Hereditary uveal melanoma: a report of a germline mutation in BAP1

Uveal Melanoma: Comprehensive Review of Its Pathophysiology, Diagnosis, Treatment, and Future Perspectives

Uveal melanoma (UM) is the most common intraocular malignancy in adults. Recent advances highlight the role of tumor-derived extracellular vesicles (TEV) and circulating hybrid cells (CHC) in UM tumorigenesis. Bridged with liquid biopsies, a novel technology that has shown incredible performance in detecting cancer cells or products derived from tumors in bodily fluids, it can significantly impact disease management and outcome. The aim of this comprehensive literature review is to provide a summary of current knowledge and ongoing advances in posterior UM pathophysiology, diagnosis, and treatment. The first section of the manuscript discusses the complex and intricate role of TEVs and CHCs. The second part of this review delves into the epidemiology, etiology and risk factors, clinical presentation, and prognosis of UM. Third, current diagnostic methods, ensued by novel diagnostic tools for the early detection of UM, such as liquid biopsies and artificial intelligence-based technologies, are of paramount importance in this review. The fundamental principles, limits, and challenges associated with these diagnostic tools, as well as their potential as a tracker for disease progression, are discussed. Finally, a summary of current treatment modalities is provided, followed by an overview of ongoing preclinical and clinical research studies to provide further insights on potential biomolecular pathway alterations and therapeutic targets for the management of UM. This review is thus an important resource for all healthcare professionals, clinicians, and researchers working in the field of ocular oncology.

Characterization and Quantitation of the Tumor Microenvironment of Uveal Melanoma

Uveal melanoma (UM) is a highly malignant tumor of the eye. Metastatic spread of UM occurs almost exclusively via blood vessels and is of tremendous interest, as half of the patients with uveal melanoma die of metastasis in the long run. The tumor microenvironment consists of all cellular and non-cellular compounds of a solid tumor, except for the tumor cells. This study aims to provide a more detailed understanding of the tumor microenvironment of UM to build the foundation for new therapeutic targets. Fluorescence immunohistochemistry was performed to examine the localization of various cell types in the tumor microenvironment in UM. Furthermore, the presence of LAG-3 and its ligands Galectine-3 and LSECtin was examined to evaluate the potential efficacy of immune checkpoint inhibitor-based therapies. The main findings are that blood vessels are mainly located in the middle of the tumor, and that immune cells are mostly found in the outer section of the tumor. LAG-3 and Galectine-3 were found to be highly represented, whereas LSECtin barely occurred in UM. Both the predominant location of tumor-associated macrophages in the outer section of the tumor and the high presence of LAG-3 and Galectine-3 in the UM serve as attainable therapeutic targets.

Novel loss-of-function variant in DENND5A impedes melanosomal cargo transport and predisposes to familial cutaneous melanoma

PURPOSE

More than half of the familial cutaneous melanomas have unknown genetic predisposition. This study aims at characterizing a novel melanoma susceptibility gene.

METHODS

We performed exome and targeted sequencing in melanoma-prone families without any known melanoma susceptibility genes. We analyzed the expression of candidate gene DENND5A in melanoma samples in relation to pigmentation and UV signature. Functional studies were carried out using microscopic approaches and zebrafish model.

RESULTS

We identified a novel DENND5A truncating variant that segregated with melanoma in a Swedish family and 2 additional rare DENND5A variants, 1 of which segregated with the disease in an American family. We found that DENND5A is significantly enriched in pigmented melanoma tissue. Our functional studies show that loss of DENND5A function leads to decrease in melanin content in vitro and pigmentation defects in vivo. Mechanistically, harboring the truncating variant or being suppressed leads to DENND5A losing its interaction with SNX1 and its ability to transport the SNX1-associated vesicles from melanosomes. Consequently, untethered SNX1-premelanosome protein and redundant tyrosinase are redirected to lysosomal degradation by default, causing decrease in melanin content.

CONCLUSION

Our findings provide evidence of a physiological role of DENND5A in the skin context and link its variants to melanoma susceptibility.

Familial Melanoma and Susceptibility Genes: A Review of the Most Common Clinical and Dermoscopic Phenotypic Aspect, Associated Malignancies and Practical Tips for Management

A family history of melanoma greatly increases the risk of developing cutaneous melanoma, a highly aggressive skin cancer whose incidence has been steadily increasing worldwide. Familial melanomas account for about 10% of all malignant melanomas and display an inheritance pattern consistent with the presence of pathogenic germline mutations, among which those involving CDKN2A are the best characterized. In recent years, a growing number of genes, such as MC1R, MITF, CDK4, POT1, TERT, ACD, TERF2IP, and BAP1, have been implicated in familial melanoma. The fact that individuals harboring these germline mutations along with their close blood relatives have a higher risk of developing multiple primary melanomas as well as other internal organ malignancies, especially pancreatic cancer, makes cascade genetic testing and surveillance of these families of the utmost importance. Unfortunately, due to a polygenic inheritance mechanism involving multiple low-risk alleles, genetic modifiers, and environmental factors, it is still very difficult to predict the presence of these mutations. It is, however, known that germline mutation carriers can sometimes develop specific clinical traits, such as high atypical nevus counts and specific dermoscopic features, which could theoretically help clinicians predict the presence of these mutations in prone families. In this review, we provide a comprehensive overview of the high- and intermediate-penetrance genes primarily linked to familial melanoma, highlighting their most frequently associated non-cutaneous malignancies and clinical/dermoscopic phenotypes.

CDKN2A genetic testing in melanoma-prone families in Sweden in the years 2015-2020: implications for novel national recommendations

Background: Inherited pathogenic variants (PVs) in the CDKN2A gene are among the strongest known risk factors for cutaneous melanoma. Carriers are at high risks to develop multiple primary melanomas and other cancers, in particular pancreatic cancer. In this study, the CDKN2A testing, carried out in Sweden in the years 2015-2020, was evaluated.Materials and methods: Included families had (1) three or more cases of melanoma and/or pancreatic cancer, (2) two melanomas in first-degree relatives, the youngest case <55 years or (3) individuals with three or more multiple primary melanomas, the first before the age of 55 years, and no other affected family members. The included families had at least one affected member that had been tested for CDKN2A PVs.Results: In total, 403 families were included, whereof 913 family members had been diagnosed with cutaneous melanoma and 129 with pancreatic cancer, 33 (8.2%) were found to have PVs in CDKN2A. Frequencies ranged from 0.9% in families with only two melanomas to 43.2% in families with three or more melanoma cases and pancreatic cancer (p < 0.001). The frequency of PVs ranged from 2.1% to 16.5% in families where the youngest case was ≥55 years or <35 years (p = 0.040). In families with or without CDKN2A PVs, 37.6% and 10.0% had melanoma cases that had died from melanoma, respectively (p < 0.001).Discussion: Significant differences were seen in the frequencies of CDKN2A PVs, dependent on numbers or age at diagnosis of melanomas and diagnoses of pancreatic cancers in the family. Further, melanoma cases belonging to families that tested positive for CDKN2A PVs had a significantly higher mortality. To summarize, the current evaluation shows that, with adequately selected criteria to guide genetic testing, CDKN2A PVs are identified at significant frequencies. Identification of carrier families is of importance to ensure that members are enrolled in a preventive surveillance program.

