Sporadic Clear Cell Research Articles

The Clinical and Molecular Features in the VHL Renal Cancers; Close or Distant Relatives with Sporadic Clear Cell Renal Cell Carcinoma?

Von Hippel-Lindau (VHL) disease is an autosomal dominant inherited cancer syndrome caused by germline mutations in the VHL tumor suppressor gene, characterized by the susceptibility to a wide array of benign and malign neoplasms, including clear-cell renal cell carcinoma. Moreover, VHL somatic inactivation is a crucial molecular event also in sporadic ccRCCs tumorigenesis. While systemic biomarkers in the VHL syndrome do not currently play a role in clinical practice, a new promising class of predictive biomarkers, microRNAs, has been increasingly studied. Lots of pan-genomic studies have deeply investigated the possible biological role of microRNAs in the development and progression of sporadic ccRCC; however, few studies have investigated the miRNA profile in VHL patients. Our review summarize all the new insights related to clinical and molecular features in VHL renal cancers, with a particular focus on the overlap with sporadic ccRCC.

The combination of medullary thyroid carcinoma and sporadic clear cell renal cell carcinoma: coincidence or new syndrome?

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Clear Cell Adenocarcinoma In Situ as a Potential Precursor Lesion for Sporadic Invasive Endocervical Clear Cell Adenocarcinoma.

Clear Cell Adenocarcinoma In Situ as a Potential Precursor Lesion for Sporadic Invasive Endocervical Clear Cell Adenocarcinoma.

Deubiquitylase OTUD6B stabilizes the mutated pVHL and suppresses cell migration in clear cell renal cell carcinoma

Von Hippel-Lindau (VHL) is an important tumor suppressor, and its inactivation is a hallmark of inherited VHL disease and most sporadic clear cell renal cell carcinoma (ccRCC). VHL protein (pVHL) with missense point mutations are unstable and degraded by the proteasome because of the disruption of elongin binding. Deubiquitylase ovarian tumor domain-containing 6B (OTUD6B) had been documented to couple pVHL and elongin B to form stable VHL - elonginB - elonginC complex, which protects pVHL from degradation. However, whether OTUD6B governs the stability of pVHL wild type and the missense mutants in ccRCC remains largely elusive. Here, we reported that low OTUD6B level predicted poorer survival in ccRCC patients with VHL missense mutation, but not frameshift deletion and nonsense mutation. OTUD6B is able to interact with wild type pVHL and tumor-derived pVHL missense mutants, except for pVHL I151T, and decrease their ubiquitylation and proteasomal degradation in ccRCC cells. Functionally, we revealed that OTUD6B depletion enhanced cell migration and HIF-2α level in ccRCC cells in a pVHL dependent manner. In addition, OTUD6B depletion reduced the inhibitory effects of ectopic pVHL missense mutants on cell migration and HIF-2α level, except for pVHL I151T. Thus, we speculated that I151 residue might be one of key sites of pVHL binding to OTUD6B. These results suggested that OTUD6B is an important regulator for the stability of pVHL missense mutants, which provides a potential therapeutic strategy for ccRCC with VHL mutations.

Natural history of Von Hippel-Lindau disease-associated and sporadic clear cell renal cell carcinoma: a comparative study.

