Increased serum levels of vascular endothelial growth factor in patients with renal cell carcinoma

The current role of cytoreductive nephrectomy for metastatic renal cell carcinoma

The management of metastatic renal cell carcinoma (mRCC) continues to be a therapeutic challenge; however, the options for systemic therapy in this setting have exploded over the past 20 years. From the advent of toxic cytokine therapy to the subsequent discovery of targeted therapy (TT) and immune checkpoint inhibitors, the landscape of viable treatment options continues to progress. With the arrival of cytokine therapy, two randomized trials demonstrated a survival benefit for upfront cytoreductive nephrectomy (CN) plus interferon therapy and this approach became the standard for surgical candidates. However, it was difficult to establish the role and the timing of CN with the subsequent advent of TT, just a few years later. More recently, two randomized phase III studies completed in the TT era questioned the use of CN and brought to light the role of risk stratification while selecting patients for CN. Careful identification of the mRCC patients who are likely to have a rapid progression of the disease is essential, as these patients need prompt systemic therapy. With the continued advancement of systemic therapy using the immune checkpoint inhibitors as a first line therapy, the role of CN will continue to evolve.

Phase IB/II Trial of Lenvatinib Plus Pembrolizumab in Patients With Advanced Renal Cell Carcinoma, Endometrial Cancer, and Other Selected Advanced Solid Tumors

PURPOSE

Modulation of vascular endothelial growth factor–mediated immune suppression via angiogenesis inhibition may augment the activity of immune checkpoint inhibitors. We report results from the dose-finding and initial phase II expansion of a phase Ib/II study of lenvatinib plus pembrolizumab in patients with selected advanced solid tumors.

METHODS

Eligible patients had metastatic renal cell carcinoma (RCC), endometrial cancer, squamous cell carcinoma of the head and neck (SCCHN), melanoma, non–small-cell lung cancer (NSCLC), or urothelial cancer. The primary objective of phase Ib was to determine the maximum tolerated dose (MTD) for lenvatinib plus pembrolizumab (200 mg intravenously every 3 weeks). In the preplanned phase II cohort expansion, the primary objective was objective response rate at week 24 (ORR_{week 24}) at the recommended phase II dose.

RESULTS

Overall, 137 patients were enrolled during phase Ib (n = 13) and the initial phase II expansion (n = 124). Two dose-limiting toxicities (DLTs; grade 3 arthralgia and grade 3 fatigue) were reported in the initial dose level (lenvatinib 24 mg/d plus pembrolizumab). No DLTs were observed in the subsequent dose–de-escalation cohort, establishing the MTD and recommended phase II dose at lenvatinib 20 mg/d plus pembrolizumab. ORR_week24 was as follows: RCC, 63% (19/30; 95% CI, 43.9% to 80.1%); endometrial cancer, 52% (12/23; 95% CI, 30.6% to 73.2%); melanoma, 48% (10/21; 95% CI, 25.7% to 70.2%); SCCHN, 36% (8/22; 95% CI, 17.2% to 59.3%); NSCLC, 33% (7/21; 95% CI, 14.6% to 57.0%); and urothelial cancer 25% (5/20; 95% CI, 8.7% to 49.1%). The most common treatment-related adverse events were fatigue (58%), diarrhea (52%), hypertension (47%), and hypothyroidism (42%).

CONCLUSION

Lenvatinib plus pembrolizumab demonstrated a manageable safety profile and promising antitumor activity in patients with selected solid tumor types.

Surgical Management of Advanced Kidney Cancer: The Role of Cytoreductive Nephrectomy and Lymphadenectomy

Despite the evolution of systemic therapy from the immunotherapy to targeted therapy eras, surgical management remains a mainstay of treatment of patients with locally advanced, lymph node-positive, and distant metastatic renal cell carcinoma. Balancing patient and disease characteristics with the potential morbidity of surgery has gained increasing attention to better define the role of cytoreductive nephrectomy and lymphadenectomy. In this review, we critically evaluate the literature for the potential therapeutic role of cytoreductive nephrectomy and lymphadenectomy in advanced kidney cancer, highlighting current evidence, limitations, and best-management practices. Although retrospective data supported a similar survival benefit for cytoreductive nephrectomy in the targeted therapy era as it did for the initial immunotherapy era (1992 to 2006), level 1 evidence from the randomized Clinical Trial to Assess the Importance of Nephrectomy (CARMENA) demonstrated no benefit for intermediate- and poor-risk patients in the setting of sunitinib therapy. Level 1 evidence among a favorable-risk subset is still awaited from the trial Targeted Therapy With or Without Nephrectomy in Metastatic Renal Cell Carcinoma: Liquid Biopsy for Biomarkers Discovery (TARIBO). Another trial, Immediate Surgery or Surgery After Sunitinib Malate in Treating Patients With Metastatic Kidney Cancer (SURTIME), has compared upfront cytoreductive nephrectomy prior to targeted therapy with the initial initiation of targeted therapy followed by deferred cytoreductive nephrectomy. Lymphadenectomy is yet another controversial but less well-defined management option for patients with kidney cancer. The role of lymphadenectomy has been studied in both the localized and advanced settings over the past few decades, with a strong suggestion of no therapeutic benefit for patients with cT1-2N0M0 and cM1 disease, and with uncertain benefit in patients with high-risk disease (ie, locally advanced or cN1M0), leading to weak statements among clinical guidelines.

Circulating Angiogenesis Regulators in Cancer Patients

Background/Aims

To date, numerous studies have demonstrated that several angiogenesis regulators circulate in the blood and may function as endocrine factors in cancer patients. This review aims to give a comprehensive insight into the possible clinical value of circulating angiogenesis regulators, mainly basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF), angiogenin, pleiotrophin, thrombospondin (TSP) and endostatin (ES) in cancer patients.

Methods

A computerized (MEDLINE) and a manual search based on the reference lists of the publications were performed to identify articles published on this topic.

Results

In a detailed literature search, approximately 100 publications were found up to the end of 1999. Circulating angiogenic factors such as bFGF, VEGF, HGF and angiogenin have been evaluated not only as diagnostic and/or prognostic factors but also as predictive factors in cancer patients. On the other hand, little is known about the clinical significance of negative regulators. Neither the source nor the mechanism of protein externalization has been clarified in detail.

Conclusions

Although there are no known factors with established clinical utility, circulating angiogenesis regulators may be useful in several situations. They could be used to determine the risk of developing cancer, to screen for early detection, to distinguish benign from malignant disease, and to distinguish between different types of malignancies. In patients with established malignancies such factors might be used to determine prognosis, to predict the response to therapy, and to monitor the clinical course. Further investigations are warranted to assess the specific utility of each factor.

Validation of Blood Collection Procedures for the Determination of Circulating Vascular Endothelial Growth Factor (VEGF) in Different Blood Compartments

Aims of the study.

