Clinical significance of cell proliferation, microvessel density, and CD44 adhesion molecule expression in renal cell carcinoma

Validation of a Novel Three-Dimensional (3D Fusion) Gross Sampling Protocol for Clear Cell Renal Cell Carcinoma to Overcome Intratumoral Heterogeneity: The Meet-Uro 18 Study

We aimed to overcome intratumoral heterogeneity in clear cell renal cell carcinoma (clearRCC). One hundred cases of clearRCC were sampled. First, usual standard sampling was applied (1 block/cm of tumor); second, the whole tumor was sampled, and 0.6 mm cores were taken from each block to construct a tissue microarray; third, the residual tissue, mapped by taking pieces 0.5 × 0.5 cm, reconstructed the entire tumor mass. Precisely, six randomly derived pieces of tissues were placed in each cassette, with the number of cassettes being based on the diameter of the tumor (called multisite 3D fusion). Angiogenic and immune markers were tested. Routine 5231 tissue blocks were obtained. Multisite 3D fusion sections showed pattern A, homogeneous high vascular density (10%), pattern B, homogeneous low vascular density (8%) and pattern C, heterogeneous angiogenic signatures (82%). PD-L1 expression was seen as diffuse (7%), low (33%) and absent (60%). Tumor-infiltrating CD8 scored high in 25% (pattern hot), low in 65% (pattern weak) and zero in 10% of cases (pattern desert). Grading was upgraded in 26% of cases (G3–G4), necrosis and sarcomatoid/rhabdoid characters were observed in, respectively, 11 and 7% of cases after 3D fusion (p = 0.03). CD8 and PD-L1 immune expressions were higher in the undifferentiated G4/rhabdoid/sarcomatoid clearRCC subtypes (p = 0.03). Again, 22% of cases were set to intermediate to high risk of clinical recurrence due to new morphological findings of all aggressive G4, sarcomatoid/rhabdoid features by using 3D fusion compared to standard methods (p = 0.04). In conclusion, we propose an easy-to-apply multisite 3D fusion sampling that negates bias due to tumor heterogeneity.

Clinicopathological correlation of stem cell markers expression in oral squamous cell carcinoma; relation to patients` outcome

Background: Squamous cell carcinoma (OSCC) is the commonest oral malignancy.The overall 5 year survival of OSCC has remained at 50%, largely unchanged for 40 years. CSCs are important within the development, invasion, drug resistance, and prediction of carcinomas treatment outcome. ALDH1 and CD44 are commonly used epithelial tumors cancer stem-like cells surface markers. Materials: Our study aimed to judge CD44 and ALDH1 immunohistochemical expressions in 44 cases of OSCC and relates the expression to patients' survival. Results: High CD44 & ALDH1 expressions were significantly expressed in variable histologic grades of OSCCs, large sized carcinomas, presence lymph vascular invasion, presence of nodal and distant metastasis, advanced TNM clinical stage, recurrence and death during follow up period (P ≤ 0.05). Reduced DFS and three years overall survival were significantly recorded in cases with high CD44 expression, and high ALDH1 expression (p < 0.05). CD44 & ALDH1 expressions, histologic grade, tumor size were the independent predictors of DFS and three years OS. Conclusion: CD44 and ALDH1 expressions are valuable prognostic factors in OSCC and could be well considered predictors for patients' 3 years OS and DFS.

Extracellular matrix and its therapeutic potential for cancer treatment

The extracellular matrix (ECM) is one of the major components of tumors that plays multiple crucial roles, including mechanical support, modulation of the microenvironment, and a source of signaling molecules. The quantity and cross-linking status of ECM components are major factors determining tissue stiffness. During tumorigenesis, the interplay between cancer cells and the tumor microenvironment (TME) often results in the stiffness of the ECM, leading to aberrant mechanotransduction and further malignant transformation. Therefore, a comprehensive understanding of ECM dysregulation in the TME would contribute to the discovery of promising therapeutic targets for cancer treatment. Herein, we summarized the knowledge concerning the following: (1) major ECM constituents and their functions in both normal and malignant conditions; (2) the interplay between cancer cells and the ECM in the TME; (3) key receptors for mechanotransduction and their alteration during carcinogenesis; and (4) the current therapeutic strategies targeting aberrant ECM for cancer treatment.

A novel definition of microvessel density in renal cell carcinoma: Angiogenesis plus vasculogenic mimicry

The present study proposed the novel concept of total microvessel density (TMVD), which is the combination of the MVD and the vasculogenic mimicry (VM) status, and evaluated its clinical significance in patients with renal cell carcinoma (RCC). For that purpose, tumor samples from 183 patients with primary RCC were examined by CD34 single or periodic acid Schiff (PAS)/CD34 dual histology staining. MVD and VM were determined according to previous literature. Clinical information (tumor stage and grade, and duration of survival) was retrieved and analyzed. Survival information and VM-associated gene expression data of patients with RCC were also retrieved from The Cancer Genome Atlas (TCGA) database and the clinical significance of each individual gene was analyzed. The results indicated that MVD exhibited obvious differences among patients with RCC; however, it was not correlated with the stage/grade or length of survival in patients with RCC. In total, 81 patients (44.3%) were CD34(−)/PAS(+) and defined as VM(+), and they had a significantly shorter survival compared with that of VM(−) patients (P=0.0002). VM was not associated with MVD. TMVD was able to distinguish between patients with high and low MVD in terms of survival, thus TMVD was better compared with MVD alone at distinguishing between patients with different survival prognoses. TCGA data analysis revealed that among the VM-associated genes, nodal growth differentiation factor, caspase-3, matrix metalloproteinase-9 and galectin-3 had a statistically significant impact on the overall/disease-free survival of patients with RCC. In conclusion, the TMVD concept may be more appropriate and sensitive compared with the MVD or VM alone in predicting tumor aggressiveness and patient survival, particularly in RCC, which is a highly vascularized, VM-rich neoplasm, and certain VM formation-associated genes are negatively associated with the survival of patients with RCC.

Exploring Biological Predictive Factors of Progression After Surgery in High-Risk Renal Cell Carcinoma: Results From the French Cohort of the Randomized S-TRAC Trial Patients

Objective: We aimed to explore biological predictive factors of progression after surgery in nonmetastatic renal cell carcinoma (RCC) using the collected tumors in the French cohort of the randomized S-TRAC trial patients.

Patients and Methods: We analyzed the tumors of the French cohort of STRAC that included 44 cases of clear cell RCC (ccRCC) that were collected from six centers. The main objective was to explore biological predictive factors of progression (defined as PFS) to sunitinib. Broad-spectrum analysis including immunohistochemistry, fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH) array, and transcriptomic analyses were performed on the tumors.