To compare the tumor growth kinetics between sporadic clear cell renal cell carcinoma (ccRCC) and Von Hippel-Lindau disease-associated renal cell carcinoma (VHL-associated RCC). To analyze predictive markers for the growth rate of these two types of RCC. The clinical data of patients with renal tumors who received active surveillance were collected retrospectively. Immunohistochemical staining was utilized to analyze the expression levels of VHL, PBRM1, H3K36me3, and BAP1 in the postoperative specimens. The age of the VHL group was significantly younger than that of the sporadic group (P < 0.0001). The mean linear growth rate (LGR) was significantly faster in the sporadic group (P = 0.0004). The tumors of those in the sporadic group tended to have a higher histologic grade (P = 0.0011). In the sporadic group, tumor histologic grade was an independent predictor for rapid mean LGR (P = 0.0022). In the VHL group, initial maximal tumor diameter (MTD) was the only independent predictor for rapid mean LGR (P < 0.0001). Tumors with low VHL expression and negative PBRM1 expression showed a faster growth rate in the sporadic group (P = 0.001 and P = 0.008, respectively). The expression levels of the four biomarkers showed no impact on the tumor growth rate in the VHL group. Sporadic ccRCC grew faster than VHL-associated RCC. High histologic grade, low VHL expression and negative PBRM1 expression were predictors of faster growth in sporadic ccRCC. A large initial MTD was a predictor of faster growth for VHL-associated RCC.

VHL suppresses RAPTOR and inhibits mTORC1 signaling in clear cell renal cell carcinoma

Inactivation of the tumor suppressor von Hippel–Lindau (VHL) gene is a key event in hereditary and sporadic clear cell renal cell carcinomas (ccRCC). The mechanistic target of rapamycin (mTOR) signaling pathway is a fundamental regulator of cell growth and proliferation, and hyperactivation of mTOR signaling is a common finding in VHL-dependent ccRCC. Deregulation of mTOR signaling correlates with tumor progression and poor outcome in patients with ccRCC. Here, we report that the regulatory-associated protein of mTOR (RAPTOR) is strikingly repressed by VHL. VHL interacts with RAPTOR and increases RAPTOR degradation by ubiquitination, thereby inhibiting mTORC1 signaling. Consistent with hyperactivation of mTORC1 signaling in VHL-deficient ccRCC, we observed that loss of vhl-1 function in C. elegans increased mTORC1 activity, supporting an evolutionary conserved mechanism. Our work reveals important new mechanistic insight into deregulation of mTORC1 signaling in ccRCC and links VHL directly to the control of RAPTOR/mTORC1. This may represent a novel mechanism whereby loss of VHL affects organ integrity and tumor behavior.

Natural history and growth kinetics of clear cell renal cell carcinoma in sporadic and von Hippel-Lindau disease.

BackgroundTo evaluate and compare the natural history and growth kinetics of sporadic clear cell renal cell carcinoma (ccRCC) with those of ccRCC in von Hippel-Lindau disease (VHL).MethodsSixty patients in the sporadic group with 61 tumors and 15 patients in the VHL group with 30 tumors whom all underwent delayed surgery after at least 12 months of active surveillance (AS) were enrolled to conduct a retrospective cohort study. The growth rate was calculated, and the growth kinetics between the sporadic and VHL groups were compared. The patient and tumor characteristics were reviewed, and their correlation with growth rate was analyzed.ResultsThe mean growth rate of sporadic ccRCC was 0.91 cm/year (ranging from 0–4.74 cm/year) and that of VHL ccRCC was 0.47 cm/year (ranging from 0.04–1.89 cm/year). The growth rate of sporadic ccRCC showed a tendency of being faster than that of VHL ccRCC but did not reach statistical significance (P=0.07). The factors affecting the growth rate were different between the two groups. For VHL ccRCC, the only factor that correlated with growth rate was initial tumor diameter (P<0.001), but for sporadic ccRCC, the only factor was pathological nuclear grade (P<0.001).ConclusionsThe growth rate of VHL-associated ccRCC might be slower than that of sporadic ccRCC. Furthermore, we identified a disparity in growth kinetics between sporadic and VHL-associated ccRCC.

