Advances in angiogenesis research: relevance to urological oncology

Therapeutic Potential of Targeting Prokineticin Receptors in Diseases

The prokineticins (PKs) were discovered approximately 20 years ago as small peptides inducing gut contractility. Today, they are established as angiogenic, anorectic, and proinflammatory cytokines, chemokines, hormones, and neuropeptides involved in variety of physiologic and pathophysiological pathways. Their altered expression or mutations implicated in several diseases make them a potential biomarker. Their G-protein coupled receptors, PKR1 and PKR2, have divergent roles that can be therapeutic target for treatment of cardiovascular, metabolic, and neural diseases as well as pain and cancer. This article reviews and summarizes our current knowledge of PK family functions from development of heart and brain to regulation of homeostasis in health and diseases. Finally, the review summarizes the established roles of the endogenous peptides, synthetic peptides and the selective ligands of PKR1 and PKR2, and nonpeptide orthostatic and allosteric modulator of the receptors in preclinical disease models. The present review emphasizes the ambiguous aspects and gaps in our knowledge of functions of PKR ligands and elucidates future perspectives for PK research. SIGNIFICANCE STATEMENT: This review provides an in-depth view of the prokineticin family and PK receptors that can be active without their endogenous ligand and exhibits "constitutive" activity in diseases. Their non- peptide ligands display promising effects in several preclinical disease models. PKs can be the diagnostic biomarker of several diseases. A thorough understanding of the role of prokineticin family and their receptor types in health and diseases is critical to develop novel therapeutic strategies with safety concerns.

Tumor Microenvironment in Prostate Cancer: Toward Identification of Novel Molecular Biomarkers for Diagnosis, Prognosis, and Therapy Development

Prostate cancer (PCa) is by far the most commonly diagnosed cancer in men worldwide. Despite sensitivity to androgen deprivation, patients with advanced disease eventually develop resistance to therapy and may die of metastatic castration-resistant prostate cancer (mCRPC). A key challenge in the management of PCa is the clinical heterogeneity that is hard to predict using existing biomarkers. Defining molecular biomarkers for PCa that can reliably aid in diagnosis and distinguishing patients who require aggressive therapy from those who should avoid overtreatment is a significant unmet need. Mechanisms underlying the development of PCa are not confined to cancer epithelial cells, but also involve the tumor microenvironment. The crosstalk between epithelial cells and stroma in PCa has been shown to play an integral role in disease progression and metastasis. A number of key markers of reactive stroma has been identified including stem/progenitor cell markers, stromal-derived mediators of inflammation, regulators of angiogenesis, connective tissue growth factors, wingless homologs (Wnts), and integrins. Here, we provide a synopsis of the stromal-epithelial crosstalk in PCa focusing on the relevant molecular biomarkers pertaining to the tumor microenvironment and their role in diagnosis, prognosis, and therapy development.

Screening candidate genes associated with bladder cancer using DNA microarray

The aim of the present study was to screen candidate genes that are closely associated with bladder cancer and to select the most distinct candidate target genes in order to provide theoretical evidence and direction for improved treatment of bladder cancer. The gene microarray dataset GSE45184 was downloaded from the Gene Expression Omnibus database. There were a total of six expression prolife microarrays from three pairs of freshly frozen bladder cancer tissues and corresponding normal adjacent tissues. Differentially expressed genes (DEGs) were identified using the limma package in R software and then subjected to further biological information analysis, including hierarchical clustering analysis and gene ontology enrichment analysis. Co‑expression networks and functional interaction networks were established using the up‑ and downregulated genes. Pathway enrichment analysis was then performed for the genes in the functional interaction networks. A total of 522 DEGs were identified, including 223 upregulated and 299 downregulated genes. Functional enrichment analysis of the target genes indicated that downregulated genes were associated with the regulation of biological processes, while the upregulated genes participated in the processes involved in the cell cycle. The functional network of the upregulated genes comprised 1,518 connections and 92 gene nodes that were associated with 10 closely‑related functions, while the network of the downregulated genes consisted of 129 connections and 24 gene nodes involving 11 significantly related functions. Pathway enrichment analysis revealed that the downregulated genes were mainly involved in the mitogen‑activated protein kinase signaling pathway, while the upregulated genes were closely associated with the cell cycle. These DEGs and the relevant cell cycle pathways have the potential to be used as targets for the treatment of bladder cancer.

Caveolin-1 and accelerated host aging in the breast tumor microenvironment: chemoprevention with rapamycin, an mTOR inhibitor and anti-aging drug

Increasing chronological age is the most significant risk factor for human cancer development. To examine the effects of host aging on mammary tumor growth, we used caveolin (Cav)-1 knockout mice as a bona fide model of accelerated host aging. Mammary tumor cells were orthotopically implanted into these distinct microenvironments (Cav-1(+/+) versus Cav-1(-/-) age-matched young female mice). Mammary tumors grown in a Cav-1-deficient tumor microenvironment have an increased stromal content, with vimentin-positive myofibroblasts (a marker associated with oxidative stress) that are also positive for S6-kinase activation (a marker associated with aging). Mammary tumors grown in a Cav-1-deficient tumor microenvironment were more than fivefold larger than tumors grown in a wild-type microenvironment. Thus, a Cav-1-deficient tumor microenvironment provides a fertile soil for breast cancer tumor growth. Interestingly, the mammary tumor-promoting effects of a Cav-1-deficient microenvironment were estrogen and progesterone independent. In this context, chemoprevention was achieved by using the mammalian target of rapamycin (mTOR) inhibitor and anti-aging drug, rapamycin. Systemic rapamycin treatment of mammary tumors grown in a Cav-1-deficient microenvironment significantly inhibited their tumor growth, decreased their stromal content, and reduced the levels of both vimentin and phospho-S6 in Cav-1-deficient cancer-associated fibroblasts. Since stromal loss of Cav-1 is a marker of a lethal tumor microenvironment in breast tumors, these high-risk patients might benefit from treatment with mTOR inhibitors, such as rapamycin or other rapamycin-related compounds (rapalogues).

Angiogenin as a molecular target for the treatment of prostate cancer

Angiogenin (ANG), a 14 kDa angiogenic ribonuclease, is upregulated in human prostate cancers, especially in hormone refractory diseases, and is the highest upregulated gene in Akt-driven prostate intraepithelial neoplasia (PIN) in mice. ANG has been shown to undergo nuclear translocation in both prostate cancer cells and cancer-associated endothelial cells where it binds to the promoter region of ribosomal DNA (rDNA) and stimulates ribosomal RNA (rRNA) transcription. ANG thus plays an essential role in prostate cancer progression by stimulating both cancer cell proliferation and tumor angiogenesis. A variety of ANG antagonists, including its antisense oligonucleotide, siRNA, soluble binding proteins, monoclonal antibody, enzymatic inhibitors, and nuclear translocation blockers, have all been shown to inhibit prostate cancer in various animal models. Accumulating evidence indicates that ANG is a molecular target for prostate cancer drug development.

