Alexander S. Parker

Tumor B7-H1 is associated with poor prognosis in renal cell carcinoma patients with long-term follow-up

B7-H1 participates in T-cell costimulation functioning as a negative regulator of immunity. Recent observations suggest that B7-H1 is expressed by renal cell carcinoma (RCC) tumor cells and is associated with poor prognosis. However, outcome analyses have been restricted to patients with fresh-frozen tissue and limited follow-up. We report the clinical effect of B7-H1 in RCC patients with a median of 10 years of follow-up. Between 1990 and 1994, 306 patients underwent nephrectomy for clear cell RCC and had paraffin tissue available for review. We did immunohistochemistry with anti-B7-H1 and conducted outcome analyses. Among the 306 patients, 73 (23.9%) harbored tumors with B7-H1 expression. Patients with tumor B7-H1 were at a significantly increased risk of both death from RCC [risk ratio (RR), 3.92; P < 0.001] and overall mortality (RR, 2.37; P < 0.001). The 5-year cancer-specific survival rates were 41.9% and 82.9% for patients with and without tumor B7-H1, respectively. In a multivariate model, tumor B7-H1 remained associated with cancer-specific death even after adjusting for tumor-node-metastasis stage, grade, and performance status (RR, 2.00; P = 0.003). In the subset of 268 patients with localized RCC, tumor B7-H1 was significantly associated with metastatic cancer progression (RR, 3.46; P < 0.001) and death from RCC (RR, 4.13; P < 0.001) even after adjusting for stage, grade, and performance status (RR, 1.78, P = 0.036). RCC patients with tumor B7-H1 are at significant risk of rapid cancer progression and accelerated rates of mortality. B7-H1 may function as a key determinant in RCC, abrogating immune responses directed against this immunogenic tumor.

Lifestyle and anthropometric risk factors for prostate cancer in a cohort of Iowa men.

PURPOSE Several lines of evidence suggest that prostate cancer has a hormonal etiology. We evaluated factors known to modulate the endocrine system, including alcohol and tobacco use, physical activity, and obesity as risk factors for prostate cancer. METHODS Cancer-free controls who participated in a population-based case-control study from 1986-1989 (81% response rate) were followed through 1995 for cancer incidence by linkage to the Iowa Cancer Registry; 101 incident prostate cancers were identified. RESULTS Compared with non-users of alcohol, men who consumed <22 grams alcohol per week (relative risk [RR] = 1.1; 95% Confidence Interval [CI] 0.6-2.1), 22-96 grams alcohol per week (RR = 2.6; 95% CI 1.4-4. 6) and >96 grams alcohol per week (RR = 3.1; 95% CI 1.5-6.3) were at increased risk of prostate cancer after adjustment for age, family history of prostate cancer, body mass index, total energy, and intake of carbohydrate, linoleic acid, lycopene, retinol, and red meat (p for trend < 0.0001). The respective RRs were similar when assessing type of alcohol consumed (beer, wine or liquor) or when well-differentiated, localized tumors were excluded. Body mass index was only weakly and positively associated with prostate cancer after adjustment for age, but this association strengthened after multivariate adjustment and exclusion of well-differentiated, localized tumors. For the latter tumors, men with a BMI of 24.1-26.6 kg/m(2) and >26.6 kg/m(2) were at elevated risk compared to men with a BMI <24.1 kg/m(2). Tobacco use (cigarettes, cigar/pipe, chewing tobacco and snuff use), height, weight, and both leisure and occupational physical activity were not associated with risk of prostate cancer in this cohort. CONCLUSIONS These data suggest that in white men obesity is a risk factor for more clinically significant prostate cancer and confirm limited previous reports showing that alcohol consumption is positively associated with prostate cancer and that this risk is not limited to any specific type of alcohol.