Studies on circulating VEGF have reported mixed results, possibly due to a lack of standardization of the pre-analytical phase. The aim of our investigation was to standardize the sampling procedure for the determination of VEGF in different blood fractions.

Basic procedures.

We evaluated various clotting times for obtaining serum in 30 subjects, as well as different procedures for the preparation of plasma Edinburgh anticoagulant mixture (EDTA, PGE1, theophylline) and CTAD. VEGF was also assayed in lysed whole blood. In vitro platelet activation was monitored by measuring the levels of PF4. VEGF and PF4 were measured using commercially available enzyme-linked immunoassays.

Main findings.

Clotting time increased the release of VEGF, which reached a plateau between 2 and 4 hours. The percent increase of VEGF at 2 hours ranged from 118% to 4515% (median 327%) compared to samples centrifuged within 10 min from withdrawal. VEGF was not different and PF4 was very low or undetectable in Edinburgh plasma and CTAD plasma, while it was significantly higher in sodium citrate plasma. VEGF in CTAD plasma was not correlated with platelet count or leukocytes. Serum VEGF did not correlate with the leukocyte number, but it correlated significantly with the platelet count.

Principal conclusions.

The procedures for sample collection described above are highly standardized and easy to perform in a routine setting. We therefore suggest systematic evaluation of VEGF in CTAD plasma, in serum (clotting for 2 hours at room temperature) and in whole blood, until prospective controlled clinical studies will have clarified in which blood compartment(s) VEGF provides clinically relevant information.

Infiltrating T cells promote renal cell carcinoma (RCC) progression via altering the estrogen receptor β-DAB2IP signals

Previous studies indicated the T cells, one of the most common types of immune cells existing in the microenvironment of renal cell carcinoma (RCC), may influence the progression of RCC. The potential linkage of T cells and the estrogen receptor beta (ERβ), a key player to impact RCC progression, however, remains unclear. Our results demonstrate that RCC cells can recruit more T cells than non-malignant kidney cells. Using an in vitro matrigel invasion system, we found infiltrating T cells could promote RCC cells invasion via increasing ERβ expression and transcriptional activity. Mechanism dissection suggested that co-culturing T cells with RCC cells released more T cell attraction factors, including IFN-γ, CCL3 and CCL5, suggesting a positive regulatory feed-back mechanism. Meanwhile, infiltrating T cells may also promote RCC cell invasion via increased ERβ and decreased DAB2IP expressions, and knocking down DAB2IP can then reverse the T cells-promoted RCC cell invasion. Together, our results suggest that infiltrating T cells may promote RCC cell invasion via increasing the RCC cell ERβ expression to inhibit the tumor suppressor DAB2IP signals. Further mechanism dissection showed that co-culturing T cells with RCC cells could produce more IGF-1 and FGF-7, which may enhance the ERβ transcriptional activity. The newly identified relationship between infiltrating T cells/ERβ/DAB2IP signals may provide a novel therapeutic target in the development of agents against RCC.

Phase 2 Study of Bevacizumab and Temsirolimus After VEGFR TKI in Metastatic Renal Cell Carcinoma

BACKGROUND

Inhibiting VEGF and mammalian target of rapamycin (mTOR) pathways are standard treatment approaches for patients with metastatic renal cell carcinoma (mRCC). Here we report the activity and safety of the VEGF ligand inhibitor bevacizumab and the mTOR inhibitor temsirolimus combination in patients with clear cell (CC) and non-clear cell (NCC) mRCC whose disease had failed to respond to prior VEGF blockade.

PATIENTS AND METHODS

In this phase 2 investigator-initiated multicenter study, patients received bevacizumab and temsirolimus. The primary end point was 4-month progression-free survival (PFS) rate. Secondary end points included overall response rate, median overall survival (OS), toxicity, and correlative studies of biomarkers downstream of mTOR.

RESULTS

Forty patients received at least 1 dose of therapy. Thirty-three (82.5%) had favorable/intermediate risk disease according to International Metastatic Renal Cell Carcinoma Database Consortium criteria, 13 (32.5%) with nccRCC histology. Nineteen (48.7%) had primary vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI)-refractory disease. The 4-month PFS rate was 65%. Overall median PFS and OS were 5.6 and 12.2 months. Median PFS and OS were 6.5 and 9.6 months in patients with primary VEGFR TKI-refractory disease, and 5.6 months and 13.1 months in patients with nccRCC. Dose reductions were needed in 80% of patients. Most frequent toxicities included fatigue, hypertension, dyslipidemia, and proteinuria. Dose discontinuation due to adverse events occurred in 27.5% of patients. Baseline tumor immunohistochemistry for phospho-S6 protein was not associated with clinical benefit.

CONCLUSION

Combining bevacizumab and temsirolimus in patients previously treated with VEGFR TKI was possible but with dose reductions and treatment discontinuations. This combination resulted in modest activity, including in patients with primary VEGF-refractory disease and NCC histology.

Cytoreductive nephrectomy and its role in the present-day period of targeted therapy

The beneficial effect of cytoreductive nephrectomy on survival of patients with metastatic renal cell carcinoma in the immunotherapy era was based on two prospective randomized trials. Unfortunately, such evidence does not yet exist in the present-day period of targeted therapy. Despite this, cytoreductive nephrectomy remains integral in the multimodal management of patients with metastatic renal cell carcinoma. Multiple retrospective studies as well as data from prospective studies examining targeted therapy support the continued use of cytoreductive nephrectomy in the properly selected patient. Ongoing studies will hopefully fine-tune the role and timing of cytoreductive nephrectomy in the context of targeted therapy.

Serum level and immunohistochemical expression of vascular endothelial growth factor for the prediction of postoperative recurrence in renal cell carcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a major role in angiogenesis. One of the functions of VEGF is to regulate neovascularization in clear cell renal cell carcinoma (CCRCC). The objective of our study was to examine whether before nephrectomy serum levels of VEGF or expression of VEGF using immunohistochemistry (IHC) could predict postoperative recurrence in nonmetastatic CCRCC.

RESULTS

Twelve patients (14.5%) had recurrence during a mean follow-up of 52.6 ± 31.2 months. The serum VEGF level was significantly higher in patients with recurrence than in those without recurrence (P = 0.038). High serum VEGF levels were above 416 pg/mL; this value was chosen based on a receiver operating characteristic analysis. The recurrence-free survival rate in patients with a high serum VEGF level was significantly lower than in those with a low serum VEGF level (P = 0.003). In total, tumors from 26 patients (31.3%) showed overexpression of VEGF using IHC. The recurrence-free survival rate in the IHC-positive group was significantly lower than that in the IHC-negative group (P = 0.044). Multivariate analysis indicated that preoperative serum VEGF levels (P = 0.013) and female gender (P = 0.004) were independent predictors of postoperative recurrence in nonmetastatic CCRCC.

CONCLUSIONS

Preoperative serum VEGF levels is a useful predictor compared with IHC analysis of VEGF of postoperative recurrence in nonmetastatic CCRCC.

