Clear cell renal cell carcinoma: gene expression analyses identify a potential signature for tumor aggressiveness

Expression of survivin in renal cell carcinomas: association with pathologic features and clinical outcome

OBJECTIVES

To investigate the expression of survivin in renal cell carcinoma and try to define its association with certain pathologic features and the clinical outcome.

METHODS

The tissue samples from 85 consecutive renal cell carcinoma specimens were obtained from patients who had undergone radical or partial nephrectomy. The mean follow-up was 45 months (range 3 to 60). Immunohistochemical staining of the paraffin sections of the pathologic sample was performed using monoclonal antibody for survivin with the standard avidin-biotin-peroxidase technique. The mean expression rate of survivin was assessed by inspection of at least five microscopic fields at 400x magnification. Expression of survivin was considered positive when more than 10% of the cancer cells in the microscopic fields demonstrated immunostaining. The degree of expression of survivin was compared with the clinicopathologic features.

RESULTS

Survivin was expressed in 67 (79%) of 85 samples. Immunostaining for survivin was demonstrated in the cytoplasm of tumor cells and in vascular endothelial cells. A significant increase in survivin expression was associated with increased T stage (P = 0.044), increased tumor grade (P = 0.0013), and low recurrence-free survival (P = 0.046). Multivariate Cox regression analysis revealed that survivin expression is an independent prognostic parameter (P = 0.021) in renal cell carcinoma.

CONCLUSIONS

The results of this study suggest that survivin-mediated inhibition of apoptosis is associated with progression and recurrence of renal cell carcinoma. Thus, survivin is a useful independent prognostic marker for this condition.

Genomics of Renal Cell Cancer: The Biology Behind and the Therapy Ahead

Renal cell cancer (RCC) is the most lethal of the urological cancers and accounts for 3% of all adult malignancies. Despite numerous recent advances in diagnostic imaging, surgical therapy, and basic molecular understanding, many patients still experience metastatic disease. For metastatic disease patients, response rates to conventional therapies rarely exceed 15% to 25% and are associated with serious adverse effects. The recent development of novel targeted therapies based on the precise biological pathways deregulated in a particular patient has paved the way for individualized, targeted patient management. Nevertheless, to achieve this goal, it is important to delineate the molecular mechanisms underlying cancer development and progression. Genomic approaches have revolutionized the field of cancer research and have led to the rapid discovery of multiple, parallel disease hypotheses, which ultimately have to be validated in large cohorts of patients and in downstream biological experiments for translation into clinical applications. The variable course of RCC and, until recently, a paucity of therapeutic options in the event of metastasis have led to the search for diagnostic and prognostic markers. We and others have used transcriptional profiling to classify different subtypes of RCC and to identify subtype- and metastasis-specific gene signatures predictive for outcome. We discuss herein recent genomic approaches to RCC and the emerging biological pathways underlying RCC development and progression. We also speculate how genomics may affect drug development and the management of patients with RCC.

Evolving principles of surgical management and prognostic factors for outcome in renal cell carcinoma

The generally accepted principles for the surgical management of renal cell carcinoma (RCC) were first described more than 30 years ago. Since then, much has changed in the understanding of the basic biology and genetics of kidney cancer. Improvements in cross-sectional imaging has allowed for more accurate preoperative clinical staging of renal tumors, and the necessity of completing all the components of the radical nephrectomy have been questioned. Surgical techniques have also evolved, and technology has advanced to make possible new methods of managing renal tumors. The TNM staging system is currently the most extensively used system to provide prognostic information for RCC. However, data published in the last few years has led to significant controversies as to whether further revisions are needed and whether improvements can be made with the introduction of new, more accurate and predictive prognostic factors. Furthermore, the recent discovery of molecular tumor markers are expected to revolutionize the staging of RCC and lead to the development of new therapies based on molecular targeting. This review will examine the evolving principles in the surgical management of RCC as well as provide an update on current staging modalities and prognostic factors.

Vascular Cell Adhesion Molecule 1 Predicts Cancer-Free Survival in Clear Cell Renal Carcinoma Patients

PURPOSE

Vascular cell adhesion molecule 1 (VCAM1) is a cell surface glycoprotein implicated in various pathophysiologic conditions. We measured VCAM1 expression levels in tumor tissues and evaluated its significance and prognostic use in renal cell carcinoma (RCC).

EXPERIMENTAL DESIGN

We used real-time quantitative PCR to examine the VCAM1 expression levels of a total of 485 sporadic renal tumors, including 429 clear cell, 21 papillary, 17 chromophobe, 11 oncocytomas, and 7 collecting duct carcinomas. We retrospectively examined the relationship of this expression to various clinicopathologic variables and the von Hippel-Lindau alteration status. We evaluated its significance with respect to patient survival rates using the Cox regression model combined with the split-sample method.

RESULTS

Compared with normal kidney samples (n = 43), VCAM1 was significantly up-regulated in clear cell RCC and papillary RCC, whereas it was down-regulated in chromophobe RCC and oncocytoma. In clear cell RCC, VCAM1 expression levels were apparently high in patients asymptomatic at presentation and in patients with small tumor size, low-stage, low-grade, microvascular invasion-negative, and von Hippel-Lindau alteration-positive tumors. Univariate analyses showed that VCAM1 high expression is strongly associated with better outcomes in clear cell and papillary RCCs. Further, Cox multivariate analysis models combined with the split-sample method revealed that this association is significant only in cancer-free survival for patients with clear cell RCC after curative surgical resection.

