Renal Cell Carcinoma in Tuberous Sclerosis Complex

Update on Pediatric Surveillance Recommendations for PTEN Hamartoma Tumor Syndrome, DICER1-Related Tumor Predisposition, and Tuberous Sclerosis Complex

Phosphate and tensin homolog hamartoma tumor syndrome, DICER1-related tumor predisposition, and tuberous sclerosis complex are rare conditions, which each increases risk for distinct spectra of benign and malignant neoplasms throughout childhood and adulthood. Surveillance considerations for each of these conditions focus on patient and family education, early detection, and multidisciplinary care. In this article, we present updated surveillance recommendations and considerations for children and adolescents with phosphate and tensin homolog hamartoma tumor syndrome, DICER1-related tumor predisposition, and tuberous sclerosis complex and provide suggestions for further research in each of these conditions.

Genetic validation of a TSC2 immunohistochemistry assay in TSC/mTOR-pathway altered renal tumors

Pathogenic mutations in the genes associated with tuberous sclerosis complex (TSC)/mTOR pathway are linked to histologically diverse renal cell neoplasms, including eosinophilic solid and cystic renal cell carcinoma (ESC RCC), low grade oncocytic tumor (LOT), eosinophilic vacuolated tumor (EVT), and xanthomatous giant cell renal cell carcinoma (XGC RCC). Here, we validate a TSC2 immunohistochemistry (IHC) assay by comparison to genomic data in these neoplasms. Automated TSC2 IHC was performed on formalin-fixed paraffin embedded (FFPE) tissues from 38 genetically-confirmed TSC/mTOR-associated renal tumors (6 ESCs, 16 EVTs, 13 LOTs, 2 XGC and 1 clear cell RCC) and visually scored in a semi-dichotomous fashion compared to internal control tissue. The positive predictive value (PPV) of TSC2 protein loss for underlying pathogenic mutation in TSC2 was 92% (11/12), while the negative predictive value (NPV) of intact TSC2 by IHC for lack of underlying pathogenic mutation in TSC2 was 81% (21/26). Intact TSC2 by IHC was 95% (21/22) specific for absence of underlying pathogenic TSC2 mutation. All the cases lacking TSC2 mutation with intact TSC2 protein had an underlying mutation in TSC1, MTOR or PIK3CA. Loss of TSC2 was 77% (10/13) sensitive for underlying TSC2 truncation mutations and 33% (1/3) sensitive for underlying TSC2 missense mutations. Overall, 73% (8/11) tumors with TSC2 IHC loss and underlying pathogenic alterations in TSC2 showed heterogeneous protein loss, with rare interspersed positively staining tumor cells. These data support TSC2 IHC as a potentially useful assay for the diagnostic workup of renal tumors suspected to belong to the TSC/mTOR-associated subgroups.

Androgen Receptor and Non-Coding RNAs' Interaction in Renal Cell Carcinoma

Renal cell carcinoma (RCC), the most prevalent among the urogenital cancers, accounts for around 3% of new cancer cases worldwide. Significantly, the incidence of RCC has doubled in developed world countries, ranking it as the sixth most common cancer in males, who represent two-thirds of RCC cases. Males with RCC exhibit a higher mortality rate and tend to develop a more aggressive form of the disease than females. Sex-related risk factors, including lifestyle and biological variations, explain this difference. The androgen receptor (AR) oncogenic signaling pathway has been extensively studied among the biological factors that affect RCC. Recent advancements in high-throughput RNA sequencing techniques have underscored the significant roles played by noncoding-RNAs (ncRNAs), previously dismissed as "junk". The oncogenic potential of AR is manifested through its dysregulation of the ncRNAs' availability and function, promoting RCC tumorigenesis. This review offers a summary of the most recent findings on the role and molecular mechanisms of the AR in dysregulating the ncRNAs that play a role in the progression of RCC and the possibility of utilizing ncRNAs to target AR as a potential therapeutic strategy.

Perivascular Epithelioid Cell-Family Tumors in Children, Adolescents, and Young Adults: Clinicopathologic Features in 70 Cases

CONTEXT.—

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors of uncertain histogenesis expressing smooth muscle and melanocytic markers. The clinicopathologic spectrum in young patients is not well documented.

OBJECTIVE.—

To describe a multi-institutional series of PEComas in children, adolescents, and young adults.

DESIGN.—

PEComas, not otherwise specified (NOS); angiomyolipomas (AMLs); lymphangioleiomyomatosis; and clear cell sugar tumors were retrospectively identified from 6 institutions and the authors' files.

RESULTS.—

Seventy PEComas in 64 patients (median age, 15 years) were identified. They were more common in females (45 of 64 patients), occurring predominantly in the kidney (53 of 70), followed by the liver (6 of 70). Thirty-four patients had confirmed tuberous sclerosis complex (TSC), 3 suspected TSC mosaicism, 2 Li-Fraumeni syndrome (LFS) and 1 neurofibromatosis type 1. Most common variants were classic (49 of 70) and epithelioid (8 of 70) AML. Among patients with AMLs, most (34 of 47) had TSC, and more TSC patients had multiple AMLs (15 of 36) than non-TSC patients (2 of 13). Two TSC patients developed malignant transformation of classic AMLs: 1 angiosarcomatous and 1 malignant epithelioid. Lymphangioleiomyomatosis (5 of 70) occurred in females only, usually in the TSC context (4 of 5). PEComas-NOS (6 of 70) occurred exclusively in non-TSC patients, 2 of whom had LFS (2 of 6). Three were malignant, 1 had uncertain malignant potential, and 2 were benign. All 4 PEComas-NOS in non-LFS patients had TFE3 rearrangements.

