Germline mutations in SUFU cause Gorlin syndrome-associated childhood medulloblastoma and redefine the risk associated with PTCH1 mutations

Update on Cancer Predisposition Syndromes and Surveillance Guidelines for Childhood Brain Tumors

Tumors of the central nervous system (CNS) comprise the second most common group of neoplasms in childhood. The incidence of germline predisposition among children with brain tumors continues to grow as our knowledge on disease etiology increases. Some children with brain tumors may present with nonmalignant phenotypic features of specific syndromes (e.g., nevoid basal cell carcinoma syndrome, neurofibromatosis type 1 and type 2, DICER1 syndrome, and constitutional mismatch-repair deficiency), while others may present with a strong family history of cancer (e.g., Li-Fraumeni syndrome) or with a rare tumor commonly found in the context of germline predisposition (e.g., rhabdoid tumor predisposition syndrome). Approximately 50% of patients with a brain tumor may be the first in a family identified to have a predisposition. The past decade has witnessed a rapid expansion in our molecular understanding of CNS tumors. A significant proportion of CNS tumors are now well characterized and known to harbor specific genetic changes that can be found in the germline. Additional novel predisposition syndromes are also being described. Identification of these germline syndromes in individual patients has not only enabled cascade testing of family members and early tumor surveillance but also increasingly affected cancer management in those patients. Therefore, the AACR Cancer Predisposition Working Group chose to highlight these advances in CNS tumor predisposition and summarize and/or generate surveillance recommendations for established and more recently emerging pediatric brain tumor predisposition syndromes.

Medulloblastoma and other neoplasms in patients with heterozygous germline SUFU variants: A scoping review

In 2002, heterozygous suppressor of fused variants (SUFU+/-) in the germline were described to have a tumor suppressor role in the development of pediatric medulloblastoma (MB). Other neoplasms associated with pathologic germline SUFU+/- variants have also been described among patients with basal cell nevus syndrome (BCNS; BCNS is also known as Gorlin syndrome, nevoid basal cell carcinoma [BCC] syndrome or Gorlin-Goltz syndrome; OMIM 109400), an autosomal-dominant cancer predisposition syndrome. The phenotype of patients with germline SUFU+/- variants is very poorly characterized due to a paucity of large studies with long-term follow-up. As such, there is a clinical need to better characterize the spectrum of neoplasms among patients with germline SUFU+/- variants so that clinicians can provide accurate counseling and optimize tumor surveillance strategies. The objective of this study is to perform a scoping review to map the evidence on the rate of medulloblastoma and to describe the spectrum of other neoplasms among patients with germline SUFU+/- variants. A review of all published literature in PubMed (MEDLINE), EMBASE, Cochrane, and Web of Science were searched from the beginning of each respective database until October 9, 2021. Studies of pediatric and adult patients with a confirmed germline SUFU+/- variant who were evaluated for the presence of any neoplasm (benign or malignant) were included. There were 176 patients (N = 30 studies) identified with a confirmed germline SUFU+/- variant who met inclusion criteria. Data were extracted from two cohort studies, two case-control studies, 18 case series, and eight case reports. The median age at diagnosis of a germline SUFU+/- variant was 4.5 years where 44.4% identified as female and 13.4% of variants were de novo. There were 34 different neoplasms (benign and malignant) documented among patients with confirmed germline SUFU+/- variants, and the most common were medulloblastoma (N = 59 patients), BCC (N = 21 patients), and meningioma (N = 19 patients). The median age at medulloblastoma diagnosis was 1.42 years (range 0.083-3; interquartile range 1.2). When data were available for these three most frequent neoplasms (N = 95 patients), 31 patients (32.6%) had neither MB, BCC nor meningioma; 51 patients (53.7%) had one of medulloblastoma or BCC or meningioma; eight patients (8.4%) had two of medulloblastoma or BCC or meningioma, and five patients (5.3%) had medulloblastoma and BCC and meningioma. This is the first study to synthesize the data on the frequency and spectrum of neoplasms specifically among patients with a confirmed germline SUFU+/- variant. This scoping review is a necessary step forward in optimizing evidence-based tumor surveillance strategies for medulloblastoma and estimating the risk of other neoplasms that could impact patient outcomes.