[Predicting postoperative recurrence of renal cell carcinoma using serum vascular endothelial growth factor]

BACKGROUND

Vascular endothelial growth factor (VEGF) is known as one of the key molecules in molecular targeting therapy for patients with renal cell carcinoma (RCC). Several studies have shown that VEGF might be useful for predicting prognosis in RCC. We examined whether pretreatment serum VEGF can be used as a predictor of recurrence-free survival in non-metastatic RCC.

MATERIALS AND METHODS

We studied 85 patients with non-metastatic clear cell RCC who underwent nephrectomy between 2001 and 2010. Serum samples were collected for VEGF before operation. We evaluated the recurrence-free survival by univariate and multivariate analysis.

RESULTS

9 patients (10.6%) showed recurrence. Serum level of VEGF in patients with recurrence showed significantly higher than those in patients without recurrence (p = 0.0310). A cutoff level of 416 pg/mL for the separation of low and high serum VEGF levels was established based on the receiver operating characteristic (ROC) curve. The recurrence-free survival rate was significantly lower in patients with a high serum VEGF level (p = 0.0039). Multivariate analysis showed that pretreatment serum VEGF value was a significant predictor of postoperative recurrence in non-metastatic clear cell RCC (p = 0.0062).

CONCLUSIONS

Pretreatment level of serum VEGF might be useful for prediction of postoperative recurrence in non-metastatic clear cell RCC.

New targeted therapies for renal cell carcinoma

INTRODUCTION

The aim of treatment in metastatic renal cell carcinoma is palliation. In the last 5 years, multiple targeted agents have been developed which have resulted in prolongation of patients' lives, but complete responses remain rare. New therapies and approaches are required to further improve the prognosis for patients with this disease.

AREAS COVERED

This review discusses the molecular targets in renal cell carcinoma relevant to the development of new treatments and describes the progress of novel therapies. The evidence is compiled from the PubMed database and proceedings of scientific meetings, searched up to December 2010.

EXPERT OPINION

A multitude of experimental agents are in clinical development and offer theoretical advantages over those currently in use. It is hoped that these treatments will result in better long-term control of metastatic renal cell carcinoma, with improved side effect profiles, but curative treatment in this disease remains elusive until the mechanisms underlying response and resistance to therapy are elucidated. Progress in the field has been limited by inadequate tissue collection within clinical trials; current and future clinical trial design will incorporate a larger translational component in an attempt to establish predictive biomarkers.

[Role of surgery (cytoreductive nephrectomy and metastasectomy) in the management of metastatic renal cell carcinoma: a literature review]

Cytoreductive nephrectomy is an established treatment option prior immunotherapy in well-selected patients with metastatic renal cell carcinoma. With the recent introduction of new targeted agents, the role of surgery has been source of controversy. This review examines the role of cytoreductive nephrectomy during the immunotherapy era, then in the new targeted therapies era. This review also summarizes the optimal timing of these treatments, the prognostic factors predicting outcome following cytoreductive nephrectomy, the role of metastasectomy, partial and laparoscopic cytoreductive nephrectomy.

Everolimus - a new approach in the treatment of renal cell carcinoma

With the increasing understanding of the biology of the disease and the development of targeted therapy, there has been a paradigm shift in the treatment of clear cell metastatic renal cell carcinoma (mRCC). Traditionally patients with metastatic RCC have been treated with immunotherapy which has limited efficacy. The multikinase inhibitors sunitinib, sorafenib and pazopanib, the VEGF antibody bevacizumab in combination with interferon and the mTOR inhibitor temsirolimus have all been shown to prolong progression-free survival in phase III studies. Here we review another mTOR inhibitor, everolimus (Afinitor(®); Novartis, USA) which was approved in March 2009 by the US FDA for treatment of targeted-therapy refractory metastatic renal cell cancer. The phase III study of everolimus (the RECORD study) was terminated early after a significant difference in efficacy was noted in the treatment arm with everolimus (progression-free survival of 4.0 months in patients on the treatment arm vs 1.9 months in the placebo arm). The most common adverse events were stomatitis, pneumonitis, fatigue and infections. We review Phase I-III data with a particular emphasis on safety data and patient focused outcomes.

Metastatic Renal Cell Carcinoma: Many Treatment Options, One Patient

There has been a recent expansion of therapeutic options in metastatic renal cell carcinoma (RCC) targeted at the vascular endothelial growth factor and mammalian target of rapamycin pathways, which are fundamental to the biology of RCC. These treatment options have similarities in antitumor effect but also important differences in regards to clinical effects, toxicity and patient populations in which they have been investigated. Further, issues regarding the role of debulking nephrectomy, timing of therapy, and appropriate sequencing of agents have emerged as clinically relevant. There are thus potentially many different treatment approaches to each metastatic RCC patient. This review discusses how to integrate the available data regarding targeted therapy in metastatic RCC into personalized cancer care.

Vascular endothelial growth factor and its type 2 receptor in tumors and serum of patients with renal cancer

It was found that renal cancer tissue is characterized by increased content of VEGF not depending on the parameters of normal tissue and expression of VEGFR2 receptor. At the same time, the content of VEGFR2 in the tumor is determined by the state of the surrounding tissue and increases in low number of patients with tumors invading the renal capsule. Serum concentrations of VEGF and VEGFR2 in patients with renal cancer did not significantly differ from the corresponding values in the control group. No significant correlations between the levels of VEGF and VEGFR2 in the blood and tumor tissue were found.

Quantitative analysis of vascular endothelial growth factor in liver metastases from pancreatic carcinoma as a predictor of chemotherapeutic effect and prognosis

PURPOSE

In pancreatic carcinoma, vascular endothelial growth factor (VEGF) expression at the primary site has been suggested to be a prognostic parameter. We quantitatively analyzed VEGF expression in liver metastases from pancreatic carcinoma and examined the correlation among VEGF expression in liver metastases, clinicopathologic factors, and clinical outcome.

EXPERIMENTAL DESIGN

The subjects consisted of 23 patients with pancreatic adenocarcinoma who had liver metastases and were treated with S-1 and gemcitabine as the first-line treatment. VEGF expression was quantitated by enzyme immunoassay in biopsy specimens of liver metastases and nontumorous liver tissue, and in plasma. In 10 of the 23 patients, VEGF expression was also quantitated in biopsy specimens of the primary pancreatic tumor. All samples were collected before treatment.

RESULTS

The VEGF level in nontumorous liver tissue was 36.6 +/- 10.0 pg/mg protein versus 376.8 +/- 106.1 pg/mg protein in liver metastases (P = 0.0016). Pretreatment VEGF levels in plasma and in primary pancreatic carcinoma did not correlate with VEGF levels in the corresponding liver metastases. The median VEGF level in liver metastases (138.9 pg/mg protein) was used as the cutoff value between high and low VEGF expression in liver metastases. Patients showing high VEGF expression had a significantly longer progression-free survival and overall survival than patients showing low VEGF expression in liver metastases (P = 0.0219 and P = 0.0074, respectively).