Genetic Association of Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

Age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are leading causes of irreversible blindness among the elderly population in developed countries. Although being considered as different subtypes of a same disease, neovascular AMD and PCV have differences in clinical, epidemiological, therapeutic, and genetic profiles. Both AMD and PCV are complex diseases involving multiple genetic and environmental risk factors. Different genetic strategies have been adopted to discover associated genes and variants for neovascular AMD and PCV, including genome-wide association study (GWAS), next-generation sequencing (NGS) based sequence analysis, and candidate gene analyses. So far, a number of susceptible genes have been identified for AMD and/or PCV, such as CFH, ARMS2-HTRA1, C2-CFB-SKIV2L, C3, CETP, and FGD6. Although many of these genes are shared by AMD and PCV, some showed difference between them, such as ARMS2-HTRA1 and FGD6. Also, some of the genes showed ethnic diversities, such as the CFH p.Tyr402His variant. Further larger-scale genomic studies should be warranted to identify more susceptibility genes for AMD and, in particular, PCV among different populations, and differentiate the genetic architectures between neovascular AMD and PCV.

Germline large deletion of BAP1 and decreased expression in non-tumor choroid in uveal melanoma patients with high risk for inherited cancer

Uveal melanoma (UM) is the most common phenotype in patients with germline BAP1 mutation. This study aimed to identify selection criteria for BAP1 germline testing and assessed the role of large deletion/duplication and epigenetic inactivation. One hundred seventy-two UM patients with high risk of hereditary cancer were included. Germline variants in BAP1 were assessed by direct sequencing and large deletion/duplication by multiplex ligation-dependent probe amplification. BAP1 expression in unaffected choroid tissue from a patient with UM was assessed by quantitative RT-PCR and methylation by pyrosequencing. Twenty-eight patients had one or more germline sequence variants in BAP1; seven of these were pathogenic. One hundred forty patients were assessed for large deletion/duplication and in one BAP1 whole gene deletion was detected. In total, eight patients (4.7%) had pathogenic alterations in BAP1 with the highest frequencies of in patients with a personal/family history of ≥2 BAP1-related cancers 6/16 (38%), age of onset <35 years 4/21 (19%) and familial UM 6/34 (18%). One of 19 non-tumor choroid tissues tested showed uncharacteristically low expression as compared to the controls decrease in BAP1 RNA expression but no evidence of constitutional promotor hypermethylation was detected. UM patients with a strong personal or family history of cancers associated with BAP1, early age of onset and familial UM should be assessed for germline variants in BAP1, including large deletions.

MOLECULAR PROGNOSTICS FOR UVEAL MELANOMA

PURPOSE

To review laboratory methods, currently available commercial tests, caveats and clinical tips regarding prognostic analysis of uveal melanoma tissue.

METHODS

A review of the literature was performed focused on the genetic abnormalities found in uveal melanoma cells, their correlation to the development of metastases, the validity of various laboratory approaches in their detection, and the existing commercially available tests for uveal melanoma prognostication.

RESULTS

Numerous laboratory methods exist for analyzing genetic material obtained from uveal melanoma cells. Older tests have been gradually replaced with contemporary methods that are simpler with greater accuracy. Two commercially available assays exist which have not been directly compared-a gene expression profiling test has been validated directly through a large, prospective multicenter study and a DNA-based test which uses laboratory methods supported by extensive historical data.

CONCLUSION

There are myriad laboratory methods for prognostic analysis of uveal melanoma tissue. These tests were historically only available to those with access to an outfitted laboratory. Newer commercially available assays have increased the accessibility of prognostic biopsy for uveal melanoma. The various caveats that exist when considering and performing prognostic biopsy of uveal melanoma are discussed.

Genotypic and Phenotypic Features of BAP1 Cancer Syndrome: A Report of 8 New Families and Review of Cases in the Literature

Importance

Patients with germline mutations in BAP1 may develop several flesh-colored melanocytic BAP1-mutated atypical intradermal tumors (MBAITs). These tumors generally develop earlier than other BAP1-associated tumors, highlighting an important role for dermatologists in identifying and screening patients with a history suggestive of a germline mutation.

Objective

To describe 8 new families with germline mutations in BAP1 and provide a comprehensive review of reported cases.

Design, Settings and Participants

Patients were identified in an outpatient dermatology clinical setting over a 6-month period (10 mutation carriers from 8 families) and through a literature review using PubMed (205 patients).

Exposures

Mutations were identified through next-generation sequencing of saliva or blood samples, and RNA was extracted from fibroblasts cultured from a patient with an intronic variant to determine the impact of the mutation on the coding sequence.

Main Outcomes and Measures

All 215 patients were assessed for personal and/or family history and genotype. These findings were compiled and assessed for any association between genotype and phenotype.

Results

Overall, this study included 215 patients (108 women, 91 men, and 16 gender unspecified; median [range] age, 46.5 [10.0-79.0] years). Nine of the 10 patients who were identified in the outpatient dermatology setting were found to have MBAITs on clinical examination. Forty of 53 patients (75%) identified in the literature review who underwent total-body skin examinations (TBSE) were found to have MBAITs, suggesting a high penetrance in patients who have undergone TBSE. The most prevalent malignancies among BAP1 mutation carriers were uveal melanoma (n =  60 [28%]), mesothelioma (n = 48 [22%]), cutaneous melanoma (n = 38 [18%]), and renal cell carcinoma (n = 20 [9%]). A total of 71 unique mutations in BAP1 have been reported.