The risk of skin cancer in women who carry BRCA1 or BRCA2 mutations

BACKGROUND

It has not been clearly established if skin cancer or melanoma are manifestations of BRCA1 or BRCA2 mutation carrier status. Estimating the risk of skin cancer is an important step towards developing screening recommendations.

METHODS

We report the findings of a prospective cohort study of 6,207 women from North America who carry BRCA1 or BRCA2 mutations. Women were followed from the date of baseline questionnaire to the diagnosis of skin cancer, to age 80 years, death from any cause, or the date of last follow-up.

RESULTS

During the mean follow-up period of eight years, 3.7% of women with a BRCA1 mutation (133 of 3,623) and 3.8% of women with a BRCA2 mutation (99 of 2,584) reported a diagnosis of skin cancer (including both keratinocyte carcinomas and melanoma). The cumulative risk of all types of skin cancer from age 20 to 80 years was 14.1% for BRCA1 carriers and 10.7% for BRCA2 carriers. The cumulative risk of melanoma was 2.5% for BRCA1 carriers and 2.3% for BRCA2 carriers, compared to 1.5% for women in the general population in the United States. The strongest risk factor for skin cancer was a prior diagnosis of skin cancer.

CONCLUSION

The risk of non-melanoma skin cancer in women who carry a mutation in BRCA1 or BRCA2 is similar to that of non-carrier women. The risk of melanoma appears to be slightly elevated. We suggest that a referral to a dermatologist or primary care provider for BRCA mutation carriers for annual skin examination and counselling regarding limiting UV exposure, the use of sunscreen and recognizing the early signs of melanoma might be warranted, but further studies are necessary.

Heterogeneity and tumoral origin of medulloblastoma in the single-cell era

Medulloblastoma is one of the most common malignant pediatric brain tumors derived from posterior fossa. The current treatment includes maximal safe surgical resection, radiotherapy, whole cranio-spinal radiation and adjuvant with chemotherapy. However, it can only limitedly prolong the survival time with severe side effects and relapse. Defining the intratumoral heterogeneity, cellular origin and identifying the interaction network within tumor microenvironment are helpful for understanding the mechanisms of medulloblastoma tumorigenesis and relapse. Due to technological limitations, the mechanisms of cellular heterogeneity and tumor origin have not been fully understood. Recently, the emergence of single-cell technology has provided a powerful tool for achieving the goal of understanding the mechanisms of tumorigenesis. Several studies have demonstrated the intratumoral heterogeneity and tumor origin for each subtype of medulloblastoma utilizing the single-cell RNA-seq, which has not been uncovered before using conventional technologies. In this review, we present an overview of the current progress in understanding of cellular heterogeneity and tumor origin of medulloblastoma and discuss novel findings in the age of single-cell technologies.

Detection of PTCH1 Copy-Number Variants in Mosaic Basal Cell Nevus Syndrome

Basal cell nevus syndrome (BCNS) is an inherited disorder characterized mainly by the development of basal cell carcinomas (BCCs) at an early age. BCNS is caused by heterozygous small-nucleotide variants (SNVs) and copy-number variants (CNVs) in the Patched1 (PTCH1) gene. Genetic diagnosis may be complicated in mosaic BCNS patients, as accurate SNV and CNV analysis requires high-sensitivity methods due to possible low variant allele frequencies. We compared test outcomes for PTCH1 CNV detection using multiplex ligation-probe amplification (MLPA) and digital droplet PCR (ddPCR) with samples from a BCNS patient heterozygous for a PTCH1 CNV duplication and the patient's father, suspected to have a mosaic form of BCNS. ddPCR detected a significantly increased PTCH1 copy-number ratio in the index patient's blood, and the father's blood and tissues, indicating that the father was postzygotic mosaic and the index patient inherited the CNV from him. MLPA only detected the PTCH1 duplication in the index patient's blood and in hair and saliva from the mosaic father. Our data indicate that ddPCR more accurately detects CNVs, even in low-grade mosaic BCNS patients, which may be missed by MLPA. In general, quantitative ddPCR can be of added value in the genetic diagnosis of mosaic BCNS patients and in estimating the recurrence risk for offspring.

