NLRC5 promotes endometrial carcinoma progression by regulating NF-κB pathway-mediated mismatch repair gene deficiency.

The innate immune molecule NLR family CARD domain-containing 5 (NLRC5) plays a significant role in endometrial carcinoma (EC) immunosurveillance. However, NLRC5 also plays a protumor role in EC cells. Mismatch repair gene deficiency (dMMR) can enable tumors to grow faster and also can exhibit high sensitivity to immune checkpoint inhibitors. In this study, we attempted to determine whether NLRC5-mediated protumor role in EC is via the regulation of dMMR. Our findings revealed that NLRC5 promoted the proliferation, migration, and invasion abilities of EC cells and induced the dMMR status of EC in vivo and in vitro. Furthermore, the mechanism underlying NLRC5 regulated dMMR was also verified. We first found NLRC5 could suppress nuclear factor-kappaB (NF-κB) pathway in EC cells. Then we validated that the positive effect of NLRC5 in dMMR was restricted when NF-κB was activated by lipopolysaccharides in NLRC5-overexpression EC cell lines. In conclusion, our present study confirmed the novel NLRC5/NF-κB/MMR regulatory mechanism of the protumor effect of NLRC5 on EC cells, thereby suggesting that the NLRC5-mediated protumor in EC was depend on the function of MMR.

Conditional Covalent Lethality Driven by Oncometabolite Accumulation.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a cancer predisposition syndrome driven by mutation of the tumor suppressor fumarate hydratase (FH). Inactivation of FH causes accumulation of the electrophilic oncometabolite fumarate. In the absence of methods for reactivation, tumor suppressors can be targeted via identification of synthetic lethal interactions using genetic screens. Inspired by recent advances in chemoproteomic target identification, here, we test the hypothesis that the electrophilicity of the HLRCC metabolome may produce unique susceptibilities to covalent small molecules, a phenomenon we term conditional covalent lethality. Screening a panel of chemically diverse electrophiles, we identified a covalent ligand, MP-1, that exhibits FH-dependent cytotoxicity. Synthesis and structure-activity profiling identified key molecular determinants underlying the molecule's effects. Chemoproteomic profiling of cysteine reactivity together with clickable probes validated the ability of MP-1 to engage an array of functional cysteines, including one lying in the Zn-finger domain of the tRNA methyltransferase enzyme TRMT1. TRMT1 overexpression rescues tRNA methylation from inhibition by MP-1 and partially attenuates the covalent ligand's cytotoxicity. Our studies highlight the potential for covalent metabolites and small molecules to synergistically produce novel synthetic lethal interactions and raise the possibility of applying phenotypic screening with chemoproteomic target identification to identify new functional oncometabolite targets.

BAPoma presenting as an incidental scalp papule: case report, literature review, and screening recommendations for BAP1 tumor predisposition syndrome.

OBJECTIVE: BRCA1-associated protein 1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is associated with an increased risk for aggressive cancers. BAP1-inactivated melanocytic tumors (BIMTs) are observed in 75% of BAP1-TPDS, often presenting as early as the second decade of life. These lesions may serve as a predictive marker to identify patients who carry germline BAP1 mutations and thus are at higher risk of developing associated cancers. Early diagnosis for these malignancies is crucial for curative treatment. METHODS: We report a patient who presented with an incidental scalp papule for which biopsy was consistent with a BIMT. A review of literature was conducted by accessing the PubMed database to delineate present knowledge of BIMTs, assess recommendations for screening of germline BAP1 mutations, and evaluate cancer surveillance strategies for BAP1-TPDS associated cancers. RESULTS: Consensus in literature indicates that genetic evaluation should be encouraged in patients presenting with multiple BIMTs or a new BIMT with significant family history of BAP1-TPDS related cancers. If positive for a germline BAP1 mutation, cancer surveillance should be recommended for early diagnosis and timely intervention. CONCLUSIONS: Further workup should be encouraged in patients who meet the proposed screening criteria for germline BAP1 mutations. Patients could benefit from cancer surveillance for earlier diagnosis, management, and improved outcomes.

Clear cell and papillary renal cell carcinomas in hereditary papillary renal cell carcinoma (HPRCC) syndrome: a case report.