CONCLUSIONS

Evaluation of VEGF levels in liver metastases might be useful in assessing the prognosis of patients with metastatic pancreatic carcinoma who are under systemic chemotherapy.

Persistent elevation of plasma vascular endothelial growth factor levels during the first month after minimally invasive colorectal resection

BACKGROUND

Elevations of plasma vascular endothelial growth factor (VEGF) have been noted early after colorectal resection. The duration of this increase is unknown. Because VEGF is a potent promoter of angiogenesis, which is critical to tumor growth, a sustained increase in blood VEGF levels after surgery may stimulate the growth of residual metastases early after surgery. This preliminary study aimed to determine VEGF levels during the first month after colorectal resection.

METHODS

Patients from three prospective studies that had late postoperative blood samples available comprised the study population. Demographic, perioperative, pathologic, and complication data were collected. Plasma samples were obtained preoperatively for all patients: on postoperative day (POD) 1 for most patients and at varying time points thereafter during the first month after surgery and beyond. Levels of VEGF were determined via enzyme-linked immunoassay (ELISA) and compared using Wilcoxon's matched pairs test. Because the numbers of specimens beyond POD 5 were limited, samples from 7-day time blocks were bundled and averaged to permit statistical analysis.

RESULTS

A total of 49 patients with cancer and 30 patients with benign indications, all of whom underwent minimally invasive colorectal resection, were assessed separately. With regard to the patients with cancer, the median preoperative plasma value was 150 pg/ml, and the peak postoperative median value for the POD 14 to 20 time block was 611.1 pg/ml. Furthermore, compared with the preoperative results, significant VEGF elevations were noted on POD 3 as well as during week 2 (POD 7-13), week 3 (POD 14-20), and week 4 (POD 21-27) (p < 0.05 for each). With regard to the benign patients, the median preoperative VEGF level was 112 pg/ml, and the peak postoperative value, 286 pg/ml, was noted during postoperative week 2. Significant elevations were noted on POD 3, and for weeks 2 and 3 as well as for POD 28 and later. Between 63% and 89% of the patients at each time point beyond POD 5 had elevated VEGF levels.

CONCLUSION

This preliminary study demonstrates that after minimally invasive colorectal resection for cancer, median VEGF levels are significantly elevated on POD 3 and remain increased for as long as 4 weeks. Significant elevations in a similar pattern also were noted for the benign patients. However, the baseline and postoperative median values were lower. The clinical impact from increased blood levels of VEGF is uncertain. It is possible that the growth of residual tumor deposits may be stimulated early after surgery. These results warrant a larger study as well as endothelial cell in vitro assays to determine whether postoperative plasma stimulates proliferation and invasion.

Post-collection, pre-measurement variables affecting VEGF levels in urine biospecimens

Angiogenesis, the development and recruitment of new blood vessels, plays an important role in tumour growth and metastasis. Vascular endothelial growth factor (VEGF) is an important stimulator of angiogenesis. Circulating and urinary VEGF levels have been suggested as clinically useful predictors of tumour behaviour, and investigations into these associations are ongoing. Despite recent interest in measuring VEGF levels in patients, little is known about the factors that influence VEGF levels in biospecimens. To begin to address this question, urine samples were collected from patients with solid tumours undergoing radiotherapy and healthy volunteers. Four factors were examined for their effects on VEGF concentrations as measured by chemiluminescent immunoassay: time from sample collection to freezing, number of specimen freeze-thaw cycles, specimen storage tube type and the inclusion or exclusion of urinary sediment. The results of this study indicate that time to freeze up to 4 hrs, number of freeze-thaw cycles between one and five, and different types of polypropylene tubes did not have statistically significant effects on measured urinary VEGF levels. Urinary sediment had higher VEGF levels than supernatant in five of six samples from healthy patients. It is not clear whether there is an active agent in the sediment causing this increase or if the sediment particles themselves are affecting the accuracy of the assay.Therefore, we recommend centrifuging urine, isolating the supernatant, and freezing the sample in polypropylene microcentrifuge tubes or cryogenic vials within 4 hrs of collection.In addition, we recommend the use of samples within five freeze-thaw cycles.

Where is VEGF in the body? A meta-analysis of VEGF distribution in cancer

Vascular endothelial growth factor (VEGF) is a major target for the inhibition of tumour vascularisation and the treatment of human cancer. Many tumours produce large quantities of VEGF, and as a result, diagnosis and prognosis of cancer may be predicted by measuring changes in VEGF concentrations in blood. In blood, the VEGF may be located in the plasma, or in the blood-borne cells and formed elements, in particular, platelets and leukocytes. In this study, we collate the measurements of VEGF in platelets, leukocytes, plasma and serum for breast, prostate, colorectal and other cancers. In addition, we analysed the concentration of VEGF in tumour tissue itself, as well as for other tissues in the human body. Although the concentration of VEGF in tumours is high, the size of tumours is small compared to other tissues, in particular, skeletal muscle. Thus, the total quantity of VEGF in tumours and in blood is small compared to the quantity in muscles. This large reservoir of VEGF may have important implications for the treatment of cancer.

Where is VEGF in the body? A meta-analysis of VEGF distribution in cancer

Vascular endothelial growth factor (VEGF) is a major target for the inhibition of tumour vascularisation and the treatment of human cancer. Many tumours produce large quantities of VEGF, and as a result, diagnosis and prognosis of cancer may be predicted by measuring changes in VEGF concentrations in blood. In blood, the VEGF may be located in the plasma, or in the blood-borne cells and formed elements, in particular, platelets and leukocytes. In this study, we collate the measurements of VEGF in platelets, leukocytes, plasma and serum for breast, prostate, colorectal and other cancers. In addition, we analysed the concentration of VEGF in tumour tissue itself, as well as for other tissues in the human body. Although the concentration of VEGF in tumours is high, the size of tumours is small compared to other tissues, in particular, skeletal muscle. Thus, the total quantity of VEGF in tumours and in blood is small compared to the quantity in muscles. This large reservoir of VEGF may have important implications for the treatment of cancer.