Insights into the molecular roles of FOXR2 in the pathology of primary pediatric brain tumors

Forkhead box gene R2 (FOXR2) belongs to the family of FOX genes which codes for highly conserved transcription factors (TFs) with critical roles in biological processes ranging from development to organogenesis to metabolic and immune regulation to cellular homeostasis. A number of FOX genes are associated with cancer development and progression and poor prognosis. A growing body of evidence suggests that FOXR2 is an oncogene. Studies suggested important roles for FOXR2 in cancer cell growth, metastasis, and drug resistance. Recent studies showed that FOXR2 is overexpressed by a subset of newly identified entities of embryonal tumors. This review discusses the role(s) FOXR2 plays in the pathology of pediatric brain cancers and its potential as a therapeutic target.

Bilateral ovarian fibromas as the sole manifestation of Gorlin syndrome in a 22-year-old woman: a case report and literature review

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS, Gorlin syndrome) is a rare autosomal dominantly inherited disorder that is characterized by multisystem disorder such as basal cell carcinomas, keratocystic odontogenic tumors and skeletal abnormalities. Bilateral and/or unilateral ovarian fibromas have been reported in individuals diagnosed with NBCCS.

CASE PRESENTATION

A 22-year-old female, presented with low back pain, and was found to have bilateral giant adnexal masses on pelvic ultrasonography, which had been suspected to be malignant ovarian tumors. Positron emission tomography/computed tomography showed multiple intracranial calcification and skeletal abnormalities. The left adnexa and right ovarian tumor were resected with laparotomy, and pathology revealed bilateral ovarian fibromas with marked calcification. We recommended the patient to receive genetic testing and dermatological examination. No skin lesion was detected. Germline testing identified pathogenic heterozygous mutation in PTCH1 (Patched1).

CONCLUSIONS

The possibility of NBCCS needs to be considered in patients with ovarian fibromas diagnosed in an early age. Skin lesions are not necessary for the diagnosis of NBCCS. Ovarian fibromas are managed with surgical excision with an attempt at preserving ovarian function. Follow-up regime and counseling on options for future fertility should be offered to patients.

Surviving the hunger games: Metabolic reprogramming in medulloblastoma

Medulloblastoma is a highly malignant pediatric brain tumor characterized by its aggressive nature and limited treatment options. Metabolic changes have recently emerged as key factors in the development, progression, and response to therapy in various types of cancer. Cancer cells exhibit remarkable adaptability by modulating glucose, lipids, amino acids, and nucleotide metabolism to survive in nutrient- and oxygen-deprived environments. Although medulloblastoma has been extensively studied from a genomic perspective, leading to the identification of four subgroups and their respective subcategories, the investigation of its metabolic phenotype has remained relatively understudied. This review focus on the available literature, aiming to summarize the current knowledge about the main metabolic pathways that are deregulated in medulloblastoma tumors, while emphasizing the controversial aspects and the progress that is yet to be made. Furthermore, we underscored the insights gained so far regarding the impact of metabolism on the development of drug resistance in medulloblastoma and the therapeutic strategies employed to target specific metabolic pathways.