CONCLUSIONS.—

Compared to the general population, TSC was more prevalent in our cohort; PEComas-NOS showed more frequent TFE3 rearrangements and possible association with LFS. This series expands the spectrum of PEComas in young patients and demonstrates molecular features and germline contexts that set them apart from older patients.

New staging criteria predicting m-tor inhibitors treatment effect of renal angiomyolipoma in tuberous sclerosis complex patients

BACKGROUND

We aimed to launched new staging criteria to predict mTOR inhibitors treatment effect of renal angiomyolipomas (r-AMLs) in TSC patients.

METHODS

40 TSC patients with 69 r-AMLs were divided into two groups based on the efficacy of 6-month mTOR inhibitor treatment. Epidemiological data, therapeutic response, and predictive factors of enrolled patients were collected and analyzed. Age, sex, maximum diameter, maximum cross-sectional area (CSAmax), unenhanced mean CT value, enhanced mean CT value, and added value of enhanced CT of largest r-AML at baseline were assessed as potential influencing factors. Receiver operating characteristic (ROC) curve analysis and the area under the ROC curve (AUC) was used to estimate prediction power.

RESULTS

After 6 months of mTOR inhibitor treatment, the tumor reduction rates in the two groups were 55.87% and 16.44% (P < 0.001). At the start of treatment, the maximum diameters, CSAmax, added value of enhanced CT of the target lesion in two groups were 7.70 ± 0.73 cm vs. 13.18 ± 1.23 cm(P = 0.028), 57.40 ± 10.76cm2 vs. 167.29 ± 33.09cm2 (P = 0.015), and 62.32 ± 5.03HU vs. 33.06 ± 3.13HU (P = 0.009), respectively. AUCs of CSAmax, added value of enhanced CT, and combination of both were 0.8024, 0.7672, and 0.8116, respectively (P < 0.001). Cut-off values of CSAmax combined with the added value of enhanced CT were 40cm2 and 46HU. AUCs of maximum diameters, combination of maximum diameters and added value of enhanced CT were 0.7600 and 0.8100, respectively (P < 0.001), with cut-off values of 6.6 cm and 46 HU.

CONCLUSION

New staging criteria, based on CSAmax and added value of enhanced CT, can predict the treatment efficiency of m-TOR inhibitors for r-AMLs in TSC patients. A simplified version based on maximum diameter and added value of enhanced CT of lesion has also been proposed.

Characteristics, aetiology and implications for management of multiple primary renal tumours: a systematic review

In a subset of patients with renal tumours, multiple primary lesions may occur. Predisposition to multiple primary renal tumours (MPRT) is a well-recognised feature of some inherited renal cancer syndromes. The diagnosis of MPRT should therefore provoke a thorough assessment for clinical and genetic evidence of disorders associated with predisposition to renal tumourigenesis. To better define the clinical and genetic characteristics of MPRT, a systematic literature review was performed for publications up to 3 April 2024. A total of 7689 patients from 467 articles were identified with MPRT. Compared to all patients with renal cell carcinoma (RCC), patients with MPRT were more likely to be male (71.8% versus 63%) and have an earlier age at diagnosis (<46 years, 32.4% versus 19%). In 61.1% of cases MPRT were synchronous. The proportion of cases with similar histology and the proportion of cases with multiple papillary renal cell carcinoma (RCC) (16.1%) were higher than expected. In total, 14.9% of patients with MPRT had a family history of cancer or were diagnosed with a hereditary RCC associated syndrome with von Hippel-Lindau (VHL) disease being the most common one (69.7%), followed by Birt-Hogg-Dubé (BHD) syndrome (14.2%). Individuals with a known or likely genetic cause were, on average, younger (43.9 years versus 57.1 years). In rare cases intrarenal metastatic RCC can phenocopy MPRT. We review potential genetic causes of MPRT and their implications for management, suggest an approach to genetic testing for individuals presenting with MPRT and considerations in cases in which routine germline genetic testing does not provide a diagnosis.

Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.

Eosinophilic Solid and Cystic Renal Cell Carcinoma-A Systematic Review and Meta-Analysis

Eosinophilic solid and cystic renal cell carcinoma (ESC-RCC) is a novel and uncommon type of renal cell carcinoma, which has been recently recognized and introduced as a distinct entity in the WHO 2022 kidney tumor classification. Previously known as "unclassified RCC", followed by "tuberous sclerosis complex (TSC)-associated RCC", ESC-RCC is now a distinct category of kidney tumor, with its own name, with specific clinical manifestations, and a unique morphological, immunohistochemical and molecular profile. Due to its recent introduction and the limited available data, the diagnosis of ESC-RCC is still a complex challenge, and it is probably frequently misdiagnosed. The secret of diagnosing this tumor lies in the pathologists' knowledge, and keeping it up to date through research, thereby limiting the use of outdated nomenclature. The aim of our case-based review is to provide a better understanding of this pathology and to enrich the literature with a new case report, which has some particularities compared to the existing cases.