Description of magnetic resonance imaging-derived enhancement variables in pathologically confirmed prostate cancer and normal peripheral zone regions

OBJECTIVE

To assess the use of a semiquantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to produce indices for enhancement curves that might enable differentiation between malignant prostatic lesions and normal peripheral zone (PZ).

PATIENTS AND METHODS

Fifty-two patients scheduled for radical prostatectomy underwent DCE-MRI before surgery using a 3 T scanner. The DCE images were used to generate variables from changes in signal intensity for pathologically confirmed malignant areas and the normal PZ, using whole-mounted pathology specimens as a reference to delineate regions of interest (ROI). These variables included maximum enhancement index (MaxEI), time to MaxEI at 30 s, the initial and final slopes of signal intensity change, and the area under curve. A threshold value for each DCE variable was identified, and the sensitivity and specificity were obtained.

RESULTS

Malignant lesions had a 56% higher MaxEI than normal PZ and took half the time to reach MaxEI (P<0.001). Hence, at 30 s, cancer lesions have double the mean (sd) EI than normal PZ, of 2.22 (1.04) vs 1.04 (0.51), respectively. Tumours showed significant washout of contrast medium, which was reflected in the final slope of the curve being negative, as opposed to positive for normal PZ. The combined data of DCE variables, using a logistic regression test, gave a mean (95% confidence interval) sensitivity and specificity of 89 (81-96)% and 90 (83-97)%, respectively.

CONCLUSION

This technique provides good discrimination of malignant lesions that might enable accurate localisation of the lesion. It is a simple, semiquantitive, noninvasive method that reflects the unusual vascular characteristics of newly formed microvessels and the changes in the interstitium that occur in prostate cancer.

Antibody library-based tumor endothelial cells surface proteomic functional screen reveals migration-stimulating factor as an anti-angiogenic target

Angiogenesis is critical for cancer development and metastasis. Here we have employed a functional antibody library-based proteomic screen to identify proteins that participate in and might be used as therapeutic targets for tumor-related angiogenesis. Mice were immunized with human esophageal cancer endothelial cells (HECEC). The antibody library was established with the mouse spleen cells the serum of which had most anti-angiogenic effect. Monoclonal antibodies were subjected to an immunoreactive and functional screen and monoclonal antibodies that reacted strongly with cell surface antigens of HECECs and influenced their behavior were selected. Antigens that recognized by the antibodies were obtained by immunoprecipitation and then identified by mass spectrometry analysis. Migration-stimulating factor (MSF), the antigen of 1D2 antibody was identified using this approach. Further studies demonstrated that the 1D2 antibody suppressed MSF-effected migration and adhesion of HECECs on fibronectin matrix. Biodistribution assay showed that MSF targeting antibody 1D2 could specifically home to the xenograft with humanized blood vessel. Targeting treatment with 1D2 antibody significantly suppressed tumor growth through inhibition of human tumor-related angiogenesis. These results indicate that the functional antibody library-based proteomic screen can successfully identify proteins that involved in tumor-related angiogenesis and MSF may be a target for the anti-angiogenic treatment of the esophageal cancer.

Antiangiogenic Effect of ZD1839 against Murine Renal Cell Carcinoma (RENCA) in an Orthotopic Mouse Model

INTRODUCTION

ZD1839 (Iressa) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). We evaluated the antitumor and antiangiogenesis activities of ZD1839 in a murine renal cell carcinoma (RENCA) model.

MATERIALS AND METHODS

The effect of ZD1839 on the cellular proliferation of RENCA cells in vitro was measured by colorimetric assay. For the in vivo studies, RENCA cells were adsorbed in Gelfoam and implanted into BALB/cJ mouse parenchyma with an agarose bar. Mice were treated with ZD1839 (40 mg/kg/day s.c.), genistein or saline for 14 days. Western blot analysis was performed to observe EGFR expression in RENCA cells and tumor tissues. Microvessel density (MVD) was quantified by immunostaining for factor VIII-related antigens and VEGF level was assayed by ELISA.

RESULTS

ZD1839 showed a dose-dependent inhibition of RENCA cellular proliferation. ZD1839 treatment resulted in a marked decrease in tumor growth compared with saline treatment. The MVD and VEGF in the RENCA tumors were decreased significantly by ZD1839 (p<0.01 and p>0.05, respectively). Genistein also suppressed tumor growth and decreased MVD and VEGF level, but the efficacies were less than with ZD1839.

CONCLUSION

The suppressive activity of ZD1839 on RENCA tumor growth was accompanied by decreases in the MVD and VEGF production. These results suggest that the antitumor effect of ZD1839 in a RENCA model is mediated partially by the inhibition of tumor angiogenesis.

Effect of Chronic Prostatitis on Angiogenic Activity and Serum Prostate Specific Antigen Level in Benign Prostatic Hyperplasia

The aim of this study was to evaluate the effect of chronic inflammatory pathology on the angiogenic activity in benign prostatic hyperplasia (BPH). Besides the presence of a relationship between serum prostate specific antigen (PSA) values and microvessel density (mvd), the intensity and extent (widespread or focal) of tissue PSA expression was also examined. The distribution of 30 cases according to the diagnosis groups was as follows: group 1, nine cases with prostatic adenocarcinoma; group 2, 10 cases with BPH and chronic prostatitis; group 3, 11 cases with BPH. The biopsy materials obtained by tru-cut biopsy (five cases) and transurethral resection (25 cases) were evaluated retrospectively. The evaluation of angiogenesis was made by CD34 immune marker, while the analysis of immunohistochemical tissue PSA expression was verified by PSA immune marker. Serum PSA levels and other clinical parameters were obtained from the clinical files of the patients. The mean age of the patients was 68 +/- 3 years (range, 48-83 years). The difference between the mean mvd values of the groups was statistically significant (chi2 = 10.492, p = 0.005). Group 1 showed higher mean mvd value than the other two groups. Although group 2 showed higher mean mvd value than group 3, the difference was not statistically significant (p = 0.863). There was no correlation between the mean mvd and serum PSA levels in any group. The intensity of PSA expression in prostate specimens was different in all groups. Maximum cases in group 3 showed high tissue PSA expression (chi2 = 12.442, p = 0.014). In group 1, there was a significant relationship between the intensity of PSA expression and the mean mvd (U = 1, p = 0.032). In group 2, a statistically significant correlation was noted between the mean serum PSA levels and the widespread occurrence of PSA expression (U = 0, p = 0.017). In the present study, we determined that chronic prostatitis had no effect on mvd in BPH cases. The correlation between tissue PSA expression and mvd was contradictory to the reports in the literature. Analyses in larger series are needed to prove the presence of a probable effect of chronic prostatitis on angiogenesis.