Hedgehog-Related Mutation Causes Bone Malformations with or without Hereditary Gene Mutations

The hedgehog (Hh) family consists of numerous signaling mediators that play important roles at various stages of development. Thus, the Hh pathway is essential for bone tissue development and tumorigenesis. Gorlin syndrome is a skeletal and tumorigenic disorder caused by gain-of-function mutations in Hh signaling. In this review, we first present the phenotype of Gorlin syndrome and the relationship between genotype and phenotype in bone and craniofacial tissues, including the causative gene as well as other Hh-related genes. Next, the importance of new diagnostic methods using next-generation sequencing and multiple gene panels will be discussed. We summarize Hh-related genetic disorders, including cilia disease, and the genetics of Hh-related bone diseases.

Cilia and Cancer: From Molecular Genetics to Therapeutic Strategies

Cilia are microtubule-based organelles that project from the cell surface with motility or sensory functions. Primary cilia work as antennae to sense and transduce extracellular signals. Cilia critically control proliferation by mediating cell-extrinsic signals and by regulating cell cycle entry. Recent studies have shown that primary cilia and their associated proteins also function in autophagy and genome stability, which are important players in oncogenesis. Abnormal functions of primary cilia may contribute to oncogenesis. Indeed, defective cilia can either promote or suppress cancers, depending on the cancer-initiating mutation, and the presence or absence of primary cilia is associated with specific cancer types. Together, these findings suggest that primary cilia play important, but distinct roles in different cancer types, opening up a completely new avenue of research to understand the biology and treatment of cancers. In this review, we discuss the roles of primary cilia in promoting or inhibiting oncogenesis based on the known or predicted functions of cilia and cilia-associated proteins in several key processes and related clinical implications.

Cadherins and catenins in cancer: connecting cancer pathways and tumor microenvironment

Cadherin-catenin complexes are integral components of the adherens junctions crucial for cell-cell adhesion and tissue homeostasis. Dysregulation of these complexes is linked to cancer development via alteration of cell-autonomous oncogenic signaling pathways and extrinsic tumor microenvironment. Advances in multiomics have uncovered key signaling events in multiple cancer types, creating a need for a better understanding of the crosstalk between cadherin-catenin complexes and oncogenic pathways. In this review, we focus on the biological functions of classical cadherins and associated catenins, describe how their dysregulation influences major cancer pathways, and discuss feedback regulation mechanisms between cadherin complexes and cellular signaling. We discuss evidence of cross regulation in the following contexts: Hippo-Yap/Taz and receptor tyrosine kinase signaling, key pathways involved in cell proliferation and growth; Wnt, Notch, and hedgehog signaling, key developmental pathways involved in human cancer; as well as TGFβ and the epithelial-to-mesenchymal transition program, an important process for cancer cell plasticity. Moreover, we briefly explore the role of cadherins and catenins in mechanotransduction and the immune tumor microenvironment.

Genetic predisposition and evolutionary traces of pediatric cancer risk: a prospective 5-year population-based genome sequencing study of children with CNS tumors

BACKGROUND

The etiology of central nervous system (CNS) tumors in children is largely unknown and population-based studies of genetic predisposition are lacking.

METHODS

In this prospective, population-based study, we performed germline whole-genome sequencing in 128 children with CNS tumors, supplemented by a systematic pedigree analysis covering 3543 close relatives.

RESULTS

Thirteen children (10%) harbored pathogenic variants in known cancer genes. These children were more likely to have medulloblastoma (OR 5.9, CI 1.6-21.2) and develop metasynchronous CNS tumors (P = 0.01). Similar carrier frequencies were seen among children with low-grade glioma (12.8%) and high-grade tumors (12.2%). Next, considering the high mortality of childhood CNS tumors throughout most of human evolution, we explored known pediatric-onset cancer genes, showing that they are more evolutionarily constrained than genes associated with risk of adult-onset malignancies (P = 5e-4) and all other genes (P = 5e-17). Based on this observation, we expanded our analysis to 2986 genes exhibiting high evolutionary constraint in 141,456 humans. This analysis identified eight directly causative loss-of-functions variants, and showed a dose-response association between degree of constraint and likelihood of pathogenicity-raising the question of the role of other highly constrained gene alterations detected.

