Thymidine phosphorylase expression causes both the increase of intratumoral microvessels and decrease of apoptosis in human esophageal carcinomas

Druggable Biomarkers Altered in Clear Cell Renal Cell Carcinoma: Strategy for the Development of Mechanism-Based Combination Therapy

Targeted therapeutics made significant advances in the treatment of patients with advanced clear cell renal cell carcinoma (ccRCC). Resistance and serious adverse events associated with standard therapy of patients with advanced ccRCC highlight the need to identify alternative 'druggable' targets to those currently under clinical development. Although the Von Hippel-Lindau (VHL) and Polybromo1 (PBRM1) tumor-suppressor genes are the two most frequently mutated genes and represent the hallmark of the ccRCC phenotype, stable expression of hypoxia-inducible factor-1α/2α (HIFs), microRNAs-210 and -155 (miR_S), transforming growth factor-beta (TGF-ß), nuclear factor erythroid 2-related factor 2 (Nrf2), and thymidine phosphorylase (TP) are targets overexpressed in the majority of ccRCC tumors. Collectively, these altered biomarkers are highly interactive and are considered master regulators of processes implicated in increased tumor angiogenesis, metastasis, drug resistance, and immune evasion. In recognition of the therapeutic potential of the indicated biomarkers, considerable efforts are underway to develop therapeutically effective and selective inhibitors of individual targets. It was demonstrated that HIF_S, miR_S, Nrf2, and TGF-ß are targeted by a defined dose and schedule of a specific type of selenium-containing molecules, seleno-L-methionine (SLM) and methylselenocystein (MSC). Collectively, the demonstrated pleiotropic effects of selenium were associated with the normalization of tumor vasculature, and enhanced drug delivery and distribution to tumor tissue, resulting in enhanced efficacy of multiple chemotherapeutic drugs and biologically targeted molecules. Higher selenium doses than those used in clinical prevention trials inhibit multiple targets altered in ccRCC tumors, which could offer the potential for the development of a new and novel therapeutic modality for cancer patients with similar selenium target expression. Better understanding of the underlying mechanisms of selenium modulation of specific targets altered in ccRCC could potentially have a significant impact on the development of a more efficacious and selective mechanism-based combination for the treatment of patients with cancer.

The value of hemoglobin-to-red blood cell distribution width ratio (Hb/RDW), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) for the diagnosis of nasopharyngeal cancer

The clinical significance of hemoglobin-to-red blood cell distribution width (Hb/RDW) for the diagnosis of nasopharyngeal cancer (NPC) has not been reported yet. This study aimed to evaluate the value of preoperative Hb/RDW, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) for the diagnosis of NPC.A total of 180 NPC patients (NPC group) and 149 healthy subjects (control group) were recruited to assess the value of Hb/RDW, NLR, and PLR for the diagnosis of NPC.It was noted that NLR and PLR were significantly higher in the NPC group than those in the control group (P < .001); however, Hb/RDW was lower in the NPC group compared with that in the control group (P < .001). NLR was also remarkably different between patients of stage I+II and those of stage III+IV (P = .043), and that was different in patients with lymph node metastases or not (P = .030). Besides, PLR was significantly different in patients with serosal invasion or not (P = .031). In receiver operating characteristic curve, compared with Hb/RDW alone (sensitivity, 66.67%; specificity, 85.23%), the sensitivity (67.78%, 72.78%) and specificity (89.62%, 90.6%) of Hb/RDW with NLR and PLR were both increased. Furthermore, Hb/RDW combined with NLR area under the ROC (AUC), 0.824; 95% confidence interval (CI): 0.779-0.864, P = .0080) or PLR (AUC: 0.851, 95% CI: 0.808-0.888, P = .0002) had a greater AUC value for the diagnosis of NPC compared with Hb/RDW alone (AUC: 0.781, 95% CI: 0.732-0.824).Hb/RDW can be used as a valuable indicator for auxiliary diagnosis of NPC. Preoperative Hb/RDW combined with NLR or PLR is of great significance in the auxiliary diagnosis and pathological staging of NPC.