Conclusions and Relevance

Our results indicate that germline mutations in both coding and noncoding regions throughout the BAP1 gene can impair protein function, leading to an increased risk for several associated malignancies. Four of the 8 probands we present had no history of BAP1-associated malignancies and were assessed for germline mutations when found to have MBAITs on dermatologic examination. Dermatologists can identify patients with a high likelihood of the BAP1 cancer syndrome through personal and family history and TBSE for the presence of possible MBAITs.

Uveal Melanoma Nuclear BRCA1-Associated Protein-1 Immunoreactivity Is an Indicator of Metastasis

PURPOSE

To examine the BRCA1-associated protein-1 (BAP1) expression of primary uveal melanomas without and with metastasis, and to analyze the correlation between the BAP1 immunoreactivity of primary uveal melanoma and other clinicopathologic features.

DESIGN

Retrospective case series.

PARTICIPANTS

Forty patients with uveal melanoma (mean age, 57.98±14.75 years) were included in this analysis, of whom 20 had no metastatic disease and 20 had metastasis.

METHODS

Medical records and histology slides of patients with primary uveal melanoma treated by enucleation were reviewed. BAP1 expression was evaluated by immunohistochemical staining of formalin-fixed, paraffin-embedded sections. Immunoreactivity in the nucleus and cytoplasm were graded by estimating the percentage of primary tumor cells showing a positive staining of their nucleus or cytoplasm per 1 high-power field 200× (grades 0-3).

MAIN OUTCOME MEASURES

Tumor size, histologic features, nuclear and cytoplasmic BAP1 immunoreactivity grade, and patient outcome, including development of metastasis.

RESULTS

Significantly lower (P = 0.025) nuclear BAP1 immunoreactivity was observed in the metastatic melanoma group. Greater tumor thickness, basal diameter, and more advanced TNM stage were associated with an increased odds ratio of developing metastasis (P < 0.05). In addition, tumors with a higher proportion of cells expressing nuclear BAP1 had decreased odds of developing metastatic disease in a multivariate model (P = 0.042). Metastasis-free survival was significantly longer in patients with uveal melanoma with high nuclear BAP1 stain (P = 0.004).

CONCLUSIONS

Time to metastasis differs in patients with primary uveal melanoma with different grades of nuclear BAP1 immunoreactivity. Nuclear BAP1 stain is the only significant independent predictor of metastatic disease in this study. Our data support the role of BAP1 immunohistochemical staining of primary uveal melanoma to evaluate metastatic risk.

BAP1, a tumor suppressor gene driving malignant mesothelioma

Like cancer generally, malignant mesothelioma (MM) is a genetic disease at the cellular level. DNA copy number analysis of mesothelioma specimens has revealed a number of recurrent sites of chromosomal loss, including 3p21.1, 9p21.3, and 22q12.2. The key inactivated driver genes located at 9p21.1 and 22q12.2 were discovered two decades ago as being the tumor suppressor loci CDKN2A and NF2, respectively. Only relatively recently was the BAP1 gene determined to be the driver gene at 3p21.1 that is somatically inactivated. In 2011, we reported germline mutations in BAP1 in two families with a high incidence of mesothelioma and other cancers such as uveal melanoma (UM). As a result of a flurry of research activity over the last 5-6 years, the BAP1 gene is now firmly linked causally to a novel tumor predisposition syndrome (TPDS) characterized by increased susceptibility to mesothelioma, UM, cutaneous melanoma (CM) and benign melanocytic tumors, as well as several other cancer types. Moreover, results from recent in vivo studies with genetically engineered Bap1-mutant mouse models and new functional studies have provided intriguing biological insights regarding BAP1's role in tumorigenesis. These and other recent findings offer new possibilities for novel preventative and therapeutic strategies for MM patients.

New concepts in the molecular understanding of uveal melanoma

PURPOSE OF REVIEW

Uveal melanoma is the most common primary intraocular malignancy, and its metastases are deadly. Significant work has been done to elucidate the molecular framework that causes uveal melanoma development and metastasis. This review is intended to highlight the most recent breakthroughs in the molecular understanding of uveal melanoma.

RECENT FINDINGS

Monosomy of chromosome 3 and class 2 gene-expression profile are well-known indicators of melanoma metastasis. However, some patients with disomy 3 and class 1 gene expression profiling (GEP) still develop metastasis. Disomy 3 tumors may be further classified based upon the presence of an SF3B1 mutation. The role of SF3B1 gene is unclear at this time but may be related to the development of late metastases among disomy 3 uveal melanoma. Class 1 GEP tumors have recently been subdivided into class 1a and class 1b, with class 1b tumors carrying a slightly higher risk of metastasis. Among patients with either class 1 or class 2 GEP, the expression of preferentially expressed antigen in melanoma (PRAME) is an independent risk factor for the development of metastasis. Mutation of GNAQ is the most commonly observed mutation in uveal melanoma, regardless of chromosome 3 status or GEP class. Inhibitors or GNAQ may be targets for therapeutic intervention in uveal melanoma. MicroRNA molecules are small noncoding RNA molecules that have been recently demonstrated to function in RNA silencing and posttranscriptional regulation of gene expression. These molecules may play a role in the development of uveal melanoma metastasis.

SUMMARY

New findings such as the presence or absence of PRAME, mutations in the SF3B1 gene and microRNA dysregulation have added new layers to our understanding of uveal melanoma. These new concepts will enhance our ability to prognosticate tumor metastasis and may provide targets for therapeutic intervention.

Germline BAP1 alterations in familial uveal melanoma

Uveal melanoma (UM) is the most commonly diagnosed primary intraocular tumor in adults. Familial UM (FUM), defined as two or more family members diagnosed with UM, is rare and estimated at less than 1% of all UM. Currently, BAP1 is the only gene known to contribute significant risk for UM. In this study we aimed to estimate the frequency of BAP1 mutation in FUM and to characterize the family and personal histories of other cancers in these families. We identified 32 families with FUM, including seven families previously reported by our group. BAP1 mutation testing was carried out by direct sequencing of the coding exons and the adjacent untranslated regions of the gene. Germline deletion and duplication analysis of BAP1 was assessed by multiplex ligation-dependent probe amplification (MLPA). Germline BAP1 mutations were found in 6/32 (19%) families. No deletions or duplications were identified in any of the 24 samples tested by MLPA. Combined with published studies, the frequency of BAP1 mutations was 14/64 (22%) in FUM. FUM families without BAP1 mutations have distinct family histories with high rates of prostate cancer in first- and second-degree relatives. It is likely that additional genes conferring risk for FUM exist. It is important to understand key shared features of FUM to focus future research on identifying these additional tumor predisposition syndromes. Though BAP1 should be tested first in these families, FUM families without BAP1 mutation should be explored for additional predisposition genes. © 2016 Wiley Periodicals, Inc.