CONCLUSIONS

Approximately 10% of pediatric CNS tumors can be attributed to rare variants in known cancer genes. Genes associated with high risk of childhood cancer show evolutionary evidence of constraint.

Immune microenvironment of medulloblastoma: The association between its molecular subgroups and potential targeted immunotherapeutic receptors

Medulloblastoma (MB) is considered the commonest malignant brain tumor in children. Multimodal treatments consisting of surgery, radiation, and chemotherapy have improved patients’ survival. Nevertheless, the recurrence occurs in 30% of cases. The persistent mortality rates, the failure of current therapies to extend life expectancy, and the serious complications of non-targeted cytotoxic treatment indicate the need for more refined therapeutic approaches. Most MBs originating from the neurons of external granular layer line the outer surface of neocerebellum and responsible for the afferent and efferent connections. Recently, MBs have been segregated into four molecular subgroups: Wingless-activated (WNT-MB) (Group 1); Sonic-hedgehog-activated (SHH-MB) (Group 2); Group 3 and 4 MBs. These molecular alterations follow specific gene mutations and disease-risk stratifications. The current treatment protocols and ongoing clinical trials against these molecular subgroups are still using common chemotherapeutic agents by which their efficacy have improved the progression-free survival but did not change the overall survival. However, the need to explore new therapies targeting specific receptors in MB microenvironment became essential. The immune microenvironment of MBs consists of distinctive cellular heterogeneities including immune cells and none-immune cells. Tumour associate macrophage and tumour infiltrating lymphocyte are considered the main principal cells in tumour microenvironment, and their role are still under investigation. In this review, we discuss the mechanism of interaction between MB cells and immune cells in the microenvironment, with an overview of the recent investigations and clinical trials

SUFU-associated Gorlin syndrome: Expanding the spectrum between classic nevoid basal cell carcinoma syndrome and multiple hereditary infundibulocystic basal cell carcinoma

Basal cell nevus syndrome (BCNS), also known as Gorlin syndrome, is characterized by an aberrant activation of the hedgehog (Hh) pathway, most cases being caused by PTCH1 mutations. However, certain features such as multiple hereditary infundibulocystic basal cell carcinomas (MHIBCC), sclerotic fibromas, childhood medulloblastoma or meningioma may be relatively specific to a SUFU mutation. We present two patients with MHIBCC, along with a more complex cutaneous and extracutaneous phenotype. MHIBCC syndrome and BCNS may share clinical features and, indeed, both syndromes probably represent different degrees of upregulation in the Hh pathway.

Medulloblastoma: Current Perspectives and Recent Advances

Medulloblastoma is the most common embryonal tumor of the central nervous system in childhood. Combined multimodality approaches, including surgery, radiation, and chemotherapy, have improved the outcome of medulloblastoma. Advances in genomic research have shown that medulloblastoma is not a biologically or clinically discrete entity. Previously, the risk was divided according to histology, presence of metastasis, degree of resection, and age at diagnosis. Through the development of integrated genomics, new biology-based risk stratification methods have recently been proposed. It is also important to understand the genetic predisposition of patients with medulloblastoma. Therefore, treatment goal aimed to improve the survival rate with minimal additional adverse effects and reduced long-term sequelae. It is necessary to incorporate genetic findings into the standard of care, and clinical trials that reflect this need to be conducted.

The Epidemiology of Brain and Spinal Cord Tumors

CNS tumors are a diverse group of neoplasms that emerge from a variety of different CNS cell types. These tumors may be benign, malignant, or borderline in nature. The majority of high grade glial tumors are fatal, with the exception of pilocytic astrocytoma. Primary malignant CNS tumors occur at a global annual rate of 2.1 to 5.8 per 100,000 persons. Males are more likely to develop malignant brain tumors than females, whereas benign meningiomas are more common in adult females. Additionally, gender inequalities in non-malignant tumors peak between the ages of 25 and 29 years. Only a small number of genetic variants have been associated with survival and prognosis. Notably, central nervous system (CNS) tumors exhibit significant age, gender, and race variation. Race is another factor that affects the incidence of brain and spinal cord tumors. Different races exhibit variation in terms of the prevalence of brain and CNS malignancies. This chapter discusses ongoing research on brain and spinal cord tumor epidemiology, as well as the associated risks and accompanied disorders.