Secreted Frizzled-Related Protein 1 Loss Contributes to Tumor Phenotype of Clear Cell Renal Cell Carcinoma

Purpose: Incidence and mortality rates for renal cell carcinoma (RCC) have been rising for decades. Unfortunately, the molecular events that support RCC carcinogenesis remain poorly understood. In an effort to gain a better understanding of signaling events in clear cell RCC (cRCC), we investigated the antitumor activity of secreted frizzled-related protein 1 (sFRP1), a negative regulator of Wnt signaling. Experimental Design: Genomic profiling of cRCC tumors and patient-matched normal tissues was done and confirmed using quantitative PCR and immunohistochemistry. Methylation-specific PCR was done on patient samples to evaluate the mechanism responsible for sFRP1 loss. sFRP1 expression was restored in cRCC cells and the effects on tumor phenotype were characterized. Results: Genomic profiling, quantitative PCR, and immunohistochemistry indicated that loss of sFRP1 occurred in cRCC and papillary RCC patient tissues. Twelve Wnt-regulated genes were up-regulated in cRCC tissues, including c-myc and cyclin D1, potentiators of cell proliferation and survival. Methylation of the sFRP1 gene was one mechanism identified for attenuation of sFRP1 mRNA. Stable reexpression of sFRP1 in cRCC cells resulted in decreased expression of Wnt target genes, decreased growth in cell culture, inhibition of anchorage-independent growth, and decreased tumor growth in athymic nude mice. Conclusions: To our knowledge, this is the first report to show that stable restoration of sFRP1 expression in cRCC cells attenuates the cRCC tumor phenotype. Our data support a role for sFRP1 as a tumor suppressor in cRCC and that perhaps loss of sFRP1 is an early, aberrant molecular event in renal cell carcinogenesis.

Clear Cell Renal Cell Carcinoma: Gene Expression Analyses Identify a Potential Signature for Tumor Aggressiveness

Purpose: The objective of this study was to use gene expression profiling to identify novel biomarkers that are predictive of aggressive behavior in clear cell renal cell carcinoma (CCRCC). Experimental Design: Candidate genes were discovered using Human Genome U133 Plus 2 Arrays and validated on independent samples by quantitative reverse transcription-PCR (RT-PCR). Both the discovery and the validation cohorts included nonaggressive primary CCRCC, aggressive primary CCRCC, metastatic CCRCC, and nonneoplastic kidney adjacent to tumor. Results: Aggressive primary and metastatic CCRCC displayed no significant differences in gene expression. In contrast, we identified significant differences in gene expression between nonaggressive and aggressive CCRCC (including metastatic CCRCC). Thirty-four of the 35 transcripts that displayed the most significant differential expression by microarray analysis also displayed significant differential expression in independent validation studies using quantitative RT-PCR (P < 0.001 for 31 candidates and P < 0.005 for the remaining three candidates). Hierarchical clustering of the quantitative RT-PCR data using our candidate markers accurately grouped 88% (23 of 26) of aggressive and metastatic CCRCC samples, 100% (14 of 14) of nonaggressive CCRCC samples, and 100% (15 of 15) of nonneoplastic samples into separate clusters. Finally, we evaluated the ability of protein expression levels of one of our candidate markers (survivin) to predict survival among a cohort of 183 CCRCC patients treated surgically at Mayo Clinic from 1990 to 1992. In multivariate analysis, expression of survivin (BIRC5) was inversely associated with cancer-specific survival (P = 0.017). Conclusion: We used a combination of genomic profiling and validation by quantitative PCR to identify a panel of candidate biomarkers for determining CCRCC aggressiveness. Our data also indicate that the gene expression alterations that result in aggressive behavior and metastatic potential can be identified in the primary tumor.

A p120 Catenin Isoform Switch Affects Rho Activity, Induces Tumor Cell Invasion, and Predicts Metastatic Disease

p120 catenin is a cadherin-associated protein that regulates Rho GTPases and promotes the invasiveness of E-cadherin-deficient cancer cells. Multiple p120 isoforms are expressed in cells via alternative splicing, and all of them are essential for HGF signaling to Rac1. However, only full-length p120 (isoform 1) promotes invasiveness. This selective ability of p120 isoform 1 is mediated by reduced RhoA activity, both under basal conditions and following HGF treatment. All p120 isoforms can bind RhoA in vitro, via a central RhoA binding site. However, only the cooperative binding of RhoA to the central p120 domain and to the alternatively spliced p120 N terminus stabilizes RhoA binding and inhibits RhoA activity. Consistent with this, increased expression of p120 isoform 1, when compared with other p120 isoforms, is predictive of renal tumor micrometastasis and systemic progression, following nephrectomy. Furthermore, ectopic expression of the RhoA-binding, N-terminal domain of p120 is sufficient to block the ability of p120 isoform 1 to inhibit RhoA and to promote invasiveness. The data indicate that the increased expression of p120 isoform 1 during tumor progression contributes to the invasive phenotype of cadherin-deficient carcinomas and that the N-terminal domain of p120 is a valid therapeutic target.