BACKGROUND: Hereditary papillary renal cell carcinoma (HPRCC) is a rare autosomal dominant disease characterized by the development of multiple and bilateral papillary type I renal cell carcinomas (RCC) and papillary adenomas caused by activating mutations in the MET proto-oncogene. Classically, distinctive histological features of RCC are described according to the familial renal cell carcinoma syndrome. To date, no clear cell RCC has been reported in HPRCC syndrome. CASE PRESENTATION: We describe the case of a 51-year-old man with a germline MET mutation detected on peripheral blood testing, and no germline VHL mutation, who developed numerous papillary tumors but also unexpectedly clear cell renal cell carcinomas. During the follow-up, an adrenal metastasis was observed 7 years after the initial diagnosis corresponding to a clear cell RCC metastasis. By immunohistochemistry, clear cell tumors showed focal cytokeratin 7, moderate racemase, and diffuse and membranous CAIX expression, while papillary tumors expressed strong diffuse cytokeratin 7 and racemase without CAIX positivity. Using FISH, VHL deletion was observed in one of the clear cell tumors, and the metastatic clear cell tumor presented a trisomy of chromosomes 7 and 17. These last genomic alterations are usually detected in papillary RCC, highlighting the potential link between both histological subtypes of tumors and the HPRCC syndrome. CONCLUSIONS: The pathologist must be aware that the presence of a non-papillary RCC associated with numerous papillary tumors should not exclude the diagnostic suspicion of HPRCC and thus to perform a thorough genomic study.

Precision Therapy for Brain Tumors in Hereditary Syndromes.

OPINION STATEMENT: Nervous system tumors arising in the setting of monogenic, hereditary cancer predisposition syndromes are unique in that the initiating genetic event in tumor formation is known. This knowledge provides a powerful treatment approach if the alteration or pathway can be targeted with a therapeutic agent. A reasonable argument can be made for the use of targeted agents in these tumor patients, even though many of them have FDA approval only for other tumor types. It is our practice to use and employ targeted therapy when standard treatments have failed or represent an unattractive option. Over time, however, targeted therapies will likely become first-line options.

MUC5AC expression is linked to mucinous/endometroid subtype, absence of nodal metastasis and mismatch repair deficiency in ovarian cancer.

Mucin 5AC (MUC5AC) is a secreted gel-forming mucin which is expressed by mucus producing cells of several organs but can also be found in cancer cells of the ovary, pancreas, and gastrointestinal tract. This study aimed to characterize the expression of MUC5AC and its potential prognostic implications in different ovarian cancer subtypes. MUC5AC expression was analyzed by immunohistochemistry on a tissue microarray containing 603 ovarian cancers. MUC5AC was commonly expressed in mucinous (27/36; 75%) and endometrioid (12/39; 31%) carcinomas, whereas malignant mixed Mullerian tumors (2/27; 7%), high-grade serous (20/373; 5%) and clear cell carcinomas (1/28; 4%) were only rarely MUC5AC positive and also showed lower expression levels. MUC5AC positive endometroid carcinomas and high-grade serous carcinomas lacked lymph node metastases (p = 0.0495 and p = 0.0216) suggesting a more favorable prognosis. Deficient mismatch repair (dMMR), associated with a favorable prognosis in different cancer types, was found in 4/39 (10%) MUC5AC positive cancers but in only 5/375 (1%) of MUC5AC negative cancers (p = 0.0052). In subgroup analyses MUC5AC positive endometroid carcinomas more frequently showed dMMR (4/10; 40%) as opposed to MUC5AC negative endometroid carcinomas (3/23; 13%; p = 0.0932). In summary, the results of our study show that MUC5AC expression is associated with mucinous and endometrioid ovarian carcinomas, lack of nodal metastases and dMMR. MUC5AC expressing ovarian cancers should be evaluated for dMMR.

Survival Benefit for Individuals With Constitutional Mismatch Repair Deficiency Undergoing Surveillance.

