Metabolite profiling of human renal cell carcinoma reveals tissue-origin dominance in nutrient availability.

The tumor microenvironment is a determinant of cancer progression and therapeutic efficacy, with nutrient availability playing an important role. Although it is established that the local abundance of specific nutrients defines the metabolic parameters for tumor growth, the factors guiding nutrient availability in tumor compared to normal tissue and blood remain poorly understood. To define these factors in renal cell carcinoma (RCC), we performed quantitative metabolomic and comprehensive lipidomic analyses of tumor interstitial fluid (TIF), adjacent normal kidney interstitial fluid (KIF), and plasma samples collected from patients. TIF nutrient composition closely resembles KIF, suggesting that tissue-specific factors unrelated to the presence of cancer exert a stronger influence on nutrient levels than tumor-driven alterations. Notably, select metabolite changes consistent with known features of RCC metabolism are found in RCC TIF, while glucose levels in TIF are not depleted to levels that are lower than those found in KIF. These findings inform tissue nutrient dynamics in RCC, highlighting a dominant role of non-cancer-driven tissue factors in shaping nutrient availability in these tumors.

Cancer cells convert nutrients into energy differently compared to healthy cells. This difference in metabolism allows them to grow and divide more quickly and sometimes to migrate to different areas of the body. The environment around cancer cells ­ known as the tumor microenvironment ­ contains a variety of different cells and blood vessels, which are bathed in interstitial fluid. This microenvironment provides nutrients for the cancer cells to metabolize, and therefore influences how well a tumor grows and how it might respond to treatment. Recent advances with techniques such as mass spectrometry, which can measure the chemical composition of a substance, have allowed scientists to measure nutrient levels in the tumor microenvironments of mice. However, it has been more difficult to conduct such studies in humans, as well as to compare the tumor microenvironment to the healthy tissue the tumors arose from. Abbott, Ali, Reinfeld et al. aimed to fill this gap in knowledge by using mass spectrometry to measure the nutrient levels in the tumor microenvironment of 55 patients undergoing surgery to remove kidney tumors. Comparing the type and levels of nutrients in the tumor interstitial fluid, the neighboring healthy kidney and the blood showed that nutrients in the tumor and healthy kidney were more similar to each other than those in the blood. For example, both the tumor and healthy kidney interstitial fluids contained less glucose than the blood. However, the difference between nutrient composition in the tumor and healthy kidney interstitial fluids was insignificant, suggesting that the healthy kidney and its tumor share a similar environment. Taken together, the findings indicate that kidney cancer cells must adapt to the nutrients available in the kidney, rather than changing what nutrients are available in the tissue. Future studies will be required to investigate whether this finding also applies to other types of cancer. A better understanding of how cancer cells adapt to their environments may aid the development of drugs that aim to disrupt the metabolism of tumors.

Prognostic significance of Klotho expression in patients with renal cell carcinoma.

INTRODUCTION: Various molecular markers have been investigated in renal cell carcinoma (RCC) without significant reliability. We analyzed Klotho (tumor suppressive protein) expression in RCC to investigate its association with tumor-stage, grade, disease-free-survival (DFS) and overall-survival (OS). METHODS: Data of histologically confirmed patients of RCC with complete clinical follow-up were retrieved from Medical-Record-Library. Tissue sections of tumor and normal parenchyma were prepared from the blocks. Immunohistochemical studies for Klotho were done with commercially available kit (EPR6856, Ab181373; Abcam, Cambridge MA, USA). Klotho expression was scored between 0-3 and grouped into weak/absent (0, 1) and moderate/strong (2, 3). Tumors stages and grades were grouped into low stage (I and II) and high stage (III and IV) and into low grade (grade 1 and 2) and high grade (grade 3 and 4) according to WHO/ISUP grading. The histopathologists were blinded as to the clinical and follow-up data. Various prognostic factors were analyzed with respect to Klotho expression. Kaplan-Meier curves were created for DFS and OS. RESULTS: Fifty-four patients of mean age 55.15 ± 13.34 years and M:F ratio of 1.8:1 were included. Normal renal tissue had strong expression of Klotho in all. In tumor tissue 20 (37%) had negative, 7 (13%) had weak, 14 (25.9%) had moderate and 13 (24.1%) had strong Klotho expression. Significantly more patients had absent/weak Klotho expression with higher grade (16/24 (66.7%) vs 7/25 (28%); p = 0.007), higher stage (22/33 (66%) vs 5/21 (23.8%); p = 0.002), LVI (12/14 (85.7%) vs 2/14 (14.3%); p = 0.002), sinus-fat-invasion (16/21 (76.2%) vs 5/21 (23.8%); p = 0.002), renal-vein-involvement (14/18 (77.8%) vs 4/18 (22.2%); p = 0.004), necrosis (17/26 (65.3%) vs 9/26 (34.6%); p = 0.029) and metastasis (8/9 (88.9%) vs 1/9 (11.1%); p = 0.01). Median DFS and OS were significantly lower in patients with weak/absent Klotho expression (12 vs 23 months, p = 0.023 and 15 vs 33 months, p = 0.006 respectively). Kaplan-Meier curves showed lower estimated DFS and OS in patients with weak/absent expression. CONCLUSIONS: We conclude that Klotho expression in renal tumor could be a good prognostic marker in patients with RCC.