Human esophageal cancer endothelial cells increase tumor growth by incorporating with mouse endothelium

Current in vivo investigations of tumor angiogenesis mainly rely on the results obtained from engrafted models in mice. In the present study, we attempt to assess the potential of human tumor endothelium to form neovasculature in different engrafted tumor models. The tumor endothelial cells were isolated from human esophageal squamous cell carcinoma, and then identified by anti-VEGFR1/2 immunoreactions and tube formation assay. Esophageal and lung cancer cells were subcutaneously inoculated into nude mice with human esophageal cancer endothelial cells (HECECs), respectively. The human umbilical vein endothelial cells (HUVECs) were also co-inoculated into mice with esophageal cancer cells as a control. The engrafted tumor growth was significantly promoted by co-inoculation of HECECs in comparison with injection of esophageal tumor cells alone. Immunohistochemistry of anti-CD31 and anti-huCD31 was performed to detect the micro-vessels in the engrafted tumors which revealed that the HECECs formed humanized micro-vessels and significantly increased the micro-vessel density in engrafted tumors comparing with the tumors without HECECs. However, HUVEC cells could not enhance the esophageal tumor growth and the growth of lung tumors could not be increased by HECECs, either. Few humanized blood vessels were found in these two groups of xenografts. These results suggest that the specific interaction between HECECs and esophageal tumor cells contributes to the neovasculature construction and esophageal tumor growth in xenografts.

The expression of thymidine phosphorylase is a prognostic predictor for the intravesical recurrence of superficial bladder cancer

BACKGROUND

Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor, has been implicated in the angiogenesis of bladder cancer. The aim of this study is to investigate the association between TP expression and the clinicopathologic findings, and the prognostic value.

METHODS

TP immunohistochemical staining was performed in specimens from 71 patients (50 men and 21 women) with superficial bladder cancer (pTa or pT1). Thirty-nine patients had received intravesical instillation of tetrahydropyranyladriamycin (THP) after transurethral resection (TUR) and the other 32 had not. For immunohistochemistry, paraffin-embedded specimens were stained with mouse monoclonal antibody against TP. When more than 10% of tumor cells were positively stained, staining was defined as positive. The correlations between TP immunostaining and clinicopathological features were analyzed. Multivariate analysis, using the Cox proportional hazard model, was performed to determine the risk factors for intravesical recurrence.

RESULTS

Specimens from 29 of the 71 patients (19 men and 10 women) were positive for TP. The expression of TP was not correlated with age, sex, histological grade, multiplicity, or morphology. Also, TP expression was not associated with whether the cases were primary or recurrent. Multivariate analysis demonstrated that the decreased expression of TP and the use of THP instillation could be independent predictors of a higher rate of intravesical recurrence-free bladder cancer.

CONCLUSION

The present study suggests that immunohistochemical TP staining is useful for predicting the intravesical recurrence of superficial bladder cancer after Transurethral resection of bladder tumor (TUR-Bt).

Dynamic CT Evaluation of Tumor Vascularity in Renal Cell Carcinoma

OBJECTIVE

The purpose of our study was to evaluate the correlation between the enhancement parameters of dynamic CT; the carcinoma tissue microvessel density (MVD, a hotspot method to provide a histologic assessment of tumor vascularity); and tumor nuclear grade in renal cell carcinomas.

SUBJECTS AND METHODS

Twenty-four patients with histologically diagnosed renal cell carcinoma underwent dynamic enhanced CT. Enhancement parameters, slope of the time-density curve, the density difference before and after tissue enhancement (deltaH), tissue blood ratio (TBR), and area under the time-density curve (AR), were calculated for all lesions. Pathology slides corresponding to the CT plane were stained using mouse antihuman CD34 monoclonal antibody and H and E. Fuhrman nuclear grade was used. Vascular hot spots of microvessels were recorded. Spearman's rank correlation was performed to determine the strength of the relationship between enhancement parameters, MVD determinations, and tumor nuclear grade.

RESULTS

MVD with CD34 staining revealed uneven distribution of positively stained vascular endothelial cells in renal cell carcinoma lesions. Heterogeneous distribution of contrast enhancement was seen among and within individual tumors. The tumors appeared as uneven patterns on time-density curves of renal cell carcinoma lesions. Enhancement parameters of H (median, 21.0 H; range, 2.2-105.8 H), TBR (median, 39%; range, 10.7-154.7%), AR (median, 1.58 H x sec; range, 0.23-3.67 H x sec), and slope (median, 2.76; range, 0.53-6.76) varied greatly. Renal cell carcinoma tissue MVD significantly correlated with all enhancement parameters of dynamic CT. The correlation coefficients (r) were 0.62, 0.54, 0.55, and 0.44, respectively, for delta H, slope, TBR, and AR (p < 0.0 5). All enhancement parameters did not significantly correlate with tumor nuclear grade. They were not predictive of nuclear grade.

CONCLUSION

Enhancement parameters of dynamic CT may be suited to evaluate tumor vascularity in vivo. Dynamic enhanced CT images may reflect the heterogeneity of tumor angiogenesis on the basis of the correlation between enhancement parameters and MVD of renal cell carcinoma.

Proliferating cell nuclear antigen (PCNA) overexpression and microvessel density predict survival in the urinary bladder carcinoma

OBJECTIVE

To study proliferating cell nuclear antigen (PCNA) over expression and angiogenesis with their relationship to tumor parameters in squamous cell carcinoma of the urinary bladder in patients who underwent radical cystectomy.

PATIENTS AND METHODS

The mean age of the patients was 53.53 years (range; 29-70 years) and the males were 98 of 154. Sections from paraffin embedded tissues were retrieved and stained with antibodies against PCNA for proliferation and CD34 for angiogenesis using immunohistochemical technique. Fisher's exact test was used to evaluate the relationship between categorical variables and the Kaplan-Meier procedure was used to assess survival outcomes. The Cox regression model was used for multivariate analysis.

RESULTS

The median follow up period was 65 months. microvessel density (MVD), PCNA, tumor grade, P-stage, DNA ploidy, lymph node status had a significant impact on the 5-year survival of patients in univariate analysis. In Cox proportional hazard model, MVD, PCNA, DNA ploidy and stage sustained their significant impact on survival of the patients.

CONCLUSIONS

MVD, PCNA, DNA ploidy and stage are independent prognostic factors in patients with squamous cell carcinoma of the urinary bladder.

A prostate secretory protein94-derived synthetic peptide PCK3145 inhibits VEGF signalling in endothelial cells: implication in tumor angiogenesis

We have previously observed that the synthetic peptide corresponding to amino acids 31-45 (PCK3145) of PSP94 can reduce prostate tumor growth in vivo. Moreover, a recently concluded phase IIa clinical trial with patients with hormone refractory prostate cancer indicated that PCK3145 down-regulates the levels of plasma matrix metalloproteinase (MMP)-9, a MMP involved in metastasis and tumor angiogenesis. The purpose of our study was to investigate the molecular mechanisms of action of PCK3145 and whether this peptide could antagonize tumor neovascularization. We show that, in a syngeneic in vivo model of rat prostate cancer, the expression of endothelial cell (EC) specific CD31, a marker of tumor vessel density, was decreased by 43% in PCK3145-treated animals. In vitro, PCK3145 specifically antagonized in a dose-dependent manner the VEGF-induced ERK phosphorylation as well as the phosphorylation of the VEGFR-2 in cultured EC (HUVEC). These anti-VEGF effects were partly reproduced by pharmacological inhibitors such as PD98059 and PTK787, suggesting that PCK3145 inhibits the tyrosine kinase activity associated to VEGFR-2, which in turn prevents intracellular signalling through the MAPK cascade. Moreover, PCK3145 was also found to inhibit the PDGF-induced phosphorylation of PDGFR in smooth muscle cells. Finally, PCK3145 inhibited in vitro EC tubulogenesis and VEGF-induced MMP-2 secretion suggesting its potential implication as an antiangiogenic agent. Our study demonstrates that PCK3145 interferes with the tyrosine kinase activity associated with VEGF signalling axis in EC. The antiangiogenic properties of this peptide could be highly beneficial and exploited in novel antiangiogenic therapies, for patients with various cancers.