Comparison and validation of the value of preoperative inflammation marker-based prognostic scores in resectable pancreatic ductal adenocarcinoma

Purpose

We aimed to compare and validate the prognostic value of inflammation-based prognostic scores for patients with resectable pancreatic ductal adenocarcinoma (PDAC) and to establish a novel, effective nomogram incorporating inflammation-based prognostic scores to predict disease-free survival (DFS) in these patients.

Patients and methods

Clinicopathological characteristics and follow-up data were retrieved from our prospective database. A total of 420 patients with PDAC who underwent radical resection were evaluated between January 2007 and December 2016. Blood samples were obtained within 7 days prior to surgical intervention. Time-dependent receiver operating characteristic curves were generated to determine optimal cutoff values for independent prognostic factors. Nomograms for DFS were established based on multivariate Cox proportional hazard models, and the results were internally validated using bootstrap resampling.

Results

Neutrophil-lymphocyte ratio (NLR) >2.13 and platelet-lymphocyte ratio (PLR) >140 were independent prognostic factors for DFS and overall survival. Stratified analyses indicated that these associations were not present among patients with stage III disease. Independent predictors of DFS, including Eastern Cooperative Oncology Group performance status score, tumor stage, differentiation, adjuvant treatment, NLR, and PLR, were incorporated into two nomograms for prediction of DFS in a cohort of PDAC patients after curative surgery. The area under receiver operating characteristic curve of the nomogram including NLR and PLR (0.804) was higher than that without NLR and PLR (0.711). The bootstrap-corrected AUC for the model including NLR and PLR was 0.803, while that for the model without NLR and PLR was 0.711.

Conclusion

Our study demonstrates that high NLR and high PLR are important clinical predictors of poor survival in patients with resectable PDAC. Additionally, a nomogram including NLR and PLR can objectively and reliably predict DFS among patients with PDAC following curative surgery.

Thymidine phosphorylase: A potential new target for treating cardiovascular disease

We recently found that thymidine phosphorylase (TYMP), also known as platelet-derived endothelial cell growth factor, plays an important role in platelet activation in vitro and thrombosis in vivo by participating in multiple signaling pathways. Platelets are a major source of TYMP. Since platelet-mediated clot formation is a key event in several fatal diseases, such as myocardial infarction, stroke and pulmonary embolism, understanding TYMP in depth may lead to uncovering novel mechanisms in the development of cardiovascular diseases. Targeting TYMP may become a novel therapeutic for cardiovascular disorders. In this review article, we summarize the discovery of TYMP and the potential molecular mechanisms of TYMP involved in the development of various diseases, especially cardiovascular diseases. We also offer insights regarding future studies exploring the role of TYMP in the development of cardiovascular disease as well as in therapy.

Pretreatment hematologic markers as prognostic factors in patients with nasopharyngeal carcinoma: A systematic review and meta-analysis

BACKGROUND

Pretreatment hematologic parameters of the inflammatory response, including lymphocyte, neutrophil, and platelet counts, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio, have emerged as prognostic factors for patients with cancer. This systematic review and meta-analysis aimed to summarize the association between the hematologic markers and prognosis of nasopharyngeal carcinoma (NPC).

METHODS

A systematic search of PubMed, Google Scholar, MEDLINE, EMBASE, Web of Science, and the Cochrane Library was conducted up to April 2016. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were extracted and synthesized to examine prognostic outcomes including cancer-specific survival (CSS), overall survival (OS), progression-free survival (PFS), distant metastasis-free survival, and local relapse-free survival (LRFS).

