Yuri Tolkach

Comprehensive Evaluation of Prostate Specific Membrane Antigen Expression in the Vasculature of Renal Tumors: Implications for Imaging Studies and Prognostic Role

Purpose: Prostate specific membrane antigen is expressed by the endothelium of many tumors. The aim of the study was to find a rationale for prostate specific membrane antigen based imaging and investigate the prognostic role of vascular prostate specific membrane antigen expression in patients with renal cell carcinoma. Materials and Methods: A total of 257 patients with renal cell carcinoma were included in study with a median followup exceeding 10.0 years. Prostate specific membrane antigen expression on tumor vessels was detected by immunohistochemistry. Vascular expression of FOLH1 gene (prostate specific membrane antigen) mRNA was investigated in clear cell carcinoma and papillary renal cell carcinoma using TCGA (The Cancer Genome Atlas) data. Results: Endothelial prostate specific membrane antigen protein expression was higher in clear cell than in papillary and chromophobe renal cell carcinoma. Higher grade and stage, metastatic and lethal clear cell renal cell carcinoma showed higher prostate specific membrane antigen expression in tumor vessels. On univariate and multivariate analysis the intensity of positive vs negative endothelial prostate specific membrane antigen protein expression was significantly associated with overall survival. TCGA based analyses confirmed the prognostic role of vascular expression of FOLH1 mRNA. The analyses also supported the usefulness of prostate specific membrane antigen based imaging in cases of clear cell but not papillary renal cell carcinoma. Conclusions: We provide a rationale for further development of prostate specific membrane antigen targeted imaging in patients with clear cell renal cell carcinoma. The prognostic role of prostate specific membrane antigen was determined at the protein level in clear cell renal cell carcinoma and at the mRNA level in clear cell and papillary renal cell carcinoma.

5′-tRNA Halves are Dysregulated in Clear Cell Renal Cell Carcinoma

Purpose: In various malignancies RNA fragments are dysregulated. Our study was designed to determine the expression of 4, 5′‐tRNA halves in the tissue and serum of patients with clear cell renal cell carcinoma. Materials and Methods: Tissue and serum samples of patients with clear cell renal cell carcinoma and nonmalignant disease were collected prospectively in our biobank. We isolated total RNA from 95 clear cell renal cell carcinomas and 50 normal renal tissues as well as serum RNA from 27 patients with clear cell renal cell carcinoma and 13 with nonmalignant urological disease. To specifically determine the expression of 5′‐tRNA halves we dephosphorylated and ligated an adaptor nucleotide to the 3′ end of the tRNA halves. The expression levels of 4, 5′‐tRNA halves (5′‐tRNA‐Arg‐CCT, 5′‐tRNA‐Glu‐CTC, 5′‐tRNA‐Leu‐CAG and 5′‐tRNA‐Lys‐TTT) were then measured by TaqMan® based quantitative reverse transcription‐polymerase chain reaction. Results: All studied 5′‐tRNA halves were down‐regulated in clear cell renal cell carcinoma tissues, indicating a potential role as a tumor suppressor. Furthermore, we noted decreased expression of 5′‐tRNA halves in patients with adverse clinicopathological parameters. All 5′‐tRNA halves were expressed at lower levels in nonorgan confined clear cell renal cell carcinoma. The 5′‐tRNA‐Lys‐TTT halves inversely correlated with ISUP (International Society of Urological Pathology) grade. In patients with clear cell renal cell carcinoma 5′‐tRNA‐Arg‐CCT, 5′‐tRNA‐Glu‐CTC and 5′‐tRNA‐Lys‐TTT halves circulated at lower levels than in control subjects, indicating relevance as noninvasive biomarkers. Conclusions: In patients with clear cell renal cell carcinoma 5′‐tRNA halves have potential as diagnostic and prognostic biomarkers. The 5′‐tRNA halves may act in a tumor suppressive manner, which requires further research to confirm.

Systematic Expression Analysis of Mitochondrial Complex I Identifies NDUFS1 as a Biomarker in Clear-Cell Renal-Cell Carcinoma