Plasma level and tissue expression of vascular endothelial growth factor in renal cell carcinoma: a prospective study of 50 cases

Vascular endothelial growth factor (VEGF) is the major factor involved in angiogenesis. Although it is known that one of the functions of VEGF is to regulate neovascularization in renal cell carcinomas, the relationship between the production of VEGF in tumor tissue and its concentration in blood has not yet been studied. The aims of this study were to determine, in a series of conventional renal cell carcinoma (CRCC) cases, (1) VEGF expression and VEGF pattern in tumor cells, (2) the relationship between VEGF expression/pattern and VEGF levels in plasma (pVEGF), and (3) the association with usual clinical and pathologic prognostic factors. Fifty patients operated on for CRCC by radical nephrectomy were included. Clinical and histologic parameters were studied. VEGF expression and VEGF pattern in tumor cells was immunohistochemically recorded. pVEGF levels and platelet count were analyzed in relation to clinical and histologic parameters. Intratumoral VEGF expression associated with a cytoplasmic VEGF pattern was significantly higher in patients with high pVEGF levels (P = .01). Both VEGF expression and pVEGF levels were significantly correlated with Fuhrman grade (P = .002 and P = .01, respectively) and tumor stage (P = .006 and P = .008, respectively). In addition, VEGF expression was also correlated with tumor necrosis (P = .001) and progression (P = .001). We demonstrated that in CRCC with tumor necrosis, VEGF expression, pVEGF levels, and platelet count were significantly higher than in CRCC with no tumor necrosis (P = .001, P = .03, and P = .001, respectively). Our results revealed that cytoplasmic VEGF expression and pVEGF levels are associated with usual prognostic factors and progression in CRCC, which may allow VEGF to be used as a prognostic marker for CRCC, especially in patients with VEGF-targeted therapy.

The evolving role of surgery for advanced renal cell carcinoma in the era of molecular targeted therapy

PURPOSE

Thoughtful integration of surgical and medical approaches to metastatic renal cell carcinoma is paramount for maximizing disease control. Accomplishing this in the current era of targeted molecular therapies presents unique challenges and opportunities.

MATERIALS AND METHODS

A systematic review of the MEDLINE and PubMed databases, and relevant urological and oncological journals was performed pertaining to cytoreductive nephrectomy, metastasectomy, targeted molecular therapies for renal cell carcinoma, and neoadjuvant and adjuvant approaches to the management of advanced renal cell carcinoma.

RESULTS

Cytoreductive nephrectomy provides an overall survival advantage in select patients with metastatic renal cell carcinoma who receive subsequent interferon-alpha. However, cytokine therapies are now being supplanted by targeted molecular approaches that block the effects of vascular endothelial growth factor and other molecular events. Although cytoreductive nephrectomy remains a standard of care, limited insight into the biological effects of nephrectomy on mechanisms such as immunoregulation and angiogenesis precludes definitive statements about how to integrate surgery and targeted agents. Ongoing investigation involving basic science and translational research is required to optimize the integration of these approaches. Adjuvant and neoadjuvant vascular endothelial growth factor targeted approaches to renal cell carcinoma are now also being explored and the unique side effects of these agents, including potential effects on wound healing and vascular integrity, require careful consideration.

CONCLUSIONS

Integrated approaches involving surgery and vascular endothelial growth factor targeted therapies hold much promise for the management of advanced renal cell carcinoma. Prospective clinical testing with vigilant attention to the risk-benefit ratio and thoughtful evaluation of biological correlates are required to optimize these approaches.

Major abdominal surgery increases plasma levels of vascular endothelial growth factor: open more so than minimally invasive methods

INTRODUCTION

Vascular endothelial growth factor (VEGF) is a potent inducer of angiogenesis that is necessary for wound healing and also promotes tumor growth. It is anticipated that plasma levels would increase after major surgery and that such elevations may facilitate tumor growth. This study's purpose was to determine plasma VEGF levels before and early after major open and minimally invasive abdominal surgery.

METHODS

Colorectal resection for cancer (n = 139) or benign pathology (n = 48) and gastric bypass for morbid obesity (n = 40) were assessed. Similar numbers of open and laparoscopic patients were studied for each indication. Plasma samples were obtained preoperatively and on postoperative days (POD) 1 and 3. VEGF levels were determined via ELISA. The following statistical methods were used: Fisher exact test, unmatched Student t test, Wilcoxon's matched pairs test, and the Mann Whitney U Test with P < 0.05 considered significant.

RESULTS

The mean preoperative VEGF level of the cancer patients was significantly higher than baseline level of benign colon patients. Regardless of indication or surgical method, on POD3, significantly elevated mean VEGF levels were noted for each subgroup. In addition, on POD1, open surgery patients for all 3 indications had significantly elevated VEGF levels; no POD1 differences were noted for the closed surgery patients. At each postoperative time point for each procedure and indication, the open group's VEGF levels were significantly higher than that of the matching laparoscopic group. VEGF elevations correlated with incision length for each indication.

CONCLUSION

As a group colon cancer patients prior to surgery have significantly higher mean VEGF levels than patients without tumors. Also, both open and closed colorectal resection and gastric bypass are associated with significantly elevated plasma VEGF levels early after surgery. This elevation is significantly greater and occurs earlier in open surgery patients. The duration and clinical importance of this finding is uncertain but merits further study.

Serum levels of vascular endothelial growth factor (VEGF) and endostatin in renal cell carcinoma patients compared to a control group

OBJECTIVES

Renal cell carcinoma (RCC) is a vascularised neoplasm. The importance of the angiogenic process in its growth and metastatic spreading is widely recognised. We assessed serum levels of endogenous endostatin and vascular endothelial growth factor (VEGF) in RCC patients and healthy volunteers, and evaluated the factors' prognostic role for patients' survival, distinguishing histologic subtypes with respect to correlation with tumour stage, grade, and size.

METHODS

We considered 146 consecutive patients with RCC and 110 healthy volunteers. Serum samples from all subjects were analysed for endostatin and VEGF by using competitive enzyme immunoassays. RCC samples were compared with serum from the control group and with clinicopathologic factors and clinical outcome.

RESULTS

Mean age was 63 years (range: 37-85 years) in RCC patients and 62 years (range: 23-88 years) in the control group. VEGF levels (median: 3.6 ng/ml+/-6.97; range: 0-48.4 ng/mL) were significantly higher in RCC patients, compared with controls (p=0.001). Endostatin levels did not differ significantly between the two groups (p=0.9) without correlation between endostatin and VEGF levels (p=0.09). No significant difference was found in the endostatin levels among the histologic subtypes (p=0.973) and VEGF (p=0.232). The median follow-up was 27 months (range: 1-57 months).

CONCLUSIONS

Serum VEGF levels are elevated in RCC patients, compared with controls, and do not correlate significantly with circulating endostatin levels. No difference in preoperative serum VEGF and endostatin levels among the different histologic subtypes was found. In multivariate analysis VEGF and endostatin failed to be prognostic; only tumour stage and grade remained independent predictors of survival.

Maximal COX-2 immunostaining and clinical response to celecoxib and interferon alpha therapy in metastatic renal cell carcinoma

BACKGROUND

Cyclooxygenase-2 (COX-2) plays a major role in the development of cancer through numerous mechanisms. COX-2 is expressed in the majority of renal cell carcinoma (RCC) tumors and correlates with stage, grade, and microvessel density. Based on potential additive or synergistic antitumor effects, interferon-alpha (IFNalpha) and celecoxib, an oral COX-2 inhibitor, were given to metastatic RCC patients in a Phase II trial.