Results:Analysis of vascular density showed type 1 vascular stroma corresponding to high vascular density was associated with progression (p < 0.034). Loss of poly bromo-1 expression showed a distinct profile: a highly histopathological aggressive tumor with a marked angiogenic profile (vascular endothelial growth factor overexpression and immature vascular stroma type 2), no PD1 or PDL1 expression, and wild-type (WT) status of the VHL gene. There were 27 chromosome regions gained in patients with progression (on chromosomes 7 and 16, and to a lesser extent 8, 12, 17, 17, 19, 20 corresponding to 605 associated genes) and 10 regions lost in these same patients on chromosomes 8 and 9, and to a lesser extent 2 and 21 corresponding to 25 associated genes.

Conclusion:We found that an angiogenic phenotype defined by a high vascular density with a vascular type 2 stroma was a predictive factor of sunitinib resistance. Regardless of adjuvant treatment, chromosomal gains and losses and genomic alterations including PBRM1 loss were associated with worse outcomes.

Clinical Trial Registration: ClinicalTrials.gov number, NCT00375674.

Contrast-enhanced magnetic resonance (MR) T1 mapping with low-dose gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) is promising in identifying clear cell renal cell carcinoma histopathological grade and differentiating fat-poor angiomyolipoma

Background

This study aimed to identify clear cell renal cell carcinoma (ccRCC) histopathological grade and differentiate it from fat-poor angiomyolipoma (AML). This was achieved through contrast-enhanced magnetic resonance (MR) T1 mapping with intravenous low-dose gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA).

Methods

In total, 56 consecutive patients received MR scanning between January 2016 and December 2018 using the pre- and post- contrast-enhanced T1 mapping sequences with low-dose Gd-DTPA (0.036 mmol/kg). RCCs were pathologically proven in 40 patients after surgery and graded according to the International Society of Urological Pathology (ISUP) classification system. Ten AMLs were pathologically proven by surgery histopathology and six AMLs were diagnosed by magnetic resonance imaging (MRI). Patients were followed up for more than half a year. The mean T1 values of the renal lesion and ipsilateral normal renal parenchyma were measured before and after Gd-DTPA administration (T1p and T1e). The reduction of T1 value (T1d) and the ratio of its reduction (T1d %) were calculated and compared.

Results

In 40 ccRCCs, higher-grade [International Society of Urologic Pathology (ISUP) grade 3 and 4] and lower-grade (ISUP grade 1 and 2) ccRCCs were noted in 13 and 27 patients, respectively. The mean T1p was 1,514.8±139.4 ms and the mean T1d was 907.7±193.7 ms in the higher-grade ccRCCs, which were significantly higher than in the lower-grade ccRCCs (T1p =1,251.7±151.5 ms and T1d =648.5±218.2 ms, respectively; P<0.001). Fat-poor AMLs had higher T1p (1,677.3±104.8 ms) and T1e (865.6±251.5 ms) as compared to ccRCCs (P<0.001). Combined T1p + T1d showed the highest area under the curve (AUC) (0.912) in the differentiation of higher-grade ccRCCs from lower-grade ccRCCs (P=0.010). Combined T1p + T1e had the highest AUC (0.956) in the differentiation between ccRCCs and fat-poor AMLs (P=0.010). All T1 mapping metrics could discriminate between normal renal parenchyma and renal lesions (P<0.001). No significant difference was found in the T1p and T1e at different parts of the ipsilateral normal renal parenchyma. Interobserver agreement for quantitative longitudinal relaxation time in the T1 maps was excellent.

Conclusions

Contrast-enhanced T1 mapping with low-dose Gd-DTPA may provide a more reliable and accurate approach in identifying ccRCCs histopathological grade and differentiating ccRCCs from fat-poor AMLs.

Cancer stem cell markers predict a poor prognosis in renal cell carcinoma: a meta-analysis

Background

Relevant markers of CSCs may serve as prognostic biomarkers of RCC. However, their actual prognostic significance remains inconclusive. Thus, a meta-analysis was performed to reevaluate the association of CSCs-relevant markers (CXCR4, CD133, CD44, CD105) expression with RCC prognosis more precisely.

Methods

PubMed and Embase were searched to look for eligible studies. The pooled hazard ratios (HR) with 95% confidence intervals (95% CI) were used to reassess the association of CSCs markers expression and RCC prognosis of overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS), and progression-free survival (PFS).

Results

There were 25 relevant articles, encompassing 2673 RCC patients, eligible for meta-analysis. Overall pooled analysis suggested that high CSCs markers expression predicted poor OS (HR, 2.10, 95% CI: 1.73–2.55) and DFS (HR, 3.77, 95% CI: 2.30–6.19). High CXCR4 expression predicted worse OS (HR, 2.57, 95% CI: 1.95–3.40), CSS (HR,1.97, 95% CI: 1.50–2.59), and DFS (HR, 5.82, 95% CI: 3.01–11.25). CD44 over-expression correlated with a poor OS(HR,1.58, 95% CI: 1.14–2.18), CSS (HR, 2.58, 95% CI: 1.27–5.23), and DFS (HR, 4.49, 95% CI: 2.12–9.53) in RCC patients. CD133 was an independent favorable prognostic factor for CSS (HR, 0.4, 95% CI: 0.29–0.54).

Conclusions

The presence of CSCs markers correlates with poor RCC outcome. CSCs may be potentially utilized as prognostic markers to stratify RCC patients, probably representing also a novel potential therapeutic target.

Tumor Microvessel Density as a Prognostic Marker in High-Risk Renal Cell Carcinoma Patients Treated on ECOG-ACRIN E2805

Purpose: Increased vascularity is a hallmark of renal cell carcinoma (RCC). Microvessel density (MVD) is one measurement of tumor angiogenesis; however, its utility as a biomarker of outcome is unknown. ECOG-ACRIN 2805 (E2805) enrolled 1,943 resected high-risk RCC patients randomized to adjuvant sunitinib, sorafenib, or placebo. We aimed to determine the prognostic and predictive role of MVD in RCC.Experimental Design: We obtained pretreatment primary RCC nephrectomy tissues from 822 patients on E2805 and constructed tissue microarrays. Using quantitative immunofluorescence, we measured tumor MVD as the area of CD34-expressing cells. We determined the association with disease-free survival (DFS), overall survival (OS), treatment arm, and clinicopathologic variables.Results: High MVD (above the median) was associated with prolonged OS for the entire cohort (P = 0.021) and for patients treated with placebo (P = 0.028). The association between high MVD and OS was weaker in patients treated with sunitinib or sorafenib (P = 0.060). MVD was not associated with DFS (P = 1.00). On multivariable analysis, MVD remained independently associated with improved OS (P = 0.013). High MVD correlated with Fuhrman grade 1-2 (P < 0.001), clear cell histology (P < 0.001), and absence of necrosis (P < 0.001) but not with gender, age, sarcomatoid features, lymphovascular invasion, or tumor size.Conclusions: High MVD in resected high-risk RCC patients is an independent prognostic, rather than predictive, biomarker of improved OS. Further studies should assess whether incorporating MVD into clinical models will enhance our ability to predict outcome and if low MVD can be used for selection of high-risk patients for adjuvant therapy trials. Clin Cancer Res; 24(1); 217-23. ©2017 AACR.