Genomic Analysis Reveals Novel Specific Metastatic Mutations in Chinese Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) accounts for more than 75% of renal cell carcinoma. Nearly 25% of ccRCC patients were diagnosed with metastasis. Though the genomic profile of ccRCC has been widely studied, the difference between localized and metastatic ccRCC was not clarified. Primary tumor samples and matched whole blood were collected from 106 sporadic patients diagnosed with renal clear cell carcinoma at Qilu Hospital of Shandong University from January 2017 to November 2019, and 17 of them were diagnosed with metastasis. A hybridization capture-based next-generation sequencing of 618 cancer-related genes was performed to investigate the somatic and germline variants, tumor mutation burden (TMB), and microsatellite instability (MSI). Five genes with significantly different prevalence were identified in the metastatic group, especially TOP1 (17.65% vs. 0%) and SNCAIP (17.65% vs. 0%). The altered frequency of PBRM1 (0% vs. 27%) and BAP1 (24% vs. 10%) differed between the metastatic and nonmetastatic groups, which may relate to the prognosis. Of these 106 patients, 42 patients (39.62%) had at least one alteration in DNA damage repair (DDR) genes, including 58.82% of metastatic ccRCC patients and 35.96% of ccRCC patients without metastasis. Ten pathogenic or likely pathogenic (P/LP) variants were identified in 11 sporadic clear cell renal cell carcinoma patients (10.38%), including rarely reported ATM (n=1), MUTYH (n=1), NBN (n=1), RAD51D (n=1), and BRCA2 (n=1). No significant difference in the ratio of P/LP variant carriers or TMB was identified between the metastatic and nonmetastatic groups. We found a unique genomic feature of Chinese metastatic ccRCC patients with a higher prevalence of alterations in DDR, TOP1, and SNCAIP. Further investigated studies and drug development are needed in the future.

Birt-Hogg-Dubé syndrome-associated renal cell carcinoma: Histopathological features and diagnostic conundrum.

Birt‐Hogg‐Dubé (BHD) syndrome is associated with the development of hereditary renal cell carcinoma (RCC) and is caused by a germline mutation in the folliculin gene. Most cases of BHD syndrome‐associated RCC (BHD‐RCC) are less aggressive than sporadic clear cell RCC and multifocal. Therefore, it is critical to distinguish BHD‐RCC from its sporadic counterparts to identify and monitor affected families and to preserve renal function for as long as possible. The World Health Organization/International Society of Urological Pathology consensus classification defined distinct entities for certain hereditary RCC; however, BHD‐RCC was not included in this classification. Although the clinical features and molecular mechanisms of BHD‐RCC have been investigated intensively over the last two decades, pathologists and urologists occasionally face difficulties in the diagnosis of BHD‐RCC that require genetic testing. Affected patients usually have miscellaneous benign disorders that often precede renal carcinogenesis. In the present review, we summarize the current understanding of the histopathological features of BHD‐RCC based on our epidemiological studies of Japanese families and a literature review. Pathological diagnostic clues and differential diagnosis of BHD‐RCC from other hereditary RCC are also briefly discussed.

The Prognostic Value of Programmed Death-Ligand 1 in a Chinese Cohort With Clear Cell Renal Cell Carcinoma.

Objective: To investigate the association between tumor PD-L1 expression and patient survival to determine whether PD-L1 represents an independent prognostic feature for patients with non-metastatic clear cell renal cell carcinoma (RCC).Patients and Methods: The tissue bank of the Fudan University Shanghai Cancer Center was queried to identity tissue samples of patients treated with radical nephrectomy, for non-metastatic sporadic clear cell RCC (ccRCC) between 2008 and 2015. Real-time polymerase chain reaction and immunohistochemistry staining was performed to detect the expression level of PD-L1 in paired cancer tissue and paracancerous tissue.Results: Three-hundred-and-thirty patients were enrolled in this study, with a mean age of 55.0 years at surgery and a mean tumor size of 5.2 cm. Two-hundred-and-forty-two (73.3%) and 88 (26.7%) patients showed a high and low expression of PD-L1 mRNA, respectively, while 254 patients had positive PD-L1 immunohistochemistry staining. Two-hundred-and-ninety-two patients had consistent results for mRNA and the PD-L1 protein based on these different detection methods. Patients with high PD-L1 expression were more likely to exhibit adverse pathologic features including an advanced T stage (P = 0.002) and lymph node metastasis (P = 0.044). The Kaplan–Meier curves of PFS and OS stratified by PD-L1 expression had a statistically significant difference. PD-L1 expression maintained a significant predictive role for PFS and OS in the multivariate cox model.Conclusions: Our data suggests that PD-L1 correlates with prognosis in RCC and targeting the PD-1/PD-L1 pathway should be considered in the treatment of RCC patients.