Concordance of MTOR Pathway Mutations and the Diagnosis of Renal Low-Grade Oncocytic Tumor (LOT)

The differential diagnosis for oncocytic renal tumors spans the spectrum from benign entities to more aggressive renal cell carcinomas (RCC). Recent work has characterized a provisional renal oncocytic neoplasm, namely the low-grade oncocytic tumor (LOT), which demonstrates overlapping morphologic features with oncocytoma and chromophobe RCC, but also has a unique immunoprofile (ie, diffusely positive for KRT7, negative for KIT) and a high rate (80% to 100%) of mTOR pathway gene alterations. Given the diagnostic overlap among oncocytic tumors, we looked for concordance between mTOR pathway mutations and LOT. Thirty low-grade renal oncocytic neoplasms underwent histologic review and immunohistochemistry for KRT7 and KIT. Tumors were classified as "determinate" (eg, LOT) for tumors with solid, nested or vaguely tubular growth and diffuse KRT7 staining and negative KIT, or "indeterminate" if the morphology and/or immunostains did not fully support a definitive LOT diagnosis. Next-generation sequencing was performed without any knowledge of the diagnoses, and identified mTOR pathway mutations in 80% (12/15) of the determinate tumors, compared with 7% (1/15) in the indeterminate group. One determinate tumor was reclassified as papillary RCC (MTOR mutation negative) and 6 indeterminate tumors were confirmed to be oncocytoma (N = 4), clear cell RCC or papillary RCC with reverse polarity, respectively. Overall, integration of morphology, immunohistochemistry, and molecular data enabled a final definitive diagnosis for 70% of tumors (21 of the total 30), with a high concordance (93%) for LOT specifically in the determinate group; the remaining 9 tumors (30%) were classified as renal oncocytic neoplasm, not otherwise specified.

Renal Cell Carcinoma Associated With TSC/MTOR Genomic Alterations: An Update on its Expanding Spectrum and an Approach to Clinicopathologic Work-up

Renal cell carcinoma (RCC) with tuberous sclerosis complex (TSC)/mammalian target of rapamycin (MTOR) pathway-related genomic alterations have been classically described in hereditary TSC syndrome setting involving germline mutations, whereby cells with a bi-allelic inactivation of genes originate tumors in a classic tumor-suppressor "two-hit" Knudson paradigm. Initial studies of TSC-associated RCC categorized tumors into 3 broad heterogeneous morphologic groups: RCC with smooth muscle stroma, chromophobe-like, and eosinophilic-macrocytic. Recently, a similar morphologic spectrum has been increasingly recognized in novel and emerging entities characterized by somatic mutations in the TSC1/2 and MTOR in patients who do not suffer from the TSC. Correct recognition of RCC with TSC / MTOR mutations is critical for accurate prognostication because such tumors with aggressive behavior have the potential to be tailored to mTOR inhibitors. Whether TSC/MTOR mutated renal epithelial neoplasms represent a distinct molecular class has been confounded by the fact that TSC1/2 , and the gene encoding the downstream protein MTOR, are mutated secondarily in ∼5% of the more common subtypes of RCC, including the commonest subtype of clear cell RCC. This review summarizes the expanding morphologic spectrum of renal tumors with TSC/mTOR pathway alterations, specifically for sporadically occurring tumors where these genomic alterations likely are primary pathologic events. Finally, a practical surgical pathology approach to handling these tumors, and a conceptual framework of renal epithelial tumors with TSC/MTOR mutations as a "family of tumors", is presented.

Case report: A collision tumor of clear cell renal cell carcinoma and clear cell papillary renal cell tumor

We report the case of a 51-year-old woman who was initially hospitalized in the respiratory department with cough and fever. Urinary computed tomography (CT) showed two different incidental masses in the right kidney. The patient underwent a radical right nephrectomy without lymph node dissection and postoperative adjuvant treatment. The pathological examination of the surgical specimens showed a collision tumor composed of a clear cell renal cell carcinoma (CCRCC) and a clear cell papillary renal cell tumor (CCPRCT). To the best of our knowledge, this is the first such case reported to date. No recurrence of local or distant metastasis was found during routine follow-up 14 months after the operation.

An overview of actionable and potentially actionable TSC1 and TSC2 germline variants in an online Database

Tuberous Sclerosis Complex (TSC) is caused by loss of function germline variants in the TSC1 or TSC2 tumor suppressor genes. Genetic testing for the detection of pathogenic variants in either TSC1 or TSC2 was implemented as a diagnostic criterion for TSC. However, TSC molecular diagnosis can be challenging due to the absence of variant hotspots and the high number of variants described. This review aimed to perform an overview of TSC1/2 variants submitted in the ClinVar database. Variants of uncertain significance (VUS), missense and single nucleotide variants were the most frequent in clinical significance (37-40%), molecular consequence (37%-39%) and variation type (82%-83%) categories in ClinVar in TSC1 and TSC2 variants, respectively. Frameshift and nonsense VUS have potential for pathogenic reclassification if further functional and segregation studies were performed. Indeed, there were few functional assays deposited in the database and literature. In addition, we did not observe hotspots for variation and many variants presented conflicting submissions regarding clinical significance. This study underscored the importance of disseminating molecular diagnostic results in a public database to render the information largely accessible and promote accurate diagnosis. We encourage the performance of functional studies evaluating the pathogenicity of TSC1/2 variants.