Infiltration of tumor-associated macrophages is involved in CD44 expression in clear cell renal cell carcinoma

Cancer stem‐like cells (CSC) or cancer‐initiating cells are now considered to be an important cell population related to cancer recurrence and the resistance to anti‐cancer therapy. Tumor‐associated macrophages (TAM) are a main component of stromal cells and are related to cancer progression in clear cell renal cell carcinoma (ccRCC). Because the detailed mechanisms allowing the maintenance of CSC in cancer tissues remain unclear, we investigated the relationship between TAM and CD44‐expressing cancer cells in ccRCC. CD44 was used as a marker for CSC, and CD163 and CD204 were used as markers for TAM. CD44‐positive cancer cells were detected in 37 of the 103 cases. Although statistical analysis showed no relationship between CD44‐positive cancer cells and the clinical course, the distribution of CD44‐positive cancer cells was significantly associated with a high density of TAM. Our in vitro study using RCC cell lines and human macrophages demonstrated that CD44 expression was upregulated by direct co‐culture with macrophages. Silencing of TNF‐alpha on macrophages abrogated the upregulation of CD44 expression in cancer cells. Macrophage‐induced CD44 overexpression was also suppressed by NF‐κB inhibitors. These results suggest that TNF‐alpha derived from TAM is linked to CD44 overexpression via NF‐κB signaling in ccRCC.

Biology of renal tumour cancer stem cells applied in medicine

The present article highlights the diverse role of stem cells in normal kidney and renal cancer, with special emphasis on surface markers. Proteins such as CD105 and CD133 have been reported as being significant in clear cell renal cell carcinoma (ccRCC) cancer stem cells. The role of normal kidney progenitor cells and their surface markers is compared with the role of those surface markers in ccRCC. Subsequently, we state the current hypothesis about origin of tumour-initiating cells along with their clinical and prognostic potential in RCC. Finally, we present future perspectives with respect to recent studies.

Vasohibin-1 is a new predictor of disease-free survival in operated patients with renal cell carcinoma

Background

Vasohibin-1 (VASH1) is an endothelium-produced angiogenesis inhibitor. Renal cell carcinoma is highly vascularised, but the significance of endogenous VASH1 in renal cell carcinoma has not been defined.

Aims

To identify VASH1 expression and its possible relationship with various clinicopathological factors and prognosis in renal cell carcinoma.

Methods

A retrospective analysis of 122 tumours obtained from 118 consecutive patients with renal cell carcinoma was performed. The expression patterns of VASH1, CD31, vascular endothelial growth factor (VEGF) and VEGF receptor type 2 (VEGFR2) were examined immunohistochemically and their relationships with clinicopathological factors were analysed.

Results

Microvessel density, VASH1 and VEGFR2 expression were significantly higher in clear cell carcinoma than in other subtypes. The VEGF expression pattern differed significantly between clear cell carcinoma and other histological subtypes. VASH1, pT factor and TNM stage were significantly associated with disease-free survival (p=0.030, p = 0.0012 and p = 0.0018, respectively). Cox models of multivariable disease-free survival analyses indicated that VASH1 and stage are independent prognostic factors (p=0.019 and p = 0.024).

Conclusions

VASH1 expression may be useful for estimating the prognosis of renal cell carcinoma. Further studies of the role of VASH1 in renal cell carcinoma involving larger sample sizes are warranted.

Vascularity of primary and metastatic renal cell carcinoma specimens

Purpose

Anti-angiogenic therapies are among the most commonly used drugs in renal cell carcinoma. Tumor vascularity, defined by microvessel area, may be associated with response to these drugs. Clinical studies suggest that metastatic sites are more responsive than primary tumors. Our purpose was to characterize microvessel area (MVA) in matched primary and metastatic samples and in samples of different histologies.

Methods

We employed a method of automated, quantitative analysis of in situ tumor components to identify the area of CD-34 staining endothelial cells within renal cell carcinoma tumors. MVA was assessed in corresponding primary and metastatic samples from 34 patients, as well as in 334 primary nephrectomy specimens with variable histologies.

Results

MVA measurements from different parts of the same tumor correlated well (R = 0.75), indicating that MVA was fairly uniform within a tumor. While MVA was slightly higher in primary tumors than corresponding metastatic sites, the difference was not statistically significant (P = 0.1). MVA in paired primary and metastatic samples correlated moderately well (R = 0.36). MVA was higher in clear cell than papillary histology and oncocytomas (P < 0.0001 and P = 0.018, respectively).

Conclusions

Lack of significant differences MVA in matched primary and metastatic samples suggests that both types of tumors should respond to anti-angiogenic drugs. This should be confirmed on additional cohorts. Given the small cohort, future predictive biomarker studies entailing MVA measurements should include specimens from both sites. Clear cell carcinomas are more vascular than other histologic subtypes, which may explain the higher response rates to anti-angiogenic therapies in clear cell tumors.

Impact of ischemia and procurement conditions on gene expression in renal cell carcinoma

PURPOSE

Previous studies have shown that ischemia alters gene expression in normal and malignant tissues. There are no studies that evaluated effects of ischemia in renal tumors. This study examines the impact of ischemia and tissue procurement conditions on RNA integrity and gene expression in renal cell carcinoma.

EXPERIMENTAL DESIGN

Ten renal tumors were resected without renal hilar clamping from 10 patients with renal clear cell carcinoma. Immediately after tumor resection, a piece of tumor was snap frozen. Remaining tumor samples were stored at 4°C, 22°C, and 37°C and frozen at 5, 30, 60, 120, and 240 minutes. Histopathologic evaluation was conducted on all tissue samples, and only those with greater than 80% tumor were selected for further analysis. RNA integrity was confirmed by electropherograms and quantitated using RNA integrity number index. Altered gene expression was assessed by paired, two-sample t test between the zero time point and aliquots from various conditions obtained from the same tumor.

RESULTS

One hundred and forty microarrays were conducted. Some RNA degradation was observed 240 minutes after resection at 37°C. The expression of more than 4,000 genes was significantly altered by ischemia times or storage conditions. The greatest gene expression changes were observed with longer ischemia time and warmer tissue procurement conditions.