Clinicopathologic and Molecular Characterization of Xanthomatous Giant Cell Renal Cell Carcinomas: Further Support for a Close Morphologic Spectrum to Eosinophilic Solid and Cystic Renal Cell Carcinomas.

A recent study described a rare subtype of tuberous sclerosis complex ( TSC )-mutated renal cell carcinoma primarily characterized by Xanthomatous giant cell morphology. Only 2 cases in young individuals have been reported so far, making the correct diagnosis challenging from a pathological perspective. It remains unknown whether this tumor represents an independent subtype or belongs to other TSC -mutated tumors. We conducted a clinicopathologic evaluation and immunohistochemical profiling of 5 cases of Xanthomatous Giant Cell Renal Cell Carcinoma (XGC RCC) with confirmed TSC2 mutations through targeted DNA sequencing. In addition, we analyzed transcriptomic profiles using RNA-seq for the following samples: XGC RCC, Low-grade Oncocytic tumors (LOT), High-grade Oncocytic tumors/Eosinophilic Vacuolar Tumors (HOT/EVT), Eosinophilic Solid and Cystic Renal Cell Carcinomas (ESC RCC), Chromophobe cell Renal Cell Carcinomas (ChRCC), Renal Oncocytomas (RO), clear cell Renal Cell Carcinomas (ccRCC), and normal renal tissues. There were 2 female and 3 male patients, aged 22 to 58 years, who underwent radical nephrectomy for tumor removal. The tumor sizes ranged from 4.7 to 9.5 cm in diameter. These tumors exhibited ill-defined boundaries, showed an expansive growth pattern, and featured distinctive tumor giant cells with abundant eosinophilic to Xanthomatous cytoplasm and prominent nucleoli. All tumors had low Ki-67 proliferation indices (<1%) and demonstrated immune reactivity for CD10, PAX8, CK20, CathepsinK, and GPNMB. Next-generation sequencing confirmed TSC2 mutations in all cases. RNA sequencing-based clustering indicated a close similarity between the tumor and ESC RCC. One patient (1/5) died of an accident 63 months later, while the remaining patients (4/5) were alive without tumor recurrences or metastases at the time of analysis, with a mean follow-up duration of 43.4 months. Our research supports the concept that Xanthomatous giant cell renal cell carcinoma (XGC RCC) shares clinicopathological and molecular characteristics with ESC RCC and shows a relatively positive prognosis, providing further support for a close morphologic spectrum between the two. We propose considering XGC RCC as a distinct subtype of ESC RCC.

L1 Cell Adhesion Molecule (L1CAM) Expression and Molecular Alterations Distinguish Low-Grade Oncocytic Tumor From Eosinophilic Chromophobe Renal Cell Carcinoma.