RESULTS

Fourteen studies comprising 11,651 NPC patients were ultimately included, and all eligible studies were conducted in East Asia. The OS, CSS, PFS, distant metastasis-free survival, and LRFS risks differed among patients according to hematologic marker levels. All of the parameters were associated with prognostic outcomes in patients with NPC. NLR and lymphocyte counts were most commonly reported. A high NLR was significantly associated with poor NPC prognosis (pooled HR 1.42, 95% CI 1.21-1.67 for CSS; pooled HR 1.77, 95% CI 1.41-2.23 for OS; pooled HR 1.67, 95% CI 1.36-2.06 for PFS; pooled HR 1.64, 95% CI 1.15-2.34 for LRFS). High lymphocyte count indicated favorable NPC prognosis (pooled HR 0.72, 95% CI 0.64-0.81 for OS; pooled HR 0.71, 95% CI 0.56-0.91 for PFS).

CONCLUSIONS

Meta-analysis indicated that NLR and lymphocyte counts could be prognostic predictors in NPC for East Asian population. Patients with a high NLR or low lymphocyte count had poor prognosis. However, due to the limitation of included population, the conclusion was limited to East Asian patients only.

Capecitabine for treating head and neck cancer

INTRODUCTION

With an increasing incidence, over half a million cases of head and neck cancer (HNC) are diagnosed annually worldwide. Various chemotherapeutic agents are utilized to achieve adequate locoregional control. Cisplatin, fluorouracil (FU), and taxanes are often used to treat HNC but these regimens have shown high toxicity and poor patient compliance. Capecitabine is an orally administered prodrug that is preferentially converted to FU in tumor cells in comparison to normal cells.

AREA COVERED

In this review, the authors evaluate the role of capecitabine in radical and palliative settings either alone or in combination with other chemotherapeutic drugs in the management of HNC. In addition, metabolic conversion, pharmacokinetics, pharmacodynamics, and toxicity profile of capecitabine are discussed.

EXPERT OPINION

Various phase II trials conducted on capecitabine in the management of recurrent HNC have shown comparable results and tolerable toxic effects especially in pre-treated fragile patients. Capecitabine, used in induction or concurrent settings in the radical management of locoregionally advanced HNC, have also shown promising results. Randomized trials are needed to validate the role of capecitabine in the management of HNC.

Pretreatment platelet count improves the prognostic performance of the TNM staging system and aids in planning therapeutic regimens for nasopharyngeal carcinoma: a single-institutional study of 2,626 patients

INTRODUCTION

Thrombocytosis has been identified as an unfavorable prognostic factor in several types of cancer. This study aimed to evaluate the prognostic value of pretreatment platelet count in association with the TNM staging system and therapeutic regimens in patients with nasopharyngeal carcinoma (NPC).

METHODS

A total of 2,626 patients with NPC were retrospectively analyzed. Platelet count >300 × 10(9)/L was defined as thrombocytosis. Matched-pair analysis was performed between patients receiving chemoradiotherapy and radiotherapy.

RESULTS

Multivariate analysis showed that platelet count was an independent unfavorable prognostic factor for overall survival (OS) [hazard ratio (HR) = 1.810, 95% confidence interval (CI) = 1.531-2.140, P < 0.001] and distant metastasis-free survival (DMFS) (HR = 1.873, 95% CI = 1.475-2.379, P < 0.001) in the entire patient cohort. Further subgroup analysis revealed that increased platelet count was an independent unfavorable prognostic factor for OS and DMFS in patients with NPC stratified by early and advanced T category, N category, or TNM classification (all P ≤ 0.001). Receiver operating characteristic (ROC) curves verified that the predictive value of TNM classification for OS was improved when combined with pretreatment platelet count (P = 0.030). Matched-pair analysis showed that chemoradiotherapy significantly improved OS only in advanced-stage NPC with thrombocytosis (HR = 0.416, 95% CI = 0.226-0.765, P = 0.005).

