Therapeutic Options for Variant Renal Cancer

Molecular Pathology of the Genitourinary Tract: Molecular Pathology of Kidney and Testes

With the advent of newer molecular technologies, our knowledge of cellular mechanisms with tumors of the kidney and testis has grown exponentially. Molecular technologies have led to better understanding of interplay between the von Hippel-Lindau gene and angiogenic cytokines in renal cancer and isochromosome 12p in testicular neoplasms. The result has been development of antiangiogenic-targeted therapy within recent years that has become the mainstay treatment for metastatic renal cell cancer. In the near future, classification and diagnosis of renal and testicular tumors through morphologic analysis will be supplemented by molecular information correlating to prognosis and targeted therapy. This article outlines tumor molecular pathology of the kidney and testis encompassing current genomic, epigenomic, and proteonomic findings.

Renal epithelial neoplasms: diagnostic applications of gene expression profiling

Renal cell carcinoma (RCC) is the most common form of kidney cancer in adults. RCC is a significant challenge for pathologic diagnosis and clinical management. The primary approach to diagnosis is by light microscopy, using the World Health Organization (WHO) classification system, which defines histopathologic tumor subtypes with distinct clinical behavior and underlying genetic mutations. However, light microscopic diagnosis of RCC subtypes can be difficult due to variable histology, morphologic features shared by tumor subtypes, and a growing frequency of small tumor biopsies with limited morphologic information. In addition to these diagnostic problems, the clinical behavior of RCC is highly variable, and therapeutic response rates are poor. Few clinical assays are available to predict outcome in RCC or correlate behavior with histology. Therefore, novel RCC classification systems based on gene expression should be useful for diagnosis, prognosis, and treatment. Recent microarray studies have shown that renal tumors are characterized by distinct gene expression profiles, which can be used to discover novel diagnostic and prognostic biomarkers. Here, we review clinical features of kidney cancer, the WHO classification system, and the growing role of molecular classification for diagnosis, prognosis, and therapy of this disease.

Role of carbonic anhydrases in the progression of renal cell carcinoma subtypes: proposal of a unified hypothesis

Renal cell carcinoma (RCC) has the highest rate of occurrence within the US when compared with other countries. Recent advances in the basic research and molecular diagnostics of this malignancy have revealed that RCC is not a single disease, but it is a mixture of several types of malignancies with unique molecular mechanisms and pathological attributes. RCC is now divided into clear cell carcinoma (80% of all kidney cancers), papillary type 1 and papillary type 2 neoplasms (10-15% of all RCC patients) and RCC with chromophobic and oncocytic features, called the Birt-Hogg-Dube (BHD) subtype, in roughly 5% of all patients. Apart from these, neoplasms such as the tuberous sclerosis (TSC) syndrome may occur with a mixed pathological features with a renal presentation. In this review, molecular evidence, both direct and indirect, published so far on all these RCC subtypes have been analyzed to find out whether there is any common thread that could run through these disparate malignancies that happen to occur in a single organ, i.e., the kidney. We believe that the role played by the expression and certain non-traditional activities of the cabonic anhydrase (CA) family members, along with the differing levels of hypoxia induced within these tumors may be the most common denominators. Evidence is presented focusing on how the CA family members could participate in the genesis and progression of each and every one of these RCC subtypes and how their function could be influenced by hypoxia, activities of receptor type protein tyrosine kinases and certain other pre-disposing factors. These rationalizations point towards a unified hypothesis that may help explain the occurrence of all these RCC subtypes in a molecular manner. We hope that these analyses would a) stimulate further studies aimed toward a better understanding of the role played by carbonic anhydrases in RCC subtypes and b) would pave way to a better and rationally designed therapies to interfere with their function to benefit patients with RCC and possibly other cancers.

Treatment outcome for metastatic papillary renal cell carcinoma patients

BACKGROUND

Most clinical trial reports in metastatic renal cell carcinoma (RCC) do not distinguish between histologic subtypes, making it difficult to assess specific treatment efficacy. The current retrospective study sought to define clinical features and outcome data for metastatic papillary RCC.