Patched Homolog 1 (PTCH1) Mutation in a CIC-Rearranged Sarcoma: Lack of Response to the Smoothened (SMO) Vismodegib

Next-generation sequencing (NGS) to identify potential targets is becoming a common approach to refractory tumors. We describe a patient with a CIC-DUX4 sarcoma that harbored a patched homolog 1 (PTCH1) mutation, a mutation not previously reported in so-called Ewing family tumors. PTCH1 is part of the hedgehog signaling pathway. Basal cell carcinomas (BCC) commonly have PTCH1 mutations, and those with PTCH1 mutations are often responsive to therapy with the hedgehog pathway inhibitor vismodegib. The effect of any mutation in a gene important in cell growth and division is likely dependent upon the background biochemistry of the cell. In the current case, vismodegib was not effective. This case is the first report of a PTCH1 mutation in an Ewing family tumor and demonstrates that the utility of targeting a potential mutation may depend upon many factors, including other mutations in the signaling pathway, and importantly, also the background biochemistry of the malignant cell that may prevent effective treatment targeting.

Splicing-Disrupting Mutations in Inherited Predisposition to Solid Pediatric Cancer

The prevalence of hereditary cancer in children was estimated to be very low until recent studies suggested that at least 10% of pediatric cancer patients carry a germline mutation in a cancer predisposition gene. A significant proportion of pathogenic variants associated with an increased risk of hereditary cancer are variants affecting splicing. RNA splicing is an essential process involved in different cellular processes such as proliferation, survival, and differentiation, and alterations in this pathway have been implicated in many human cancers. Hereditary cancer genes are highly susceptible to splicing mutations, and among them there are several genes that may contribute to pediatric solid tumors when mutated in the germline. In this review, we have focused on the analysis of germline splicing-disrupting mutations found in pediatric solid tumors, as the discovery of pathogenic splice variants in pediatric cancer is a growing field for the development of personalized therapies. Therapies developed to correct aberrant splicing in cancer are also discussed as well as the options to improve the diagnostic yield based on the increase in the knowledge in splicing.

Suppressor of Fused Regulation of Hedgehog Signaling is Required for Proper Astrocyte Differentiation

Hedgehog signaling is essential for vertebrate development; however, less is known about the negative regulators that influence this pathway. Using the mouse P19 embryonal carcinoma cell model, suppressor of fused (SUFU), a negative regulator of the Hedgehog (Hh) pathway, was investigated during retinoic acid (RA)-induced neural differentiation. We found Hh signaling increased activity in the early phase of differentiation, but was reduced during terminal differentiation of neurons and astrocytes. This early increase in pathway activity was required for neural differentiation; however, it alone was not sufficient to induce neural lineages. SUFU, which regulates signaling at the level of Gli, remained relatively unchanged during differentiation, but its loss through CRISPR-Cas9 gene editing resulted in ectopic expression of Hh target genes. Interestingly, these SUFU-deficient cells were unable to differentiate toward neural lineages without RA, and when directed toward these lineages, they showed delayed and decreased astrocyte differentiation; neuron differentiation was unaffected. Ectopic activation of Hh target genes in SUFU-deficient cells remained throughout RA-induced differentiation and this was accompanied by the loss of Gli3, despite the presence of the Gli3 message. Thus, the study indicates the proper timing and proportion of astrocyte differentiation requires SUFU, likely acting through Gli3, to reduce Hh signaling during late-stage differentiation.