310 - Differential expression of PD-L1 between sporadic and VHL-associated hereditary clear cell renal cell carcinoma and its correlation with clinicopathological features

310 - Differential expression of PD-L1 between sporadic and VHL-associated hereditary clear cell renal cell carcinoma and its correlation with clinicopathological features

Specific Localization of Missense Mutations in the VHL Gene in Clear Cell Renal Cell Carcinoma.

Missense mutations in the VHL gene during sporadic clear cell renal cell carcinoma were studied to evaluate their localization in relation to functionally important motifs of the VHL protein. Somatic mutations were identified in 124 of 307 samples. All missense mutations in the α-domain were localized in the binding site for elongin C. Substitutions in the β-domain (77%) were found in the HIF-binding site. Five missense mutations were absent in these sites, which illustrates their role in VHL protein formation or suppressor function of other protein cofactors. Mutation c.392A→T (p.N131I) was identified for the first time. Our results hold much promise to estimate the boundaries of functionally important sites in the VHL suppressor gene and contribute to the interpretation of a pathogenic role of mutations in direct DNA diagnostics.

Quantitative proteomics to study a small molecule targeting the loss of von Hippel-Lindau in renal cell carcinomas.

Inactivation of the tumor suppressor gene, von Hippel-Lindau (VHL), is known to play an important role in the development of sporadic clear cell renal cell carcinomas (ccRCCs). Even if available targeted therapies for metastatic RCCs (mRCCs) have helped to improve progression-free survival rates, they have no durable clinical response. We have previously shown the feasibility of specifically targeting the loss of VHL with the identification of a small molecule, STF-62247. Understanding its functionality is crucial for developing durable personalized therapeutic agents differing from those available targeting hypoxia inducible factor (HIF-) pathways. By using SILAC proteomics, we identified 755 deregulated proteins in response to STF-62247 that were further analyzed by ingenuity pathway analysis (IPA). Bioinformatics analyses predicted alterations in 37 signaling pathways in VHL-null cells in response to treatment. Validation of some altered pathways shows that STF-62247's selectivity is linked to an important inhibition of mTORC1 activation in VHL-null cells leading to protein synthesis arrest, a mechanism differing from two allosteric inhibitors Rapamycin and Everolimus. Altogether, our study identified signaling cascades driving STF-62247 response and brings further knowledge for this molecule that shows selectivity for the loss of VHL. The use of a global SILAC approach was successful in identifying novel affected signaling pathways that could be exploited for the development of new personalized therapeutic strategies to target VHL-inactivated RCCs.

Loss of chromosome Y leads to down regulation of KDM5D and KDM6C epigenetic modifiers in clear cell renal cell carcinoma

Recent genomic studies of sporadic clear cell renal cell carcinoma (ccRCC) have uncovered novel driver genes and pathways. Given the unequal incidence rates among men and women (male:female incidence ratio approaches 2:1), we compared the genome-wide distribution of the chromosomal abnormalities in both sexes. We observed a higher frequency for the somatic recurrent chromosomal copy number variations (CNVs) of autosomes in male subjects, whereas somatic loss of chromosome X was detected exclusively in female patients (17.1%). Furthermore, somatic loss of chromosome Y (LOY) was detected in about 40% of male subjects, while mosaic LOY was detected in DNA isolated from peripheral blood in 9.6% of them, and was the only recurrent CNV in constitutional DNA samples. LOY in constitutional DNA, but not in tumor DNA was associated with older age. Amongst Y-linked genes that were downregulated due to LOY, KDM5D and KDM6C epigenetic modifiers have functionally-similar X-linked homologs whose deficiency is involved in ccRCC progression. Our findings establish somatic LOY as a highly recurrent genetic defect in ccRCC that leads to downregulation of hitherto unsuspected epigenetic factors, and suggest that different mechanisms may underlie the somatic and mosaic LOY observed in tumors and peripheral blood, respectively.