CONCLUSIONS

Pretreatment platelet count, when combined with TNM classification, is a useful indicator for metastasis and survival in patients with NPC. It may improve the predictive value of the TNM classification and help to identify patients likely to benefit from more aggressive therapeutic regimens.

Pretreatment platelet count as a predictor for survival and distant metastasis in nasopharyngeal carcinoma patients

The aim of the present study was to investigate the prognostic value of different pretreatment platelet (PLT) counts on the treatment outcome in nasopharyngeal carcinoma (NPC) patients receiving concurrent chemoradiotherapy (CCRT) or radiotherapy (RT) alone. A total of 1,501 NPC patients, including 412 receiving CCRT and 1,089 receiving RT, were enrolled in the present study. The PLT count cut-off points for the CCRT and RT groups were 150 and 300×10⁹/l, respectively, and the PLT counts were categorized it into three groups: Low (PLT≤150×10⁹/l), moderate (150×10⁹/l<PLT≤300×10⁹/l) and high (PLT>300×10⁹/l). To identify independent predictors of overall survival (OS), the Cox proportional hazards model was used to determine local-regional recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) rates in the CCRT and RT patients. Furthermore, univariate and multivariate analysis indicated that compared with a moderate PLT count, a low PLT count was an independent unfavorable prognostic factor for OS rate in CCRT patients [hazard ratio (HR), 2.024; 95% confidence interval (CI), 1.165–3.516], and a high PLT count was an independent unfavorable prognostic factor for OS and DMFS rates in CCRT (OS: HR, 1.742; 95% CI, 1.090–2.786; DFMS: HR, 2.110; 95%CI, 1.084–4.108) and RT (OS: HR, 1.740; 95%CI, 1.283–2.362; DMFS: HR, 2.819; 95% CI, 1.766–4.497) patients. Compared with a low PLT count, a high PLT count was significantly and independently associated with a poor DMFS rate in the RT patients (P=0.025; HR, 2.454; 95% CI, 1.121–5.372). Therefore, the present study indicates that low and high PLT counts may be useful indicators of survival and distant metastasis in NPC patients who have undergone radiation treatment.

Expression of thymidine phosphorylase in lymph nodes involved with mycosis fungoides and sézary syndrome

Thymidine phosphorylase may be overexpressed in both neoplastic cells and tumor stromal cells in a variety of malignancies. Our study explores thymidine phosphorylase expression in lymph nodes (LNs) from patients with mycosis fungoides (MF) or Sézary syndrome (SS). In MF/SS, the LNs may have a pathologic diagnosis of either dermatopathic lymphadenopathy (LN-DL) or involvement by MF/SS (LN-MF). We performed immunohistochemical staining on MF/SS lymph nodes using antibodies to thymidine phosphorylase, CD68, CD21, CD3, and CD4. In both LN-DL and benign nodes, thymidine phosphorylase staining was noted only in macrophages, dendritic cells, and endothelial cells. In LN-MF, thymidine phosphorylase expression was also noted in subsets of intermediate to large neoplastic T cells. Concurrent CD68, CD21, CD3, and CD4 staining supported the above observations. Similar results were noted in the skin and in LN-MF with large cell transformation. Other T-cell lymphomas were also examined (total 7 cases); only enteropathy-type T-cell lymphoma (1 case) showed TP positivity in neoplastic T lymphocytes. We demonstrated that thymidine phosphorylase staining is present in neoplastic T cells in mycosis fungoides. The exact mechanism needs further investigation.