The genetics of uveal melanoma: current insights

Uveal melanoma (UM) is the most common malignant eye tumor in adults affecting ~7,000 individuals per year worldwide. UM is a rare subtype of melanoma with distinct clinical and molecular features as compared to other melanoma subtypes. UMs lack the most typical cutaneous melanoma-associated mutations (BRAF, NRAS, and NF1) and are instead characterized by a different set of genes with oncogenic or loss-of-function mutations. By next-generation sequencing efforts on UM tumors, several driver genes have been detected. The most frequent ones are BAP1, EIF1AX, GNA11, GNAQ, and SF3B1. In many cases, mutations in these genes appear in a mutually exclusive manner, have different risk of metastasis, and are consequently of prognostic importance. The majority of UM cases are sporadic but a few percentage of the cases occurs in families with an inherited predisposition for this malignancy. In recent years, germline mutations in the BAP1 gene have been found to segregate in an autosomal dominant pattern with numerous different cancer types including UM in cancer-prone families. This cancer syndrome has been denoted as the tumor predisposition syndrome.

The role of germline alterations in the DNA damage response genes BRIP1 and BRCA2 in melanoma susceptibility

We applied a targeted sequencing approach to identify germline mutations conferring a moderately to highly increased risk of cutaneous and uveal melanoma. Ninety-two high-risk melanoma patients were screened for inherited variation in 120 melanoma candidate genes. Observed gene variants were filtered based on frequency in reference populations, cosegregation with melanoma in families and predicted functional effect. Several novel or rare genetic variants in genes involved in DNA damage response, cell-cycle regulation and transcriptional control were identified in melanoma patients. Among identified genetic alterations was an extremely rare variant (minor allele frequency of 0.00008) in the BRIP1 gene that was found to cosegregate with the melanoma phenotype. We also found a rare nonsense variant in the BRCA2 gene (rs11571833), previously associated with cancer susceptibility but not with melanoma, which showed weak association with melanoma susceptibility in the Swedish population. Our results add to the growing knowledge about genetic factors associated with melanoma susceptibility and also emphasize the role of DNA damage response as an important factor in melanoma etiology. © 2016 Wiley Periodicals, Inc.

The Pediatric Choroidal and Ciliary Body Melanoma Study: A Survey by the European Ophthalmic Oncology Group

PURPOSE

To collect comprehensive data on choroidal and ciliary body melanoma (CCBM) in children and to validate hypotheses regarding pediatric CCBM: children younger than 18 years, males, and those without ciliary body involvement (CBI) have more favorable survival prognosis than young adults 18 to 24 years of age, females, and those with CBI.

DESIGN

Retrospective, multicenter observational study.

PARTICIPANTS

Two hundred ninety-nine patients from 24 ocular oncology centers, of whom 114 were children (median age, 15.1 years; range, 2.7-17.9 years) and 185 were young adults.

METHODS

Data were entered through a secure website and were reviewed centrally. Survival was analyzed using Kaplan-Meier analysis and Cox proportional hazards regression.

MAIN OUTCOME MEASURES

Proportion of females, tumor-node-metastasis (TNM) stage, cell type, and melanoma-related mortality.

RESULTS

Cumulative frequency of having CCBM diagnosed increased steadily by 0.8% per year of age between 5 and 10 years of age and, after a 6-year transition period, by 8.8% per year from age 17 years onward. Of children and young adults, 57% and 63% were female, respectively, which exceeded the expected 51% among young adults. Cell type, known for 35% of tumors, and TNM stage (I in 22% and 21%, II in 49% and 52%, III in 30% and 28%, respectively) were comparable for children and young adults. Melanoma-related survival was 97% and 90% at 5 years and 92% and 80% at 10 years for children compared with young adults, respectively (P = 0.013). Males tended to have a more favorable survival than females among children (100% vs. 85% at 10 years; P = 0.058). Increasing TNM stage was associated with poorer survival (stages I, II, and III: 100% vs. 86% vs. 76%, respectively; P = 0.0011). By multivariate analysis, being a young adult (adjusted hazard rate [HR], 2.57), a higher TNM stage (HR, 2.88 and 8.38 for stages II and III, respectively), and female gender (HR, 2.38) independently predicted less favorable survival. Ciliary body involvement and cell type were not associated with survival.

CONCLUSIONS

This study confirms that children with CCBM have a more favorable survival than young adults 18 to 25 years of age, adjusting for TNM stage and gender. The association between gender and survival varies between age groups.

Connecting molecular pathways to hereditary cancer risk syndromes

An understanding of the genetic causes and molecular pathways of hereditary cancer syndromes has historically informed our knowledge and treatment of all types of cancers. For this review, we focus on three rare syndromes and their associated genetic mutations including BAP1, TP53, and SDHx (SDHA, SDHB, SDHC, SDHD, SDHAF2). BAP1 encodes an enzyme that catalyzes the removal of ubiquitin from protein substrates, and germline mutations of BAP1 cause a novel cancer syndrome characterized by high incidence of benign atypical melanocytic tumors, uveal melanomas, cutaneous melanomas, malignant mesotheliomas, and potentially other cancers. TP53 mutations cause Li-Fraumeni syndrome (LFS), a highly penetrant cancer syndrome associated with multiple tumors including but not limited to sarcomas, breast cancers, brain tumors, and adrenocortical carcinomas. Genomic modifiers for tumor risk and genotype-phenotype correlations in LFS are beginning to be identified. SDH is a mitochondrial enzyme complex involved in the tricarboxylic acid (TCA) cycle, and germline SDHx mutations lead to increased succinate with subsequent paragangliomas, pheochromocytomas, renal cell carcinomas (RCCs), gastrointestinal stromal tumors (GISTs), and other rarer cancers. In all of these syndromes, the molecular pathways have informed our understanding of tumor risk and successful early tumor surveillance and screening programs.