PURPOSE: Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS: Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS: A total of 193 malignant tumors in 110 patients were identified. Median age of first cancer diagnosis was 9.2 years (range: 1.7-39.5 years). For patients undergoing surveillance, all GI and other solid tumors, and 75% of brain cancers were detected asymptomatically. By contrast, only 16% of hematologic malignancies were detected asymptomatically (P < .001). Eighty-nine patients were followed prospectively and used for survival analysis. Five-year overall survival (OS) was 90% (95% CI, 78.6 to 100) and 50% (95% CI, 39.2 to 63.7) when cancer was detected asymptomatically and symptomatically, respectively (P = .001). Patient outcome measured by adherence to the surveillance protocol revealed 4-year OS of 79% (95% CI, 54.8 to 90.9) for patients undergoing full surveillance, 55% (95% CI, 28.5 to 74.5) for partial surveillance, and 15% (95% CI, 5.2 to 28.8) for those not under surveillance (P < .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION: Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD.

Lynch Syndrome in Thai Endometrial Cancer Patients.

BACKGROUND: Lynch syndrome increases lifetime risk of endometrial cancer to 40-60%. Screening with molecular tumor testing for mismatch repair (MMR) proteins have been recommended. This study aims to evaluate the incidence of MMR deficiency and germline mutation in endometrial cancer Thai patients. METHODS: Immunohistochemistry for MMR proteins, including MLH1, MSH2, MSH6 and PMS2 were tested in 166 surgical specimens. Patients who had MMR deficiencies were offered genetic counseling and a germline testing using gene-panel next generation sequencing. RESULTS: Fifty-eight of 166 patients (34.9%) had one or more MMR deficiencies which were: MLH1 and PMS2 in 42 patients (25.3%), MSH2 and MSH6 in 11 patients (6.6%), and MSH6 in 5 patients (3.0%). Of the 40 patients (24.1%) who met the revised Bethesda guidelines, 19 patients (47.5%) had MMR deficiency. In contrast, MMR deficiency was found in 39 of the 126 patients (31.0%) who did not meet the revised Bethesda guidelines. A total of 27 patients with MMR deficiencies agreed to have germline genetic testing. Germline MMR mutations were detected in 5 patients (18.5%) including MSH6 (n=2), PMS2 (n=2), and MLH1 mutations (n=1). Incidental germline mutations in other genes were detected in 3 patients (1 BRCA1, 1 PTEN, and 1 BARD1). Among 5 Lynch syndrome patients, 2 patients (40%) did not meet the revised Bethesda guidelines. Eight patients who met the revised Bethesda Guidelines but having MMR proficiency had genetic testing, but no germline mutation was detected. CONCLUSION: MMR deficiencies were detected in 34.9% of the endometrial cancer patients. Germline mutations were diagnosed in 3.0% of this cohort (5/166 patients). Lynch syndrome screening with MMR immunohistochemistry should be considered in all patients regardless of personal or family history of Lynch syndrome-related cancers.

Proteogenomic landscape of uterine leiomyomas from hereditary leiomyomatosis and renal cell cancer patients.

Pathogenic mutations in fumarate hydratase (FH) drive hereditary leiomyomatosis and renal cell cancer (HLRCC) and increase the risk of developing uterine leiomyomas (ULMs). An integrated proteogenomic analysis of ULMs from HLRCC (n = 16; FH-mutation confirmed) and non-syndromic (NS) patients (n = 12) identified a significantly higher protein:transcript correlation in HLRCC (R = 0.35) vs. NS ULMs (R = 0.242, MWU p = 0.0015). Co-altered proteins and transcripts (228) included antioxidant response element (ARE) target genes, such as thioredoxin reductase 1 (TXNRD1), and correlated with activation of NRF2-mediated oxidative stress response signaling in HLRCC ULMs. We confirm 185 transcripts previously described as altered between HLRCC and NS ULMs, 51 co-altered at the protein level and several elevated in HLRCC ULMs are involved in regulating cellular metabolism and glycolysis signaling. Furthermore, 367 S-(2-succino)cysteine peptides were identified in HLRCC ULMs, of which sixty were significantly elevated in HLRCC vs. NS ULMs (LogFC = 1.86, MWU p < 0.0001). These results confirm and define novel proteogenomic alterations in uterine leiomyoma tissues collected from HLRCC patients and underscore conserved molecular alterations correlating with inactivation of the FH tumor suppressor gene.