CONCLUSION

RNA from kidney cancer remains intact for up to 4 hours post surgical resection regardless of storage conditions. Despite excellent RNA preservation, time after resection and procurement conditions significantly influence gene expression profiles. Meticulous attention to preacquisition variables is of paramount importance for accurate tumor profiling.

Feasibility of perfusion CT technique integrated into conventional 18FDG/PET-CT studies in lung cancer patients: clinical staging and functional information in a single study

PURPOSE

To assess the additional functional vascular information and the relationship between perfusion measurements and glucose metabolism (SUVmax) obtained by including a perfusion CT study in a whole-body contrast-enhanced PET/CT protocol in primary lung cancer lesions.

METHODS

Enrolled in this prospective study were 34 consecutive patients with a biopsy-proven diagnosis of lung cancer who were referred for contrast-enhanced PET/CT staging. This prospective study was approved by our institutional review board, and informed consent was obtained from all patients. Perfusion CT was performed with the following parameters: 80 kV, 200 mAs, 30 scans during intravenous injection of 50 ml contrast agent, flow rate 5 ml/s. Another bolus of contrast medium (3.5 ml/s, 80 ml, 60-s delay) was administered to ensure a full diagnostic contrast-enhanced CT scan for clinical staging. The perfusion CT data were used to calculate a range of tumour vascularity parameters (blood flow, blood volume and mean transit time), and tumour FDG uptake (SUVmax) was used as a metabolic indicator. Quantitative and functional parameters were compared and in relation to location, histology and tumour size. The nonparametric Kruskal-Wallis rank sum test was used for statistical analysis.

RESULTS

A cut-off value of 3 cm was used according to the TNM classification to discriminate between T1 and T2 tumours (i.e. T1b vs. T2a). There were significant perfusion differences (lower blood volumes and higher mean transit time) between tumours with diameter >30 mm and tumours with diameter <30 mm (p < 0.05; blood volume 5.6 vs. 7.1 ml/100 g, mean transit time 8.6 vs. 3.9 s, respectively). Also there was a trend for blood flow to be lower in larger lesions (p < 0.053; blood flow 153.1 vs. 98.3 ml/100 g tissue/min). Significant inverse correlations (linear regression) were found between blood volume and SUVmax in tumours with diameter >30 mm in diameter.

CONCLUSION

Perfusion CT combined with PET/CT is feasible technique that may provide additional functional information about vascularity and tumour aggressiveness as a result of lower perfusion and higher metabolism shown by larger lesions.

Predictive value of intratumoral microvascular density in patients with advanced non-small cell lung cancer receiving chemotherapy plus bevacizumab

INTRODUCTION

The use of bevacizumab combined with chemotherapy represents a recent advance in clinical oncology for significantly improving the survival of patients who have non-small cell lung cancer (NSCLC). There is an unmet need for biomarkers that can predict response to such treatment and identify patients sensitive to it. Our study was designed to investigate the predictive value of intratumoral microvascular density (MVD) in patients with NSCLC treated with bevacizumab.

METHODS

Sixteen patients with NSCLC who underwent chemotherapy combined with bevacizumab were included into this study. Paraffin-embedded tumor samples were sectioned and stained immunohistochemically for the blood vessel markers CD34 and CD31 to characterize the intratumoral vasculature. A computerized image analysis program was used to quantitatively calculate the intratumoral MVD. Treatment response was evaluated by computed tomography scanning.

RESULTS

Two types of blood vessels, undifferentiated (CD31*/CD34*) and differentiated (CD34*), were identified. A positive correlation was found between the largest percentage of tumor shrinkage and the MVD of undifferentiated (CD31*/CD34*) vessels, with Spearman correlation coefficient being 0.576 (p = 0.019). No correlation between tumor shrinkage and differentiated vessel MVD (CD34*) was found. Moreover, seven of the eight patients with more undifferentiated vessels showed a partial response, versus only one of the seven patients with fewer undifferentiated vessels (p = 0.009).

CONCLUSIONS

There are two major types of microvessel in lung cancer vasculature. The MVD of undifferentiated vessels is a favorable predictor for patients with NSCLC treated with a chemotherapy regimen plus bevacizumab, with a higher MVD value correlating with better treatment response. Further studies are needed to verify the predictive role of MVD in treatment of NSCLC with bevacizumab.

CD44 is associated with tumor recurrence and is an independent poor prognostic factor for patients with localized clear cell renal cell carcinoma after nephrectomy

CD44 has been implicated in tumor development and progression in several types of cancer. CD44 expression is altered in renal cell carcinoma (RCC) and has been suggested as a useful prognostic marker, but its prognostic role in RCC remains controversial. We investigated the expression of CD44 in a large homogeneous set of localized clear cell RCC to determine its potential prognostic value. We examined 110 patients with localized clear cell RCC who underwent nephrectomy. The clinicopathological data were obtained retrospectively and the expression level of CD44 was studied by immunohistochemistry. Correlations between CD44 expression and clinical parameters as well as survival were determined. The CD44-high expression group (HEG) was significantly associated with a higher nuclear grade (P=0.014) and tumor recurrence (P<0.001) when compared with the CD44-low expression group (LEG). Concerning survival, the 5-year recurrence-free survival (RFS) rates for the CD44-HEG and CD44-LEG groups were 38.9 and 91.3%, respectively (P<0.001), and the 5-year disease-specific survival (DSS) rates for the CD44-HEG and CD44-LEG groups were 55.6 and 94.6%, respectively (P<0.001). Multivariate analyses showed that CD44 expression [hazard ratio (HR), 9.204; P<0.001] was an independent risk factor predicting RFS in patients with clear cell RCC. CD44 expression remained an independent prognostic factor for DSS (P=0.002). In conclusion, these data indicate that CD44 expression is associated with the progression of clear cell RCC and is an independent poor prognostic factor for tumor recurrence and survival, suggesting that CD44 may serve as a useful molecular marker.

Identification of pro-MMP-7 as a serum marker for renal cell carcinoma by use of proteomic analysis

BACKGROUND

No validated renal cell carcinoma (RCC) marker is known for detection of asymptomatic disease in selected populations or for prognostic purposes or treatment monitoring. We identified immunogenic proteins as tumor markers for RCC by combining conventional proteome analysis with serological screening, and we investigated the diagnostic clinical value of such markers in serum.

METHODS

We studied the immunogenic protein expression profile of CAL 54, a human RCC cell line, by 2-dimensional electrophoresis combined with immunoblotting using sera from healthy donors compared with RCC patients. We developed a homogeneous, fluorescent, dual-monoclonal immunoassay for metalloproteinase 7 (MMP-7) and used it to measure MMP-7 in sera from 30 healthy donors, 30 RCC patients, and 40 control patients.