Targeting of pericytes diminishes neovascularization and lymphangiogenesis in prostate cancer

BACKGROUND

The walls of capillaries in prostate cancer are composed of endothelial cells, and pericytes. NG2 is a transmembrane proteoglycan on nascent pericytes with a functional role in neovascularization.

METHODS

The anti-angiogenic effect of hydron pellets containing NG2 neutralizing antibody was quantified in intracorneal PC-3 and LNCaP xenografts. TRAMP and TRAMP-C1 tumors grafted in NG2 knockout mice represented intrinsic pericyte targeting. TRAMP and TRAMP-C1 grafts were analyzed with confocal microscope for microvascular density (MVD) and lymphatic vascular density (LVD).

RESULTS

NG2 neutralizing antibody decreased corneal neovascularization in PC3 (P<0.0001), and LNCaP (P=0.0079) xenografts. Mean MVD in TRAMP and TRAMP-C1 tumors in NG2 knockout mice were 71% (P=0.0006) and 63% (P=0.0011) lower than wild type controls, respectively. Mean LVD in TRAMP and TRAMP-C1 tumors in NG2 knockout mice were 73% (P=0.0003) and 84% (P<0.0001) lower than wild type controls, respectively.

CONCLUSIONS

Targeting of pericyte-NG2 decreases neovascularization and lymphangiogenesis in prostate cancer significantly.

Elevated expression of angiogenin in prostate cancer and its precursors

PURPOSE

Angiogenin is a polypeptide involved in the formation and establishment of new blood vessels necessary for growth and metastasis of numerous malignant neoplasms, including prostatic adenocarcinoma. Antiangiogenin therapy inhibits the establishment, growth, and metastasis of prostatic adenocarcinoma in animal studies. In this study, we have investigated the expression of angiogenin in prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia, and adjacent benign prostatic epithelium in a large cohort of prostatectomy specimens.

METHODS

We have studied the expression of angiogenin by immunohistochemistry in prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia, and adjacent benign prostatic tissue in 107 human total prostatectomy specimens.

RESULTS

The percentage of cells staining positively for angiogenin in benign prostatic glandular epithelium (mean = 17%) was significantly less than for high-grade prostatic intraepithelial neoplasia (mean = 58%, P < 0.001) and prostatic adenocarcinoma (mean = 60%, P < 0.001). Compared with adjacent benign prostatic epithelium, the staining intensity was significantly greater in high-grade prostatic intraepithelial neoplasia (P < 0.001) and prostatic adenocarcinoma (P < 0.001). Furthermore, staining intensity has significantly stronger in prostatic adenocarcinoma versus high-grade prostatic intraepithelial neoplasia (P = 0.0023). However, there was no correlation of angiogenin expression with various clinical and pathologic variables examined, including age at surgery, Gleason scores, pathologic stage, tumor extent, angiolymphatic invasion, extraprostatic extension, seminal vesical invasion, lymph node metastasis, surgical margin status, presence of prostatic intraepithelial neoplasia, and perineural invasion.

CONCLUSION

Angiogenin expression in prostatic tissue increases as prostatic epithelial cells evolve from a benign to an invasive phenotype. The increasing expression of prostatic adenocarcinoma in the progression from benign prostate to high-grade prostatic intraepithelial neoplasia and ultimately to prostatic adenocarcinoma are consistent with previous studies showing the influential role that angiogenin plays in the growth, invasion, and metastasis of prostatic adenocarcinoma and many other malignant tumors.

Renal cell carcinoma: Current status and future prospects

The incidence of renal cell carcinoma (RCC) is increasing. Despite improvements in the management of localized RCC, most patients are diagnosed with advanced RCC, which is often refractory and associated with a poor prognosis. Although surgery is the only curative treatment for localized RCC, improved diagnostic methods facilitating early detection and characterization of renal tumors have enabled more effective use of less invasive treatments. Adrenal-sparing radical total nephrectomy, and laparoscopic radical and total nephrectomy are increasingly being performed in preference to radical nephrectomy. However, standard treatments for advanced RCC are largely unsuccessful. Radiotherapy is often used to control symptoms associated with RCC in patients unsuitable for surgery. Immunotherapy with cytokines is the standard systemic treatment for advanced RCC, and is associated with prolonged survival in a subset of patients, but is generally poorly tolerated. An increased knowledge of the underlying pathophysiology of RCC has resulted in the identification of molecular pathways involved in tumor growth. Promising new agents designed to target these pathways are in development.

Enhancement of radiation effects by pXLG-mEndo in a lung carcinoma model

PURPOSE

Endostatin is a potent antiangiogenesis protein with little or no toxicity that has potential to enhance radiotherapy. The major goal of this study was to evaluate the combination of radiation and endostatin gene therapy in a preclinical lung cancer model.

METHODS

Plasmid pXLG-mEndo, constructed in our laboratory, includes the mouse endostatin gene cloned into the pWS4 vector. The kinetics of endostatin expression and efficacy of the pXLG-mEndo and radiation ((60)Co gamma-rays) combination was evaluated in the C57BL/6 mouse-Lewis lung carcinoma (LLC) model. The LLC cells were implanted s.c. and pXLG-mEndo was injected intratumorally 12-14 days later without any transfection agent; a dose of 10 Gy radiation was applied approximately 16 h thereafter. Some groups received each modality twice. Endostatin, vascular endothelial growth factor (VEGF), and transforming growth factor-beta1 (TGF-beta1) were quantified in plasma and tumors, and tumor vasculature was examined.

RESULTS

Endostatin expression within LLC tumors peaked on Day 7 after pXLG-mEndo injection. Addition of radiation to pXLG-mEndo significantly enhanced the level of tumor endostatin compared with plasmid alone (p < 0.05). Tumor growth was significantly delayed in mice receiving pXLG-mEndo plus radiation compared with no treatment (p < 0.005), radiation (p < 0.05), and control plasmid (p < 0.05). The number of LLC tumor vessels was reduced after combined treatment (p < 0.05), and significant treatment-related changes were observed in both VEGF and TGF-beta1.

CONCLUSIONS

The data demonstrate that delivery of endostatin by pXLG-mEndo as an adjuvant to radiation can significantly enhance the antitumor efficacy of radiotherapy in the LLC mouse tumor model and support further investigation of this unique combination therapy.

A lower dose of thalidomide is better than a high dose in metastatic renal cell carcinoma

OBJECTIVE

To conduct a dose-finding trial using a single low dose and dose escalation of a higher dose of thalidomide in patients with metastatic renal cell carcinoma (RCC), and to evaluate the antineoplastic effectiveness of thalidomide as an anti-angiogenic agent on RCC.