Loss of SETD2, but not H3K36me3, correlates with aggressive clinicopathological features of clear cell renal cell carcinoma patients.

Recent studies facilitated by DNA sequencing identified the histone modifying gene SETD2 as the second most frequent mutant gene in sporadic clear cell renal cell carcinoma (ccRCC) patients. SETD2 functions as a tumor suppressor in ccRCC. However, its clinical association and biological functions are not fully delineated. The aim of this study is to evaluate the clinical significance of SETD2 in ccRCC patients. SETD2 and its canonical histone modification product H3K36me3 were analyzed by immunohistochemistry (IHC) in 155 ccRCC patients from two independent cohorts retrospectively. Both SETD2 and H3K36me3 were heterogeneously stained and down-regulated in ccRCC tissues, compared with normal controls. The SETD2 protein deficiency rate was 34.07%, which is much higher than the reported SETD2 gene inactive mutation rate. Furthermore, low SETD2 protein expression, but not H3K36me3 expression, was associated with the aggressive phenotype of ccRCC patients. In addition, cox multivariate analysis identified low SETD2 protein expression as an independent prognostic factor for overall survival of ccRCC patients. Consistently, using RNA-Seq data of ccRCC patients from The Cancer Genome Atlas, we validated our findings that low SETD2 mRNA expression is significantly associated with the aggressive phenotypes, and predicted a worse outcome for ccRCC patients. In conclusion, our study demonstrated a massive down-regulation of SETD2 protein in ccRCC, and identified SETD2 protein, but not H3K36me3, as an independent good prognostic marker, which warrants further study focusing on the non-methyltransferase role of SETD2 in kidney tumor biology.

Haploinsufficiency in tumor predisposition syndromes: altered genomic transcription in morphologically normal cells heterozygous for VHL or TSC mutation.

Tumor suppressor genes and their effector pathways have been identified for many dominantly heritable cancers, enabling efforts to intervene early in the course of disease. Our approach on the subject of early intervention was to investigate gene expression patterns of morphologically normal one-hit cells before they become hemizygous or homozygous for the inherited mutant gene which is usually required for tumor formation. Here, we studied histologically non-transformed renal epithelial cells from patients with inherited disorders that predispose to renal tumors, including von Hippel-Lindau (VHL) disease and Tuberous Sclerosis (TSC). As controls, we studied histologically normal cells from non-cancerous renal epithelium of patients with sporadic clear cell renal cell carcinoma (ccRCC). Gene expression analyses of VHLmut/wt or TSC1/2mut/wt versus wild-type (WT) cells revealed transcriptomic alterations previously implicated in the transition to precancerous renal lesions. For example, the gene expression changes in VHLmut/wt cells were consistent with activation of the hypoxia response, associated, in part, with the Warburg effect. Knockdown of any remaining VHL mRNA using shRNA induced secondary expression changes, such as activation of NF?B and interferon pathways, that are fundamentally important in the development of RCC. We posit that this is a general pattern of hereditary cancer predisposition, wherein haploinsufficiency for VHL or TSC1/2, or potentially other tumor susceptibility genes, is sufficient to promote development of early lesions, while cancer results from inactivation of the remaining normal allele. The gene expression changes identified here are related to the metabolic basis of renal cancer and may constitute suitable targets for early intervention.

Characterization of VHL missense mutations in sporadic clear cell renal cell carcinoma: hotspots, affected binding domains, functional impact on pVHL and therapeutic relevance.