The dual role of thymidine phosphorylase in cancer development and chemotherapy

Thymidine phosphorylase (TP), also known as "platelet-derived endothelial cell growth factor" (PD-ECGF), is an enzyme, which is upregulated in a wide variety of solid tumors including breast and colorectal cancers. TP promotes tumor growth and metastasis by preventing apoptosis and inducing angiogenesis. Elevated levels of TP are associated with tumor aggressiveness and poor prognosis. Therefore, TP inhibitors are synthesized in an attempt to prevent tumor angiogenesis and metastasis. TP is also indispensable for the activation of the extensively used 5-fluorouracil prodrug capecitabine, which is clinically used for the treatment of colon and breast cancer. Clinical trials that combine capecitabine with TP-inducing therapies (such as taxanes or radiotherapy) suggest that increasing TP expression is an adequate strategy to enhance the antitumoral efficacy of capecitabine. Thus, TP plays a dual role in cancer development and therapy: on the one hand, TP inhibitors can abrogate the tumorigenic and metastatic properties of TP; on the other, TP activity is necessary for the activation of several chemotherapeutic drugs. This duality illustrates the complexity of the role of TP in tumor progression and in the clinical response to fluoropyrimidine-based chemotherapy.

Preoperative administration of xeloda on the angiogenesis and expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor in colorectal cancer

AIM: To investigate the effect of capecitabine (xeloda) by preoperation administration on the microvessel density (MVD) and expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) in patients with colorectal cancer.

METHODS: Immunohistochemical staining of CD34 and TP/PD-ECGF monoclonal antibodies was performed in 32 colorectal cancer patients with preoperative xeloda chemotherapy and 25 cases without chemotherapy (served as controls), and then the expression of TP/PD-ECGF and MVD were analyzed.

RESULTS: The positive rate of TP/PD-ECGF expression in patients with chemotherapy was significantly lower than that in the controls (31.2% vs 60.0%, P < 0.05). As compared with that in the controls, the value of MVD in patients with chemotherapy was markedly different (20.7 ± 8.5 vs 42.3 ± 7.8, P < 0.05).

CONCLUSION: Preoperation chemotherapy of xeloda can decrease the activity of TP/PD-ECGF and inhibit the angiogenesis in colorectal cancer.

Expression of thymidine phosphorylase in choroidal malignant melanoma associated with neovascular glaucoma

Reported herein is a case of 62-year-old man who complained of blurred vision and ocular pain in his right eye. The patient was diagnosed with choroidal melanoma complicated by neovascular glaucoma (NVG) and total retinal detachment, and he underwent enucleation of the eye. The isolated tumor was 2.5 x 2.5 cm in size. It was accompanied by intratumoral calcification, and consisted of epithelioid and spindle melanoma cells. There were a variety of microvessels in the stroma of the iris. The expression of thymidine phosphorylase (dThdPase), an angiogenic factor, was examined immunohistochemically. Cytoplasmic immunoreactivity for dThdPase was more prominent in the epithelioid cells than in spindle tumor cells. Another case of choroidal melanoma without NVG had less marked immunoreactivity. These results suggest that the production of dThdPase by melanoma cells correlates with the pathogenesis of NVG.

Phase II trial of cisplatin and capecitabine in patients with squamous cell carcinoma of the head and neck, and correlative study of angiogenic factors

The combination of cisplatin and capecitabine was evaluated in patients with recurrent or unresectable squamous cell carcinoma of the head and neck (HNSCC), and outcome parameters were correlated with the expression of thymidine phosphorylase (TP), thymidilate syntetase (TS), vascular endothelial growth factor receptor (VEGFR) 1–3, and microvessel density (MVD). Patients with recurrent or unresectable HNSCC were eligible if they had received prior neoadjuvant chemotherapy, concurrent chemo-radiotherapy, or no prior systemic therapy. Patients received cisplatin (75 mg m⁻² day 1), and capecitabine (2000 mg m⁻² day 1–14) every 3 weeks. A total of 41 patients received 194 cycles. In all, 16 complete responses (39%) and 12 partial responses (29%) were documented, for an overall response rate of 68% (95% CI, 53–80%). Grade 3–4 uncomplicated neutropenia was documented in five subjects. Asthenia, anorexia, hand–foot syndrome, and constipation were the most frequent nonhaematologic events. Median progression-free and overall survival were 6.4 and 12.6 months. Cytoplasmic TP expression was more prevalent in patients with a laryngeal location vs other, and in patients with a recurrence vs primary disease. Microvessel density count was higher in patients with recurrent vs primary disease. The combination of cisplatin and capecitabine is effective in recurrent or unresectable HNSCC, and shows a manageable toxicity.