METHODS

Patients with untreated, metastatic RCC received IFNalpha 3 million units (MU) daily and celecoxib 400 mg orally (p.o.) twice daily continuously until disease progression or unacceptable toxicity. Pretreatment, paraffin-embedded RCC tumor samples were immunohistochemically stained for COX-2 expression and plasma basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) levels were assayed to determine predictive or prognostic potential.

RESULTS

There were three partial responses among 25 patients treated (objective response rate, 12%; 95% confidence interval [CI], 3-31%). The observed median time to disease progression (TTP) for the entire cohort was 3.3 months. A significant association between maximal COX-2 staining and clinical response was observed: all patients who experienced an objective response demonstrated 3+ COX-2 tumor immunostaining (trend test: P=0.03). Therapy was well tolerated without cardiac or other notable toxicity.

CONCLUSIONS

The addition of celecoxib to IFNalpha did not increase the objective response rate or TTP of this unselected cohort. Maximal COX-2 tumor immunostaining may identify RCC patents more likely to achieve clinical benefit with COX-2 inhibition in combination with IFNalpha. Further investigation of this combination in 3+ COX-2-overexpressing RCC tumors is warranted.

Biology and clinical development of vascular endothelial growth factor-targeted therapy in renal cell carcinoma

PURPOSE

To review the biology of renal cell carcinoma (RCC) leading to vascular endothelial growth factor (VEGF) overexpression and the clinical results of VEGF blockade in metastatic RCC.

METHODS

A review of relevant published literature regarding VEGF, von Hippel-Lindau (VHL) gene inactivation and VEGF overexpression in RCC was performed. Further, a review of the mechanism, toxicity, and clinical development of VEGF-targeted therapy in metastatic RCC was undertaken.

RESULTS

VEGF is the major proangiogenic protein that exerts a biologic effect through interaction with cellular receptors. The majority of sporadic clear-cell RCC tumors are characterized by VHL tumor suppressor gene inactivation. The resulting VHL gene silencing leads to VEGF overexpression. An antibody to VEGF (bevacizumab) has demonstrated a significant prolongation of time to disease progression compared with placebo in patients with metastatic RCC. Small molecules with inhibitory effects against the VEGF receptor have undergone initial clinical testing in metastatic RCC with substantial objective response rates.

CONCLUSION

Therapeutic targeting of VEGF in RCC has strong biologic rationale and preliminary clinical efficacy. Further investigation will determine the optimal timing, sequence, and utility of these agents in RCC.

Expanding the Clinical Development of Bevacizumab

Bevacizumab (Avastin; Genentech, Inc.; South San Francisco, CA) is a recombinant, humanized monoclonal antibody to vascular endothelial growth factor, a key regulator of tumor angiogenesis. Bevacizumab demonstrated potent antitumor activity in preclinical models and has also shown biologic activity and clinical benefit in clinical studies. Notably, a randomized, placebo-controlled phase II trial in renal cell carcinoma demonstrated a significantly longer time to tumor progression with bevacizumab monotherapy. Furthermore, in a phase III trial for untreated advanced colorectal cancer, the addition of bevacizumab to chemotherapy led to significantly longer overall survival and progression-free survival times than chemotherapy alone. The clinical development of bevacizumab has been expanded to include confirmatory phase III trials and exploratory phase II trials in a variety of solid tumors and hematologic malignancies. Treatment regimens being examined include bevacizumab alone and in combination with conventional chemotherapy, radiation, immune therapy, and biologically targeted agents.

Serum KIT and KIT ligand levels in patients with gastrointestinal stromal tumors treated with imatinib

Imatinib mesylate is a selective inhibitor of a few tyrosine kinases including KIT, and it is the first effective treatment for gastrointestinal stromal tumors (GISTs). We monitored the serum levels of KIT, KIT ligand (stem cell factor, SCF), and the vascular endothelial growth factor (VEGF) in patients with advanced GISTs treated with imatinib in a prospective randomized trial. Patients with GISTs (n = 66) had elevated pretreatment serum KIT and VEGF levels as compared with controls (median, 292 AU/mL [409 ng/mL] vs 238 AU/mL [333 ng/mL], P =.037; and median, 303 pg/mL vs 190 pg/mL, P =.013, respectively), but lower levels of SCF (median, 645 pg/mL vs 950 pg/mL; P < or =.0001). After 1 and 6 months of imatinib treatment the average serum KIT levels decreased 31% and 52% from pretreatment levels, whereas SCF levels increased 11% and 33%, respectively. Serum VEGF levels decreased during treatment in responding patients. The median serum SCF/KIT ratio increased with treatment duration, and was 7.7-fold higher after 12 months of treatment than at baseline (range, 3.1-259-fold). A high serum SCF/KIT ratio may increase SCF-induced cell signaling with prolonged imatinib treatment, at the time when imatinib treatment is withdrawn, and in patients whose GIST has wild-type receptors.

Interferon Alfa-2b Three Times Daily and Thalidomide in the Treatment of Metastatic Renal Cell Carcinoma

Purpose: The antiangiogenic effect of interferon (IFN) may improve with frequent dosing and by combination with other agents with antiangiogenic activity. To evaluate this potential, we treated patients with metastatic renal cell carcinoma (RCC) with frequently dosed IFN and thalidomide.

Patients and Methods: Thirty patients were given IFN-α-2b 0.9 MU subcutaneously three times daily for 1 month and subsequently 1.2 MU tid unless serious toxicity was encountered. Thalidomide was first given 100 mg/d for 1 week and 300 mg/d thereafter. Sera were collected before and during treatment for serum vascular endothelial growth factor (S-VEGF) analyses performed using enzyme-linked immunosorbent assay.

Results: The intention-to-treat response rate was 20% (95% CI, 6% to 34%) and response rate for assessable patients (n = 27) was 22% (95% CI, 6% to 38%). All responses were partial. In addition, 17 patients (63%; 95% CI, 45% to 81%) had stable disease for 3 months or longer. The median time to treatment failure was 7.7 months, and median survival time was 14.9 months. The most common cause of thalidomide discontinuation was neuropathy. S-VEGF levels decreased more in patients who responded to therapy compared with those in patients whose condition had stabilized or who had progressive disease (P = .036).

Conclusion: The combination of frequently dosed IFN-α-2b and low-dose thalidomide is feasible and active in advanced RCC, but the clinical benefit may remain small compared with that of IFN alone. Results from an ongoing phase III trial comparing IFN-α with or without thalidomide need to be analyzed before this combination can be recommended for use outside clinical studies.

Thrombospondin-1, vascular endothelial growth factor expression and microvessel density in renal cell carcinoma and their relationship with multifocality

OBJECTIVE

To evaluate the relevance of microvessel density (MVD) and the angiogenic factors, vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumors) and thrombospondin-1 (TSP-1, a potent inhibitor of angiogenesis), to multifocality of renal cell carcinoma (RCC).