Hereditary Renal Cancer Syndromes

Familial kidney tumors represent a rare variety of hereditary cancer syndromes, although systematic gene sequencing studies revealed that as many as 5% of renal cell carcinomas (RCCs) are associated with germline pathogenic variants (PVs). Most instances of RCC predisposition are attributed to the loss-of-function mutations in tumor suppressor genes, which drive the malignant progression via somatic inactivation of the remaining allele. These syndromes almost always have extrarenal manifestations, for example, von Hippel-Lindau (VHL) disease, fumarate hydratase tumor predisposition syndrome (FHTPS), Birt-Hogg-Dubé (BHD) syndrome, tuberous sclerosis (TS), etc. In contrast to the above conditions, hereditary papillary renal cell carcinoma syndrome (HPRCC) is caused by activating mutations in the MET oncogene and affects only the kidneys. Recent years have been characterized by remarkable progress in the development of targeted therapies for hereditary RCCs. The HIF2aplha inhibitor belzutifan demonstrated high clinical efficacy towards VHL-associated RCCs. mTOR downregulation provides significant benefits to patients with tuberous sclerosis. MET inhibitors hold promise for the treatment of HPRCC. Systematic gene sequencing studies have the potential to identify novel RCC-predisposing genes, especially when applied to yet unstudied populations.

Pathology of hereditary renal cell carcinoma syndromes: Tuberous sclerosis complex (TSC)

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease characterized by hamartomatous tumors involving multiple organs such as the brain, skin, heart, lung and kidney. TSC is caused by inactivating mutations in TSC1/TSC2, which encodes hamartin and tuberin, respectively, and forms a complex that regulates mechanistic target of rapamycin complex 1 (mTORC1), resulting in cell overgrowth and oncogenesis. Since a leading cause of morbidity and mortality in TSC relates to chronic kidney disease and the ability to preserve renal function, this review describes the important pathologic findings in TSC-associated renal neoplasms and their correlating sporadic counterparts. The most common renal tumor in TSC patients are AMLs, followed by a heterogeneous spectrum of renal epithelial tumors, which may provide clues to establishing a diagnosis of TSC.

Evaluation of an institutional series of low-grade oncocytic tumor (LOT) of the kidney and review of the mutational landscape of LOT

The 2022 WHO classification of urinary and male genital tumors introduced several novel kidney entities exhibiting eosinophilic/oncocytic features with specific mutational backgrounds. Thus, molecular techniques, such as next-generation sequencing (NGS), became more commonly used for their evaluation. We studied 12 low-grade oncocytic tumors (LOT) of the kidney (from 11 patients), identified in a cohort of 210 eosinophilic/oncocytic renal tumors, diagnosed in our institution between October 2019 and May 2023, which represented 5.7% (12/210) of all eosinophilic/oncocytic renal tumors during this period. We reviewed their clinicopathologic, histologic, and immunohistochemical features, as well as their mutational profiles. We also reviewed the literature on NGS-derived data of LOT, by selecting papers in which LOT diagnosis was rendered according to the criteria proposed initially. Median age was 65 years (mean: 63.5; range 43-79) and median tumor size was 2.0 cm (mean: 2.2; range: 0.9-3.1). All tumors were positive for PAX8, CK7, and GATA3, and negative or focally positive for CD117/KIT. We found the following gene mutations: MTOR ((6/11), 54.5%)), TSC1 ((2/11), 18.2%)), and 1 had both NOTCH1 and NOTCH4 ((1/11), 9.1%)). Wild-type status was found in 2/11 (18.2%) patients and one tumor was not analyzable. A review of 8 previous studies that included 79 LOTs revealed frequent mutations in the genes that regulate the mammalian target of rapamycin (mTOR) pathway: MTOR (32/79 (40.5%)), TSC1 (21/79 (26.6%)), and TSC2 (9/79 (11.4%)). Other mutated genes included PIK3CA, NF2, and PTEN, not typically known to affect the mTOR pathway, but potentially acting as upstream and downstream effectors. Our study shows that LOT is increasingly diagnosed in routine practice when applying the appropriate diagnostic criteria. We also confirm that the mTOR pathway is strongly implicated in the pathogenesis of this tumor mainly through MTOR, TCS1, and TSC2 mutations, but other genes could also be involved in the pathway activation, especially in LOTs without "canonical" mutations.