The nucleoside derivative 5'-O-trityl-inosine (KIN59) suppresses thymidine phosphorylase-triggered angiogenesis via a noncompetitive mechanism of action

Thymidine phosphorylase (TPase) catalyzes the reversible phosphorolysis of pyrimidine deoxynucleosides to 2-deoxy-d-ribose-1-phosphate and their respective pyrimidine bases. The enzymatic activity of TPase was found to be essential for its angiogenesis-stimulating properties. All of the previously described TPase inhibitors are either pyrimidine analogues that interact with the nucleoside-binding site of the enzyme or modified purine derivatives that mimic the pyrimidine structure and either compete with thymidine or act as a multisubstrate (competitive) inhibitor. We now describe the inhibitory activity of the purine riboside derivative KIN59 (5'-O-tritylinosine) against human and bacterial recombinant TPase and TPase-induced angiogenesis. In contrast to previously described TPase inhibitors, KIN59 does not compete with the pyrimidine nucleoside or the phosphate-binding site of the enzyme but noncompetitively inhibits TPase when thymidine or phosphate is used as the variable substrate. In addition, KIN59 was far more active than other TPase inhibitors, previously tested by us, against TPase-induced angiogenesis in the chorioallantoic membrane assay. The observed anti-angiogenic effect of KIN59 was not accompanied by inflammation or any visible toxicity. Inosine did not inhibit the enzymatic or angiogenic activity of the enzyme, indicating that the 5'-O-trityl group in KIN59 is essential for the observed effects. In contrast with current concepts, our data indicate that the angiogenic activity of TPase is not solely directed through its functional nucleoside and phosphate-binding sites. Other regulatory (allosteric) site(s) in TPase may play an important role in the mechanism of TPase-triggered angiogenesis stimulation and apoptosis inhibition. Identification of these site(s) is important to obtain a better insight into the molecular role of TPase in the progression of cancer and angiogenic diseases.

High level concentration of pyrimidine nucleoside phosphorylase in esophageal squamous cell carcinoma but no correlation with clinicopathological parameters

Pyrimidine nucleoside phosphorylase (PyNPase) converts 5'-deoxy-5-fluorouridine to 5'-fluorouracil, which exerts an anticancer effect before being catabolized by dihydropyrimidine dehydrogenase (DPD). Recently, PyNPase has been shown to be identical to a potent angiogenic factor, platelet-derived endothelial cell growth factor. We analyzed the concentration of PyNPase and DPD in 33 patients with esophageal squamous cell carcinoma in fresh-frozen samples by enzyme-linked immunosorbent assay. In addition, we evaluated the clinical significance and prognostic value of PyNPase expression in esophageal carcinoma. The PyNPase concentration of tumor tissue was statistically higher than that of normal tissue of the esophagus (248 +/- 146 U/mg protein vs 73 +/- 63 U/mg protein, P = 0.0001), whereas DPD showed no difference (90 +/- 62 U/mg protein vs 88 +/- 62 U/mg protein, P = 0.825). The ratio of PyNPase to DPD of tumor tissue was statistically higher than that of normal tissue of the esophagus (3.3 vs 0.95, P = 0.0001). There were no significant differences between the group with high tumor to normal tissue ratios of PyNPase concentration and the low-ratio group in terms of the tumor length, depth, lymph node metastasis, lymph vessel invasion, vascular invasion, stage and survival. In conclusion, 5'-deoxy-5-fluorouridine may be effective on esophageal carcinoma and PyNPase concentration in esophageal carcinoma may not be a useful prognostic marker for patients with esophageal squamous cell carcinoma.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Expression and significance of thymidine phosphorylase/platelet-derived endothelial cell growth factor in human colorectal cancer tissue

AIM

To study the relationship between thymidine phosphorylase(TP)/platelet-derived endothelial cell growth factor(PD-ECGF), microvessel density (MVD) and the clinical pathological characteristics of colorectal carcinoma.