RESULTS

Pro-MMP-7 (29 kDa; pI 7.7) in the CAL 54 cell line secretome was an immunogenic protein reactive with RCC patient sera but not with control sera. The concentrations of pro-MMP-7 were increased (P <0.0001) in sera of RCC patients (median 7.56 microg/L; range 3.12-30.5 microg/L) compared with healthy controls (median 2.13 microg/L; range 0.17-3.5 microg/L). Serum pro-MMP-7 had a sensitivity of 93% (95% CI 78%-99%) at a specificity of 75% (59%-87%) for RCC in the samples tested.

CONCLUSION

Proteomics technology combined with serology led to the identification of serum pro-MMP-7 as a marker of RCC and represents a powerful tool in searching for candidate proteins as biomarkers.

Molecular markers for predicting prognosis of renal cell carcinoma

Metastatic or recurrent renal cell carcinoma (RCC) carries a poor prognosis and long term survival is rare. However, many small RCCs that are incidentally discovered have an indolent course even without treatment. The variability in clinical outcome is a reflection of the underlying tumor biology. Currently, clinical variables such as tumor stage and histologic grade are widely accepted surrogates for tumor-specific cellular and molecular processes. Ongoing advances in genomic and proteomic technologies have produced an expanding list of molecular markers for predicting prognosis. We review expression array studies evaluating molecular signatures for predicting prognosis in patients with RCC and describe specific prognostic markers that have been validated in at least 50 cases of RCC.

Outcome prediction for renal cell carcinoma: evaluation of prognostic factors for tumours divided according to histological subtype

A wide variety of parameters have been investigated for their prognostic significance in mixed series of renal cell carcinoma (RCC). The classification of RCC into separate types with differing morphology, genotype and probable clinical outcome has led to a re-evaluation of many prognostic parameters with studies confined to a single RCC morphotype. Tumour stage remains the most important predictor of RCC outcome and recent investigations have focused upon tumour diameter and the prognostic significance of stromal, vascular and lymphatic invasion within the renal sinus. In large tumour series, morphotype has been correlated with patient survival, with clear cell RCC being associated with a less favourable outcome than chromophobe RCC and to a lesser extent papillary RCC, for organ confined tumours. The prognostic significance of nuclear grading remains controversial. Fuhrman grading has been shown to have prognostic utility for clear cell RCC in some series. Recent studies have shown that for papillary RCC, grading should be based upon nucleolar size and that Fuhrman grading is inappropriate for chromophobe RCC. Proliferative indices based upon a variety of markers have been correlated with outcome for clear cell RCC (Ki-67, AgNORs, p21(waf1/cip1) and p27(Kip1)) and papillary RCC (Ki-67, AgNORs), although in some series prognostic significance was lost on multivariate analysis. The presence of tumour necrosis has been shown to predict survival for clear cell and chromophobe RCC, and in clear cell RCC quantification of tumour vascular density has been correlated with outcome. Several molecular markers have been investigated for prognostic significance, mostly in clear cell RCC. Although some of these markers have been shown to be significantly associated with survival, these findings remain to be confirmed in large scale follow-up studies.

Automated immunofluorescence analysis defines microvessel area as a prognostic parameter in clear cell renal cell cancer

Microvessel density (MVD) has been reported to have prognostic relevance for clear cell renal cell carcinoma (ccRCC). However, this finding is controversial because of the difficulty of MVD evaluation in this complex vascularized tumor type. The present study evaluates the use of an automated quantitative analysis (AQUA) system for objective and reproducible determination of tumor vascularization in clear cell renal cell carcinoma (ccRCC). The AQUA system was applied to tissue microarrays with 284 primary ccRCC tumors. To determine angiogenesis in ccRCC, we created an epithelial/stromal mask consisting of CD10, epithelial membrane antigen, and vimentin to distinguish epithelial tumor cells from CD34-positive endothelial cells. Using immunofluorescence and computer-aided quantification of CD34 expression, we measured the relative microvessel area (MVA) and compared the MVA to the manually counted MVD. The MVA determined by AQUA in a test set with 209 ccRCCs ranged from 0% to 30.3% (mean +/- SD, 10.1% +/- 6.3%). The manually determined MVD ranged from 6 to 987 vessels/mm(2) (416.8 +/- 252.8 vessels/mm(2)). MVA and MVD were significantly correlated (P < .001). A larger MVA was associated with histologic grade (P < .001), tumor stage (P =.008), presence of metastasis (P = .005), presence of sarcomatoid areas (P < .001), and tumor-specific survival (P < .001). Using MVA as defined in the test set, all associations with clinical and pathologic parameters were confirmed in a second independent validation set. MVA determination by AQUA is an objective and reliable method to quantify tumor vascularization in ccRCC. A large MVA correlates with a high MVD and is associated with better patient prognosis.

Association between microvessel density and histologic grade in renal cell carcinomas

Angiogenesis seems to contribute to tumor growth and the development of metastases. There may be an association between the vascular density of individual tumors and their prognosis. In the present survey we studied 53 cases of renal cell carcinoma investigating possible relationship between histologic grade and microvessel density (MVD) measured by an image analysis system. According to our results MVD was significantly associated with the histologic grade, higher grades being accompanied with a higher MVD. Further studies are needed to investigate a possible connection of MVD with the prognostic role of grade in RCCs.

Evaluation of CD31 (PECAM-1) expression using tissue microarray in patients with renal cell carcinoma

Intratumoural microvessel density (MVD) has prognostic significance in selected neoplasms. To evaluate the prognostic information of MVD in renal cell carcinoma (RCC) we assessed the immunohistochemical expression of CD31 in 208 tumours using the tissue microarray technique. The expression was related to tumour cell type, TNM stage, nuclear grade and survival. CD31 expression was significantly (p < 0.001) higher in 167 conventional RCCs (clear cell) compared to 28 papillary RCCs. In conventional RCC, CD31 expression was inversely correlated to TNM stage (p = 0.024) and nuclear grade (p = 0.010). To evaluate the impact of CD31 expression on tumour-specific survival, the conventional RCC tumours were subdivided into quartiles according to the CD31 expression. In univariate analysis, patients with tumours in the quartile with the highest expression had a more favourable prognosis (p = 0.01) compared to those with lower CD31 expression. A multivariate analysis of prognostic factors in conventional RCC showed that TNM stage and nuclear grade were independent predictors of prognosis, but CD31 expression did not add further prognostic information.