CONCLUSIONS

VCAM1 expression levels were found to be histologically subtype specific in renal tumors. Determination of the VCAM1 expression level as a biomarker can provide useful prognostic information for patients with clear cell RCC.

Kinase inhibitors in the treatment of renal cell carcinoma

Immunotherapy confers a small but significant overall survival advantage in metastatic renal cell carcinoma (RCC) but a need exists to develop more effective systemic therapies. Angiogenesis has a key role in the pathophysiology of renal cell carcinoma and vascular endothelial growth factor (VEGF) is an important mediator of this process. Sunitinib, sorafenib and axitinib are new agents which belong to a class of drugs called kinase inhibitors and inhibit the VEGF, platelet-derived growth factor (PDGF) and c-KIT receptor tyrosine kinases. Temsirolimus inhibits the mammalian target of rapamycin (mTOR). All these agents have shown significant activity with manageable toxicity in metastatic RCC in phase 2 studies in patients generally pretreated with immunotherapy, whilst prolonged progression-free survival in a phase 3 study has been reported with sorafenib in comparison with placebo. Further phase 3 trials are recruiting and the combination of kinase inhibitors with other therapies is under investigation.

[Microarrays for the identification of molecular markers in the diagnosis and therapy of renal cell carcinomas]

Within the framework of the large interdisciplinary projects in biology, in particular the human genome project, a variety of novel technologies with unprecedented value for the analysis of clinical issues have been developed. DNA microarrays are a prominent example of this: they are powerful tools to investigate global gene expression in tumors and their corresponding normal tissues, to classify tumors based on their molecular properties, and to identify novel targets for future tumor therapy. Here, we review recent results of global gene expression analyses in renal cell carcinoma and discuss their implications for the diagnosis, prognosis, and therapy of human cancer.

The Use of MN/CA9 Gene Expression in Identifying Malignant Solid Renal Tumors

OBJECTIVE

Small solid renal tumors are increasingly encountered. It is important to determine the malignancy of solid renal tumors for the choice of treatment. MN/CA9 is expressed in malignant renal cells but absent in normal cells. MN/CA9 is one of the most powerful gene markers available for RCC. The objective of this pilot study is to utilize MN/CA9 gene expression in FNA biopsy to determine the malignancy of imaging-indeterminate solid renal tumors.

METHODS

A total of 35 patients with an imaging-indeterminate solid renal mass entered into this study. The molecular protocol consisted of a rapid column extraction of RNA and one-step RT-PCR for the detection of MN/CA9 gene expression. The preoperative molecular diagnosis was compared with postoperative pathology.

RESULTS

There were 28 RCCs (19 clear cell carcinomas, 7 papillary carcinomas and 2 chromophobe carcinomas) and 7 benign tumors proved by postoperative pathology. The overall sensitivity and specificity for MN/CA9 were respectively 68% and 100%. MN/CA9 was positive in 16/19 (84%) FNA biopsies of clear cell RCCs. No false positive appeared for MN/CA9 gene expression. Moreover, MN/CA9 gene expression was positive in 8/13 (62%) of false negative or suspect cytology.

CONCLUSION

Detection of MN/CA9 gene expression in FNA biopsy is possible. Its detection can be helpful in identifying the malignancy among renal tumors.

High expression levels of survivin protein independently predict a poor outcome for patients who undergo surgery for clear cell renal cell carcinoma

BACKGROUND

In a previous study of gene array data, the authors identified survivin as a candidate marker of aggressiveness in clear cell renal cell carcinoma (ccRCC). What remained in question was whether survivin expression at the protein level is an independent predictor of disease progression and cancer-specific survival.

METHODS

Between 1990 and 1994, 312 patients underwent nephrectomy for ccRCC at Mayo Clinic Rochester and had paraffin tissue available. The authors performed immunohistochemistry with antisurvivin antibody, quantitated the expression by using an image-analysis system, and analyzed the association of survivin expression with disease progression and cancer-specific survival.

RESULTS

Within the cohort, 97 patients (31.1%) had high levels of survivin expression. Patients who had high survivin expression levels were at significantly increased risk of death from RCC compared with patients who had low expression levels (risk ratio [RR], 5.3; 95% confidence interval [95% CI], 3.5-7.9). The 5-year cancer-specific survival rate was 43.0% for patients with high survivin expression and 87.2% for patients with low survivin expression. In multivariate analysis, survivin expression remained associated with death from RCC even after adjusting for the Eastern Cooperative Oncology Group performance status; 2002 Tumor, Lymph Node, Metastases (TNM) stage groupings and nuclear grade (RR, 2.4; 95%CI, 1.5-3.8); and the Mayo Clinic composite TNM stage groupings, tumor size, nuclear grade, and tumor necrosis (SSIGN) score (RR, 1.8; 95%CI, 1.1-2.9). Among 273 patients who had localized ccRCC, survivin expression was associated significantly with cancer progression (RR, 3.9; 95%CI, 2.4-6.2).

CONCLUSIONS

Survivin expression is an independent predictor of ccRCC progression and death from RCC. Thus, survivin has the potential to offer additional prognostic information and to provide a novel target for the development of new adjuvant therapies.