Combined vaccine-immune-checkpoint inhibition constitutes a promising strategy for treatment of dMMR tumors.

BACKGROUND: Mlh1-knock-out-driven mismatch-repair-deficient (dMMR) tumors can be targeted immunologically. By applying therapeutic tumor vaccination, tumor growth is delayed but escape mechanisms evolve, including upregulation of immune-checkpoint molecules (LAG-3, PD-L1). To counteract immune escape, we investigated the therapeutic activity of a combined tumor vaccine-immune-checkpoint inhibitor therapy using α-PD-L1. DESIGN: In this trial, Mlh1-knock-out mice with established gastrointestinal tumors received single or thrice injections of α-PD-L1 monoclonal antibody clone 6E11 (2.5 mg/kg bw, q2w, i.v.) either alone or in combination with the vaccine. Longitudinal flow cytometry and PET/CT imaging studies were followed by ex vivo functional immunological and gene expression assays. RESULTS: 6E11 monotherapy slightly increased median overall survival (mOS: 6.0 weeks vs. control 4.0 weeks). Increasing the number of injections (n = 3) improved therapy outcome (mOS: 9.2 weeks) and was significantly boosted by combining 6E11 with the vaccine (mOS: 19.4 weeks vs. 10.2 weeks vaccine monotherapy). Accompanying PET/CT imaging confirmed treatment-induced tumor growth control, with the strongest inhibition in the combination group. Three mice (30%) achieved a complete remission and showed long-term survival. Decreased levels of circulating splenic and intratumoral myeloid-derived suppressor cells (MDSC) and decreased numbers of immune-checkpoint-expressing splenic T cells (LAG-3, CTLA-4) accompanied therapeutic effects. Gene expression and protein analysis of residual tumors revealed downregulation of PI3K/Akt/Wnt-and TGF-signaling, leading to T cell infiltration, reduced numbers of macrophages, neutrophils and MDSC. CONCLUSIONS: By successful uncoupling of the PD-1/PD-L1 axis, we provide further evidence for the safe and successful application of immunotherapies to combat dMMR-driven malignancies that warrants further investigation.

Critical role of Aquaporin-1 and telocytes in infantile hemangioma response to propranolol beta blockade.

Propranolol, a nonselective ß-adrenergic receptor (ADRB) antagonist, is the first-line therapy for severe infantile hemangiomas (IH). Since the incidental discovery of propranolol efficacy in IH, preclinical and clinical investigations have shown evidence of adjuvant propranolol response in some malignant tumors. However, the mechanism for propranolol antitumor effect is still largely unknown, owing to the absence of a tumor model responsive to propranolol at nontoxic concentrations. Immunodeficient mice engrafted with different human tumor cell lines were treated with anti-VEGF bevacizumab to create a model sensitive to propranolol. Proteomics analysis was used to reveal propranolol-mediated protein alteration correlating with tumor growth inhibition, and Aquaporin-1 (AQP1), a water channel modulated in tumor cell migration and invasion, was identified. IH tissues and cells were then functionally investigated. Our functional protein association networks analysis and knockdown of ADRB2 and AQP1 indicated that propranolol treatment and AQP1 down-regulation trigger the same pathway, suggesting that AQP1 is a major driver of beta-blocker antitumor response. Examining AQP1 in human hemangioma samples, we found it exclusively in a perivascular layer, so far unrecognized in IH, made of telocytes (TCs). Functional in vitro studies showed that AQP1-positive TCs play a critical role in IH response to propranolol and that modulation of AQP1 in IH-TC by propranolol or shAQP1 decreases capillary-like tube formation in a Matrigel-based angiogenesis assay. We conclude that IH sensitivity to propranolol may rely, at least in part, on a cross talk between lesional vascular cells and stromal TCs.

