressing hexokinase II had a relatively higher risk for poor prognosis (hazard ratio = 2.049). These results suggest that hexokinase II is highly expressed in hepatocellular carcinoma and has prognostic significance. Hexokinase II represents a potential new therapeutic target in this malignancy.

Relation between fluorodeoxyglucose uptake and glucose transporter-1 expression in gastric signet ring cell carcinoma

PURPOSE

Gastric signet ring cell carcinoma (GSRC) is known to have low fluorodeoxyglucose (FDG) uptake. The aim of the study was to investigate the relation between FDG uptake and glucose transporter (GLUT)-1 expression and clinicopathologic parameters in cases of GSRC.

MATERIALS AND METHODS

Forty patients (28 men, mean age 54 ± 12 years) with histologically confirmed GSRC who underwent pre-operative [(18)F]FDG PET/CT were enrolled. Maximum standardized uptake values (SUVmax) were compared with clinicopathologic parameters and GLUT-1 expression. Cases were divided based on GLUT-1 expression in tumor tissues into a membranous group (n = 17) and a cytoplasmic group (n = 23).

RESULTS

Mean SUVmax was significantly higher in the membranous group than in the cytoplasmic group (6.06 ± 2.79 vs. 3.67 ± 1.54, P = 0.03). Gastric wall invasion, depth of invasion, extent of LN metastasis, overall stage, and tumor size were found to be related to SUVmax. On the other hand, age, sex, and the presence of distant metastasis were not related to SUVmax. Multivariate analysis revealed that membranous GLUT-1 expression and the extent of LN metastasis independently predicted high FDG uptake.

CONCLUSIONS

This study demonstrates that high FDG uptake is mediated by membranous GLUT-1 expression in GSRC.

Glucose transporter expression of an esophageal gastrointestinal tumor detected by F-18 FDG PET/CT

A 74-year-old woman had dysphagia and underwent esophagogastroduodenoscopy. A giant submucosal tumor was seen from the middle to the lower esophagus. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG-PET/CT) was performed and F-18 FDG was found to accumulate in the submucosal tumor. The maximum standardized uptake value of the early phase was 4.93 and that of the delayed phase was 6.48. Gastrointestinal stromal tumor (GIST) was confirmed by both fine needle aspiration under endoscopic ultrasound and postoperative histopathologic findings. We stained the postoperative histopathologic specimen to investigate glucose transporter (GLUT) expression using immunohistochemistry, which revealed that GLUT-1 had a weak expression on membranes and GLUT-4 had a strong expression on membranes or in cytoplasm. GLUT-3 had no expression on membranes or in cytoplasm. Esophageal GIST is rare and the relationship between GLUT expression and F-18 FDG accumulation in GIST is probably rare.

The role of dysregulated glucose metabolism in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer and also one of the most poorly understood. Other health issues that are affecting women with increasing frequency are obesity and diabetes, which are associated with dysglycemia and increased blood glucose. The Warburg Effect describes the ability of fast-growing cancer cells to preferentially metabolize glucose via anaerobic glycolysis rather than oxidative phosphorylation. Recent epidemiological studies have suggested a role for hyperglycemia in the pathogenesis of a number of cancers. If hyperglycemia contributes to tumour growth and progression, then it is intuitive that antihyperglycemic drugs may also have an important antitumour role. Preliminary reports suggest that these drugs not only reduce available plasma glucose, but also have direct effects on cancer cell viability through modification of molecular energy-sensing pathways. This review investigates the effect that hyperglycemia may have on EOC and the potential of antihyperglycemic drugs as therapeutic adjuncts.

Imaging pharmacodynamics in oncology: the potential significance of "flares"

The clinical use of (18)F-fluorodeoxyglucose (FDG) positron emission tomography in monitoring anticancer treatment is expanding. At the same time a number of radiotracers aiming to image different aspects of tumour biology such as proliferation and apoptosis are being developed. However, the factors determining changes of radiotracer uptake parameters in response to treatment are not well understood. In many cases, cellularity may be the primary determinant of changes of FDG uptake and may confound the interpretation of metabolic changes. Early imaging assessments have in some cases showed transient increases of uptake parameters, commonly termed "flares", which are likely to be unaffected by cellularity and directly reflect pharmacodynamics at a cellular level. In this review a number of settings where molecular imaging "flares" have been described are discussed. Such changes may often be clinically informative and warrant careful study as potential predictive biomarkers.