Introduction Mitochondrial dysfunction is common in cancer, and the mitochondrial electron transport chain is often affected in carcinogenesis. So far, little is known about the expression of the mitochondrial complex I (NADH:ubiquinone oxidoreductase) subunits in clear‐cell renal‐cell carcinoma (ccRCC). Materials and Methods An expression profile of the mitochondrial complex I subunits was determined using the NextBio database. Subsequently, the expression of selected subunits was experimentally validated on mRNA (quantitative real‐time polymerase chain reaction) and protein (Western blot analysis, immunohistochemistry) level. Results We observed that 7 subunits of the complex I were down‐regulated in at least 3 microarray studies. Deregulated mRNA expression was confirmed for NDUFA3, NDUFA, NDUFB1, NDUFB9, NDUFS1, NDUFS8, and NDUFV1. Low NDUFS1 mRNA expression was a significant and independent adverse predictor of a shorter overall survival in our mRNA cohort and the ccRCC cohort of The Cancer Genome Atlas project. NDUFS1 expression was furthermore analyzed on the protein level, and a distinct down‐regulation was observed in ccRCC as well as in the chromophobe and the sarcomatoid subtype compared to normal renal tissue. Conclusion Expression alterations occur in only a few subunits of the mitochondrial complex I subunits in ccRCC, and altered mRNA and protein expression levels of NDUFS1 may be useful to distinguish between renal‐cell carcinoma and normal renal tissue. Micro‐Abstract Mitochondrial dysfunction is common in cancer. A meta‐analysis of published microarray gene expression studies led to the identification of 7 (of 44) down‐regulated subunits of the mitochondrial complex I in clear‐cell renal‐cell carcinoma. NDUFS1 mRNA and protein expression levels were validated and may serve as diagnostic biomarkers. Altered activity of the electron transport chain is related to altered expression of specific subunits.

Sensitivity of HOXB13 as a Diagnostic Immunohistochemical Marker of Prostatic Origin in Prostate Cancer Metastases: Comparison to PSA, Prostein, Androgen Receptor, ERG, NKX3.1, PSAP, and PSMA

Aims: Determining the origin of metastases is an important task of pathologists to allow for the initiation of a tumor-specific therapy. Recently, homeobox protein Hox-B13 (HOXB13) has been suggested as a new marker for the detection of prostatic origin. The aim of this study was to evaluate the diagnostic sensitivity of HOXB13 in comparison to commonly used immunohistochemical markers for prostate cancer. Materials and methods: Histologically confirmed prostate cancer lymph node metastases from 64 cases were used to test the diagnostic value of immunohistochemical markers: prostate specific antigen (PSA), Prostatic acid phosphatase (PSAP), prostate specific membrane antigen (PSMA), homeobox gene NKX3.1, prostein, androgen receptor (AR), HOXB13, and ETS-related gene (ERG). All markers were evaluated semi-quantitatively using Remmele’s immune reactive score. Results: The detection rate of prostate origin of metastasis for single markers was 100% for NKX3.1, 98.1% for AR, 84.3% for PSMA, 80.8% for PSA, 66% for PSAP, 60.4% for HOXB13, 59.6% for prostein, and 50.0% for ERG. Conclusions: Our data suggest that HOXB13 on its own lacks sensitivity for the detection of prostatic origin. Therefore, this marker should be only used in conjunction with other markers, preferably the highly specific PSA. The combination of PSA with NKX3.1 shows a higher sensitivity and thus appears preferable in this setting.

The Heterogeneity of Prostate Cancer: A Practical Approach

Prostate cancer is a paradigm tumor model for heterogeneity in almost every sense. Its clinical, spatial, and morphological heterogeneity divided by the high-level molecular genetic diversity outline the complexity of this disease in the clinical and research settings. In this review, we summarize the main aspects of prostate cancer heterogeneity at different levels, with special attention given to the spatial heterogeneity within the prostate, and to the standard morphological heterogeneity, with respect to tumor grading and modern classifications. We also cover the complex issue of molecular genetic heterogeneity, discussing it in the context of the current evidence of the genetic characterization of prostate carcinoma; the interpatient, intertumoral (multifocal disease), and intratumoral heterogeneity; tumor clonality; and metastatic disease. Clinical and research implications are summarized and serve to address the most pertinent problems stemming from the extreme heterogeneity of prostate cancer.

Systematic expression analysis of the mitochondrial complex III subunits identifies UQCRC1 as biomarker in clear cell renal cell carcinoma.

Mitochondrial dysfunction is common in cancer, and the mitochondrial electron transport chain is often affected in carcinogenesis. So far, few is known about the expression of the mitochondrial complex III (ubiquinol-cytochrome c reductase complex) subunits in clear cell renal cell carcinoma (ccRCC). In this study, the NextBio database was used to determine an expression profile of the mitochondrial complex III subunits based on published microarray studies. We observed that five out of 11 subunits of the complex III were downregulated in at least three microarray studies. The decreased mRNA expression level of UQCRFS1 and UQCRC1 in ccRCC was confirmed using PCR. Low mRNA levels UQCRC1 were also correlated with a shorter period of cancer-specific and overall survival. Furthermore, UQCRFS1 and UQCRC1 were also decreased in ccRCC on the protein level as determined using Western blotting and immunohistochemistry. UQCRC1 protein expression was also lower in ccRCC than in papillary and chromophobe subtypes. Analyzing gene expression and DNA methylation in The Cancer Genome Atlas cohort revealed an inverse correlation of gene expression and DNA methylation, suggesting that DNA hypermethylation is regulating the expression of UQCRC1 and UQCRFS1. Taken together, our data implicate that dysregulated UQCRC1 and UQCRFS1 are involved in impaired mitochondrial electron transport chain function.