BackgroundThe VHL protein (pVHL) is a multiadaptor protein that interacts with more than 30 different binding partners involved in many oncogenic processes. About 70 % of clear cell renal cell carcinoma (ccRCC) have VHL mutations with varying impact on pVHL function. Loss of pVHL function leads to the accumulation of Hypoxia Inducible Factor (HIF), which is targeted by current targeted treatments. In contrast to nonsense and frameshift mutations that highly likely nullify pVHL multipurpose functions, missense mutations may rather specifically influence the binding capability of pVHL to its partners. The affected pathways may offer predictive clues to therapy and response to treatment. In this study we focused on the VHL missense mutation pattern in ccRCC, and studied their potential effects on pVHL protein stability and binding partners and discussed treatment options.MethodsWe sequenced VHL in 360 sporadic ccRCC FFPE samples and compared observed and expected frequency of missense mutations in 32 different binding domains. The prediction of the impact of those mutations on protein stability and function was assessed in silico. The response to HIF-related, anti-angiogenic treatment of 30 patients with known VHL mutation status was also investigated.ResultsWe identified 254 VHL mutations (68.3 % of the cases) including 89 missense mutations (35 %). Codons Ser65, Asn78, Ser80, Trp117 and Leu184 represented hotspots and missense mutations in Trp117 and Leu 184 were predicted to highly destabilize pVHL. About 40 % of VHL missense mutations were predicted to cause severe protein malfunction. The pVHL binding domains for HIF1AN, BCL2L11, HIF1/2α, RPB1, PRKCZ, aPKC-λ/ι, EEF1A1, CCT-ζ-2, and Cullin2 were preferentially affected. These binding partners are mainly acting in transcriptional regulation, apoptosis and ubiquitin ligation. There was no correlation between VHL mutation status and response to treatment.ConclusionsVHL missense mutations may exert mild, moderate or strong impact on pVHL stability. Besides the HIF binding domain, other pVHL binding sites seem to be non-randomly altered by missense mutations. In contrast to LOF mutations that affect all the different pathways normally controlled by pVHL, missense mutations may be rather appropriate for designing tailor-made treatment strategies for ccRCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2688-0) contains supplementary material, which is available to authorized users.

Abstract A19: A novel cell line model for chromophobe renal cell carcinoma, UOK276, derived from an aggressive sarcomatoid differentiated tumor