Update in genetic susceptibility in melanoma

Melanoma is the most deadly of the common skin cancers and its incidence is rapidly increasing. Approximately 10% of cases occur in a familial context. To date, cyclin-dependent kinase inhibitor 2A (CDKN2A), which was identified as the first melanoma susceptibility gene more than 20 years ago, is the main high-risk gene for melanoma. A few years later cyclin-dependent kinase 4 (CDK4) was also identified as a melanoma susceptibility gene. The technologic advances have allowed the identification of new genes involved in melanoma susceptibility: Breast cancer 1 (BRCA1) associated protein 1 (BAP1), CXC genes, telomerase reverse transcriptase (TERT), protection of telomeres 1 (POT1), ACD and TERF2IP, the latter four being involved in telomere maintenance. Furthermore variants in melanocortin 1 receptor (MC1R) and microphthalmia-associated transcription factor (MITF) give a moderately increased risk to develop melanoma. Melanoma genetic counseling is offered to families in order to better understand the disease and the genetic susceptibility of developing it. Genetic counseling often implies genetic testing, although patients can benefit from genetic counseling even when they do not fulfill the criteria for these tests. Genetic testing for melanoma predisposition mutations can be used in clinical practice under adequate selection criteria and giving a valid test interpretation and genetic counseling to the individual.

Melanoma genetics

Approximately 10% of melanoma cases report a relative affected with melanoma, and a positive family history is associated with an increased risk of developing melanoma. Although the majority of genetic alterations associated with melanoma development are somatic, the underlying presence of heritable melanoma risk genes is an important component of disease occurrence. Susceptibility for some families is due to mutation in one of the known high penetrance melanoma predisposition genes: CDKN2A, CDK4, BAP1, POT1, ACD, TERF2IP and TERT. However, despite such mutations being implicated in a combined total of approximately 50% of familial melanoma cases, the underlying genetic basis is unexplained for the remainder of high-density melanoma families. Aside from the possibility of extremely rare mutations in a few additional high penetrance genes yet to be discovered, this suggests a likely polygenic component to susceptibility, and a unique level of personal melanoma risk influenced by multiple low-risk alleles and genetic modifiers. In addition to conferring a risk of cutaneous melanoma, some 'melanoma' predisposition genes have been linked to other cancers, with cancer clustering observed in melanoma families at rates greater than expected by chance. The most extensively documented association is between CDKN2A germ line mutations and pancreatic cancer, and a cancer syndrome including cutaneous melanoma, uveal melanoma and mesothelioma has been proposed for BAP1 germ line mutations. Other medium to high penetrance melanoma predisposition genes have been associated with renal cell carcinoma (MITF, BAP1) and glioma (POT1). These associations between melanoma and other cancers hint at the possibility of common pathways for oncogenesis, and better knowledge of these pathways may improve understanding of the genetic basis underpinning familial melanoma. It is likely that 'melanoma' risk genes will impact on mutation screening and genetic counselling not only for melanoma but also a range of other cancers.

An asbestos-exposed family with multiple cases of pleural malignant mesothelioma without inheritance of a predisposing BAP1 mutation

We report a family with domestic exposure to asbestos and diagnosis of multiple cancers, including eight pleural malignant mesotheliomas and several other lung or pleural tumors. DNA sequence analysis revealed no evidence for an inherited mutation of BAP1. Sequence analysis of other potentially relevant genes, including TP53, CDKN2A, and BARD1, also revealed no mutation. DNA microarray analysis of tissue from two mesotheliomas revealed multiple genomic imbalances, including consistent losses of overlapping segments in 2q, 6q, 9p, 14q, 15q, and 22q, but no losses of chromosome 3 harboring the BAP1 locus. However, the results of immunohistochemical analysis demonstrated loss of nuclear BAP1 staining in three of six mesotheliomas tested, suggesting that somatic alterations of BAP1 occurred in a subset of tumors from this family. Since mesothelioma could be confirmed in only a single generation, domestic exposure to asbestos may be the predominant cause of mesothelioma in this family. Given the existence of unspecified malignant pleural tumors and lung cancers in a prior generation, we discuss the possibility that some other tumor susceptibility or modifier gene(s) may contribute to the high incidence of mesothelioma in this family. Because the incidence of mesothelioma in this family is higher than that expected even in workers heavily exposed to asbestos, we conclude that both asbestos exposure and genetic factors have played a role in the high rate of mesothelioma and potentially other pleural or lung cancers seen in this family. 

Non-ocular primary malignancies in patients with uveal melanoma: the Liverpool experience

AIM

To identify the prevalence of self-reported non-ocular primary malignancies in patients at the time of diagnosis with uveal melanoma (UM) and to describe the cohort's characteristics.

METHODS

A data query for cases of UM seen at the Liverpool Ocular Oncology Centre between January 1993 and May 2014 was performed. Only patients who had UM with other non-ocular primary malignancies were included. Demographic and clinical data were analysed.

RESULTS

A total of 5042 (2563 males, 50.8%) patients with UM were found in the database; of whom, 216 (4.3%) had at least one other primary non-ocular malignancy. Of these 216 patients, 119 were males (55.1%). Forty five males (37.8%) had been diagnosed with prostate cancer, 30 (25.2%) with unspecified skin cancers, 15 (12.6%) with colon and bowel carcinoma, eight (6.7%) with systemic lymphoma and the remaining patients with less common tumours. Of the 97 females, 45 (46.4%) had been diagnosed with breast carcinoma, 19 (19.6%) had unspecified skin cancers, seven (7.2%) renal cell carcinoma, six (6.2%) colon and bowel carcinoma, and the remaining patients had other less common tumour types. In this cohort, the frequency of the most common additional malignancy in male and female patients with UM was comparable with their prevalence in the general UK population.

CONCLUSIONS

Additional primary malignancies can occur in association with UM; therefore, medical history taking in patients with UM should always include this aspect. Apart from providing demographic and clinical data in such cases, future collaborative studies, which would include germline mutational testing, may reveal relevant common patterns.

Comprehensive review of BAP1 tumor predisposition syndrome with report of two new cases

The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a recently identified hereditary cancer syndrome. Germline mutations in this tumor suppressor gene predispose families to the development of various malignancies. The molecular functions of the gene as well as the clinical phenotype of the syndrome are still being clarified. We sought to conduct a comprehensive review of published research into BAP1-TPDS to more thoroughly delineate the clinical implications of germline BAP1 mutations. We also report two additional families with germline BAP1 mutations. Current evidence demonstrates that germline BAP1 mutations predispose families to uveal melanoma, renal cell carcinoma, malignant mesothelioma, cutaneous melanoma, and possibly to a range of other cancers as well. Some of these cancers tend to be more aggressive, have a propensity to metastasize, and onset earlier in life in patients with BAP1 mutations as compared to non-predisposed patients with equivalent cancers. Although further research is necessary, this information can aid in the management, diagnosis, and therapy of these patients and their families, and highlights the importance of genetic counseling.

