Cryptic splice mutation in the fumarate hydratase gene in patients with clinical manifestations of Hereditary Leiomyomatosis and Renal Cell Cancer.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant condition characterized by the development of cutaneous and uterine leiomyomas and risk for development of an aggressive form of papillary renal cell cancer. HLRCC is caused by germline inactivating pathogenic variants in the fumarate hydratase (FH) gene, which encodes the enzyme that catalyzes the interconversion of fumarate and L-malate. We utilized enzyme and protein mobility assays to evaluate the FH enzyme in a cohort of patients who showed clinical manifestations of HLRCC but were negative for known pathogenic FH gene variants. FH enzyme activity and protein levels were decreased by 50% or greater in three family members, despite normal FH mRNA expression levels as measured by quantitative PCR. Direct Nanopore RNA sequencing demonstrated 57 base pairs of retained intron sequence between exons 9 and 10 of polyadenylated FH mRNA in these patients, resulting in a truncated FH protein. Genomic sequencing revealed a heterozygous intronic alteration of the FH gene (chr1: 241498239 T/C) resulting in formation of a splice acceptor site near a polypyrimidine tract, and a uterine fibroid obtained from a patient showed loss of heterozygosity at this site. The same intronic FH variant was identified in an unrelated patient who also showed a clinical phenotype of HLRCC. These data demonstrate that careful clinical assessment as well as biochemical characterization of FH enzyme activity, protein expression, direct RNA sequencing, and genomic DNA sequencing of patient-derived cells can identify pathogenic variants outside of the protein coding regions of the FH gene.

Deep learning-based decision forest for hereditary clear cell renal cell carcinoma segmentation on MRI.

BACKGROUND: von Hippel-Lindau syndrome (VHL) is an autosomal dominant hereditary syndrome with an increased predisposition of developing numerous cysts and tumors, almost exclusively clear cell renal cell carcinoma (ccRCC). Considering the lifelong surveillance in such patients to monitor the disease, patients with VHL are preferentially imaged using MRI to eliminate radiation exposure. PURPOSE: Segmentation of kidney and tumor structures on MRI in VHL patients is useful in lesion characterization (e.g., cyst vs. tumor), volumetric lesion analysis, and tumor growth prediction. However, automated tasks such as ccRCC segmentation on MRI is sparsely studied. We develop segmentation methodology for ccRCC on T1 weighted precontrast, corticomedullary, nephrogenic, and excretory contrast phase MRI. METHODS: We applied a new neural network approache using a novel differentiable decision forest, called hinge forest (HF), to segment kidney parenchyma, cyst, and ccRCC tumors in 117 images from 115 patients. This data set represented an unprecedented 504 ccRCCs with 1171 cystic lesions obtained at five different MRI scanners. The HF architecture was compared with U-Net on 10 randomized splits with 75% used for training and 25% used for testing. Both methods were trained with Adam using default parameters ( α = 0.001 , ß 1 = 0.9 , ß 2 = 0.999 $\alpha = 0.001,\ \beta _1 = 0.9,\ \beta _2 = 0.999$ ) over 1000 epochs. We further demonstrated some interpretability of our HF method by exploiting decision tree structure. RESULTS: The HF achieved an average kidney, cyst, and tumor Dice similarity coefficient (DSC) of 0.75 ± 0.03, 0.44 ± 0.05, 0.53 ± 0.04, respectively, while U-Net achieved an average kidney, cyst, and tumor DSC of 0.78 ± 0.02, 0.41 ± 0.04, 0.46 ± 0.05, respectively. The HF significantly outperformed U-Net on tumors while U-Net significantly outperformed HF when segmenting kidney parenchymas ( α < 0.01 $\alpha < 0.01$ ). CONCLUSIONS: For the task of ccRCC segmentation, the HF can offer better segmentation performance compared to the traditional U-Net architecture. The leaf maps can glean hints about deep learning features that might prove to be useful in other automated tasks such as tumor characterization.

Differences in risk factors for molecular subtypes of clear cell renal cell carcinoma.