Hereditary leiomyomatosis and renal cell carcinoma syndrome associated uterine smooth muscle tumors: Bridging morphology and clinical screening.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an autosomal dominant familial syndrome that results from germline mutation in the fumarate hydratase (FH) gene and is associated with an increased risk for smooth muscle tumors of the uterus and skin and renal cell carcinoma. HLRCC associated RCC develop in up to 25% of patients, often presenting in the fourth decade and are high stage, aggressive tumors with poor clinical outcome. Most women with HLRCC develop large and bulky uterine smooth muscle tumors (USMT) in the second to third decade, thus presenting the ideal opportunity for early detection of HLCC to enable timely implementation of surveillance for their RCC risk. However, the concept of screening women with USMT for HLRCC is challenging given that HLRCC is rare but USMT are common. In addition, FH deficiency in USMT can also result from sporadic FH gene aberrations, unrelated to HLRCC, further complicating any potential screening process. Recent studies show that tumor morphology can be used to identify FH deficiency in USMT and thereby direct patients to formal genetic counseling. The low magnification clues of staghorn shaped blood vessels and alveolar pattern should prompt for high magnification examination for eosinophilic cytoplasmic inclusions and oval nuclei containing prominent eosinophilic macronucleoli surrounded by a halo. Additional clues include Schwannoma-like growth and chain-like distribution of the tumor cells. Although immunostains exist for FH and 2SC, their role is limited in the presence of well-developed FH deficient morphology. The prevalence of germline pathogenic mutation in FH among women with USMT with FH deficient morphology is as high as 50% in some studies, with somatic FH mutation accounting for the remainder. Therefore, morphologic evaluation of USMT for features of FH deficiency can serve as a screening tool for HLRCC syndrome by triaging patients to formal hereditary risk assessment.

Mismatch repair protein loss in cutaneous head and neck squamous cell carcinoma.

BACKGROUND: The treatment of advanced cutaneous head and neck cutaneous squamous cell carcinomas (HNcSCC) results in significant morbidity. Recently, immune checkpoint inhibitor treatment has been approved for DNA mismatch repair (MMR) deficient patients in a histology-agnostic manner. This study aims to evaluate the incidence of MMR deficiency in advanced HNcSCC and its association with clinicopathologic factors. METHODS: The cohort included 176 consecutive HNcSCC cases treated with curative intent. Immunohistochemistry for MMR proteins (hMLH1, hMSH2, hMSH6, and hPMS2) was performed. Clinicopathological and survival data was collected prospectively. RESULTS: The incidence of MMR protein deficiency was 9.1%. There was no association between age, incidence of metachronous malignancies, clinicopathological factors, or survival outcomes. CONCLUSION: A higher incidence of MMR deficiency was observed in this cohort of advanced HNcSCC. The lack of association with young age at onset or increased incidence of metachronous malignancies suggests that MMR deficiency is likely to be sporadic in HNcSCC.

Heterogeneous adaptation of cysteine reactivity to a covalent oncometabolite.

An important context in which metabolism influences tumorigenesis is the genetic cancer syndrome hereditary leiomyomatosis and renal cell carcinoma (HLRCC), a disease in which mutation of the tricarboxylic acid cycle enzyme fumarate hydratase (FH) causes hyperaccumulation of fumarate. This electrophilic oncometabolite can alter gene activity at the level of transcription, via reversible inhibition of epigenetic dioxygenases, as well as posttranslationally, via covalent modification of cysteine residues. To better understand the potential for metabolites to influence posttranslational modifications important to tumorigenesis and cancer cell growth, here we report a chemoproteomic analysis of a kidney-derived HLRCC cell line. Using a general reactivity probe, we generated a data set of proteomic cysteine residues sensitive to the reduction in fumarate levels caused by genetic reintroduction of active FH into HLRCC cell lines. This revealed a broad up-regulation of cysteine reactivity upon FH rescue, which evidence suggests is caused by an approximately equal proportion of transcriptional and posttranslational modification-mediated regulation. Gene ontology analysis highlighted several new targets and pathways potentially modulated by FH mutation. Comparison of the new data set with prior studies highlights considerable heterogeneity in the adaptive response of cysteine-containing proteins in different models of HLRCC. This is consistent with emerging studies indicating the existence of cell- and tissue-specific cysteine-omes, further emphasizing the need for characterization of diverse models. Our analysis provides a resource for understanding the proteomic adaptation to fumarate accumulation and a foundation for future efforts to exploit this knowledge for cancer therapy.

Multiple Cutaneous Leiomyomas Showing Increased FDG Uptake.