CDKN2a mutation-negative melanoma families have increased risk exclusively for skin cancers but not for other malignancies

Germline CDKN2A mutations are found in 5-20% of melanoma families. Numerous studies have shown that carriers of CDKN2A mutations have increased risks of non-melanoma cancers, but so far there have been no studies investigating cancer risks in CDKN2A wild type (wt) melanoma families. In this prospective cohort study, index melanoma cases (n = 224) and their first-degree relatives (n = 944) were identified from 154 confirmed CDKN2A wt melanoma families. Cancer diagnoses in family members and matched controls were obtained from the Swedish Cancer Registry. Relative risks (RR), odds ratios (OR) and two-sided 95% confidence intervals (95% CI) were calculated. In index cases and first-degree relatives, the prospective RR for melanoma was 56.9 (95% CI 31.4-102.1) and 7.0 (95% CI 4.2-11.4), respectively, and for squamous cell skin cancers 9.1 (95% CI 6.0-13.7) and 3.4 (95% CI 2.2-5.2), respectively. In neither group, elevated risks were seen for non-skin cancers. In a subgroup analysis, CDKN2A wt melanoma families with young (<40 years) melanoma cases were found to have increased risk of non-skin cancers (RR 1.5, 95% CI 1.0-1.5). Further, MC1R gene variants were increased in familial melanoma cases compared to controls (OR 2.4, 95% CI 1.6-3.4). Our findings suggest that in the majority of CDKN2A wt melanoma families, a segregation of variants in low-risk melanoma genes such as MC1R causes increased skin cancer susceptibility, rather than mutations in high-risk cancer predisposing genes, such mutations are more probable to be found in melanoma families with young melanoma cases. This study further supports an implication of CDKN2A mutation screening as a clinical test that determines counseling and follows up routines of melanoma families.

Prevalence of Germline BAP1, CDKN2A, and CDK4 Mutations in an Australian Population-Based Sample of Cutaneous Melanoma Cases

Mutations in Cyclin-Dependent Kinase Inhibitor 2A (CDKN2A) and Cyclin-Dependent Kinase 4 (CDK4) contribute to susceptibility in approximately 40% of high-density cutaneous melanoma (CMM) families and about 2% of unselected CMM cases. BRCA-1 associated protein-1 (BAP1) has been more recently shown to predispose to CMM and uveal melanoma (UMM) in some families; however, its contribution to CMM development in the general population is unreported. We sought to determine the contribution of these genes to CMM susceptibility in a population-based sample of cases from Australia. We genotyped 1,109 probands from Queensland families and found that approximately 1.31% harbored mutations in CDKN2A, including some with novel missense mutations (p.R22W, p.G35R and p.I49F). BAP1 missense variants occurred in 0.63% of cases but no CDK4 variants were observed in the sample. This is the first estimate of the contribution of BAP1 and CDK4 to a population-based sample of CMM and supports the previously reported estimate of CDKN2A germline mutation prevalence.

Genetics of familial melanoma: 20 years after CDKN2A

Twenty years ago, the first familial melanoma susceptibility gene, CDKN2A, was identified. Two years later, another high-penetrance gene, CDK4, was found to be responsible for melanoma development in some families. Progress in identifying new familial melanoma genes was subsequently slow; however, with the advent of next-generation sequencing, a small number of new high-penetrance genes have recently been uncovered. This approach has identified the lineage-specific oncogene MITF as a susceptibility gene both in melanoma families and in the general population, as well as the discovery of telomere maintenance as a key pathway underlying melanoma predisposition. Given these rapid recent advances, this approach seems likely to continue to pay dividends. Here, we review the currently known familial melanoma genes, providing evidence that most additionally confer risk to other cancers, indicating that they are likely general tumour suppressor genes or oncogenes, which has significant implications for surveillance and screening.

Analysis of BAP1 Germline Gene Mutation in Young Uveal Melanoma Patients

BACKGROUND

To evaluate the prevalence of BAP1 germline mutations in a series of young patients with uveal melanoma (UM), diagnosed before age 30.

MATERIALS AND METHODS

The study was carried out on 14 young uveal melanoma patients (average age 21.4 years, range 3 months to 29 years). Germline DNA was extracted from peripheral blood. BAP1 sequencing was carried out using direct sequencing of all exons and adjacent intronic sequences. We also tested for germline mutations in additional melanoma-associated candidate genes CDKN2A and CDK4 (exon 4).

RESULTS

We identified one patient with a pathogenic mutation (c. 1717delC, p.L573fs*3) in BAP1. This patient was diagnosed with UM at age 18 years and had a family history of a father with UM and a paternal grandfather with cancer of unknown origin. One additional patient had an intronic variant of uncertain significance (c.123-48T > G) in BAP1 while the remaining 12 patients had no alteration. None of the patients had CDKN2A or CDK4 (Exon 4) mutations. Family history was positive for a number of additional malignancies in this series, in particular for cutaneous melanoma, prostate, breast and colon cancers. There were no families with a history of mesothelioma or renal cell carcinoma.

CONCLUSIONS

This study suggests that a small subset of patients with early onset UM has germline mutation in BAP1. While young patients with UM should be screened for germline BAP1 mutations, our results suggest that there is a need to identify other candidate genes which are responsible for UM in young patients.

[Recommendations for genetic testing and management of individuals genetically at-risk of cutaneous melanoma]

Cutaneous melanoma is a multifactorial disease resulting from both environmental and genetic factors. Five susceptibility genes have been identified over the past years, comprising high-risk susceptibility genes (CDKN2A, CDK4, and BAP1 genes) and intermediate-risk susceptibility genes (MITF, and MC1R genes). The aim of this expert consensus was to define clinical contexts justifying genetic analyses, to describe the conduct of these analyses, and to propose surveillance recommendations. Given the regulatory constraints, it is recommended that dermatologists work in tandem with a geneticist. Genetic analysis may be prescribed when at least two episodes of histologically proven invasive cutaneous melanoma have been diagnosed before the age of 75 years in two 1st or 2nd degree relatives or in the same individual. The occurrence in the same individual or in a relative of invasive cutaneous melanoma with ocular melanoma, pancreatic cancer, renal cancer, mesothelioma or a central nervous system tumour are also indications for genetic testing. Management is based upon properly managed photoprotection and dermatological monitoring according to genetic status. Finally, depending on the mutated gene and the familial history, associated tumour risks require specific management (e.g. ocular melanoma, pancreatic cancer). Due to the rapid progress in genetics, these recommendations will need to be updated regularly.