The ccA and ccB molecular subtypes of clear cell renal cell carcinoma (ccRCC) have well-characterized prognostic relevance. However, it is not known whether they possess distinct etiologies. We investigated the relationships between these subtypes and RCC risk factors within a case-control study conducted in Eastern Europe. We analyzed risk factor data for ccA (n = 144) and ccB (n = 106) cases and 1476 controls through case-only and case-control comparisons to assess risk factor differences across subtypes using logistic and polytomous regression models. We also performed a meta-analysis summarizing case-only results from our study and three patient cohorts. Patients with ccB tumors had poorer survival than those with ccA tumors and were more likely to be male (case-only odds ratio [OR] 2.68, 95% confidence interval [CI] 1.43-5.03). In case-control analyses, body mass index was significantly associated with ccA tumors (OR 2.45, 95% CI 1.18-5.10 for ≥35 vs <25 kg/m2 ) but not with ccB tumors (1.52, 0.56-4.12), while trichloroethylene was associated with ccB but not ccA (OR 3.09, 95% CI 1.11-8.65 and 1.25, 0.36-4.39 respectively for ≥1.58 ppm-years vs unexposed). A polygenic risk score of genetic variants identified from genome-wide association studies was associated with both ccA and, in particular, ccB (OR 1.82, 1.11-2.99 and 2.87, 95% CI 1.64-5.01 respectively for 90th vs 10th percentile). In a meta-analysis of case-only results including three patient cohorts, we still observed the ccB excess for male sex and the ccA excess for obesity. In conclusion, our findings suggest the existence of etiologic heterogeneity across ccRCC molecular subtypes for several risk factors.

Renal medullary carcinoma: molecular, immunohistochemistry, and morphologic correlation.

Renal medullary carcinoma, a highly aggressive tumor mainly occurring in patients with sickle cell hemoglobinopathy, is characterized by advanced stage at the time of presentation and poor response to treatment. Currently, the pathogenesis of this tumor is not well understood. In this study, the clinicopathologic features and molecular changes of 15 renal medullary carcinoma cases were evaluated. These cases demonstrated male predominance (M:F=2:1) with a median age of 26 years. The tumors occurred predominantly in the right kidney with an average size of 5.9 cm. Immunohistochemistry analysis showed that the neoplastic cells were positive for CEA (7/8), AE1/3 (8/8), CAM5.2 (7/7), CK7 (5/5), CK20 (4/6), and vimentin (6/6). Absence of SMARCB1 protein expression in tumor cells was demonstrated in all of the 7 cases analyzed. By polymerase chain reaction-based microsatellite analysis, loss of heterozygosity of SMARCB1 was identified in 9 of 10 cases. These data suggest that inactivation of SMARCB1 may play a role in the pathogenesis of renal medullary carcinoma.

Morphologic and molecular characteristics of uterine leiomyomas in hereditary leiomyomatosis and renal cancer (HLRCC) syndrome.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a hereditary cancer syndrome in which affected individuals are predisposed to the development of multiple leiomyomas of the skin and uterus and aggressive forms of kidney cancer. Affected individuals harbor a germline heterozygous loss-of-function mutation of the fumarate hydratase (FH) gene. Uterine leiomyomas are present in up to 77% of women with this syndrome. Previous studies have shown that inactivation of the FH gene is unusual for nonsyndromic leiomyomas. Therefore, it might be possible to distinguish 2 genetic groups of smooth muscle tumors: the most common group of sporadic uterine leiomyomas without FH gene inactivation and the more unusual group of HLRCC leiomyomas in patients who harbor a germline mutation of FH, although the exact prevalence of hereditary HLRCC is unknown. We reviewed the clinical, morphologic, and genotypic features of uterine leiomyomas in 19 HLRCC patients with FH germline mutations. Patients with HLRCC syndrome were younger in age compared with those with regular leiomyomata. DNA was extracted by microdissection, and analysis of loss of heterozygosity (LOH) at 1q43 was performed. Uterine leiomyomas in HLRCC have young age of onset and are multiple, with size ranging from 1 to 8 cm. Histopathologically, HLRCC leiomyomas frequently had increased cellularity, multinucleated cells, and atypia. All cases showed tumor nuclei with large orangeophilic nucleoli surrounded by a perinucleolar halo similar to the changes found in HLRCC. Occasional mitoses were found in 3 cases; however, the tumors did not fulfill the criteria for malignancy. Our study also showed that LOH at 1q43 was frequent in HLRCC leiomyomas (8/10 cases), similarly to what has been previously found in renal cell carcinomas from HLRCC patients. LOH is considered to be the second hit that inactivates the FH gene. We conclude that uterine leiomyomas associated with HLRCC syndrome have characteristic morphologic features. Both, uterine leiomyomas and renal cell carcinoma share some morphologic nuclear changes and genotypic features in HLRCC patients. The specific morphologic features of the uterine leiomyomas that we describe may help in the identification of patients who may be part of the hereditary syndrome.