PATIENTS AND METHODS

Using immunohistochemistry the expression of CD34, TSP-1 and VEGF was assessed in 38 archival tissue specimens from 19 patients with unifocal RCC and 19 with multifocal RCC. Immunostaining results for VEGF was scored for the appropriate percentage of positive tumor cells and relative immunostaining intensity (score range 0-12). Only extracellular immunoreactivity was considered positive for TSP-1 and the same method was used to score the stromal staining. The microvessel density was measured by immunohistochemical staining with anti-CD34 monoclonal antibody.

RESULTS

VEGF immunoreactivity> or =1% was detectable in all unifocal and multifocal tumors. TSP-1 immunoreactivity was detected in 14 (73.7%) of 19 unifocal RCCs and in 16 (84.2%) of 19 multifocal RCC specimens (p=0.69). There were no statistically significant differences in the immunostaining intensity, percentage of immunopositive cells and the staining scores of VEGF and TSP-1 among the two groups. Additionally, there was no difference in MVD in multifocal and unifocal tumors.

CONCLUSION

As there is no difference in MVD count, and expression of angiogenic factors (VEGF and TSP-1) in multifocal and unifocal tumors, multifocality of RCC is not determined by VEGF/TSP-1 expression.

Expression of vascular endothelial growth factor in renal cell carcinoma is correlated with cancer advancement

Vascular endothelial growth factor (VEGF) functions as a regulator of neovascularization in malignant cells. VEGF as a mitogen is thought to alter renal cell carcinoma formation and tumor progression. We investigated the expression of the VEGF gene in order to evaluate its clinical significance in renal cell carcinoma. Tissue samples from 198 patients with renal cell carcinoma were examined with an immunohistochemical stain for the expression of the VEGF gene. The expression rate was compared to 34 normal renal cortical samples obtained from renal surgery from noncancer patients. There were significant differences between normal renal cortex (0%) and cancer tissue (54.5%) in positive staining of VEGF protein (P<0.001). With the progression of tumor grade, the positive rate of VEGF gene expression significantly increased. The expression rate of the VEGF gene in the advanced group, such as with lymph node involvement or vein invasion, was greater than that in the locally confined group (P<0.001). The results revealed that expression of the VEGF gene is proportional to the formation and progression of renal cell carcinoma, which may allow VEGF to be used as a prognostic marker for renal cell carcinoma.

Renal-cell carcinoma: tumour markers, T-cell epitopes, and potential for new therapies

Advanced renal-cell carcinoma is a very difficult tumour to treat, and response rates to biological therapies are less than 20%. The identification of various molecular and cellular markers has led to the development of novel therapies. Despite evaluation of their association with histological subtype, immune infiltration, molecular markers of cell proliferation, p53 mutation, and growth-factor-receptor expression, none of these markers has proved better predictive factors than tumour stage and histological grade. The identification of tumour-associated antigens and the specificity of cellular immune responses have led to the development of targeted immunotherapy with monoclonal antibodies, radioimmunotherapy, and T-cell therapies. In this review, we evaluate a range of markers associated with renal-cell carcinoma and new treatment approaches based on tumour-associated antigens and, in particular, T-cell epitopes.

Gene Expression Profiling of Renal Cell Carcinoma and Its Implications in Diagnosis, Prognosis, and Therapeutics

Renal cell carcinoma (RCC) is the 10th most common cancer in the United States. It is a histologically heterogeneous disease with various histologic types being characterized by distinct genetic alterations. This chapter reviews advances in the gene expression profiling of RCC and discusses their clinical implications. Data are promising, and many more RCC-related microarray studies are currently underway or in planning. Undoubtedly these data will have an impact on the diagnosis, prognosis, and treatment of RCCs in the future. Finally, this chapter discusses what additional studies should be performed to help uncover the molecular mechanisms of RCC and to bring this new knowledge into use in the clinical arena.

Single nucleotide polymorphisms in the 3' untranslated region of vascular endothelial growth factor gene in Japanese population with or without renal cell carcinoma

We investigated native Japanese subjects whether C702T, C936T and G1612A polymorphisms in the 3' untranslated region (3'-UTR) of vascular endothelial growth factor (VEGF) gene are associated with the risk of renal cell carcinoma (RCC). Genomic DNAs from 145 RCC patients and 145 healthy controls were examined by polymerase chain reaction-based restriction fragment length polymorphism. Variant allele frequencies of C702T, C936T and G1612A were 0.00, 0.20 and 0.13 in the controls, respectively. The C702T and G1612A allele frequencies were significantly different between the Japanese population and the Caucasian population reported elsewhere. For each of C936T and G1612A polymorphisms, there was no statistically significant difference in the distribution of genotype frequencies between the cases and controls. Odds ratios and 95% confidence intervals computed by logistic regression analyses were not statistically significant. Stratification for the RCC cases according to pathological cell subtype, grade or stage failed to reveal any significant heterogeneity with respect to the genotype of each VEGF polymorphism. We revealed that there are significant ethnic differences in the C702T and G1612A allele frequencies, but suggested that C702T, C936T and G1612A polymorphisms in the 3'-UTR of VEGF gene are not associated with the risk of RCC, at least in Japanese population.

Plasma vascular endothelial growth factor levels have prognostic significance in patients with acute myeloid leukemia but not in patients with myelodysplastic syndromes

BACKGROUND

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are positive regulators of angiogenesis. Increased levels in urine, serum, plasma, or malignant tissue have been associated with an adverse prognosis in patients with solid tumors.

METHODS

The authors used an enzyme-linked immunosorbent assay to measure VEGF and bFGF levels in plasma samples from 99 patients with previously untreated myelodysplastic syndromes (MDS) (n = 41 patients; 42%) or acute myeloid leukemia (AML) (n = 58 patients; 58%) and compared the results with the results from a group of normal control participants.

RESULTS

Increased expression levels of VEGF and bFGF were found in the plasma from patients with AML and MDS (P < 0.01) compared with the levels found in the control group. Plasma levels of VEGF in patients with AML or MDS were similar (median, 30.63 pg/mL and 34.41 pg/mL, respectively). There was no significant difference in bFGF levels between patients with AML and patients with MDS (median, 6.38 pg/mL and 6.98 pg/mL, respectively). Elevated levels of VEGF were associated with reduced survival (P = 0.02) in patients with AML as well as lower complete remission (CR) rates (P = 0.004). Elevated VEGF levels were not associated with reduced remission duration (CRD) in patients with AML. There was no correlation between VEGF levels and survival, CRD, or CR rates in patients with MDS. There was no correlation between bFGF levels and CR rates or survival in patients with either AML or MDS.

CONCLUSIONS

Plasma VEGF levels have prognostic significance in patients with AML. The lack of clinical relevance of VEGF levels in patients with MDS suggests some biologic difference between AML and MDS.