Mesothelioma patients with germline BAP1 mutations have 7-fold improved long-term survival

BRCA1-associated protein-1 (BAP1) mutations cause a new cancer syndrome, with a high rate of malignant mesothelioma (MM). Here, we tested the hypothesis that MM associated with germline BAP1 mutations has a better prognosis compared with sporadic MM. We compared survival among germline BAP1 mutation MM patients with that of all MM (N = 10 556) recorded in the United States Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 2010. We identified 23 MM patients--11 alive--with germline BAP1 mutations and available data on survival. Ten patients had peritoneal MM, ten pleural MM and three MM in both locations. Thirteen patients had one or more malignancies in addition to MM. Actuarial median survival for the MM patients with germline BAP1 mutations was 5 years, as compared with <1 year for the median survival in the United States SEER MM group. Five-year survival was 47%, 95% confidence interval (24-67%), as compared with 6.7% (6.2-7.3%) in the control SEER group. Analysis of the pooled cohort of germline BAP1 mutation MM showed that patients with peritoneal MM (median survival of 10 years, P = 0.0571), or with a second malignancy in addition to MM (median survival of 10 years, P = 0.0716), survived for a longer time compared with patients who only had pleural MM, or MM patients without a second malignancy, respectively. In conclusion, we found that MM patients with germline BAP1 mutations have an overall 7-fold increased long-term survival, independently of sex and age. Appropriate genetic counseling and clinical management should be considered for MM patients who are also BAP1 mutation carriers.

A recurrent germline BAP1 mutation and extension of the BAP1 tumor predisposition spectrum to include basal cell carcinoma

We report four previously undescribed families with germline BRCA1-associated protein-1 gene (BAP1) mutations and expand the clinical phenotype of this tumor syndrome. The tumor spectrum in these families is predominantly uveal malignant melanoma (UMM), cutaneous malignant melanoma (CMM) and mesothelioma, as previously reported for germline BAP1 mutations. However, mutation carriers from three new families, and one previously reported family, developed basal cell carcinoma (BCC), thus suggesting inclusion of BCC in the phenotypic spectrum of the BAP1 tumor syndrome. This notion is supported by the finding of loss of BAP1 protein expression by immunochemistry in two BCCs from individuals with germline BAP1 mutations and no loss of BAP1 staining in 53 of sporadic BCCs consistent with somatic mutations and loss of heterozygosity of the gene in the BCCs occurring in mutation carriers. Lastly, we identify the first reported recurrent mutation in BAP1 (p.R60X), which occurred in three families from two different continents. In two of the families, the mutation was inherited from a common founder but it arose independently in the third family.

Melanoma: clinical features and genomic insights

Recent efforts in genomic research have enabled the characterization of molecular mechanisms underlying many types of cancers, ushering novel approaches for diagnosis and therapeutics. Melanoma is a molecularly heterogeneous disease, as many genetic alterations have been identified and the clinical features can vary. Although discoveries of frequent mutations including BRAF have already made clinically significant impact on patient care, there is a growing body of literature suggesting a role for additional mutations, driver and passenger types, in disease pathophysiology. Although some mutations have been strongly associated with clinical phenotypes of melanomas (such as physical distribution or morphologic subtype), the function or implications of many of the recently identified mutations remains less clear. The phenotypic and clinical impact of genomic mutations in melanoma remains a promising opportunity for progress in the care of melanoma patients.

Update on Ophthalmic Oncology 2013: Retinoblastoma and Uveal Melanoma

PURPOSE

The aim of this study was to discuss the clinical and translational content of the literature as well as advancement in our knowledge pertaining to retinoblastoma and uveal melanoma that were published from January to December 2013.

DESIGN

This study is a literature review.

METHODS

The search terms retinoblastoma and uveal melanoma were used in a MEDLINE literature search. Abstracts were studied, and the most relevant articles were selected for inclusion and further in-depth review.

RESULTS

In retinoblastoma, fewer eyes are lost because of the expanded use of ophthalmic artery chemosurgery and intravitreal melphalan, and the past year marks a deepening in our understanding of these modalities. Knowledge on the genetic underpinnings of uveal melanoma has broadened to include genes associated with a favorable prognosis. This is accompanied by promising results in the treatment of metastatic uveal melanoma.

CONCLUSIONS

This past year, there were important advancements in our knowledge of retinoblastoma and uveal melanoma.

The Importance of Multidisciplinary Approach in Early Detection of BAP1 Tumor Predisposition Syndrome: Clinical Management and Risk Assessment

Germline BAP1 (BRCA1-associated protein-1) mutations are involved into a novel specific cancer syndrome and strictly associated with a high cancer susceptibility. Recent data suggest that BAP1 has activity toward target substrates explaining why loss of BAP1 causes a pro-tumorigenic deregulation of gene expression. The recently published data reviewed raise the hypothesis that BAP1 regulates a common subset of substrates, which in turn causes a pro-tumorigenic deregulation of gene expression, and alternatively suggest the role of BAP1 as tumorigenesis suppressor/promoter also by independent mechanisms. The clinical phenotype of BAP1 alterations includes MBAITs (melanocytic BAP1-mutated atypical intradermal tumors), uveal melanoma (UM), cutaneous melanoma (CM), renal cell carcinoma (RCC), mesothelioma (MM), and possibly several other tumors. In clinical practice, early diagnosis is crucial for curative resection of all these tumor types. The uniformed and unambiguous definition of MBAITs as clinical/pathological predictive markers could provide physicians means to identify patients who may carry germline BAP1 mutations and thus could be at high risk of developing CM, UM, MM, RCC, and possibly other tumors. As part of a novel multidisciplinary approach, physicians, pathologists, and clinicians involved into diagnostics should be aware of the histological features and the spectrum of tumors associated with BAP1 loss. Further clinical, epidemiological, and functional studies are required to fully explain the roles of BAP1 and its interaction partners in neoplasia, to define mechanisms behind shared and non-shared clinical and pathological criteria.