A new hypoxia inducible factor-2 inhibitory pyrrolinone alkaloid from roots and stems of Piper sarmentosum.

A new trimethoxycinnamoyl-2-pyrrolinone alkaloid, langkamide (1), along with the known compounds piplartine (2) and 3,4,5-trimethoxycinnamic acid (3) were isolated from the roots and stems of the shrub Piper sarmentosum ROXB. The structures were established by spectroscopic analyses and comparison of their spectral data with values reported in the literature. The compounds were tested for their ability to modulate hypoxia inducible factor-2 (HIF-2) transcription activity and all three showed HIF-2 inhibitory activity with EC50 values of 14.0, 4.8, and 60.6 µM, respectively, for compounds 1, 2, and 3.

Outcomes and timing for intervention of partial adrenalectomy in patients with a solitary adrenal remnant and history of bilateral phaeochromocytomas.

OBJECTIVE: To evaluate the outcomes and timing of intervention for adrenal-sparing surgery in patients left with a solitary adrenal remnant after bilateral adrenal surgeries. PATIENTS AND METHODS: Patients were included in the study if they had undergone bilateral adrenal surgery as a treatment for phaeochromocytoma and were left with a solitary adrenal remnant. Perioperative, functional and oncological outcomes were evaluated in 21 patients who met the inclusion criteria. RESULTS: There was minimal perioperative morbidity and no perioperative mortality. After a median (range) follow-up of 21 (3-143) months, there were two cases of persistent disease. Ten patients (48%) required steroid supplementation upon discharge, with four subsequently discontinuing this treatment. Patients were more likely to require steroid supplementation after surgery if they underwent simultaneous adrenalectomy and contralateral partial adrenalectomy, rather than staged procedures (86 vs 40%, P = 0.02). Patients who underwent surgery for tumours > 4 cm were more likely to require long-term steroids than patients who underwent surgery for lesions < 4 cm (75 vs 18%, P = 0.05). CONCLUSIONS: Patients left with a solitary adrenal remnant after bilateral adrenal surgery have low surgical morbidity, reasonable functional outcomes and low rates of recurrence at an intermediate follow-up period. A staged approach could decrease the immediate postoperative need for steroids, and intervention before the largest tumour reaches 4 cm could decrease the rate of long-term steroid dependence.

The morphologic spectrum of kidney tumors in hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant familial syndrome characterized by the development of cutaneous and uterine leiomyomas as well as renal tumors. The mutation of this condition has been identified in the fumarate hydratase (FH, 1q42.3-q43) gene. The histology of the renal cancers has not been well described or illustrated because of the newness of the syndrome. We reviewed 40 renal tumors resected from 38 patients belonging to HLRCC families with proven fumarate hydratase germline mutation. Patients ranged in age from 17 to 75 years of age. Tumors were unilateral in all but 2 cases. The size of the tumors varied between 2.3 and 20 cm and there was no laterality preference. Several different architectural patterns were recognized: papillary (25 cases), tubulo-papillary (8 cases), tubular (2 cases), and solid (1 case). Mixed patterns were also present in 4 cases. The most important histologic feature of these neoplasms, which we believe to be the hallmark of the HLRCC tumors, is the presence of a characteristic large nucleus with a very prominent inclusion like orangiophilic or eosinophilic nucleolus, surrounded by a clear halo. Immunohistochemical studies did not provide a specific marker for these tumors, however, loss of heterozygosity at 1q32 and 1q42-44 was frequently found. These tumors are associated with poor prognosis and frequent spread to regional lymph nodes. At the moment, morphology is the best tool to recognize these tumors. Proper diagnosis of this syndrome by the pathologist may assist in early detection of these tumors.