High-grade clear cell renal cell carcinoma has a higher angiogenic activity than low-grade renal cell carcinoma based on histomorphological quantification and qRT-PCR mRNA expression profile

Clear cell renal cell carcinoma (CC-RCC) is a highly vascularised tumour and is therefore an attractive disease to study angiogenesis and to test novel angiogenesis inhibitors in early clinical development. Endothelial cell proliferation plays a pivotal role in the process of angiogenesis. The aim of this study was to compare angiogenesis parameters in low nuclear grade (n=87) vs high nuclear grade CC-RCC (n=63). A panel of antibodies was used for immunohistochemistry: CD34/Ki-67, carbonic anhydrase IX, hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF). Vessel density (MVD - microvessel density), endothelial cell proliferation fraction (ECP%) and tumour cell proliferation fraction (TCP%) were assessed. mRNA expression levels of angiogenesis stimulators and inhibitors were determined by quantitative RT-PCR. High-grade CC-RCC showed a higher ECP% (P=0.049), a higher TCP% (P=0.009), a higher VEGF protein expression (P<0.001), a lower MVD (P< 0.001) and a lower HIF-1alpha protein expression (P=0.002) than low-grade CC-RCC. Growth factor mRNA expression analyses revealed a higher expression of angiopoietin 2 in low-grade CC-RCC. Microvessel density and ECP% were inversely correlated (Rho=-0.26, P=0.001). Because of the imperfect association of nuclear grade and ECP% or MVD, CC-RCC was also grouped based on low/high MVD and ECP%. This analysis revealed a higher expression of vessel maturation and stabilisation factors (placental growth factor, PDGFB1, angiopoietin 1) in CC-RCC with high MVD, a group of CC-RCC highly enriched in low nuclear grade CC-RCC, with low ECP%. Our results suggest heterogeneity in angiogenic activity and vessel maturation of CC-RCC, to a large extent linked to nuclear grade, and, with probable therapeutic implications.

Two distinct types of blood vessels in clear cell renal cell carcinoma have contrasting prognostic implications

PURPOSE

Intratumoral microvascular density (MVD) has been controversial as an indicator of prognosis in clear cell renal cell carcinoma (CCRCC). Classification of the intratumoral blood vessels based on differential expressions of blood vessel markers has not been correlated with patient prognosis in CCRCC. In this study, we aimed to evaluate the association of different categories of blood vessels with the patients' outcomes.

EXPERIMENTAL DESIGN

Seventy-eight CCRCC patients who underwent nephrectomy alone were enrolled. Paraffin-embedded CCRCC tissues, together with 16 nonmalignant kidney cortex tissues, were used in tissue microarray analyses and conventional section analyses. The characteristics of intratumoral blood vessels were identified by multiple blood vessel markers and pericyte markers. A computerized image analysis program was used to quantitatively calculate the vascular density.

RESULTS

Two distinct types of microvessels were identified in CCRCC: undifferentiated (CD31(+)/CD34(-)) and differentiated (CD34(+)) vessels. A higher undifferentiated MVD significantly correlated with higher tumor grades and shorter patient survival. In contrast, a higher differentiated MVD significantly correlated with lower tumor grade and longer survival. Multivariate analyses showed that undifferentiated MVD was an independent prognostic factor for patient survival. An inverse correlation between undifferentiated MVD and differentiated MVD was also identified in CCRCC.

CONCLUSIONS

This is the first report showing distinct types of vasculature in CCRCC correlated with contrasting prognoses. A refined classification of CCRCC based on vasculature is therefore important for evaluating prognosis, and it may also have therapeutic implications.

Prognostic significance of CD44, platelet-derived growth factor receptor alpha, and cyclooxygenase 2 expression in renal cell carcinoma

CONTEXT

Pathologic stage is the main prognostic factor for predicting outcome in renal cell carcinoma (RCC). Because of its unreliability in predicting tumor progression, other factors are needed to provide additional prognostic information.

OBJECTIVE

The expression of CD44, cyclooxygenase 2, and platelet-derived growth factor receptor alpha (PDGFR-alpha) was evaluated as a potential prognostic factor for survival in patients with RCC.

DESIGN

Sixty-two patients (42 men and 20 women; median age, 61 years), undergoing partial (10 cases) or radical (55 cases) nephrectomy for RCC were retrospectively analyzed by immunohistochemical analysis for CD44, cyclooxygenase 2, and PDGFR-alpha expression. Impact of various factors on disease-specific and overall survival was calculated using Cox proportional hazards models.

RESULTS

There was a gradual increase in CD44 and cyclooxygenase 2 expression with increasing RCC nuclear grade. In contrast, PDGFR-alpha expression showed no consistent relationship with nuclear grade. On univariate analysis, metastasis at time of surgery (P < .001), tumor size (P = .004), pathologic stage group (P = .001), and nuclear grade (P = .004) were correlated with disease-specific survival. On multivariate analysis, only the presence of metastasis at diagnosis (P < .001) was significant. For overall survival, metastasis (P < .001), tumor size (P = .02), pathologic stage group (P = .01), nuclear grade (P = .003), and PDGFR-alpha (P = .03) were significant on univariate analysis. Only metastasis (P = .001) and PDGFR-alpha (P = .03) were significant on multivariate analysis.

CONCLUSIONS

When combined with other variables, PDGFR-alpha expression in RCC may provide additional predictive value related to the patient's overall survival. However, CD44 and cyclooxygenase 2 do not seem to be independent prognostic indicators in predicting outcomes for patients with RCC.

[Survival analysis for localized renal cell carcinoma. Prognostic value of 1997 TNM classification]

BACKGROUND

The 5th edition of TNM classification for renal cell carcinoma changed the cut-off point of the tumor size for localized tumors, achieving a better distribution of patients with similar survival. Nevertheless, because of the variable evolution of renal cell carcinoma, the prognostic significance of tumor size is questioned as a staging criterion in organ-confined renal cell carcinoma. We analyse renal cell carcinoma specific survival and the prognostic significance of tumor size in I and II stage.

METHODS

We made a retrospective study with 158 renal cell carcinoma surgically treated in our hospital along 12 years. It was created a data base with clinical variables from patient and tumor and analyzed pathological staging, nuclear grade and specific survival, overall stage I and II.

RESULTS

27 renal cell carcinoma were pT1 (17.08%), 52 pT2 (32.91%), 45 pT, (28.45%), 10 pT3B (6.32%), y 24 pT4 (15.18%). The specific survival at 5 years for pT1-pT2, I-II stage, was 100% and 94% respectively, and no statistic significant differences were found between stage I and II (log-rank test 0.53, p>0.05). The specific survival at 5 years for pT3a, pT3B, y pT4 was 76.5%, 66.6% y 38.4%. There was a significant difference in survival in accordance with the tumor location, intrarenal (T1 y T2) versus extrarenal (T3A, T3B, T4) (log-rank test 9.06, p< 0.05). According to nuclear grade we don't find significant differences for pT1 y pT2 (Fisher test, p=1). Regarding the relation between pT stage and nuclear grade of the tumor we obtained a chi-square inear tendency of 38.19, p<0.001.