Cystic kidney disease in tuberous sclerosis complex: current knowledge and unresolved questions

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder with an estimated incidence of one in 5000 to 10,000 live births worldwide. Two million people of all races and genders are estimated to have TSC secondary to mutations in one of two tumor suppressor genes, TSC1 or TSC2. The respective TSC1 and 2 gene products - hamartin and tuberin - form cytoplasmic heterodimers that inhibit mTOR-mediated cell growth and division. When mTOR inhibition is lost, people with TSC develop characteristic and usually benign tumors in various organ systems. Kidney tumors and cysts are common, particularly in the setting of TSC2 gene mutations. In most TSC patients, the number of kidney cysts is limited, their morphology is simple, their size is small, and their clinical significance is negligible. In some, cyst morphology progresses from simple to complex with the risk of malignant transformation. In others, aggressive accumulation and growth of kidney cysts can cause hypertension, impaired kidney function, and progression to kidney failure. This educational review summarizes current knowledge and remaining open questions regarding cystic kidney disease in TSC, emphasizing detection, classification, surveillance, and treatment options.

Chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma (ChRCC) is the second most common variant histology (non-clear cell) RCC. ChRCC is distinct from clear cell RCC (ccRCC) in terms of genetics, genomics, metabolism, cell of origin, and response to targeted and immune therapies. The pathogenesis of ChRCC remains unclear, but current data suggest two potential mechanisms: mTORC1 hyperactivation through PTEN pathway mutations and mitochondrial dysfunction leading to oxidative stress. There are no specific approved treatments for ChRCC, although some responses to tyrosine kinase and mTOR inhibitors have been observed. Response to immunotherapy is generally limited. Targetable pathways involving innate lymphoid cells/IL-15 and cysteine homeostasis/ferroptosis have recently been identified.

Recent Advances in Renal Tumors with TSC/mTOR Pathway Abnormalities in Patients with Tuberous Sclerosis Complex and in the Sporadic Setting

A spectrum of renal tumors associated with frequent TSC/mTOR (tuberous sclerosis complex/mechanistic target of rapamycin) pathway gene alterations (in both the germline and sporadic settings) have recently been described. These include renal cell carcinoma with fibromyomatous stroma (RCC FMS), eosinophilic solid and cystic renal cell carcinoma (ESC RCC), eosinophilic vacuolated tumor (EVT), and low-grade oncocytic tumor (LOT). Most of these entities have characteristic morphologic and immunohistochemical features that enable their recognition without the need for molecular studies. In this report, we summarize recent advances and discuss their evolving complexity.

PI3K/AKT/mTOR Dysregulation and Reprogramming Metabolic Pathways in Renal Cancer: Crosstalk with the VHL/HIF Axis

Renal cell carcinoma (RCC) represents 85-95% of kidney cancers and is the most frequent type of renal cancer in adult patients. It accounts for 3% of all cancer cases and is in 7th place among the most frequent histological types of cancer. Clear cell renal cell carcinoma (ccRCC), accounts for 75% of RCCs and has the most kidney cancer-related deaths. One-third of the patients with ccRCC develop metastases. Renal cancer presents cellular alterations in sugars, lipids, amino acids, and nucleic acid metabolism. RCC is characterized by several metabolic dysregulations including oxygen sensing (VHL/HIF pathway), glucose transporters (GLUT 1 and GLUT 4) energy sensing, and energy nutrient sensing cascade. Metabolic reprogramming represents an important characteristic of the cancer cells to survive in nutrient and oxygen-deprived environments, to proliferate and metastasize in different body sites. The phosphoinositide 3-kinase-AKT-mammalian target of the rapamycin (PI3K/AKT/mTOR) signaling pathway is usually dysregulated in various cancer types including renal cancer. This molecular pathway is frequently correlated with tumor growth and survival. The main aim of this review is to present renal cancer types, dysregulation of PI3K/AKT/mTOR signaling pathway members, crosstalk with VHL/HIF axis, and carbohydrates, lipids, and amino acid alterations.

Reprint of: lessons from histopathologic examination of nephrectomy specimens in patients with tuberous sclerosis complex: cysts, angiomyolipomas & renal cell carcinoma

Renal manifestations in patients with tuberous sclerosis complex (TSC) include cysts, angiomyolipoma, and renal cell carcinoma. Unlike many hereditary predisposition syndromes, the spectrum of renal tumors in TSC patients (including both angiomyolipoma and renal cell carcinoma) is broad, with significant morphologic heterogeneity. An improved understanding of histopathologic findings in TSC patients and associated clinicopathologic correlates has significant implications not just in establishing a diagnosis of TSC, but also in the recognition of sporadic tumors occurring secondary to somatic alterations of TSC1/TSC2/MTOR pathway genes and accurate prognostication. In this review, we have discussed issues relevant to clinical management based on histopathologic findings in nephrectomy specimens from patients with TSC. This includes discussions related to screening for TSC, diagnosis of PKD1/TSC2 contiguous gene deletion syndrome, the morphologic spectrum of angiomyolipoma and renal epithelium-derived neoplasia, including the risk of disease progression.

Progress in Tuberous Sclerosis Complex Renal Disease

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects both fetal development and postnatal tissue growth, resulting in altered brain structures and a tumor predisposition syndrome. Although every organ system is affected by the disease, kidney involvement is a leading cause of death in adults with TSC. Over the past decade, significant progress has been made in understanding the renal disease. This review focuses on the cystic and solid renal lesions in TSC, including their pathobiology and treatment.