PATIENTS AND METHODS

The 14 patients enrolled in the study had progressive measurable metastatic RCC and consented to participate. Patients were randomized to either a fixed low dose of 200 mg of thalidomide or to a high dose of 800 mg that was increased to a maximum dose of 1200 mg daily. Patients were evaluated for response after 8 weeks of therapy.

RESULTS

Stable disease was achieved in six patients and was seen in both the low-dose and high-dose thalidomide groups. The median overall survival was 9 months. The low-dose thalidomide regimen was better tolerated and patients survived longer than those on the high-dose regimen (16 vs 6 months, P = 0.04)

CONCLUSION

The use of low-dose thalidomide in patients with metastatic RCC was well tolerated and they survived for longer than those on the high-dose regimen.

The relationship between angiogenesis and cyclooxygenase-2 expression in prostate cancer

OBJECTIVE

To test the hypothesis that angiogenesis in prostate cancer is associated with tumour invasion and metastasis, and that this is mediated through increased cyclooxygenase-2 (COX-2) expression.

PATIENTS AND METHODS

Angiogenesis was assessed in 105 patients with either prostate cancer (79) or benign prostatic hyperplasia (BPH, 26) and these data correlated with levels of COX-2 expression in the same dataset. The mean microvessel density (MVD) was analysed as a marker of angiogenesis, using the endothelial antigen CD34 stained by immunohistochemistry.

RESULTS

There was no difference in MVD in progressive tumour stages compared with BPH. There was a negative correlation between MVD and COX-2 expression, but the effect of increased COX-2 expression on MVD was not marked.

CONCLUSION

These data suggest that COX-2 drives tumour spread in prostate cancer by means other than the promotion of angiogenesis.

Bladder transitional cell carcinoma: correlation of contrast enhancement on computed tomography with histological grade and tumour angiogenesis

AIM

To investigate the correlation between the degree of contrast enhancement of bladder cancer in the early enhanced phase of helical computed tomography (CT) and microvessel density (MVD), vascular endothelial growth factor (VEGF) and histological grade.

MATERIALS AND METHODS

Sixty-five patients with transitional cell carcinoma of the bladder were examined by incremental unenhanced CT and helical CT at 40-45 s after initiation of intravenous administration of contrast medium before surgery. The CT density in Hounsfield units of bladder carcinomas were measured in the middle of the maximum diameter section of the cancer lesions on unenhanced and enhanced CT. The degree of contrast enhancement of the tumour was determined as the absolute increase in Hounsfield units. Histological grade, VEGF and MVD were analysed for each cancer. The Pearson and Spearman correlation tests were used to determine the strength of the relationships between CT enhancement and histological grade, VEGF expression and MVD.

RESULTS

Different degrees of enhancement were observed in 91 cancers during the early enhanced phase of helical CT. Mean MVDs and mean CT enhancing values of different histological grade groups were statistically different (p < 0.001). A positive correlation was found in the CT-enhancing value of bladder cancer and MVD (Pearson correlation test; r = 0.938, p < 0.001) and histological grade (Spearman rank correlation; r = 0.734, p < 0.001). VEGF of bladder cancer did not correlate with the change in CT attenuation (Spearman rank correlation; r = 0.087, p = 0.410) and MVD (Spearman rank correlation, r = 0.103, p = 0.330).

CONCLUSION

In bladder cancer, the degree of contrast enhancement during the early enhanced helical CT is correlated with the MVD and histological grade of tumour. It is possible that MVD is the histopathological basis of early contrast enhancement of bladder cancer.

Antiproliferative and antiangiogenic activities of genistein in human renal cell carcinoma

OBJECTIVES

To determine whether genistein, an isoflavone that is plentiful in soy beans, could inhibit the growth of human renal cell carcinoma (RCC) cells in vitro, induce apoptosis, and suppress neovascularization in vivo induced by human RCC cells.

METHODS

We investigated the effect of genistein on cell proliferation in four human RCC cell lines, SMKT R-1, R-2, R-3, and R-4. The terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assay was performed to examine whether genistein could induce apoptosis in SMKT R-1 cells. To evaluate the effect of genistein on in vivo angiogenesis, we used a new mouse dorsal air sac model in which we could evaluate it simply and quantitatively. Radioisotope-labeled red blood cells were injected into a tail vein in mice bearing a Millipore filter chamber containing genistein, and the vascular volume was examined by measuring the radioactivity of the mouse dorsal skin.

RESULTS

Treatment with genistein for 48 hours inhibited cell proliferation in a dose-dependent manner and 100 microg/mL genistein inhibited it in a time-dependent manner. A dose of 50 microg/mL genistein clearly induced cell apoptosis. The vascular volume after implantation of the Millipore filter chamber containing RCC cells increased to threefold that without RCC cells. Genistein in the Millipore filter chamber significantly decreased the neovascularization induced by human RCC cells in vivo.

CONCLUSIONS

The results of this study demonstrated that genistein inhibited cell proliferation, induced apoptosis, and suppressed in vivo angiogenesis in human RCC cells. Genistein may be a promising antitumorigenic and antiangiogenic agent for the treatment and prevention of RCC.

Metastasis markers in bladder cancer: a review of the literature and clinical considerations

Cancer invasion and metastasis develop through a sequence of processes involving loss of cell-cell and cell-matrix adhesions, proteolysis and induction of angiogenesis. We reviewed the current literature on the molecules that have been shown to play a significant role in these three steps of metastatisation in bladder cancer (BC) cells and their host microenvironment. Particular emphasis was given to markers that are assessable through immunohistochemistry and for which an additional prognostic value over the TNM variables has been recognized, in order to identify a subset of tumour markers readily available for application in daily clinical practice. We conclude that markers such as E-cadherin, Sialosyl-LeX, laminin, collagen IV, TSP-1 and MVD are useful prognostic markers, alpha, beta, and gamma catenin, MMP-2 and -9, uPAR, PD-ECGF and Bfgf can be considered potentially useful, while research on CD44, MMP-1 and -3, uPA, cathepsin D and VEGF has proved inconclusive. Further research in this field should concentrate on the molecules listed in the first group.