CONCLUSION

The differences in the evolution of the organ-confined renal cell carcinoma with respect to the tumor size may be due to other molecular and biological variables, probably associated with stage, not controlled in essays. The TNM classification for organ-confined renal cell carcinoma based in tumor size seems artificial. New revisions of the classification system are necessary to identify which organ-confined carcinoma will have unfavourable evolution and to include them in a different category.

Nonmetastatic renal-cell carcinoma: is it really possible to define rational guidelines for post-treatment follow-up?

Defining rational follow-up guidelines in patients treated for cancer is important, from both a medical and an economical perspective. Renal-cell carcinoma is reputed to be unpredictable in its course and only a few, and often contradictory, follow-up guidelines exist for patients treated for nonmetastatic renal-cell carcinoma. Recent advances in tumor biology have contributed to a better understanding of this cancer and have indicated that personalized follow-up regimens, based on tumor and host molecular characteristics, might be possible in the near future.

High microvascular density is correlated with high VEGF, iNOS and COX-2 expression in penetrating growth-type early gastric carcinomas

AIMS

Early gastric carcinomas have two characteristic growth types, superficial spreading (SUP) and penetrating (PEN). Higher mucosal apoptotic activity and lower p21(WAF1/CIP1) expression and submucosal low proliferative activity have been shown in the former, compared with the latter. In order to cast light on whether angiogenesis contributes to these growth patterns, the present immunohistochemical study was performed with cancer tissues.

METHODS AND RESULTS

Of a total of 807 early gastric carcinomas, 30 PEN and 33 SUP type submucosal invasive carcinoma cases were immunohistochemically compared. CD34 positivity, microvascular density (MVD), and expression of vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS), but not cyclooxygenase 2 (COX-2) were higher in cancer cells in both mucosal and submucosal layers in PEN than in SUP (P < 0.05). Submucosal MVD in PEN type was greater (P < 0.01) in cases with high than with low Ki67 labelling. Significant correlations were shown between MVD and VEGF, iNOS and COX-2, and VEGF and iNOS expression in the PEN type, but only a weak correlation between iNOS and COX-2 expression was evident with the SUP type.

CONCLUSIONS

Increased MVD in PEN type has an intimate causal relationship to angiogenic factors, high VEGF and iNOS expression. The SUP type, in contrast, has characteristics of low angiogenesis.

Inverse correlation of microvessel density with metastasis and prognosis in renal cell carcinoma

BACKGROUND

Although a correlation between microvessel density (MVD) and tumor aggressiveness has been established for several malignancies, the data for renal cell carcinoma (RCC) is conflicting. In order to clarify the significance of MVD, we investigated the relationships between MVD and tumor stage, grade, size, occurrence of metastasis and patient survival.

METHODS

Tumor specimens from 70 patients with primary renal cell carcinoma were examined by immunohistochemical staining for CD34.

RESULTS

There was a tendency for MVD to decrease from G1 to G3 tumors or from stage T1 to T3 tumors, although this was not statistically significant. However, the MVD for 56 non-metastatic and 14 metastatic tumors were significantly different (P = 0.005) at 109 +/- 67 and 58 +/- 35 per x400 field (mean +/- SD), respectively. Microvessel density for 36 large and 34 small tumors was also significantly different (P < 0.0001) at 48 +/- 22 and 142 +/- 54 per x400 field, respectively. The survival rate of patients with small, low grade and hypervascular tumors was significantly higher than that of patients with large (P = 0.0015), high grade (P = 0.05) or low MVD (P = 0.039) tumors. Cox proportional hazards regression analysis showed that tumor grade and size emerged as independent prognostic factors.

CONCLUSION

High MVD in RCC was inversely associated with tumor aggressiveness, but MVD was not the independent prognostic factor.

The L1 Cell Adhesion Molecule Is Induced in Renal Cancer Cells and Correlates with Metastasis in Clear Cell Carcinomas

Purpose: The L1 cell adhesion molecule is overexpressed in many human carcinomas. The objectives of the study were to provide a comprehensive description of L1 distribution in human kidney and to establish the prognostic relevance of L1 expression in renal cell carcinomas (RCC).

Experimental Design: Using two antibodies to the extracellular part and the cytoplasmic domain, respectively, we first compared L1 expression in normal kidney and renal tumors of diverse histopathologic origin, then we studied L1 expression together with tumor stage, grade, molecular prognostic biomarkers, and metastatic behavior.

Results: In normal kidney, L1 immunoreactive with both antibodies was expressed in all epithelial cells originating from the ureteric bud except for intercalated cells. In renal tumors, L1 was mainly detected in those originating from cells that do not express L1 in the normal kidney [i.e., 33 of 72 clear cell RCC (ccRCC) and 25 of 88 papillary RCC (papRCC)]. Both in ccRCC and papRCC, L1 reacted only with the antibody to the extracellular domain, suggesting that the protein was truncated. In these carcinomas, L1 expression was strongly correlated with Ki-67 proliferation index (ccRCC, P = 0.0059; papRCC, P = 0.0039), but only in ccRCC, the presence of L1 was associated with the risk of metastasis (P = 0.0121). This risk was higher if cyclin D1 was concurrently absent in tumor cells (P &lt; 0.0001). The L1+/cyclin D1− profile was an independent prognostic factor of metastasis occurrence in multivariate analysis (P = 0.0023).

Conclusion: We have found a combination of markers that can serve to identify a subgroup of high-risk patients with ccRCC that may require more aggressive therapies.

Inhibitory and apoptosis-inducing effects of CD44 antisense oligodeoxyribonucleotides on human gastric cancer cell line MGC80-3

AIM: To study the role and mechanism of antisense oligodeoxyribonucleotides (ASODN) on proliferation and apoptosis of MGC80-3 cells.

METHODS: Flow cytometry was used to detect CD44, Fas expression and apoptosis of MGC80-3 cells. Reverse transcription polymerase chain reaction (RT-PCR) assay was used to examine CD44 mRNA level; MTT assay was used to detect cell proliferation.

RESULTS: CD44 mRNA and CD44 protein expression in MGC80-3 cells was blocked and down-regulated after transfected with CD44ASODN (1.6 μmol/L). CD44ASODN inhibited the growth of MGC80-3 cells with depression ratios of 31.0%, 46.3% (P < 0.01), and 49.6% (P < 0.01) at 48 h, 72 h, and 96 h respectively in a time-dependant manner. With the existence of hyaluronic acid, CD44ASODN improved Fas expression in MGC80-3 cells from 6.7% to 16.8% (P < 0.01). At the same time, it enhanced the susceptibility of MGC80-3 cells to Fas mAb and the apoptotic rate of the cells increased from 0% to 26.5% (P < 0.01).