Spectrum of germline and somatic mitochondrial DNA variants in Tuberous Sclerosis Complex

Tuberous Sclerosis Complex (TSC) is caused by loss of function variants in either TSC1 or TSC2 and is characterized by broad phenotypic heterogeneity. Currently, there is limited knowledge regarding the role of the mitochondrial genome (mtDNA) in TSC pathogenesis. In this study, we aimed to determine the prevalence and spectrum of germline and somatic mtDNA variants in TSC and identify potential disease modifiers. Analysis of mtDNA amplicon massively parallel sequencing (aMPS) data, off-target mtDNA from whole-exome sequencing (WES), and/or qPCR, revealed mtDNA alterations in 270 diverse tissues (139 TSC-associated tumors and 131 normal tissue samples) from 199 patients and six healthy individuals. Correlation of clinical features to mtDNA variants and haplogroup analysis was done in 102 buccal swabs (age: 20-71 years). No correlation was found between clinical features and either mtDNA variants or haplogroups. No pathogenic variants were identified in the buccal swab samples. Using in silico analysis, we identified three predicted pathogenic variants in tumor samples: MT-ND4 (m.11742G>A, p. Cys328Tyr, VAF: 43%, kidney angiomyolipoma), MT-CYB (m.14775T>C, p. Leu10Pro, VAF: 43%, LAM abdominal tumor) and MT-CYB (m.15555C>T, p. Pro270Leu, VAF: 7%, renal cell carcinoma). Large deletions of the mitochondrial genome were not detected. Analysis of tumors from 23 patients with corresponding normal tissue did not reveal any recurrent tumor-associated somatic variants. The mtDNA/gDNA ratio between tumors and corresponding normal tissue was also unchanged. Overall, our findings demonstrate that the mitochondrial genome is highly stable across tissues and within TSC-associated tumors.

Rare renal cell carcinoma with haemangioblastoma-like features and leiomyomatous stroma: report of a unique case with TSC2 and SETD2 variations

BACKGROUND

Renal cell carcinoma (RCC) with haemangioblastoma-like characteristics is a type of RCC reported in recent years. RCC with (angio) leiomyomatous stroma (RCCLMS) was included as a provisional entity of the 2016 World Health Organization (WHO) classification. RCC with haemangioblastoma-like characteristics and leiomyomatous stroma is extremely rare. This is the first report of a rare tumour harbouring TSC2 and SETD2 variations.

CASE PRESENTATION

The patient was a 38-year-old woman who presented with discomfort in the area of her right kidney. Ultrasound and enhanced CT showed a right renal mass, and clear cell renal cell carcinoma (CCRCC) was suspected; hence, robot-assisted laparoscopic nephron-sparing partial nephrectomy was performed. Gross examination revealed a well-circumscribed tumour measuring 2.0 cm × 1 cm × 0.7 cm under the renal capsule adjacent to the stripping edge that was greyish yellow and greyish red in colour. Histologic examination showed that the tumour consisted of three different structures: a CCRCC-like region, a haemangioblastoma-like region, and a focal leiomyomatous stroma component. Based on immunohistochemistry, the CCRCC-like region was diffusely strongly positive for AE1/AE3, vimentin, CAIX, PAX8, PAX2, CK7, and CAM5.2, partly positive for HNF1α, and negative for CD10, α-inhibin, NSE, S-100, CD34, and TFE3. The haemangioblastoma-like area was diffusely positive for vimentin, CAIX; partly positive for PAX8, PAX2, α-inhibin, and S-100; mostly positive for NSE; and slightly positive for HNF1α; the CD34 staining highlighted the complex capillary network. The Ki67 index was approximately 1-2% in the two above areas, and the leiomyomatous stroma was strongly positive for SMA. The whole-exon sequencing (WES) showed TSC2 and SETD2 variations. There was no progression after 18 months of follow-up.

CONCLUSION

We report for the first time a unique case of RCC with haemangioblastoma-like features and leiomyomatous stroma accompanied by rare molecular abnormalities. Whether this is a new tumour entity or a variant of clear cell carcinoma remains to be determined. The biological behaviour and clinical characteristics need to be further examined.

Identification and validation of ubiquitin-proteasome system related genes as a prognostic signature for papillary renal cell carcinoma

Dysregulation of the ubiquitin-proteasome system (UPS) pathway greatly affects uncontrolled proliferation, genomic instability, and carcinogenesis, particularly in those with renal papillary cell carcinoma (PRCC). However, there is little information at the molecular level about the full link between changes in the genes involved in ubiquitin-mediated proteolysis and PRCC.

METHODS

The Cancer Genome Atlas (TCGA) and GeneCards databases were utilized to find the clinical data and gene expression patterns of patients with PRCC. Univariate Cox regression analysis and absolute shrinkage and selection operator (LASSO) analyses identified a risk signature formed by ten optimal UPS genes. The predictive value of the risk signature in TCGA-PRCC cohorts was evaluated using Kaplan-Meier analysis and receiver operating characteristic (ROC) curves. By utilizing GO enrichment and the KEGG pathway, the interactions of differentially expressed genes connected to ubiquitin-mediated proteolysis were functionally examined. The protein expression of the hub genes was affirmed using the Human Protein Atlas (HPA) database. The effectiveness of particular CDC20 and UBE2C in vitro was confirmed by experimental research.