Cutaneous leiomyomas are rare, sporadic, or inherited benign tumors arising from smooth muscle cells of the skin associated with various disorders. We present a case of multiple cutaneous leiomyomas showing increased FDG uptake with SUVmax of 19.9. This case indicates cutaneous leiomyoma should be considered as a rare differential diagnosis in patients with hypermetabolic cutaneous lesions. Careful correlation with clinical history is needed to avoid misdiagnosis.

Histopathologic Analysis of Signet-ring Cell Carcinoma In Situ in Patients With Hereditary Diffuse Gastric Cancer.

Hereditary diffuse gastric cancer (HDGC) is a rare autosomal dominant syndrome associated with an increased risk of developing Laurén's diffuse-type gastric carcinoma and lobular breast carcinoma. Although signet-ring cell carcinoma (SRCC) in situ (SRCC-pTis) has been reported as a characteristic lesion in HDGC cases with CDH1 germline mutations (CDH1 pathogenic variant), and a precursor of conventional intramucosal SRCC (SRCC-pT1a), its histopathologic features and specificity have not been sufficiently clarified. Here, we examined gastrectomy samples from 6 Japanese HDGC patients with CDH1 germline mutation, belonging to 4 families, and analyzed SRCC lesions histologically and immunohistochemically. Of the 274 foci found in the 6 samples, SRCC-pT1a accounted for 225 lesions (range: 8 to 107, mean 45.7 lesions per patient), while 46 foci were of SRCC-pTis (range: 1 to 15, mean 7.67 foci per patient). All SRCC-pTis foci were observed in the fundic gland area and on the superficial side of the mucosa. Histologically, tumor cells of SRCC-pTis were found between normal foveolar epithelial cells and the basement membrane, following a typical pagetoid spread pattern. Immunohistochemically, E-cadherin expression was lost in SRCC-pTis (27/28, 96.4%) more frequently than in SRCC-pT1a (95/197, 48.2%; P<0.001). To elucidate the specificity of SRCC-pTis for HDGC, 60 samples (range: 0.12 to 1.49 m, total 28.8 m of mucosal length) from gastric cancer cases were analyzed as controls, in which no SRCC-pTis were identified. Our results indicate that SRCC-pTis is a distinct histologic feature with high specificity for HDGC cases with CDH1 germline mutations.

Clinical-Grade Detection of Microsatellite Instability in Colorectal Tumors by Deep Learning.

BACKGROUND & AIMS: Microsatellite instability (MSI) and mismatch-repair deficiency (dMMR) in colorectal tumors are used to select treatment for patients. Deep learning can detect MSI and dMMR in tumor samples on routine histology slides faster and less expensively than molecular assays. However, clinical application of this technology requires high performance and multisite validation, which have not yet been performed. METHODS: We collected H&E-stained slides and findings from molecular analyses for MSI and dMMR from 8836 colorectal tumors (of all stages) included in the MSIDETECT consortium study, from Germany, the Netherlands, the United Kingdom, and the United States. Specimens with dMMR were identified by immunohistochemistry analyses of tissue microarrays for loss of MLH1, MSH2, MSH6, and/or PMS2. Specimens with MSI were identified by genetic analyses. We trained a deep-learning detector to identify samples with MSI from these slides; performance was assessed by cross-validation (N = 6406 specimens) and validated in an external cohort (n = 771 specimens). Prespecified endpoints were area under the receiver operating characteristic (AUROC) curve and area under the precision-recall curve (AUPRC). RESULTS: The deep-learning detector identified specimens with dMMR or MSI with a mean AUROC curve of 0.92 (lower bound, 0.91; upper bound, 0.93) and an AUPRC of 0.63 (range, 0.59-0.65), or 67% specificity and 95% sensitivity, in the cross-validation development cohort. In the validation cohort, the classifier identified samples with dMMR with an AUROC of 0.95 (range, 0.92-0.96) without image preprocessing and an AUROC of 0.96 (range, 0.93-0.98) after color normalization. CONCLUSIONS: We developed a deep-learning system that detects colorectal cancer specimens with dMMR or MSI using H&E-stained slides; it detected tissues with dMMR with an AUROC of 0.96 in a large, international validation cohort. This system might be used for high-throughput, low-cost evaluation of colorectal tissue specimens.