Renal low-grade oncocytic tumor (LOT) is a recently recognized renal cell neoplasm designated within the "other oncocytic tumors" category in the 2022 World Health Organization classification system. Although the clinicopathologic, immunohistochemical, and molecular features reported for LOT have been largely consistent, the data are relatively limited. The morphologic overlap between LOT and other low-grade oncocytic neoplasms, particularly eosinophilic chromophobe renal cell carcinoma (E-chRCC), remains a controversial area in renal tumor classification. To address this uncertainty, we characterized and compared large cohorts of LOT (n = 67) and E-chRCC (n = 69) and revealed notable differences between the 2 entities. Clinically, LOT predominantly affected women, whereas E-chRCC showed a male predilection. Histologically, although almost all LOTs were dominated by a small-nested pattern, E-chRCC mainly showed solid and tubular architectures. Molecular analysis revealed that 87% of LOT cases harbored mutations in the tuberous sclerosis complex (TSC)-mTOR complex 1 (mTORC1) pathway, most frequently in MTOR and RHEB genes; a subset of LOT cases had chromosomal 7 and 19q gains. In contrast, E-chRCC lacked mTORC1 mutations, and 60% of cases displayed chromosomal losses characteristic of chRCC. We also explored the cell of origin for LOT and identified L1 cell adhesion molecule (L1CAM), a collecting duct and connecting tubule principal cell marker, as a highly sensitive and specific ancillary test for differentiating LOT from E-chRCC. This distinctive L1CAM immunohistochemical labeling suggests the principal cells as the cell of origin for LOT, unlike the intercalated cell origin of E-chRCC and oncocytoma. The ultrastructural analysis of LOT showed normal-appearing mitochondria and intracytoplasmic lumina with microvilli, different from what has been described for chRCC. Our study further supports LOT as a unique entity with a benign clinical course. Based on the likely cell of origin and its clinicopathologic characteristics, we propose that changing the nomenclature of LOT to "Oncocytic Principal Cell Adenoma of the Kidney" may be a better way to define and describe this entity.

Immunohistochemical expression of cytochrome P4A11 (CYP4A11), carbonic anhydrase 9 (CAIX) and Ki67 in renal cell carcinoma; diagnostic relevance and relations to clinicopathological parameters.

BACKGROUND: Cytochrome P4A11 (CYP4A11) is a member of cytochrome p450 family, which is involved in arachidonic acid metabolism that participates in promoting malignant cell proliferation, progression, and angiogenetic capacity. Carbonic Anhydrase 9 (CAIX) is a transmembrane protein that plays an integral part in regulating hypoxia which affects cancer cell metabolism, proliferation and promotes metastasis. The aim of this study was to evaluate the immunohistochemical expression of CYP4A11, CAIX and ki67 in RCC subtypes in relation to clinicopathological parameters and to evaluate the diagnostic significance of CYP4A11 and CAIX in differentiating renal cell carcinoma (RCC) subtypes. MATERIALS AND METHODS: one hundred primary RCC cases, collected from Pathology Department, Faculty of Medicine, Tanta University and from private laboratories, were evaluated for immunohistochemical expression of CYP4A11, CAIX and ki67. RESULTS: CYP4A11 was expressed in 59% of RCC; with 91.7% sensitivity and 90% specificity in differentiating clear cell and non-clear cell subtypes. CAIX was expressed in 50% of RCC; with 95% sensitivity, 80% specificity. High expression of CYP4A11 was statistically positively associated with higher tumor grade, high expression of CAIX was statistically positively associated with lower tumor grade and absence of necrosis and high ki67 labeling index was significantly associated with clear cell subtype, larger tumor sizes, higher tumor grade, advanced tumor stage, fat invasion and vascular invasion. CONCLUSIONS: CYP4A11 and CAIX can be used as diagnostic markers to differentiate clear cell RCC from other subtypes. CYP4A11 is more diagnostically accurate and specific than CAIX. High expression of CYP4A11, low CAIX expression and high ki67 labeling index were related to features of aggressive tumor behavior.

Reclassifying Papillary, Oncocytic and Chromophobe Renal Tumours Based on the 5 < sup > th < /sup > Who Classification 2022.

OBJECTIVE: The classification of renal tumors is expanding with the addition of new molecular entities in the 5th World Health Organization classification. Apart from this, the major updates in the definition of papillary renal cell carcinoma are that these tumors are no longer subtyped into type 1 and type 2. In oncocytic tumors, the new molecularly defined renal tumors, emerging and novel entities need to be considered in the diagnosis of oncocytic and chromophobe renal tumors. MATERIAL AND METHODS: This is a retrospective study to review and reclassify papillary, oncocytic, and chromophobe renal tumors based on the new WHO classification and correlate with clinical data, gross, microscopic features, and immunohistochemistry markers. RESULTS: A total of thirteen cases were reviewed and the tumor grade was changed for three out of four cases of papillary renal cell carcinoma and a single case was recategorized and graded. In nine cases of oncocytic and chromophobe renal tumors, the diagnoses were modified in 3 cases. CONCLUSION: Newly defined molecular renal tumors require advanced immunohistochemistry markers and molecular tests. This poses diagnostic challenges to pathologists practicing in low resource settings where molecular tests are not available.