RESULTS

Ten of the best ubiquitin-mediated proteolysis genes (UBE2C, DDB2, CBLC, BIRC3, PRKN, UBE2O, SIAH1, SKP2, UBC, and CDC20) were detected to create a risk signature. The high-risk score group stratified was associated with advanced tumor status and poor survival of PRCC patients. 10 genes were also found to be associated with the cell cycle pathway and ubiquitin-mediated proteolysis to GO and KEGG analysis. Of these 10 genes, CDC20 and UBE2C are highly expressed in tumor tissue and correlated with cancer immunity founded on the analyses of the expression of human protein atlas and TISIDB. The downregulation of UBE2C facilitated tumor inhibition and the anti-immune effect was confirmed by in vitro experiments.

CONCLUSION

Our results indicate that the risk model created from the ubiquitin-mediated proteolysis genes can be reliably and accurately predict the prognosis of PRCC patients, highlighting its targeted value for PRCC treatment. Particularly, the expression of UBE2C may be crucial for the prognosis and immunological treatment of renal cancer.

Tumorigenesis Mechanisms Found in Hereditary Renal Cell Carcinoma: A Review

Renal cell carcinoma is a heterogenous cancer composed of an increasing number of unique subtypes each with their own cellular and tumor behavior. The study of hereditary renal cell carcinoma, which composes just 5% of all types of tumor cases, has allowed for the elucidation of subtype-specific tumorigenesis mechanisms that can also be applied to their sporadic counterparts. This review will focus on the major forms of hereditary renal cell carcinoma and the genetic alterations contributing to their tumorigenesis, including von Hippel Lindau syndrome, Hereditary Papillary Renal Cell Carcinoma, Succinate Dehydrogenase-Deficient Renal Cell Carcinoma, Hereditary Leiomyomatosis and Renal Cell Carcinoma, BRCA Associated Protein 1 Tumor Predisposition Syndrome, Tuberous Sclerosis, Birt-Hogg-Dubé Syndrome and Translocation RCC. The mechanisms for tumorigenesis described in this review are beginning to be exploited via the utilization of novel targets to treat renal cell carcinoma in a subtype-specific fashion.

Lessons from histopathologic examination of nephrectomy specimens in patients with tuberous sclerosis complex: cysts, angiomyolipomas, and renal cell carcinoma

Renal manifestations in patients with tuberous sclerosis complex (TSC) include cysts, angiomyolipoma, and renal cell carcinoma. Unlike many hereditary predisposition syndromes, the spectrum of renal tumors in TSC patients (including both angiomyolipoma and renal cell carcinoma) is broad, with significant morphologic heterogeneity. An improved understanding of histopathologic findings in TSC patients and associated clinicopathologic correlates has significant implications not just in establishing a diagnosis of TSC, but also in the recognition of sporadic tumors occurring secondary to somatic alterations of TSC1/TSC2/MTOR pathway genes and accurate prognostication. In this review, we have discussed issues relevant to clinical management based on histopathologic findings in nephrectomy specimens from patients with TSC. This includes discussions related to screening for TSC, diagnosis of PKD1/TSC2 contiguous gene deletion syndrome, the morphologic spectrum of angiomyolipoma and renal epithelium-derived neoplasia, including the risk of disease progression.

Low grade oncocytic tumors of the kidney: a clinically relevant approach for the workup and accurate diagnosis

Renal oncocytoma and chromophobe renal cell carcinoma were accepted as unique renal tumors in the late 1990s. Since their formal description, criteria for diagnosis have evolved and additional distinct tumor subtypes originally considered as one these two entities are now recognized. The last two decades have witnessed unprecedented interest in the spectrum of low grade oncocytic renal neoplasms in three specific areas: (1) histologic characterization of tumors with overlapping morphologic features between oncocytoma and chromophobe renal cell carcinoma; (2) description of potentially unique entities within this spectrum, such as eosinophilic vacuolated tumor and low-grade oncocytic tumor; and (3) better appreciation of the association between a subset of low grade oncocytic tumors and hereditary renal neoplasia. While this important work has been academically rewarding, the proposal of several histologic entities with overlapping morphologic and immunophenotypic features (which may require esoteric adjunctive immunohistochemical and/or molecular techniques for confirmation) has created frustration in the diagnostic pathology and urology community as information evolves regarding classification within this spectrum of renal neoplasia. Pathologists, including genitourinary subspecialists, are often uncertain as to the "best practice" diagnostic approach to such tumors. In this review, we present a practical clinically relevant algorithmic approach to classifying tumors within the low grade oncocytic family of renal neoplasia, including a proposal for compressing terminology for evolving categories where appropriate without sacrificing prognostic relevance.

Molecular uropathology and cancer genetics for the urologist: key findings for classification and diagnosis

PURPOSE OF REVIEW

To highlight the latest changes in prostate cancer (PCa), urothelial carcinoma, upper tract urothelial carcinoma (UTUC) and renal cell carcinoma (RCC) diagnosis and the impact of genetics in this field.