Functional evaluation of five BRCA2 unclassified variants identified in a Sri Lankan cohort with inherited cancer syndromes using a mouse embryonic stem cell-based assay.

Next-generation sequencing of Sri Lankan families with inherited cancer syndromes resulted in the identification of five BRCA2 variants of unknown clinical significance. Interpreting such variants poses significant challenges for both clinicians and patients. Using a mouse embryonic stem cell-based functional assay, we found I785V, N830D, and K2077N to be functionally indistinguishable from wild-type BRCA2. Specific but mild sensitivity to olaparib and reduction in homologous recombination (HR) efficiency suggest partial loss of function of the A262T variant. This variant is located in the N-terminal DNA binding domain of BRCA2 that can facilitate HR by binding to dsDNA/ssDNA junctions. P3039P is clearly pathogenic because of premature protein truncation caused by exon 23 skipping. These findings highlight the value of mouse embryonic stem cell-based assays for determining the functional significance of variants of unknown clinical significance and provide valuable information regarding risk estimation and genetic counseling of families carrying these BRCA2 variants.

Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers: III: Molecular Pathology of Kidney Cancer.

Renal cell carcinoma (RCC) subtypes are increasingly being discerned via their molecular underpinnings. Frequently this can be correlated to histologic and immunohistochemical surrogates, such that only simple targeted molecular assays, or none at all, are needed for diagnostic confirmation. In clear cell RCC, VHL mutation and 3p loss are well known; however, other genes with emerging important roles include SETD2, BAP1, and PBRM1, among others. Papillary RCC type 2 is now known to include likely several different molecular entities, such as fumarate hydratase (FH) deficient RCC. In MIT family translocation RCC, an increasing number of gene fusions are now described. Some TFE3 fusion partners, such as NONO, GRIPAP1, RBMX, and RBM10 may show a deceptive fluorescence in situ hybridization result due to the proximity of the genes on the same chromosome. FH and succinate dehydrogenase deficient RCC have implications for patient counseling due to heritable syndromes and the aggressiveness of FH-deficient RCC. Immunohistochemistry is increasingly available and helpful for recognizing both. Emerging tumor types with strong evidence for distinct diagnostic entities include eosinophilic solid and cystic RCC and TFEB/VEGFA/6p21 amplified RCC. Other emerging entities that are less clearly understood include TCEB1 mutated RCC, RCC with ALK rearrangement, renal neoplasms with mutations of TSC2 or MTOR, and RCC with fibromuscular stroma. In metastatic RCC, the role of molecular studies is not entirely defined at present, although there may be an increasing role for genomic analysis related to specific therapy pathways, such as for tyrosine kinase or MTOR inhibitors.

Synthetically Lethal Interactions of Heme Oxygenase-1 and Fumarate Hydratase Genes.

Elevated expression of heme oxygenase-1 (HO-1, encoded by HMOX1) is observed in various types of tumors. Hence, it is suggested that HO-1 may serve as a potential target in anticancer therapies. A novel approach to inhibit HO-1 is related to the synthetic lethality of this enzyme and fumarate hydratase (FH). In the current study, we aimed to validate the effect of genetic and pharmacological inhibition of HO-1 in cells isolated from patients suffering from hereditary leiomyomatosis and renal cell carcinoma (HLRCC)-an inherited cancer syndrome, caused by FH deficiency. Initially, we confirmed that UOK 262, UOK 268, and NCCFH1 cell lines are characterized by non-active FH enzyme, high expression of Nrf2 transcription factor-regulated genes, including HMOX1 and attenuated oxidative phosphorylation. Later, we demonstrated that shRNA-mediated genetic inhibition of HMOX1 resulted in diminished viability and proliferation of cancer cells. Chemical inhibition of HO activity using commercially available inhibitors, zinc and tin metalloporphyrins as well as recently described new imidazole-based compounds, especially SLV-11199, led to decreased cancer cell viability and clonogenic potential. In conclusion, the current study points out the possible relevance of HO-1 inhibition as a potential anti-cancer treatment in HLRCC. However, further studies revealing the molecular mechanisms are still needed.