Mutational analysis of renal angiomyolipoma associated with tuberous sclerosis complex and the outcome of short-term everolimus therapy

Renal epithelioid angiomyolipomas overexpress TFE3 and the TFE3-regulated gene TRIM63 in the absence of TFE3 rearrangement

Angiomyolipoma (AML) is a neoplasm within the perivascular epithelioid cell tumor family that occurs somewhat frequently in the kidney. Most are indolent and discovered incidentally, with rare tumors demonstrating malignant clinical behavior. A small subset of renal AMLs with epithelioid features are associated with aggressive behavior, and may demonstrate morphologic overlap with renal cell carcinomas (e.g., clear cell renal cell carcinoma (RCC), TFE3-rearranged RCC). Prior studies of spindle cell and epithelioid AMLs have identified rare examples with underlying TFE3 gene fusions. TFE3 protein expression (demonstrated by immunohistochemistry) with no evidence of concurrent TFE3 rearrangements has been reported previously in 4/24 AMLs (17%) (Argani et al. Am J Surg Pathol 34:1395-1406, 2010). Currently, the relationship between TFE3 protein expression, TFE3 fusions, and expression of TFE3-mediated genes remains incompletely understood in renal epithelioid AMLs. We sought to explore these relationships using TFE3 break-apart fluorescence in situ hybridization (FISH) and TRIM63 RNA in situ hybridization (ISH) on epithelioid AMLs with moderate to strong TFE3 expression by immunohistochemistry. RNA sequencing (fusion panel) was performed on two cases with negative FISH results to assess for FISH-cryptic gene fusions. The series comprised five epithelioid AMLs from four patients (three women, one man) aged 13 to 76 years. All were considered positive for TFE3 by immunohistochemistry (2 + /3 + expression). TRIM63 ISH was performed on four specimens from three patients, yielding positive results in 3/3 tumors (100%) that were successfully analyzed. TFE3 break-apart FISH was performed on all samples, demonstrating a TFE3 rearrangement in only 1/4 tumors (25%). RNA sequencing demonstrated the absence of productive TFE3 gene fusions in three tumors with negative break-apart TFE3 FISH results. This study demonstrates that renal epithelioid AMLs overexpress TFE3 and TFE3-mediated genes (TRIM63) even in the absence of TFE3 rearrangements. This finding could be explained by functional upregulation of TFE3 secondary to activation of the mammalian target of rapamycin complex 1 (mTORC1). Expression of TFE3 and TRIM63 in this tumor type represents a potential pitfall, given the morphologic and immunophenotypic overlap between epithelioid AML and TFE3-altered renal cell carcinoma.

The emerging role of NF2 alterations in new and established subtypes of renal cell carcinoma

Genomic alterations are increasingly important in the current paradigms for the classification, diagnosis, and treatment of renal cell carcinoma. Biallelic alterations involving NF2 have been identified across several currently recognized subtypes of renal cell carcinoma including clear cell renal cell carcinoma and papillary renal cell carcinoma among others and may be associated with a more aggressive disease course as well as advanced stage at presentation. In addition, emerging evidence suggests the existence of a clinicopathologically distinct subset of renal cell carcinoma cases driven by biallelic loss of NF2 expression. This subset of tumors is morphologically characterized by a constellation of morphologic features including hyalinizing fibrosis, eosinophilic cytology, psammomatous calcifications, and a nested growth pattern. These tumors include the recently described entities of biphasic hyalinizing psammomatous renal cell carcinoma as well as renal cell tumor with sex cord/gonadoblastoma-like features. Despite their oftentimes aggressive behavior, there is some evidence that these tumors may respond favorably to treatment regimens incorporating immune checkpoint inhibitors.

Renal phenotypes correlate with genotypes in unrelated individuals with tuberous sclerosis complex in China

Purpose

To explore the relationship between the genotype and renal phenotype in a Chinese cohort and guide clinical decision-making for treating tuberous sclerosis complex (TSC).

Materials and methods

We reviewed 173 patients with definite TSC at three centers in China from September 2014 to September 2020. All the patients underwent TSC1 and TSC2 genetic testing as well as renal phenotypic evaluation. All analyses were performed using the SPSS software, version 19.0, with a cut-off P value of 0.05 considered statistically significant.