Short-term human prostate primary xenografts: an in vivo model of human prostate cancer vasculature and angiogenesis

Transgenic spontaneously occurring and transplantable xenograft models of adenocarcinoma of the prostate (CaP) are established tools for the study of CaP progression and metastasis. However, no animal model of CaP has been characterized that recapitulates the response of the human prostate vascular compartment to the evolving tumor microenvironment during CaP progression. We report that primary xenografts of human CaP and of noninvolved areas of the human prostate peripheral zone transplanted to athymic nude mice provide a unique model of human angiogenesis occurring in an intact human prostate tissue microenvironment. Angiogenesis in human kidney primary xenografts established from human renal cell carcinoma and noninvolved kidney tissue, a highly vascular organ and cancer, was compared with angiogenesis in xenografts from the relatively less vascularized prostate. Immunohistochemical identification of the human versus mouse host origin of the endothelial cells and of human endothelial cell proliferation in the human prostate and human kidney xenografts demonstrated that: (a) the majority of the vessels in primary xenografts of benign and malignant tissue of both organs were lined with human endothelial cells through the 30-day study period; (b) the mean vessel density was increased in both the CaP and benign prostate xenografts relative to the initial tissue, whereas there was no significant difference in mean vessel density in the renal cell carcinoma and benign kidney xenografts compared with the initial tissue; and (c) the number of vessels with proliferating endothelial cells in primary xenografts of CaP and benign prostate increased compared with their respective initial tissue specimens, whereas the number of vessels with proliferating endothelial cells decreased in the benign kidney xenografts. Short-term primary human prostate xenografts, therefore, represent a valuable in vivo model for the study of human angiogenesis within a human tissue microenvironment and for comparison of angiogenesis in CaP versus benign prostate.

Prognostic factors and clinical trials of new agents in patients with metastatic renal cell carcinoma

Metastatic renal cell carcinoma (RCC) remains a disease highly resistant to systemic therapy. Results of recent reports in the literature on prognostic factors and clinical trials for patients with metastatic RCC were reviewed. Small numbers of patients exhibit complete or partial responses to interferon and/or interleukin-2, but most patients do not respond and there are few long-term survivors. Therefore, the identification of new agents with better antitumor activity against metastases remains the highest priority of clinical investigation in this refractory tumor. Prospective identification of patients more likely to benefit from cytokine therapy could be used as a stratification factor in Phase III trials, and in risk-directed therapy.

Transrectal colour Doppler ultrasonography for quantifying angiogenesis in prostate cancer

OBJECTIVE

To assess the correlation between angiogenesis and Doppler signal intensity using transrectal colour Doppler ultrasonography (CDUS) in patients with prostate cancer.

PATIENTS AND METHODS

The study comprised 56 patients who underwent radical prostatectomy and had untreated tumours with a volume of> 0.1 mL in the peripheral zone. CDUS images were recorded on videotape before surgery. The Doppler signal intensity in tumours was evaluated using the colour pixel intensity (PI). Microvessel density (MVD) and vascular endothelial growth factor (VEGF) immunoreactivity were determined in the prostatectomy specimens. Microvessels were identified by immunohistochemical staining of endothelial cells for CD31.

RESULTS

The PI in the tumour correlated with MVD (P < 0.001) and increased with higher levels of VEGF immunoreactivity (P = 0.004). There was no correlation between Gleason score and MVD or PI in the tumour.

CONCLUSION

Blood flow assessed by CDUS may reflect the state of angiogenesis in prostate cancer. CDUS may be a useful technique for predicting tumour progression or prognosis, and may be useful for monitoring the effects of anti-angiogenic agents in the future.

Angiogenesis in prostate cancer: its role in disease progression and possible therapeutic approaches

The interaction between cancer cells and their microenvironment is a promising area for the development of novel therapeutic anti-cancer modalities. The formation of new blood vessels, angiogenesis, is an important step in cancer progression. Angiogenesis is a complex multistep process involving close orchestration of endothelial cells, extracellular matrix, and soluble factors. Essentially every step has been found to be regulated by inducers and inhibitors. Prostate cancer has the ability to produce angiogenic factors such as metalloproteinases, vascular endothelial growth factor, fibroblast growth factor 2, transforming growth factor-beta and cyclooxygenase-2. In several studies in prostate cancer an increased microvessel density is associated with poorer prognosis. On the other hand several endogenous inhibitors of angiogenesis have been described in prostate cancer e.g., angiostatin, endostatin, prostate specific antigen (PSA), thrombospondin-1, interleukin 10, interferons and retinoids. The expanding insight in the process of angiogenesis has resulted in a large number of pharmaceutical agents that have been tested in preclinical studies and are currently tested in clinical trials. These agents inhibit endothelial cell proliferation or migration and induce apoptosis. This ultimately will affect the formation of new vessels thereby inducing tumor dormancy. Because antiangiogenic treatment is cytostatic rather than cytotoxic, patients will need long-term therapy to prevent regrowth of the tumor. Prostate cancer is an ideal tumor for antiangiogenic studies because of the availability of a reliable tumor marker, PSA, the indolent clinical course of this cancer and the low rate of proliferation even in metastatic sites. Furthermore, clinical studies showed limited side effects, which is advantageous in this elderly patient group. Whether the ultimate antiangiogenic treatment is effective as a single agent or in combination with radiation therapy, chemotherapy or immunotherapy remains to be determined.

Prognostic value of angiogenesis in schistosoma-associated squamous cell carcinoma of the urinary bladder

OBJECTIVES

To evaluate angiogenesis as a prognostic marker in squamous cell carcinoma of the urinary bladder in 154 patients who underwent radical cystectomy.

METHODS

The tumors from 98 men and 56 women (mean age 46.3 +/- 8.4 years) were examined. Vessels were stained using an antibody to the platelet endothelial cell adhesion molecule CD31. Microvessels were counted in active areas of angiogenesis within the tumors. Microvessel density (MVD) was quantified using the mean of three counts. Age, sex, tumor grade and stage, DNA ploidy, and MVD were evaluated in relation to outcome. Univariate and multivariate analyses of survival were performed.

RESULTS

The median follow-up period was 63 months. The overall 5-year survival rate was 56 +/- 4.1. Tumor grade, tumor stage, DNA ploidy, and MVD had a significant impact on the survival of patients in univariate analysis. The 5-year survival rate in patients with a low MVD (11 or less) was 68.1% compared with 50.4% for those with a high MVD (greater than 11; P <0.01). Men had more vascular tumors than did women. Also, high-grade tumors had significantly higher vascular counts. In a Cox proportional hazard model, tumor angiogenesis sustained its significant impact on survival of the patients in addition to tumor stage and DNA ploidy.

CONCLUSIONS

These findings suggest that angiogenesis and DNA ploidy are independent additional prognostic factors in patients with squamous cell carcinoma of the urinary bladder.

p53 and microvessel density in primary resection specimens of superficial bladder cancer

PURPOSE

p53 Regulates angiogenesis in fibrosarcoma and correlative studies suggest a similar role for muscle invasive bladder cancer. We evaluated the associations of p53 status and microvessel density with pathological features and clinical outcomes in a large population of patients with superficial bladder cancer. In addition, we assessed the correlation of p53 status with microvessel density, which would suggest the regulation of angiogenesis by p53.

MATERIALS AND METHODS

We stained 84 primary bladder resection specimens, including 55 stage pTa, 29 stage pT1, 27 grade 1, 35 grade 2 and 22 grade 3 samples, for p53, CD31 and CD34. The relationships of p53 or microvessel density and tumor stage-grade or clinical recurrence-progression were analyzed by analysis of variance and pairwise comparison analysis for least significant difference, and Pearson correlation coefficients. Only patients with no previous biopsy were included in analysis to preclude interference by granulation tissue related neovascularization. The 4 samples with significant inflammation were also excluded from study.

