Warburg phenotype in renal cell carcinoma: high expression of glucose-transporter 1 (GLUT-1) correlates with low CD8(+) T-cell infiltration in the tumor.

Many tumor cells are characterized by a dysregulated glucose metabolism associated with increased glycolysis in the presence of oxygen ("Warburg Effect"). Here, we analyzed for the first time a possible link between glucose metabolism and immune cell infiltration in renal cell carcinoma (RCC). RCC specimens revealed a highly significant increase in the expression of lactate dehydrogenase A (LDHA) and glucose-transporter 1 (GLUT-1) compared to the corresponding normal kidney tissue on mRNA level. Accordingly, tumor cell lines of different origin such as RCC, melanoma and hepatocellular carcinoma strongly expressed LDHA and GLUT-1 compared to their nonmalignant counterparts. In line with this finding, tumor cells secreted high amounts of lactate. High expression of GLUT-1 and LDH5, a tetramer of 4 LDHA subunits, was confirmed by tissue microarray analysis of 249 RCC specimens. Overall, 55/79 (69.6%) and 46/71 (64.7%) cases of clear cell carcinoma showed a constitutive, but heterogeneous expression of GLUT-1 and LDH5, respectively. The number of CD3(+), CD8(+) and FOXP3(+) T cells was significantly elevated in RCC lesions compared to normal kidney epithelium, but effector molecules such as granzyme B and perforin were decreased in tumor infiltrating T cells. Of interest, further analysis revealed an inverse correlation between GLUT-1 expression and the number of CD8(+) T cells in RCC lesions. Together, our data suggest that an accelerated glucose metabolism in RCC tissue is associated with a low infiltration of CD8(+) effector T cells. Targeting the glucose metabolism may represent an interesting tool to improve the efficacy of specific immunotherapeutic approaches in RCC.

Prognostic factors of papillary renal cell carcinoma: results from a multi-institutional series after pathological review.

PURPOSE: We examined papillary renal cell carcinoma prognostic variables and validated the 2002 UICC TNM staging system in a multicenter analysis. MATERIALS AND METHODS: From 10 urological institutions in Germany followup data were collected on a total of 675 patients with papillary renal cell carcinoma. Central pathological review was done to validate external histopathological diagnoses. The Kaplan-Meier method was used to derive cumulative cancer specific and overall survival, and the log rank test was used to compare the curves of 2 or more groups. For multivariate analysis of prognostic factors Cox regression analysis was done. All proportional hazard assumptions were systemically verified using the Grambsch-Therneau test. RESULTS: Cancer specific survival was significantly related to TNM stage and histological grading on univariate and multivariate analyses. Five-year cancer specific survival in pT1b cases was significantly shorter than in pT1a cases (90.0% vs 98.3%, p = 0.017). No significant difference was found between pT1b and pT2 tumors. Patients with pT3 or greater disease were at high risk for metastasis (50.6%) while metastatic disease associated with pT2 or less tumors occurred in 7.8% (p <0.0001). After metastatic disease was present the prognosis was poor with 7.2% 5-year cancer specific survival. Age was associated with poor prognosis in the subgroup with pT3 or greater tumors on univariate analysis (p = 0.026) but not on multivariate analysis. CONCLUSIONS: In its current form the 2002 UICC TNM staging system is not applicable to papillary renal cell carcinoma. Clinical and radiological followup should be offered at frequent intervals to patients with venous thrombus and/or locally advanced disease. The role of age remains unclear but should not be underestimated in risk stratification after surgery.

Pax-5 protein expression in bladder cancer: a preliminary study that shows no correlation to grade, stage or clinical outcome.

AIMS: Pax (paired box) genes comprise a gene family crucial for cell differentiation that encodes a set of transcription factors. Recently, Pax-5 mRNA expression was suggested as a prognostic marker in bladder cancer (BC). However, a functional role of Pax-5 in BC is questionable because the protein expression was not determined in these studies. Therefore, we evaluated Pax-5 protein expression in an unselected, consecutive series of BC. METHODS: We immunohistochemically investigated Pax-5 protein expression in 100 archival bladder tumours and 22 normal urothelial samples using tissue microarray (TMA) technology and a monoclonal antibody against Pax-5. Staining intensity and percentage of positively stained cells were determined and correlated to histopathological characteristics of the tumours and clinical follow-up data. RESULTS: All 22 samples of histopathologically normal urothelium were negative for Pax-5 protein expression. Overall, 70 of 100 tumours gave interpretable results. Only seven of 70 (10%) cases showed a positive nuclear Pax-5 staining but without significant correlation to clinicopathological characteristics. Interestingly, we could observe Pax-5 positive lymphocytes located within the tumour or closely adjacent in the underlying stroma in 24 of 70 (34%) cases in our series. CONCLUSIONS: Pax-5 protein expression is infrequent in BC. Absence of correlation to clinicopathological characteristics suggests a minor functional role of Pax-5 in BC. Pax-5 positive lymphocytes within reactive infiltrates adjacent to the tumour warrant further studies evaluating biological, immunological and clinical relevance.