RECENT FINDINGS

Breast cancer1/2 mutations start to play a major role in PCa treatment with regard to personalized medicine. In urothelial carcinoma an overlap between histological pathological and molecular findings exists, fibroblast growth factor receptor alteration are starting to play a major role, programmed death-ligand 1 although problematic is still important in the treatment setting. UTUC is rare, but genetically different from urothelial carcinoma. In the development of RCC, different genetic pathways such as Von Hippel-Lindau, but also tuberous sclerosis 1/2 and others play a major role in tumor development.

SUMMARY

Over the last years, genetics has become increasingly important role in the diagnosis and the treatment of patients with urological malignancies. The upcoming 5th edition (1) of the WHO still considers conventional surgical pathology as the diagnostic gold standard, but molecular pathology is gaining importance not only for diagnosis, but also in personalized treatment, of prostate, kidney cancer and urothelial carcinomas. Therefore, a close collaboration between surgical urology, pathology and oncology departments is mandatory. In this review, we will discuss the latest evolutions in PCa, urothelial carcinoma, upper urinary tract carcinomas and RCC s in the field of genetics in urology.

Epidemiology and Prevention of Renal Cell Carcinoma

With 400,000 diagnosed and 180,000 deaths in 2020, renal cell carcinoma (RCC) accounts for 2.4% of all cancer diagnoses worldwide. The highest disease burden developed countries, primarily in Europe and North America. Incidence is projected to increase in the future as more countries shift to Western lifestyles. Risk factors for RCC include fixed factors such as gender, age, and hereditary diseases, as well as intervening factors such as smoking, obesity, hypertension, diabetes, diet and alcohol, and occupational exposure. Intervening factors in primary prevention, understanding of congenital risk factors and the establishment of early diagnostic tools are important for RCC. This review will discuss RCC epidemiology, risk factors, and biomarkers involved in reducing incidence and improving survival.

Hypersensitivity to ferroptosis in chromophobe RCC is mediated by a glutathione metabolic dependency and cystine import via solute carrier family 7 member 11

Chromophobe (Ch) renal cell carcinoma (RCC) arises from the intercalated cell in the distal nephron. There are no proven treatments for metastatic ChRCC. A distinguishing characteristic of ChRCC is strikingly high levels of reduced (GSH) and oxidized (GSSG) glutathione. Here, we demonstrate that ChRCC-derived cells exhibit higher sensitivity to ferroptotic inducers compared with clear-cell RCC. ChRCC-derived cells are critically dependent on cystine via the cystine/glutamate antiporter xCT to maintain high levels of glutathione, making them sensitive to inhibitors of cystine uptake and cyst(e)inase. Gamma-glutamyl transferase 1 (GGT1), a key enzyme in glutathione homeostasis, is markedly suppressed in ChRCC relative to normal kidney. Importantly, GGT1 overexpression inhibits the proliferation of ChRCC cells in vitro and in vivo, suppresses cystine uptake, and decreases levels of GSH and GSSG. Collectively, these data identify ferroptosis as a metabolic vulnerability in ChRCC, providing a potential avenue for targeted therapy for these distinctive tumors.

The Role of Ferric Nitrilotriacetate in Renal Carcinogenesis and Cell Death: From Animal Models to Clinical Implications

Iron is essential for cellular growth, and various ferroproteins and heme-containing proteins are involved in a myriad of cellular functions, such as DNA synthesis, oxygen transport, and catalytic reactions. As a consequence, iron deficiency causes pleiotropic effects, such as hypochromic microcytic anemia and growth disturbance, while iron overload is also deleterious by oxidative injury. To prevent the generation of iron-mediated reactive oxygen species (ROS), ferritin is synthesized to store excess iron in cells that are consistent with the clinical utility of the serum ferritin concentration to monitor the therapeutic effect of iron-chelation. Among the animal models exploring iron-induced oxidative stress, ferric nitrilotriacetate (Fe-NTA) was shown to initiate hepatic and renal lipid peroxidation and the development of renal cell carcinoma (RCC) after repeated intraperitoneal injections of Fe-NTA. Here, current understanding of Fe-NTA-induced oxidative stress mediated by glutathione-cycle-dependent iron reduction and the molecular mechanisms of renal carcinogenesis are summarized in combination with a summary of the relationship between the pathogenesis of human RCC and iron metabolism. In addition to iron-mediated carcinogenesis, the ferroptosis that is triggered by the iron-dependent accumulation of lipid peroxidation and is implicated in the carcinogenesis is discussed.

What’s new in molecular genetic pathology 2022: immune checkpoint inhibitor biomarkers and select solid tumors

Predictive biomarker testing plays a critical role in targeted immuno-oncology, including the use of immune checkpoint inhibitors (ICI) for various solid tumors. Molecular advancements in cancers of the breast, kidney and brain have continued to propel tumor classification and precision therapy.

Seventh BHD international symposium: recent scientific and clinical advancement

The 7th Birt-Hogg-Dubé (BHD) International Symposium convened virtually in October 2021. The meeting attracted more than 200 participants internationally and highlighted recent findings in a variety of areas, including genetic insight and molecular understanding of BHD syndrome, structure and function of the tumor suppressor Folliculin (FLCN), therapeutic and clinical advances as well as patients' experiences living with this malady.