RESULTS

At a mean followup of 33 months (range 1 to 93) 34 of 84 patients (40.4%) experienced 1 or more tumor recurrences and 10 (11.9%) had stage and/or grade progression. Statistically significant associations were observed of p53 immunostaining and microvessel density with tumor stage and grade (p <0.05). However, the association of p53 status with microvessel density was weak and not statistically significant. Similar results were observed for the CD31 and CD34 based estimates of microvessel density. Neither p53 status nor microvessel density correlated with recurrence or progression.

CONCLUSIONS

Our study confirms the strong association of p53 and microvessel density with the well established prognostic factors of grade and stage in superficial bladder cancer, supporting other evidence of an important role for p53 and angiogenesis in the tumor biology of this disease. However, our data argue against a primary role of p53 in the regulation of angiogenesis in superficial bladder cancer. This study, which to our knowledge is the first to focus on primary resection specimens, suggests that other genetic or environmental factors may contribute to the regulation of angiogenesis in superficial bladder cancer.

Significance of angiogenesis and microvascular invasion in renal cell carcinoma

The aim of this study is to evaluate the relationship between tumor angiogenesis and microvascular invasion, and the subsequent development of metastatic disease in patients undergoing surgery for renal cell carcinoma (RCC). The study group consisted of 102 patients who underwent surgery for RCC between the years 1990 and 1997 in our institute with a mean follow up period of 81.3 months. Paraffin blocks were stained for Factor VIII - related antigen and CD34 which decorate endothelial cells in order to assess angiogenesis and microvascular invasion and their relevance for developing metastatic disease. When Factor VIII- related antigen staining was used we found that the microvessel count correlated with the development of metastatic disease with a mean count of 49.7 for patients with no evidence of disease and a mean count of 95.5 for patients who developed metastatic disease (p<0.05). We also found that microvascular invasion correlated with the development of metastatic disease. It was demonstrated in 55.5% of patients who developed metastatic disease versus 23.8% of patients with no evidence of disease with Factor VIII staining (p<0.05), and in 33.3% and 7.1%, respectively (p<0.05) with CD34 staining. This study suggest that demonstration of intense angiogenesis and micro-vascular invasion may be a predictor of a more aggressive tumor mandating closer follow up and consideration of adjuvant therapy.

Phase II trial of thalidomide for patients with advanced renal cell carcinoma

PURPOSE

To assess efficacy and toxicity of thalidomide in patients with advanced renal cell carcinoma (RCC).

PATIENTS AND METHODS

Twenty-six patients with RCC were treated with thalidomide at a starting dose of 200 mg daily. Thalidomide was increased by 200 mg every 2 weeks until a maximum dose of 800 mg or prohibitive toxicity was reached. Fifteen patients had prior nephrectomy, 11 patients had no prior systemic therapy, and 15 had received one prior systemic regimen.

RESULTS

A maximum dose of 800 mg, 600 mg, 400 mg, and 200 mg was reached in five, 10, eight, and three patients, respectively. Grade 2 and 3 dyspnea occurred in four and three patients, respectively. Grade 2 and 3 neurologic toxicity was observed in five and two patients, respectively. Of the 25 assessable patients, the best response was stable disease in 16 (95% confidence interval [CI], 43% to 82%) patients. The 6-month progression-free survival rate was 32% (95% CI, 14% to 50%). Three patients achieved prolonged stable disease of 16, 16+, and 18+ months, including two patients who were refractory to previous cytokine therapy. Fifty-seven percent were alive at 1 year (95% CI, 37% to 76%).

CONCLUSION

This trial does not support the routine use of thalidomide to induce partial response for metastatic RCC. Because disease stabilization occurs as a part of the natural history of metastatic RCC, the potential effect of thalidomide on progression-free and overall survival for patients with advanced RCC is being addressed in a randomized phase III trial. New immunomodulatory analogs of thalidomide that have shown potentially greater antitumor effects in preclinical models warrant study in metastatic RCC.

Blood vessels are regulators of growth, diagnostic markers and therapeutic targets in prostate cancer

The vasculature plays an important role in the normal and malignant prostate. Under basal conditions both glandular epithelial and stromal prostate cells produce an abundance of blood flow and angiogenesis regulating substances and the expression of these is generally increased in prostate tumors. The proportion of proliferating endothelial cells is high in the normal prostate compared to other tissues in the body. After castration effects on the vasculature, such as decreased blood flow and vascular regression, precede effects on the glandular compartment. Correspondingly, hormone induced prostate growth is characterized by early effects on the vasculature such as increased blood flow and endothelial cell proliferation, thus indicating that the vasculature may be involved in the androgenic regulation of the prostate. Prostatic intraepithelial neoplasia (PIN) and prostate cancer are associated with increased vascular density and in experimental models prostate cancer growth is apparently angiogenesis-dependent since tumor growth and progression can be inhibited by antiangiogenic treatment. Moreover, vascular density has been related to prognosis in prostate cancer patients. A better understanding of the pathways regulating angiogenesis in the normal prostate and how these pathways change during malignant transformation can hopefully lead to better prognostic markers and therapies for the large group of patients with prostate cancer. The purpose of this review is therefore to summarize the current knowledge on the role and regulation of the vasculature in the prostate and its potential clinical applications.

Ultrasound for prostate imaging and biopsy

Transrectal ultrasound guided systemic sextant needle biopsy of the prostate has been the procedure of choice for the diagnosis of prostate cancer. Several shortcomings of this procedure have been recognized and there is concern that it may represent an inadequate sampling of the prostate. Refinements include modifications of biopsy location and an increase in the number of cores obtained. Enhanced ultrasound techniques may improve the accuracy of prostate biopsy. In addition, research continues to develop prognostic factors derived from the core biopsy that may enhance the prediction of tumor biology. This paper provides a basic review of transrectal ultrasound diagnosis of prostate cancer with emphasis on advances in this area.

Vascular endothelial growth factor-mediated autocrine stimulation of prostate tumor cells coincides with progression to a malignant phenotype

Vascular endothelial growth factor (VEGF), which is often produced at high levels by tumor cells, is a well-known mediator of tumor angiogenesis. VEGF receptor tyrosine kinases, KDR/Flk-1 and Flt-1, have been thought to be expressed exclusively by endothelial cells. In this study, we have used a prostate tumor progression series comprised of a differentiated rat prostate epithelial cell line, NbE-1, and its highly motile clonal derivative, FB2. Injection of NbE-1 cells into the inferior vena cava of syngeneic rats indicated that these cells are nontumorigenic. Using the same model, FB2 cells generated rapidly growing and well-vascularized tumors in the lungs. NbE-1 expressed marginal levels of VEGF, whereas high levels of VEGF protein were detected in FB2-conditioned medium and in FB2 tumors in vivo. Analysis of (125)I-VEGF(165) binding to NbE-1 and FB2 cells indicated that only motile FB2 cells expressed the VEGF receptor Flt-1. Consistent with this finding, physiological concentrations of VEGF induced chemotactic migration in FB2 but not in NbE-1 cells. This is the first documentation of a functional Flt-1 receptor in prostate tumor cells. Our results suggest two roles for VEGF in tumor progression: a paracrine role as an angiogenic factor and a previously undescribed role as an autocrine mediator of tumor cell motility.