METHODS

TP/PD-ECGF protein expression and microvessel density (MVD) in 50 colorectal carcinomas were examined by means of immunohistochemical staining S-P method and the relationship of TP/PD-ECGF, MVD and clinical pathological characteristics and its prognosis of colorectal cancers were analysed.

RESULTS

MVD and TP/PD-ECGF expression positively correlated with the size of the tumour, Dukes stage, lymph node metastasis and depth of invasion (P<0.01), but no significant correlation with the histologic type (P>0.05) was found.There was a positive correlation between MVD and TP/PD-ECGF expression (r = 0.72).

CONCLUSION

TP/PD-ECGF is highly related to angiogenesis of colorectal carcinoma and promotes invasion and metastasis. TP/PD-ECGF expression or MVD may be one of the predictors of the biological behaviors of colorectal carcinoma, and they may serve as prognostic factors and guide the treatment.

Clinical significance of angiogenesis in gastrointestinal cancers: a target for novel prognostic and therapeutic approaches

OBJECTIVE

To review the current data on the prognostic and therapeutic implications of tumor angiogenesis in gastrointestinal cancers.

SUMMARY BACKGROUND DATA

Numerous studies have evaluated the prognostic value of tumor angiogenesis and the potential role of antiangiogenic therapy in various gastrointestinal cancers.

METHODS

A Medline literature search was conducted using "angiogenesis" or the names of various angiogenic factors in combination with the names of gastrointestinal cancers as the key words.

RESULTS

Several studies have demonstrated a significant prognostic impact of tumor microvessel density and tumor expression of angiogenic factors, in particular vascular endothelial growth factor (VEGF), in various gastrointestinal cancers. A few studies have suggested that circulating VEGF might be a useful prognostic marker. However, results were not consistent across all studies and were limited by the retrospective nature of most studies. Antiangiogenic therapy has been shown to be effective against all common gastrointestinal cancers in preclinical studies, but currently there are few clinical data with regard to antiangiogenic therapy in gastrointestinal cancers.

CONCLUSIONS

There is mounting evidence to suggest that assessment of tumor angiogenesis might provide a novel approach of prognostication in patients with gastrointestinal cancers. However, current results from retrospective studies need to be validated by prospective studies. Antiangiogenic therapy is a promising strategy of cancer treatment that might be particularly useful in combination therapy for unresectable cancers or as an adjuvant therapy for resectable tumors.

Anti-angiogenic activity of a novel multi-substrate analogue inhibitor of thymidine phosphorylase

7-Deazaxanthine (7-DX) was recently identified as the first purine derivative with pronounced inhibitory activity against Escherichia coli thymidine phosphorylase (TP) and angiogenesis. In order to "freeze" the enzyme in an open, inactive conformation, a novel multi-substrate analogue inhibitor of TP, containing an alkyl phosphonate moiety covalently linked to 7-DX, was synthesized. The prototype compound TP65 (9-(8-phosphonooctyl)-7-deazaxanthine) (at 250 microM) completely inhibited TP-induced formation of microvascular sprouts from endothelial cell aggregates in a three-dimensional fibrin gel. In the chick chorioallantoic membrane assay, TP caused a dose-dependent stimulation of angiogenesis, which was completely inhibited by 250 nmol TP65. This dose proved to be non-toxic for the developing chick embryo. TP65 thus emerges as a potent and specific inhibitor of TP and TP-induced angiogenesis, which opens new perspectives for multi-substrate analogue inhibitors of TP as potential anti-cancer agents and as inhibitors of angiogenesis and of diseases with enhanced expression of TP.