Abstract Background: Renal cell carcinoma (RCC) represents a heterogeneous group of cancers that arise from the nephron and are subtyped by histopathological features. The most common subtypes are clear cell RCC (~75%) and papillary RCC (~15%); whereas chromophobe renal cell carcinoma (ChRCC) represents only 5% of RCC cases. ChRCC typically demonstrate a well-known karyotype of multiple chromosomal losses and a relatively indolent pattern of local growth, but can present with aggressive features and demonstrate resistance to treatment in a metastatic setting. Some ChRCC cases demonstrate regions of sarcomatoid RCC and the exact cause of this differentiation has yet to be elucidated. Cell line models are an important tool for both the investigation of tumor biology and therapeutic drug efficacy. Currently, numerous cell lines models exist that have been derived from sporadic clear cell or papillary RCCs, but there are few cell lines derived from chromophobe RCCs and none are well characterized. This study produced a novel ChRCC-derived cell line model and provides an initial genetic and metabolic characterization. Materials and Methods: A patient presented with a 20 cm ChRCC with regions of sarcomatoid differentiation that was surgically excised and a section of this tumor was used to establish a spontaneously immortal cell line model, UOK276. This line was grown for over 20 passages and cytogenetically assessed by spectral karyotyping (SKY). Mutation analysis was performed using a cancer gene specific chip, OncoVar V3, which analyses 232 genes. Identified mutations were confirmed in both UOK276 and the original tumor tissue and further investigated for their effects of mRNA and protein expression. UOK276 cells were injected into nude mice to assess the production of xenograph tumors. The metabolic, bioenergetic profile was assessed using a Seahorse XF96 Extracellular Flux Analyzer. Results: The chromosomal SKY analysis did not demonstrate the classic pattern of chromophobe chromosomal losses, but demonstrated hyper-aneuploidy, with a modal number of 49 chromosomes per cell, and identified a balanced translocation t(X;8)(q10;q24). The break on chromosome 8q occurred near the MYC gene, but break-apart FISH analysis demonstrated no alterations to MYC although amplification of this derivative chromosome was observed and increased MYC mRNA expression was demonstrated. Mutation analysis identified a missense mutation (p.H193Y) of TP53, commonly mutated in ChRCC, which was only present in the sarcomatoid region of the tumor. Mutation of TP53 has previously been associated with sarcomatoid differentiation. Protein expression analysis demonstrated the presence of the mutant TP53 protein in UOK276. A heterozygous germline mutation in TRAF7 was identified resulting in an in-frame loss of 4 amino acids (del T22-P25) that was homozygous in the sarcomatoid tumor region and UOK276. Xenograph tumors were successfully grown in nude mice and provide an in vivo animal model for the investigation of potential therapeutic regimes. The recent TCGA study of ChRCC demonstrated increased expression of the electron transport chain (ETC) genes suggesting increased oxidative phosphorylation within these tumors. Metabolic analysis of UOK276 demonstrated a relatively low level of oxygen consumption (OCR) in comparison to a normal kidney cell line and this was supported by mRNA expression data showing normal or reduced levels of expression for several ETC-related genes. Conclusions: Our study has produced a novel ChRCC cell line model that exhibits a TP53 mutation, commonly seen in ChRCC, and represents a sarcomatoid differentiated region of the tumor. UOK276 should provide a unique in vitro and in vivo preclinical model system for studying the deregulated pathways and testing therapeutic strategies in sarcomatoid differentiated ChRCC. Citation Format: Youfeng Yang, Cathy D. Vocke, Christopher J. Ricketts, Darmood Wei, Hesed M. Padilla-Nash, Shawna L. Boyle, Robert Worrell, Thomas Ried, Maria J. Merino, W. Marston Linehan. A novel cell line model for chromophobe renal cell carcinoma, UOK276, derived from an aggressive sarcomatoid differentiated tumor. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr A19.

Abstract A1-31: Molecular characteristics and predictors of poor prognosis in sporadic clear cell renal cancer among central/eastern European and United States patients