Does angiogenesis predict recurrence in superficial transitional cell carcinoma of the bladder?

OBJECTIVES

To investigate the role of angiogenesis in predicting tumor recurrence and its correlation with established clinicopathologic prognostic factors in superficial transitional cell carcinoma of the bladder.

METHODS

The paraffin sections of 80 superficial papillary transitional cell bladder carcinoma specimens were stained with CD31 antibody to label the vascular endothelium using the standard streptavidin-biotin-immunoperoxidase method. The vascular surface density (VSD) equivalent to the vascular surface area per unit of tissue volume and number of vessels per square millimeter of stroma (NVES) were assessed by means of stereology, and these morphometric parameters of angiogenesis were statistically analyzed to interpret the relation to tumor recurrence in addition to tumor stage, grade, size, and number and the presence of carcinoma in situ.

RESULTS

VSD and NVES values showed no statistically significant difference between pTa and pT1 tumors or patients with and without recurrence. In contrast, VSD and NVES values were found to increase in higher grade tumors (P = 0.019). VSD values were also higher in patients with coexisting carcinoma in situ in pTa tumors (P <0.001). Tumor number and size and recurrence number and time to the first recurrence did not correlate with any vascular parameters.

CONCLUSIONS

Stereologic assessment of angiogenesis does not help to predict recurrence in superficial bladder cancer. Angiogenic parameters appeared to be well correlated with the conventional histologic grading system. Otherwise, the present study did not show any correlation of angiogenesis with any potential prognostic factors. This may be due to the diverse angiogenic pathways occurring in invasive and superficial tumors.

Angiogenesis as a potential biomarker in prostate cancer chemoprevention trials

Prostate cancer is a multistep process in which progression rather than initiation may be the rate-limiting step. A strong possibility is that prostatic intraepithelial neoplasia lesions that switch to angiogenic phenotype eventually progress to cancer. However, it is a challenging task to quantitate angiogenesis in preneoplastic lesions. A promising approach to measuring angiogenesis involves real-time TaqMan polymerase chain reaction to quantitate mRNAs encoding a panel of angiogenesis markers. This highly sensitive molecular technique has potential for quantitating angiogenesis in clinical settings and can be used as a high-throughput screening procedure in prostate cancer clinical trials.

New developments in ultrasonography for the detection of prostate cancer

The introduction of contrast agents has changed the diagnostic role of ultrasonography dramatically. Advanced ultrasound techniques, although currently largely unexplored, especially for prostate applications, were introduced to improve, for example, differential diagnosis. Also, new technologies became available using the interaction of the angioemboli with the transmitted ultrasound waves, and sensitive methods to detect microbubbles were developed. As the traveling of microbubbles through the vascular system is a dynamic process, new information becomes available: when the concentration of the contrast agent can be determined as a function of time, a measure for the actual blood flow can be obtained that provides quantitative information. Initially developed to enhance the ultrasound examinations in cardiac applications, contrast agents can currently be found in radiologic applications as well. The first reports of enhanced Doppler examinations of prostatic blood flow have been published, and the results indicate that contrast agents are a promising addition to the conventional ultrasound examination. In this paper, we present a short overview of the status of transrectal ultrasound imaging in prostate cancer, background information on contrast agents and imaging modalities, and early results of enhanced Doppler studies of the prostate to identify cancer. The early results suggest the feasibility of using angioemboli to enhance ultrasound imaging of prostate diseases, and although many issues remain to be solved, angioemboli in combination with a dedicated imaging modality have the potential to improve the diagnostic application of ultrasound in evaluating the prostate for disease.

Prognostic value of tumor-associated macrophage count in human bladder cancer

BACKGROUND

We determined the tumor-associated macrophage (TAM) count to investigate its importance in predicting clinical outcome or prognosis in patients with bladder cancer.

METHODS

The TAM count and microvessel count (MVC) were determined immunohistochemically in 63 patients with bladder cancer, including 40 superficial bladder cancers and 23 invasive bladder cancers. To examine the relationship between TAM count and clinical outcome or prognosis in bladder cancer, cystectomy rates, distant metastasis rates, vascular invasion rates and 5 year survival rates were compared between patients with low (< 67) and high (> or = 67) TAM counts.

RESULTS

The TAM count in invasive bladder cancers (154.22+/-11.98) was significantly higher than in superficial bladder cancers (49.05+/-7.76; P<0.0001). The MVC in invasive bladder cancers (71.55+/-10.44) was also significantly higher than in superficial bladder cancers (47.02+/-5.57; P<0.05). There was a positive correlation between TAM count and MVC (r=0.30; P=0.02). Immunohistochemical staining using CD68/horseradish peroxidase monoclonal antibody showed more infiltrating cells in invasive than superficial bladder cancers. Patients with a high TAM count (> or =67) showed significantly higher rates of cystectomy, distant metastasis and vascular invasion than those with a lower TAM count (<67). The 5 year survival rate estimated using the Kaplan-Meier method was significantly lower in patients with a high TAM count than in those with a low TAM count (P<0.0001).

CONCLUSIONS

Our results suggest that determination of TAM count in bladder cancer tissues is of value to predict the clinical outcome or prognosis and to select appropriate treatment strategies in patients with bladder cancer.

Angiogenesis and lymphangiogenesis in stage 1 germ cell tumours of the testis

OBJECTIVE

To determine whether angiogenesis can be used as an additional prognostic indicator in patients with stage 1 germ cell tumours of the testis.

PATIENTS AND METHODS

Paraffin sections were assessed immunohistochemically from 51 patients with clinical stage 1 germ cell tumours of the testis (28 seminoma, 23 teratoma) treated by orchidectomy and surveillance only. Sections were analysed for microvascular density (MVD), and expression of the angiogenic factors vascular endothelial growth factor (VEGF) and thymidine phosphorylase (TP). In addition, in the seminoma cases the presence of mRNA for the lymphangiogenic factor VEGF-C was examined by in situ hybridization, and its corresponding receptor VEGFR-3 by immunohistochemistry.

RESULTS

Teratoma specimens had a significantly higher mean (range) MVD (85, 26-163; P < 0.01) than both seminoma (37, 16-91) and four normal specimens (26, 18-30). Teratoma specimens also had significantly higher VEGF expression than both seminoma and normal specimens (P < 0.01). Despite these differences between groups, and indeed individual tumours, there was no significant correlation between MVD and VEGF, or between either MVD or VEGF and relapse-free survival. TP expression was significantly greater in tumours than in normal specimens (P < 0.02) but with very little inter-tumour variation. VEGF-C mRNA and VEGFR-3 protein were detected in a third to a half of cases, with expression mostly around endothelial vessels.

CONCLUSIONS

The marked differences between normal testis and tumours implicate angiogenesis in the biology of germ cell tumours of the testis. In addition, the detection of factors involved in lymphangiogenesis in some seminomas, tumours which initially metastasize primarily to lymph nodes, indicate that although not prognostic in this study, further studies are warranted in both these areas in the search for further prognostic indicators and therapeutic targets.