Results

We identified variants in 93% (161/173) cases, including 16% TSC1 and 77% TSC2 variants. Analysis of the relationship between the genotype and renal phenotype, revealed that those with TSC2 variants were more likely to develop severe renal AML (> 4) (P = 0.044). In terms of treatment, TSC2 variants were more likely to undergo nephrectomy/partial nephrectomy (P = 0.036) and receive mTOR medication such as everolimus (P < 0.001). However, there was no significant difference between the two groups in terms of their response to the everolimus treatment.

Conclusion

Patients with TSC2 variants exhibit more severe renal phenotypes, especially those associated with renal angiomyolipomas (AML), and they often require nephrectomy/partial nephrectomy or mTOR medication. Detection of the genotype is helpful in TSC management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02443-1.

Perfect match: mTOR inhibitors and tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome that presents with diverse and complex clinical features and involves multiple human systems. TSC-related neurological abnormalities and organ dysfunction greatly affect the quality of life and can even result in death in patients with TSC. It is widely accepted that most TSC-related clinical manifestations are associated with hyperactivation of the mammalian target of rapamycin (mTOR) pathway caused by loss‑of‑function mutations in TSC1 or TSC2. Remarkable progress in basic and translational research has led to encouraging clinical advances. Although mTOR inhibitors (rapamycin/everolimus) demonstrate great potential in TSC management, two major concerns hamper their generalized application. One is the frequent manifestation of adverse events, such as stomatitis, infections, and menstrual disorders; and the other is the poor response in certain patients. Thus, indicators are required to effectively predict the efficacy of mTOR inhibitors. Herein, we have summarized the current utilization of mTOR inhibitors in the treatment of TSC and focused on their efficacy and safety, in an attempt to provide a reference to guide the treatment of TSC.

Hyperactivation of mammalian target of rapamycin (mTOR) is essential in the pathogenesis of tuberous sclerosis complex (TSC) and can serve as a therapeutic target.

mTOR inhibitors have shown considerable success in multiple clinical trials for the treatment of TSC, including neurological, pulmonary, cardiac, renal, and cutaneous phenotypes.

mTOR inhibitors are associated with adverse events, which should be considered during the management of TSC.

Indicators to predict mTOR inhibitor efficacy are required to select patients who are likely to benefit from such therapy.

Genotype-phenotype correlation of renal lesions in the tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disease caused by loss-of-function mutations in either of two tumor suppressor genes, TSC1 and TSC2. These mutations lead to the growth of benign tumors and hamartomas in many organs, including those of the central nervous system, the skin, and the kidneys. To investigate the genotype-phenotype correlation, we performed sequence analysis of the TSC1/2 genes using next-generation sequencing. We classified 30 patients with TSC whose pathogenic variants were identified into two groups: those with mutations producing premature termination codons (PTCs) and those with missense mutations. Then, we compared the phenotypes between the two groups. Patients with a PTC were significantly more likely to manifest the major symptoms of the diagnostic criteria than those without a PTC (P = 0.035). The frequencies of subependymal nodules (P = 0.026), cortical tubers (P = 0.026), and renal cysts (P = 0.026) were significantly higher in PTC-containing variants than in cases without a PTC. When the analyses were limited to renal angiomyolipoma (AML) cases with TSC2 mutations, there was no difference in tumor size between cases with and without a PTC. However, the cases with a PTC showed a trend toward disease onset at a younger age and multiple tumors, and bilateral disease was observed in their AML lesions. TSC patients with PTC-producing mutations might potentially manifest more severe TSC phenotypes than those with missense mutations. A larger-scale study with appropriate samples deserves further investigation.

Sequential everolimus for angiomyolipoma associated with tuberous sclerosis complex: a prospective cohort study

Background

To evaluate the efficacy, safety and health economics of sequential everolimus in treating angiomyolipoma (AML) associated with tuberous sclerosis complex (TSC).

Methods

In this prospective cohort study, patients met the inclusion criteria received standard or sequential treatment according to their willingness. All patients received an initial dose of everolimus (10 mg oral, once a day) for 3 months. The standard treatment group maintained 10 mg QD for 12 months, while the sequential treatment group reduced the dose to 5 mg QD from the 4th month. The efficacy, serum everolimus concentration and safety were evaluated at 1, 3, 6, 9 and 12 months after treatment. The primary efficacy endpoint was the proportion of patients with confirmed angiomyolipoma response of at least a 50% reduction in the total volume of target AML relative to baseline.