Role of the STK15 Phe31Ile polymorphism in renal cell carcinoma.

The search of inherited cancer susceptibility factors is an important subject in cancer epidemiology. Analyses of single nucleotide polymorphisms (SNP) in various genes revealed a correlation between the presence of specific allelic variants and cancer predisposition in diverse malignancies. STK15 is an important protein in control of the integrity of the mitotic spindle apparatus and genomic stability. We analysed the distribution of the functionally important T91A SNP in the STK15 gene in a cohort of renal cell carcinoma (RCC) patients and compared it to the distribution in a control group without malignancies. DNA from formalin-fixed, paraffin-embedded healthy renal tissue (RCC patients) or peripheral blood samples (control group) was isolated according to standard protocols. Allelic variant of STK15 nucleotide 91 was determined using restriction fragment length polymorphism (RFLP) analysis. Overall, 156 RCC patients and 158 patients without any malignancy were analysed. The distribution of the STK15 SNP in RCC patients (T/T, 58.97%; A/T, 36.53%; A/A, 4.49%) did not significantly differ from that of the control group (T/T, 51.27%; A/T, 41.14%; A/A, 7.59%). There was also no correlation between genotype and tumour grade or stage or other histopathological characteristics of the tumours. This first analysis of the STK15 T91A SNP in RCC patients revealed no correlation between a certain allelic variant and an increased risk for RCC.

Elevated microsatellite alterations at selected tetranucleotides (EMAST) and mismatch repair gene expression in prostate cancer.

Elevated microsatellite alterations at selected tetranucleotides (EMAST), a new form of microsatellite instability (MSI) affecting tetranucleotide repeats, was recently described to be frequent in several tumor types (e.g., bladder, lung, ovarian, and skin cancers). EMAST was found as a form of microsatellite alteration distinct from the MSI phenotype in hereditary nonpolyposis colorectal cancer (HNPCC)-related tumors which mostly affects mono- and dinucleotide repeats. To date, no study has investigated the role of EMAST in prostate cancer. We therefore analyzed 81 prostate tumors using 10 markers frequently detecting EMAST in other cancer types and the National Cancer Institute-consensus panel for HNPCC detection plus BAT40. In addition, we investigated p53 gene alterations [loss of heterozygosity (LOH)] and the expression of p53 and the mismatch repair (MMR) genes hMLH1 and hMSH2 on tissue microarrays. EMAST was detected in 4/81 (5%) cases and MSI in 6/79 (7.6%) cases. LOH of p53 was found in 9/45 (20%) informative cases. There was no correlation between MSI status and the histopathological or molecular characteristics of the tumors. Immunohistochemistry revealed p53 positivity in 5/61 (8%) tumors. There was a significant correlation between tumors showing a recurrence within 3 years after treatment and p53 positivity (p=0.029). Reduced hMLH1 expression, but no complete loss, was detected in 9/41 (22%) tumors without any correlations to histopathological or clinical features. Analysis of hMSH2 expression was available from 58/81 (72%) tumors. Staining intensity was as follows: negative in 7/58 (12%), weak staining in 16/58 (27.5%) samples, moderate staining in 19/58 (33%) samples, and strong staining in 16/58 (27.5%) samples. When negative/weak staining and moderate/strong staining were considered as two groups, there was a significant association between hMSH2 expression and tumor recurrence (p=0.039). In conclusion, our data show that MSI and EMAST are infrequent but distinct patterns of MSI in prostate tumors not related to MMR defects, p53 alterations, and histopathological characteristics. p53 positivity and moderate to strong hMSH2 expression of prostate tumors are correlated with early disease recurrence and indicate an unfavorable clinical course of the disease. These two genes could be useful biomarkers for the prediction of patients' outcome and should be analyzed in prospective studies.