Alpha adrenergic receptors in renal pelvis and calyces: can rat models be used?

We aimed, in this study, to determine the distribution of α-1 AR subtypes in rat and human pelvis and calyces, and to evaluate, by comparing these two species, the possibility of rats to be used as models for humans. Twenty patients with renal carcinoma were included into the study. The patients underwent radical nephrectomy for renal cell carcinoma (RCC). After nephrectomy, specimens were evaluated and excisional biopsies from healthy pelvis and calyces tissues were performed. When pathology confirmed the non-invasion of RCC, specimen was included into the study. A total of 7 adult Wistar Albino (250-300 g) female rats were used in this study. Specimens included renal pelvis and calyces. All specimens were evaluated under light microscope histopathologically. The concentrations of the receptor densities did not differ between the two groups. With the demonstration of the α receptors in rat kidneys and calyces, many receptor-based studies concerning both humans and rats can take place. Novel medication targeting these subtypes -in this matter α1A and α1D for renal pelvis and calyces- may be helpful for expulsive therapy and/or pain relief. With the demonstration of similar receptor densities between human and rat tissues, rat model may be useful for α-receptor trials for renal pelvis and calyces.

Differencial proteome of clear-cell renal cell carcinoma (ccRCC) tissues

Purpose We attempted to detect, for the first time in a Brazilian cohort, differences in protein expression between clear-cell renal cell carcinoma (ccRCC) and their normal adjacent tissues, aiming to identify biomarkers and/or therapeutic target candidates for this disease. Material and Methods Twenty-four ccRCC and adjacent normal tissues were collected after surgery and their protein extracts were quantified, pooled and separated by two-dimensional polyacrylamide gel electrophoresis (2DE), followed by statistical analysis of the stained gels. Spots of interest were excised from the gels, digested with trypsin and identified by MALDI-TOF-TOF mass spectrometry. Results Twenty-six differential spots were detected between the two classes of tissues, among which twenty were identified by mass spectrometry and sixteen were found to be non-redundant. Eleven proteins were either underexpressed or undetected in the ccRCC extracts, such as prohibitin and peroxiredoxin-3, whereas five were found to be overexpressed or exclusively detected in the ccRCC extract, including αβ crystalin and heat shock protein 27. CONCLUSIONS Several proteins were detected at differential levels when compared to normal adjacent tissues, and, moreover, many have been previously described by their relationship with RCC. Therefore, this work corroborates previous reports on the search for biomarkers for ccRCC, as well as it points out new candidates that may be validated in future studies. .

Immunohistochemical expression of CD44s in renal cell carcinoma lacks independent prognostic significance

PURPOSE: To analyze the immunohistochemical expression of the standard isoform of CD44 (CD44s) adhesion molecule in clear cell renal cell carcinoma (CCRCC) and its impact on clinical outcomes. MATERIALS AND METHODS: Ninety-nine consecutive patients treated surgically for RCC between 1992 and 2009 were selected. A single pathologist reviewed all cases to effect a uniform reclassification and determine the most representative tumor areas for construction of a tissue microarray. The same pathologist, who was blinded to the outcome of the cases, semi-quantitatively scored the staining intensity of CD44s in all specimens. The counting was done using the H-Score algorithm. RESULTS: Of the 99 immunostained RCC specimens, 57(57.7%) showed low expression, and 42(42.4%) showed high expression levels of CD44s. The expression of CD44s was directly associated with tumor size (p = 0.03), clinical stage (p = 0.02) and Fuhrman grade (p = 0.02). Disease specific survival (DSS) rates for patients whose specimens expressed low and high levels of CD44s was 88.1% and 67.5%, respectively (p = 0.009). Progression free survival (PFS) rates in patients with low and high expression of CD44s were 78.8% and 61.7%, respectively (p = 0.05). Classical features such as the presence of metastasis and clinical stage remained isolated predictors of survival. CONCLUSIONS: Immunohistochemical expression of CD44s was associated with important clinical variables such as stage and Fuhrman grade. However, it was not an independent predictor of survival. Therefore, we believe it has a limited role as a prognostic marker in patients with CCRCC.