CONCLUSION: CD44ASODN can down-regulate the expression of CD44 mRNA and protein, inhibit MGC80-3 cell proliferation and promote apoptosis induced by Fas mAb.

Optical imaging and tumor angiogenesis

Tumor angiogenesis is essential for tumor growth and progression. Therefore, targeting tumor blood vessels is a promising approach for cancer therapy. Angiogenesis, the formation of blood vessels, is a multistep process, and strongly influenced by the microenvironment. There are no in vitro assays that can resemble this dynamic process in vivo. For this reason, animal models and imaging technologies are critical for studying tumor angiogenesis, identifying therapeutic targets as well as validating the targets. Non-invasive molecular imaging in animal models presents an unprecedented opportunity and ability for us to perform repetitive observations and analysis of the biological processes underlying tumor angiogenesis and tumor progression in living animals in real time. As we gain a better understanding of the fundamental molecular nature of cancer, these techniques will be an important adjunct in translating the knowledge into clinical practice. This important information may elucidate how the tumor blood vessels behave and respond to certain treatments and therapies.

Prognostic value of the expression of Ki-67, CD44 and vascular endothelial growth factor, and microvessel invasion, in renal cell carcinoma

OBJECTIVE

To determine if use of cell proliferation, cell adhesion, level of angiogenesis-related factors and presence of microscopic vascular invasion (MVI) could better predict the biological behaviour of renal cell carcinoma (RCC), which has a widely variable clinical outcome despite the use of conventional prognostic factors (staging and grading).

MATERIALS AND METHODS

The expression of Ki-67, CD44H and vascular endothelial growth factor (VEGF) were assessed immunohistochemically in formalin-fixed, paraffin-embedded tissues from 48 RCCs, using a Ki-67 labelling index (LI), CD44 LI and level of VEGF expression, respectively. In addition all the pathological slides were reviewed retrospectively for the presence and absence of MVI. The prognostic value of all the variables assessed was then evaluated, and correlated with the usual prognostic variables and cancer-specific survival.

RESULTS

Univariate analysis of cancer-specific survival showed that tumour stage (P < 0.001), tumour size (P = 0.005), metastasis, MVI, Ki-67 LI, CD44H LI and VEGF expression (all P < 0.001) were predictors of tumour-related death. There was a statistical correlation between CD44H LI and each of Ki-67 LI (r = 0.61), expression level of VEGF (r = 0.72) and presence of MVI (r = 0.71). Independent predictors of cancer-specific survival in a multivariate analysis were: in all patients with RCC, the MVI (P = 0.003) and VEGF expression (P = 0.01); in those with no metastases, MVI (P = 0.01); in patients with no MVI, VEGF (P = 0.04); and in patients with MVI, Ki-67 LI (P = 0.003). No independent predictor was identified in patient with metastases.

CONCLUSION

This study suggests that cell proliferation, cell adhesion, the level of VEGF expression and the presence of MVI represent a complex tumour-host interaction that may favour the progression of RCC. Cell proliferation, CD44H and VEGF expression appear to be powerful markers for identifying patients with an adverse prognosis.

Increased expression of caveolin-1 and microvessel density correlates with metastasis and poor prognosis in clear cell renal cell carcinoma

OBJECTIVE

To investigate the relationship of caveolin-1 expression and microvessel density (MVD), a reflection of angiogenesis, with metastasis and prognosis in patients with clear cell renal cell carcinoma (RCC).

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tissue sections of clear cell RCC from 67 patients who had undergone radical nephrectomy were stained immunohistochemically with specific antibodies against caveolin-1 and CD34. Caveolin-1 immunostaining was semi-quantitatively estimated based on the proportion (percentage of positive cells) and intensity. MVD was determined with CD34-stained slides. The expression pattern of caveolin-1 and MVD was compared with the clinicopathological variables.

RESULTS

Eighteen patients had either synchronous or metachronous metastases and 11 died during the follow-up. Caveolin-1 intensity was significantly correlated with tumour size (P = 0.005), TNM stage (P = 0.028), M stage (P = 0.012), grade (P = 0.015), and metastasis (synchronous or metachronous; P < 0.001). The caveolin-1 proportion (P = 0.037) and MVD (P = 0.011) were significantly correlated with metastasis. MVD was correlated with caveolin-1 intensity (r = 0.385, P = 0.001) and caveolin-1 proportion (r = 0.388, P = 0.001). There was no difference in the expression of caveolin-1 and MVD between primary and metastatic sites. The survival of patients with higher caveolin-1 intensity was significantly worse than that of patients with lower caveolin-1 intensity. Multivariate analyses indicated that only M-stage was an independent prognostic factor for cancer-specific survival and caveolin-1 expression was not an independent factor.

CONCLUSIONS

Increased expression of caveolin-1 and MVD is associated with metastasis and a worse prognosis in clear cell RCC. Caveolin-1 expression is correlated with MVD. These results suggest that caveolin-1 may be important in the progression of clear cell RCC and angiogenesis may be affected by caveolin-1 during the progression of RCC.

In vivo assessment of the antiproliferative properties of interferon-alpha during immunotherapy: Ki-67 (MIB-1) in patients with metastatic renal cell carcinoma

The aim of the present study was to investigate the in vivo antiproliferative effect of interferon alpha (IFN-α) in patients with metastatic renal cell carcinoma (mRCC). Core needle biopsies of metastatic and/or the primary kidney cancer were obtained before interleukin-2 (IL-2)- and IFN-α-based immunotherapy in 34 patients and repeated after 5 weeks in 25 patients. Tumour proliferation was assessed by use of the anti-Ki-67 antibody MIB-1 and evaluated in multiple, random systematic sampled fields of vision. Ki-67 labelling index (LI) at baseline was median 13.6% (range 1.2–85.0) and median 10.6% (range 1.3–48.6%) at week 5 with a median overall decline of 15.2% (range −95 to +258%) from baseline to week 5. There was no difference between responding and nonresponding patients. Ki-67 LI at week 5 was significantly correlated to survival. Thus, median survival of patients with Ki-67 LI ⩽10.6% at week 5 was 25.1 months compared to 11.5 months for patients with Ki-67 LI >10.6% (P=0.016). Baseline or change in Ki-67 LI did not correlate to survival. These data suggest that IFN-α in vivo has only modest effect on tumour proliferation in patients with mRCC. Tumour Ki-67 (MIB-1) reactivity after 1 month of immunotherapy appears to be a significant predictor of patient survival.