Three‐dimensional reconstruction of prostate cancer architecture with serial immunohistochemical sections: hallmarks of tumour growth, tumour compartmentalisation, and implications for grading and heterogeneity

Conventional morphology of prostate cancer considers only the two‐dimensional (2D) architecture of the tumour. Our aim was to examine the feasibility of three‐dimensional (3D) reconstruction of tumour morphology based on multiple consecutive histological sections and to decipher relevant features of prostate cancer architecture.

Adipophilin as prognostic biomarker in clear cell renal cell carcinoma

Objective To study the expression of adipophilin (PLIN2), a lipid storage-associated cell protein, in different subtypes of renal cell cancer and to elucidate its prognostic value. Materials and Methods Two-hundred-seventy-five patients with renal cell carcinoma (RCC) were included in this study. Immunohistochemistry with a polyclonal antibody to adipophilin was used on the tissue microarray (formalin-fixed, paraffin-embedded tissue) for detection of adipophilin. Median follow-up time was 91 (range 1-159) months in the whole cohort and 100 (1-159) months for patients with clear-cell RCC. Additional validation for adipophilin was performed using publicly available gene expression data for clear cell RCC from The Cancer Genome Atlas (TCGA). Results Adipophilin expression was detected in 14.3% of papillary RCC, in 0% of chromophobe RCC and in 58.7% of clear-cell RCC in the cytoplasm or at the membrane. Only membrane expression was correlated with other clinical parameters (pT-stage, pN-stage, R-status, sex) and showed a prognostic significance in univariate analysis with regard to overall survival of patients with clear cell subtype (HR 2.90, 95% CI 1.55-5.42, p=0.001), which failed significance on multivariate analysis. mRNA expression of PLIN2 on TCGA data using best selected cut-off was prognostically significant in both univariate (HR 1.76, 95% CI 1.28-2.42, p = 0.0005) and multivariate analyses (HR 1.46, 95% CI 1.05-2.04, p = 0.0257). Conclusions Adipophilin is a novel and still understudied prognostic biomarker in clear cell renal cell carcinoma which deserves further study.

Is high-grade prostatic intraepithelial neoplasia (HGPIN) a reliable precursor for prostate carcinoma? Implications for clonal evolution and early detection strategies: HGPIN: a precursor of prostate cancer?

High‐grade prostatic intraepithelial neoplasia (HGPIN) is a documented putative precursor lesion for invasive prostate adenocarcinoma. However, the precise mechanisms of the carcinomas development from HGPIN are unclear. Many studies have attempted a comparative molecular genetic characterisation of HGPIN and its corresponding carcinoma to study this transformation. However, to date, some HGPIN mimickers, such as intraductal carcinoma, which can engage in retrograde colonisation of the prostatic acini in an HGPIN‐like manner, have been described. In this work, we hypothesise that the lesion formerly known as HGPIN adjacent to invasive carcinoma does not necessarily represent its respective precursor lesion. This hypothesis stems from recent morphological, experimental, and theoretical evidence on the development of tumour clonality, as well as recent studies outlining the three‐dimensional architecture of prostate adenocarcinomas (most importantly, their interconnection with the tumoural glandular system). Copyright

Die Heterogenität des Prostatakrebses: Ein praxisorientierter Ansatz

Prostatakrebs ist in nahezu jeder Hinsicht ein beispielhaftes Tumormodell für Heterogenität. Seine klinische, räumliche und morphologische Heterogenität, dividiert durch die hochgradige molekular-genetische Diversität, umreißt die Komplexität dieses Krankheitsbildes im Klinik- und Forschungsumfeld. In dem vorliegenden Review fassen wir die Hauptaspekte der Heterogenität des Prostatakrebses auf verschiedenen Ebenen zusammen, unter besonderer Berücksichtigung der räumlichen Heterogenität innerhalb der Prostata sowie der morphologischen Standardheterogenität in Bezug auf Tumor-Grading und moderne Klassifikationen. Wir befassen uns auch mit der komplexen Frage der molekulargenetischen Heterogenität und diskutieren sie im Zusammenhang mit den aktuellen Erkenntnissen zur genetischen Charakterisierung von Prostatakarzinomen, mit der Heterogenität zwischen Patienten und Tumoren (multifokale Erkrankung) sowie der Heterogenität innerhalb eines Tumors, mit der Tumorklonalität und mit der Metastasierung. Die möglichen Konsequenzen für Klinik und Forschung werden zusammengefasst und dazu verwendet, die relevantesten Probleme zu diskutieren, die sich aus der extremen Heterogenität des Prostatakrebses ergeben. Übersetzung aus Tolkach Y, Kristiansen G: Pathobiology 2018;85:108-116.