Expanding the clinical phenotype of hereditary BAP1 cancer predisposition syndrome, reporting three new cases

The clinical phenotype of BAP1 hereditary cancer predisposition syndrome (MIM 614327) includes uveal melanoma (UM), cutaneous melanoma (CM), renal cell carcinoma (RCC), and mesothelioma. However, the frequency of the syndrome in patients with UM and the association with other cancers are still not clear. In this study, we screened 46 previously untested, unrelated UM patients with high risk for hereditary cancer for germline mutation in BAP1. We also studied four additional patients with a personal or family history suggestive of BAP1 hereditary cancer syndrome. We identified three patients with germline pathogenic mutations (c.2050 C>T, pGln684*; c.1182C>G, p.Tyr394*, and c.1882_1885delTCAC, p. Ser628Profs*8) in BAP1. Two of these three patients presented with UM and the third with a metastatic adenocarcinoma likely from a hepatic cholangiocarcinoma. Reported family histories included UM, mesothelioma, RCC, CM, and several other internal malignancies. The results of this study confirm the association between germline BAP1 mutation and predisposition to UM, mesothelioma, CM and RCC. However, other cancers, such as cholangiocarcinoma and breast carcinoma may be part of the phenotype of this hereditary cancer predisposition syndrome. In addition, the results support the existence of other candidate genes in addition to BAP1 contributing to hereditary predisposition to UM.

Further evidence for germline BAP1 mutations predisposing to melanoma and malignant mesothelioma

We describe a new family with a novel germline BAP1 nonsense mutation, c.723T>G, which leads to a predicted truncated protein, p.Y241*, or nonsense-mediated decay of the BAP1 mRNA. The proband had uveal melanoma (UM), and his paternal family has a remarkable history of multiple cancers. The proband's father had both pleural malignant mesothelioma (MM) and cutaneous melanoma (CM); a paternal uncle had lung cancer, CM, and UM; and a grandmother had CM. The findings in this family provide further support for the existence of a BAP1 cancer syndrome that predisposes to MM, various melanocytic neoplasms, and potentially other cancers. The fact that several members of the family manifested two or more different types of cancer suggests widespread BAP1-related tumor susceptibility targeting tissues of multiple organs. In addition, a review of BAP1 cancer syndrome families reported to date indicates that the location of the BAP1 mutation does not have any bearing on the spectrum of cancer types observed, either for mesothelial or melanocytic tumors.

A novel germline mutation in BAP1 predisposes to familial clear-cell renal cell carcinoma

Renal cell carcinoma (RCC) clusters in some families. Familial RCC arises from mutations in several genes, including the von Hippel-Lindau (VHL) tumor suppressor, which is also mutated in sporadic RCC. However, a significant percentage of familial RCC remains unexplained. Recently, we discovered that the BRCA1-associated protein-1 (BAP1) gene is mutated in sporadic RCC. The BAP1 gene encodes a nuclear deubiquitinase and appears to be a classic two-hit tumor suppressor gene. Somatic BAP1 mutations are associated with high-grade, clear-cell RCC (ccRCC) and poor patient outcomes. To determine whether BAP1 predisposes to familial RCC, the BAP1 gene was sequenced in 83 unrelated probands with unexplained familial RCC. Interestingly, a novel variant (c.41T>A; p.L14H) was uncovered that cosegregated with the RCC phenotype. The p.L14H variant targets a highly conserved residue in the catalytic domain, which is frequently targeted by missense mutations. The family with the novel BAP1 variant was characterized by early-onset ccRCC, occasionally of high Fuhrman grade, and lacked other features that typify VHL syndrome. These findings suggest that BAP1 is an early-onset familial RCC predisposing gene.

IMPLICATIONS

BAP1 mutations may drive tumor development in a subset of patients with inherited renal cell cancer.

A BAP1 mutation in a Danish family predisposes to uveal melanoma and other cancers

Truncating germline mutations in the tumor suppressor gene BRCA-1 associated protein-1 (BAP1) have been reported in families predisposed to developing a wide range of different cancer types including uveal melanoma and cutaneous melanoma. There has also been an association between amelanotic tumor development and germline BAP1 mutation suggesting a possible phenotypic characteristic of BAP1 mutation carriers. Though there have been many types of cancer associated with germline BAP1 mutation, the full spectrum of disease association is yet to be ascertained. Here we describe a Danish family with predominantly uveal melanoma but also a range of other tumor types including lung, neuroendocrine, stomach, and breast cancer; as well as pigmented skin lesions. Whole-exome sequencing identified a BAP1 splice mutation located at c.581-2A>G, which leads to a premature truncation of BAP1 in an individual with uveal melanoma. This mutation was carried by several other family members with melanoma or various cancers. The finding expands on the growing profile of BAP1 as an important uveal and cutaneous melanoma tumor suppressor gene and implicates its involvement in the development of lung, and stomach cancer.

Connecting molecular pathways to hereditary cancer risk syndromes

An understanding of the genetic causes and molecular pathways of hereditary cancer syndromes has historically informed our knowledge and treatment of all types of cancers. For this review, we focus on three rare syndromes and their associated genetic mutations including BAP1, TP53, and SDHx (SDHA, SDHB, SDHC, SDHD, SDHAF2). BAP1 encodes an enzyme that catalyzes the removal of ubiquitin from protein substrates, and germline mutations of BAP1 cause a novel cancer syndrome characterized by high incidence of benign atypical melanocytic tumors, uveal melanomas, cutaneous melanomas, malignant mesotheliomas, and potentially other cancers. TP53 mutations cause Li-Fraumeni syndrome (LFS), a highly penetrant cancer syndrome associated with multiple tumors including but not limited to sarcomas, breast cancers, brain tumors, and adrenocortical carcinomas. Genomic modifiers for tumor risk and genotype-phenotype correlations in LFS are beginning to be identified. SDH is a mitochondrial enzyme complex involved in the tricarboxylic acid (TCA) cycle, and germline SDHx mutations lead to increased succinate with subsequent paragangliomas, pheochromocytomas, renal cell carcinomas (RCCs), gastrointestinal stromal tumors (GISTs), and other rarer cancers. In all of these syndromes, the molecular pathways have informed our understanding of tumor risk and successful early tumor surveillance and screening programs.