Abstract We investigated patient/tumor characteristics/inherited variants, hypoxia inducible factor 1 and 2 alpha (HIF1A/HIF2A) protein expression, and patient survival among Central European (CE) and United States (US) clear cell renal cancer (ccRCC) patients from two case-control studies. VHL inactivation, HIF1A, and HIF2A expression have been implicated in RCC and angiogenesis. GWAS studies have identified EPAS1 variants encoding the protein HIF2A associated with RCC risk. We conducted a hospital-based case-control study in Central/Eastern Europe (CE) and a population-based study in the US (Detroit, Chicago) that included whites and blacks. We used data on: i) patient/tumor characteristics, ii) inherited tagging single nucleotide polymorphisms (SNPs) in genes involved in the VHL-HIF pathway (HIF1A, EPAS1, VHL), HIF1A and HIF2A protein expression using immunohistochemical (IHC) methods, and survival from 696 CEERCC and 328 US ccRCC cases. ccRCC patients from CE Europe were older, presented at a higher grade, stage, with larger tumors, had lower BMI, less family history and smoked less (all p&amp;lt;0.0001) compared to US cases. US cases demonstrated higher intensity HIF1A and HIF2A protein expression compared to CE cases (p&amp;lt;0.0001). Black US ccRCC cases were more likely to be hypertensive (p&amp;lt;0.0001) and have lower HIF2A protein expression compared to white US cases. HIF1A and HIF2A were examined for associations with patient/tumor characteristics. In the US study, younger patients had higher levels of HIF2A expression compared to older cases and high BMI was associated with HIF1A expression. In both studies, tumor grade, stage and size at diagnosis were associated with lower HIF1A and HIF2A expression. In analyses adjusted for center, race, sex, age, hypertension, BMI, smoking, tumor grade and stage, HIF1A expression was significantly associated with HIF2A expression (P-trend&amp;lt;0.0001). We assessed associations of variants in EPAS1 (N=16), HIF1A (N=11), and VHL (N=9) with HIF1A and HIF2A expression in ccRCC tissue using tissue microarrays. Seven HIF1A SNPs were significantly associated with HIF1A expression and one EPAS1 SNP (rs1374748) with HIF2A expression. Median survival time was longer in CE compared to USRCC cases (100.3 vs. 86.0 months, p=0.001), women than men (97.1 vs 91.0 months, p=0.02) but similar among whites and blacks in the US study (86.0 vs 87.0 months). In Cox proportional hazard models, in both studies combined, risk of death was higher for those with large tumors (&amp;gt;4cm, p&amp;lt;0.0001) and with a higher stage 1 vs 2, 3+4 (p&amp;lt;0.0001, both) In contrast, ccRCC-specific survival was higher among USRCC than CE patients (19.8 vs 38.0 months, p=0.04) but similar among white compared to black US ccRCC patients (37.0 vs 40.0 months, p=0.50). Citation Format: Lee Moore, Petra Lenz, Meredith Yeager, Ruth Pfeiffer, Ghislaine Scelo, Mark Purdue, David Zaridze, Kendra Schwartz, Neonilia szeszenia-Dabrowska, Faith Davis, Joanne Colt, vladimir Janout, Marie Navritalova, Paolo Boffetta, Laurie Burdette, Sara Karami, Paul Brennan, Jon Hofmann, Michael Nickerson, Wong-Ho Chow, Margaret Tucker, Stephen Chanock, Stephen Hewitt, Jorge Toro, Nat Rothman. Molecular characteristics and predictors of poor prognosis in sporadic clear cell renal cancer among central/eastern European and United States patients. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-31.

PI3K/AKT/mTOR pathway plays a major pathogenetic role in glycogen accumulation and tumor development in renal distal tubules of rats and men.

Activation of the PI3K/AKT/mTOR pathway is a crucial molecular event in human clear cell renal cell carcinoma (ccRCC), and is also upregulated in diabetic nephropathy. In diabetic rats metabolic changes affect the renal distal tubular epithelium and lead to glycogen-storing Armanni-Ebstein lesions (AEL), precursor lesions of RCC in the diabetes induced nephrocarcinogenesis model. These lesions resemble human sporadic clear cell tubules (CCT) and tumor cells of human ccRCC.Human sporadic CCT were examined in a collection of 324 nephrectomy specimen, in terms of morphologic, metabolic and molecular alterations, and compared to preneoplastic CCT and RCC developed in the rat following streptozotocin-induced diabetes or N-Nitrosomorpholine administration. Diabetic and non-diabetic rats were subjected to the dual PI3K/mTOR inhibitor, NVP/BEZ235.Human sporadic CCT could be detected in 17.3% of kidney specimens. Human and rat renal CCT display a strong induction of the PI3K/AKT/mTOR pathway and related metabolic alterations. Proteins involved in glycolysis and de novo lipogenesis were upregulated. In in vivo experiments, dual inhibition of PI3K and mTOR resulted in a reduction of proliferation of rat diabetes related CCT and increased autophagic activity.The present data indicate that human sporadic CCT exhibit a pattern of morphologic and metabolic alterations similar to preneoplastic lesions in the rat model. Activation of the PI3K/AKT/mTOR pathway in glycogenotic tubuli is a remarkable molecular event and suggests a preneoplastic character of these lesions also in humans.