Results

Between June 1, 2016 and June 1, 2017, a total of 53 patients were included. Twenty-three patients received standard treatment, 30 patients received sequential treatment. At 1, 3, 6, 9 and 12 months after treatment, the proportion of patients whose total target tumor volume decreased by ≥ 50% from baseline was 39.1% versus 36.7%, 43.5% versus 56.7%, 47.8% versus 50%, 47.8% versus 60% and 47.8% versus 23.3% respectively (P > 0.05 for all). The overall response rate of skin lesions in the two groups was 40.4%, and the response rates of skin lesions at different times were similar for two groups (P > 0.05 for all). Major adverse effects (AEs) included mouth ulceration, hypertriglyceridemia, hypercholesterolemia, menstrual disorders. There was no significant difference between the two groups in the incidence of AEs at 3 months after treatment. The incidence of overall and grade 3/4 AEs at 12 months after treatment were significantly lower in the sequential treatment group. The average direct cost of the two groups in 12 months was $15,466 and $11,120, respectively.

Conclusions

Compared to standard treatment, sequential treatment was equally effective, with a lower incidence of adverse events and a lower direct cost, suggesting that it may be an alternative treatment for AML associated with TSC.

The Correlation Between Tuberous Sclerosis Complex Genotype and Renal Angiomyolipoma Phenotype

Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that occurs between 1 in 6,000 and 1 in 10,000 live births. Additionally, renal angiomyolipoma is the most common form of renal disease in patients affected by TSC. Although a genetic mutation analysis of TSC is not rare, the correlation between the TSC gene mutation and renal angiomyolipoma phenotype is poorly understood. This study aims to analyze the mutation sites in 261 types of selected TSC patients. The results reveal that: (1) female patients develop more renal angiomyolipoma than male patients [p = 0.008, OR = 2.474, 95%CI (1.258–4.864)]; (2). The missense mutation of TSC1 led to a higher risk of renal angiomyolipoma [p < 0.01, OR = 15, 95%CI (2.859–78.691)], and in contrast, showed a reduced risk in patients with frameshift mutation [p = 0.03, OR = 0.252, 95%CI (0.07–0.912)]; (3). Patients with TSC2 mutations in the transcription activation domain 1 coding genes, had increased renal angiomyolipoma [p = 0.019, OR = 3.519, 95%CI (1.226–10.101)]. Therefore, our genotype-phenotype correlation study might shed light on the early monitoring and evaluation of renal angiomyolipoma in TSC patients.

Renal angiomyolipoma with tuberous sclerosis complex: How it differs from sporadic angiomyolipoma in both management and care

Renal angiomyolipoma (AML) is the most common benign tumor of the kidney. It consists of blood vessels, smooth muscle and fat components in varying proportions. AML is divided into the sporadic type and tuberous sclerosis complex (TSC)-associated type. TSC-associated AML develops at a younger age and tends to exhibit a much faster growth rate over time than sporadic AML. AMLs are classified as classic AML, fat-poor AML and epithelioid AML. Epithelioid AML, though rare, shows aggressive behavior leading to distant metastasis and mortality. TSC-associated AML is more likely to have an epithelioid component than sporadic AML. Active surveillance is the suggested management for small AML. Clinical intervention is mainly indicated when there is a substantial risk of rupture. Minimally invasive therapies, including partial nephrectomy, transcatheter arterial embolization, and mammalian target of rapamycin (mTOR) inhibitor treatment are employed for patients who require treatment. An updated algorithm for the management of AML is herein described. According to this algorithm, treatment intervention is recommended for TSC-associated AML >3 cm, even in asymptomatic cases. In cases with asymptomatic sporadic AML >4 cm in size or with an intra-tumoral aneurysm of >5 mm, treatment, including transcatheter arterial embolization or partial nephrectomy, is advised. The major complication of AML is intra-tumoral or retroperitoneal hemorrhage due to rupture that may be serious and life threatening. Thus, correct diagnosis, proper observation, and appropriate treatment are very important in the management of renal AML.