Inhibition of renal cell carcinoma angiogenesis and growth by antisense oligonucleotides targeting vascular endothelial growth factor

Angiogenesis is critical for growth and metastatic spread of solid tumours. It is tightly controlled by specific regulatory factors. Vascular endothelial growth factor has been implicated as the key factor in tumour angiogenesis. In the present studies we evaluated the effects of blocking vascular endothelial growth factor production by antisense phosphorothioate oligodeoxynucleotides on the growth and angiogenic activity of a pre-clinical model of renal cell carcinoma (Caki-1). In vitro studies showed that treating Caki-1 cells with antisense phosphorothioate oligodeoxynucleotides directed against vascular endothelial growth factor mRNA led to a reduction in expressed vascular endothelial growth factor levels sufficient to impair the proliferation and migration of co-cultured endothelial cells. The observed effects were antisense sequence specific, dose dependent, and could be achieved at a low, non-toxic concentration of phosphorothioate oligodeoxynucleotides. When vascular endothelial growth factor antisense treated Caki-1 cells were injected into nude mice and evaluated for their angiogenic potential, the number of vessels initiated were approximately half that induced by untreated Caki-1 cells. To test the anti-tumour efficacy of vascular endothelial growth factor antisense, phosphorothioate oligodeoxynucleotides were administrated to nude mice bearing macroscopic Caki-1 xenografts. The results showed that the systemic administration of two doses of vascular endothelial growth factor antisense phosphorothioate oligodeoxynucleotides given 1 and 4 days after the tumours reached a size of approximately 200 mm(3) significantly increased the time for tumours to grow to 1000 mm(3).

Prognostic importance of serum vascular endothelial growth factor in relation to platelet and leukocyte counts in human renal cell carcinoma

It has been shown that both serum vascular endothelial growth factor (VEGF) and also platelet counts are associated with survival in renal cell carcinoma (RCC). It is not known, however, whether VEGF in serum relates to the angiogenic activity of the tumour or is derived from circulating blood components. Therefore, the interrelation between serum VEGF, platelet and leukocyte counts compared with health history, clinicopathological findings and outcome was evaluated in patients with RCC. Blood samples were collected before nephrectomy in 161 patients. Serum VEGF165 was assessed by a quantitative ELISA method. Platelet and leukocyte counts were analysed routinely and obtained from medical records. The variables were compared using univariate and multivariate analysis. There were significant correlations between VEGF levels, and platelet (P < 0.001) and leukocyte counts (P < 0.001). Serum VEGF levels, platelet counts, as well as leukocyte counts correlated significantly to stage and grade. Platelet counts were significantly lower in men with medication (P = 0.042), and decreased with age particularly in women (P = 0.001). Age or medication did not affect VEGF levels or leukocyte counts. Both VEGF and platelets gave significant prognostic information in univariate analysis. Using Cox multivariate analysis, VEGF was the last variable to be excluded. Only stage and grade remained as independent prognostic factors. Both VEGF levels and platelet counts gave prognostic information but VEGF was more reliable as predictor of survival in patients with RCC.

Prognostic factors for biologic therapy in kidney cancer

Renal cell cancer is resistant to most forms of therapy. Cytokine therapy with either interleukin-2 or interferon-alpha yields the best results, with response rates from 10% to 20%. Therapy is not without toxicity, which means that the majority of patients treated with cytokines suffer toxicity without any therapeutic benefit. Recent endeavors have tried to find new ways to identify responders to cytokine therapy. Prognostic factors, such as good performance status, lack of anemia, normal calcium, normal lactate dehydrogenase, and prior nephrectomy, correlate with an increased likelihood of responding to cytokine therapy. Recent studies have examined whether altered subpopulations of lymphocytes, the presence of eosinophils, or altered levels of cytokines can predict response to cytokine therapy. Although prior nephrectomy does correlate with improved survival while the patient is receiving cytokine therapy, it is unclear if this is due to a significant alteration in the tumor's response to cytokine or some unrelated benefit from surgery. Further studies are needed to confirm the current immune parameters and disease characteristics that suggest a better response to cytokine therapy.

New agents for the treatment of renal cell carcinoma

One-third of patients with renal cell carcinoma present with unresectable or metastatic disease. Immunotherapy, the current standard treatment, induces response in only 10-20% of patients. Chemotherapy with current agents is minimally effective. Other approaches including allogeneic stem cell transplant, vaccine and gene therapy and signal transduction inhibitors, offer promise in early Phase studies. This paper reviews the current treatment options and promising new agents in development.

Clinical significance of urinary vascular endothelial growth factor and microvessel density in patients with renal cell carcinoma

OBJECTIVES

To investigate the urinary vascular endothelial growth factor (VEGF) levels from patients with renal cell carcinoma (RCC). Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. VEGF is thought to exert potent angiogenic activity.

METHODS

Urine samples were obtained before radical nephrectomy from 27 patients with RCC and 10 control subjects with no evidence of cancer or inflammatory disease. VEGF was measured by enzyme-linked immunosorbent assay in the urine and corrected according to the 24-hour urine concentration of creatinine. The microvessel density was measured by immunohistochemical staining with CD31 monoclonal antibody. Nuclear morphometry was performed by photomicroscopy.

RESULTS

The corrected urinary VEGF levels in patients with RCC were much higher than those in the normal control group (P = 0.039) and were more elevated in patients with higher stages of RCC (Stages III and IV versus Stages I and II; P = 0.024). A tendency was also noted for the VEGF levels to be higher according to cell grade. However, no statistical correlation was found between the corrected urinary VEGF and age, sex, tumor size, cell type, microvessel density, platelet count, or hemoglobin. The nuclear area was higher with more advanced-stage tumors (P = 0.043) and tended to increase according to the tumor cell grade.

CONCLUSIONS

The results of this study indicate that urinary VEGF levels are increased in patients with RCC. However, they may not reflect the underlying angiogenic activity, and it may be that other angiogenic factors play a more prominent role.

Quantitative analysis of gene expressions of vascular endothelial growth factor-related factors and their receptors in renal cell carcinoma

Vascular endothelial growth factor (VEGF)-related factors are believed to regulate angiogenesis, an essential event in the growth of solid tumors. In this study, we investigated the expression of VEGF-related factor genes (VEGF, VEGF-B, and VEGF-C) and their receptor genes (VEGFR-1 and VEGFR-2) in renal cell carcinoma (RCC). There were significant differences in the expression level of VEGF, VEGFR-1 and VEGFR-2 between RCC and the corresponding normal renal tissue. The expression level of VEGF in the tumor tissue significantly correlated with those of VEGFR-1 and VEGFR-2. Expression levels VEGF-B and VEGF-C genes were not significantly different between RCC and normal renal tissue. A moderate to high protein expression for VEGF, VEGFR-1, and VEGFR-2 was observed in both the tumor cells and the endothelial cells, whereas the protein expression was low for VEGF-B and VEGF-C. The present results suggested that VEGF and its receptors VEGFR-1 and VEGFR-2 cooperates to play a crucial role in the angiogenesis of RCC, while VEGF-B and VEGFR-C may not. Furthermore, since VEGFR-1 and VEGFR-2 proteins were expressed in the tumor cells as well as in the endothelial cells, these receptors may also be responsible for the progression of RCC.