METHODS

Clinical features, treatment outcome, and survival were evaluated in 38 patients with metastatic papillary RCC who underwent clinical evaluation at Memorial Sloan-Kettering Cancer Center (MSKCC) between 1985 and 2005. Twenty-three of 513 individuals were identified from a clinical trial database, 14 of 1895 from a surgery database, and 1 of 357 from a pathology database. A literature review of systemic therapy in metastatic papillary RCC was performed.

RESULTS

Among the 38 patients, 30 had been treated at MSKCC with various systemic therapies, including cytokines. Twelve therapies resulted in stable disease, 30 in initial progression of disease, and 1 in an unknown response. One patient had a partial response to sunitinib, a novel multitargeted tyrosine kinase inhibitor. The median overall survival time for the entire study group was 8 months (95% confidence interval, 5-12). A literature review on treatment of metastatic papillary RCC produced 4 reports, confirming a lack of efficacy for systemic therapy.

CONCLUSIONS

A resistance to systemic therapy characterizes patients with metastatic papillary RCC. Further understanding of the genetics and molecular biology and subtypes involved may provide the basis for more effective agents. Treatment with targeted therapies or other experimental agents is warranted.

Chemotherapy for non-clear-cell renal cell carcinoma

Clear-cell carcinoma is the most common histopathologic subtype of kidney tumors. Consequently, clinical trials for advanced-stage kidney cancer have focused on patients with clear-cell carcinoma and not on the less common subtypes, including papillary, chromophobe, collecting-duct carcinoma, and sarcomatoid-variant tumors. Whereas immunotherapy has constituted the standard treatment for patients with clear-cell renal cell carcinoma (RCC), it does not appear to have activity in the management of patients with other histologic subtypes. Novel therapies, including those targeting the vascular endothelial growth factor pathway, have recently demonstrated significant activity in clear-cell RCC. Historically, chemotherapy has shown limited activity in advanced-stage RCC; however, clinical trials to date have failed to individualize treatment based on histologic subtype. In this article, we will review the literature and present our experience with the use of chemotherapy in patients with non-clear-cell kidney cancer by histologic subtype.

A phase II trial of 17-(Allylamino)-17-demethoxygeldanamycin in patients with papillary and clear cell renal cell carcinoma

The aim of this study was to determine the antitumor activity of 17-(Allylamino)-17-demethoxyge-ldanamycin (17-AAG), a heat shock protein 90(hsp90) inhibitor in patients with metastatic papillary renal cell carcinoma (RCC) or metastatic clear cell RCC. Eligible patients were divided into 2 cohorts based on histological subtype: papillary or clear cell RCC. All patients had advanced RCC with measurable disease, a Karnofsky performance status of at least 70, and no evidence of brain metastases. Twelve patients with clear cell RCC and 8 patients with papillary RCC were treated with 17-AAG on this phase II trial. 17-AAG was given intravenously at 220 mg/m(2) twice weekly for 2 weeks followed by a week of rest. Cycle length was 21 days. No patient in either cohort achieved a complete or partial response. Toxicities included elevated liver function tests, optic neuritis, dyspnea, fatigue, and gastrointestinal side effects. Six of the 20 patients required dose reduction. At the dose and schedule used in this trial, 17-AAG did not achieve objective response in the treatment of clear cell or papillary renal cell carcinoma patients.

Identification of fatty acid binding proteins as markers associated with the initiation and/or progression of renal cell carcinoma

Renal cell carcinoma (RCC) representing the most common neoplasia of the kidney in Western countries is a histologic diverse disease with an often unpredictable course. The prognosis of RCC is worsened with the onset of metastasis, and the therapies currently available are of limited success for the treatment of metastatic RCC. Although gene expression analyses and other methods are promising tools clarifying and standardizing the pathological classification of RCC, novel innovative molecular markers for the diagnosis, prognosis, and for the monitoring of this disease during therapy as well as potential therapeutic targets are urgently needed. Using proteome-based strategies, a number of RCC-associated markers either over-expressed or down-regulated in tumor lesions in comparison to the normal epithelium have been identified which have been implicated in tumorigenesis, but never linked to the initiation and/or progression of RCC. These include members of the fatty acid binding protein family, which have the potential to serve as diagnostic or prognostic markers for the screening of RCC patients.