External validation of IMP3 expression as an independent prognostic marker for metastatic progression and death for patients with clear cell renal cell carcinoma

High‐quality external validation studies have recently been highlighted to be of paramount importance for proper translation of prognostic markers into the clinical setting. To that end, the authors examined associations of the insulin‐like growth factor‐II mRNA binding protein, IMP3, with clinical and pathologic features of clear cell renal cell carcinoma (ccRCC) in an independent cohort of patients to validate recent work showing IMP3 as a prognostic marker for RCC progression and death.

Development and evaluation of BioScore: a biomarker panel to enhance prognostic algorithms for clear cell renal cell carcinoma.

The authors previously showed that increased tumor expression levels of B7‐H1, survivin, and Ki‐67 are independent predictors of poor outcome for patients with clear cell renal cell carcinoma (ccRCC). In the current study, they described the creation of a scoring system based on this panel of biomarkers that can be used in tandem with existing clinicopathologic features and algorithms to improve ccRCC outcome prediction.

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

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.

Survivin and B7-H1 Are Collaborative Predictors of Survival and Represent Potential Therapeutic Targets for Patients with Renal Cell Carcinoma

Purpose: Clear cell renal cell carcinoma (ccRCC) is an immunogenic tumor that can progress in the presence of an intact host immune system. We previously reported that survivin and B7-H1 are independently associated with disease progression and death when expressed by ccRCC tumors. Herein, we examine the clinical effect of ccRCC combined expression of both survivin and B7-H1. Experimental Design: Specimens from 298 patients who underwent nephrectomy for ccRCC between 1990 and 1994 were immunohistochemically stained for survivin and B7-H1. Cancer-specific survival was estimated using the Kaplan-Meier method. Associations of both markers with ccRCC death were assessed using Cox proportional hazards regression models. Results: At last follow-up, 94 patients died from ccRCC. Among the living patients, the median follow-up was 11.2 years (range, 0-15 years). There were 177 (59.4%) survivinLow/B7-H1−, 51 (17.1%) survivinHi/B7-H1−, 29 (9.7%) survivinLow/B7-H1+, and 41 (13.8%) survivinHi/B7-H1+ tumors. The 5-year cancer-specific survival rates for patients within each group were 89.3%, 59.7%, 70.0%, and 16.2%, respectively. Combined survivinHi/B7-H1+ expression was associated with ccRCC death univariately (risk ratio, 12.82; 95% confidence interval, 7.50-21.92; P < 0.001) and in multivariate analysis (risk ratio, 2.81; 95% confidence interval, 1.56-5.04; P < 0.001). SurvivinHi/B7-H1+ tumors exhibited increased levels of infiltrating mononuclear cells and survivin-specific T cells compared with survivinLow/B7-H1− tumors. Conclusion: Patients with survivinHi/B7-H1+ ccRCC tumors are at increased risk of ccRCC death. SurvivinHi/B7-H1+ tumors also harbor increased amounts of infiltrating mononuclear cells and survivin-specific T cells relative to survivinLow/B7-H1− tumors. Taken together, dual expression of survivin and B7-H1 can be used to predict ccRCC tumor aggressiveness.

Loss of BAP1 Protein Expression Is an Independent Marker of Poor Prognosis in patients with Low Risk Clear Cell Renal Cell Carcinoma

The majority of patients diagnosed with clear cell renal cell carcinoma (ccRCC) have low‐risk disease with a < 10% chance of ccRCC‐specific death. DNA sequencing revealed that mutations in BAP1 (BRCA1 associated protein‐1) occur in 5% to 15% of ccRCC cases and are associated with poor outcomes. The vast majority of BAP1 mutations abolish protein expression. In this study, we used a highly sensitive and specific immunohistochemistry (IHC) assay to test whether BAP1 expression is an independent marker of ccRCC‐specific survival, particularly in patients with low‐risk disease.