Germline intergenic duplications at Xq26.1 underlie Bazex-Dupré-Christol basal cell carcinoma susceptibility syndrome

BACKGROUND

Bazex-Dupré-Christol syndrome (BDCS; MIM301845) is a rare X-linked dominant genodermatosis characterized by follicular atrophoderma, congenital hypotrichosis and multiple basal cell carcinomas (BCCs). Previous studies have linked BDCS to an 11·4-Mb interval on chromosome Xq25-q27.1. However, the genetic mechanism of BDCS remains an open question.

OBJECTIVES

To investigate the genetic aetiology and molecular mechanisms underlying BDCS.

METHODS

We ascertained multiple individuals from eight unrelated families affected with BDCS (F1-F8). Whole-exome (F1 and F2) and genome sequencing (F3) were performed to identify putative disease-causing variants within the linkage region. Array comparative genomic hybridization and quantitative polymerase chain reaction (PCR) were used to explore copy number variations, followed by long-range gap PCR and Sanger sequencing to amplify the duplication junctions and to define the head-tail junctions. Hi-C was performed on dermal fibroblasts from two affected individuals with BDCS and one control. Public datasets and tools were used to identify regulatory elements and transcription factor binding sites within the minimal duplicated region. Immunofluorescence was performed in hair follicles, BCCs and trichoepitheliomas from patients with BDCS and sporadic BCCs. The ACTRT1 variant c.547dup (p.Met183Asnfs*17), previously proposed to cause BDCS, was evaluated with t allele frequency calculator.

RESULTS

In eight families with BDCS, we identified overlapping 18-135-kb duplications (six inherited and two de novo) at Xq26.1, flanked by ARHGAP36 and IGSF1. Hi-C showed that the duplications did not affect the topologically associated domain, but may alter the interactions between flanking genes and putative enhancers located in the minimal duplicated region. We detected ARHGAP36 expression near the control hair follicular stem cell compartment, and found increased ARHGAP36 levels in hair follicles in telogen, in BCCs and in trichoepitheliomas from patients with BDCS. ARHGAP36 was also detected in sporadic BCCs from individuals without BDCS. Our modelling showed the predicted maximum tolerated minor allele frequency of ACTRT1 variants in control populations to be orders of magnitude higher than expected for a high-penetrant ultra-rare disorder, suggesting loss of function of ACTRT1 variants to be an unlikely cause for BDCS.

CONCLUSIONS

Noncoding Xq26.1 duplications cause BDCS. The BDCS duplications most likely lead to dysregulation of ARHGAP36. ARHGAP36 is a potential therapeutic target for both inherited and sporadic BCCs. What is already known about this topic? Bazex-Dupré-Christol syndrome (BDCS) is a rare X-linked basal cell carcinoma susceptibility syndrome linked to an 11·4-Mb interval on chromosome Xq25-q27.1. Loss-of-function variants in ACTRT1 and its regulatory elements were suggested to cause BDCS. What does this study add? BDCS is caused by small tandem noncoding intergenic duplications at chromosome Xq26.1. The Xq26.1 BDCS duplications likely dysregulate ARHGAP36, the flanking centromeric gene. ACTRT1 loss-of-function variants are unlikely to cause BDCS. What is the translational message? This study provides the basis for accurate genetic testing for BDCS, which will aid precise diagnosis and appropriate surveillance and clinical management. ARHGAP36 may be a novel therapeutic target for all forms of sporadic basal cell carcinomas.

Genetic predisposition to central nervous system tumors in children - what the neurosurgeon should know

BACKGROUND

Historically, few pediatric central nervous system (CNS) tumors were thought to result from genetic predisposition. However, within the last decade, new DNA sequencing methods have led to an increased recognition of high-risk cancer predisposition syndromes in children with CNS tumors. Thus, genetic predisposition is increasingly impacting clinical pediatric neuro-oncology.

METHODS

In this narrative review, we discuss the current understanding of genetic predisposition to childhood CNS tumors and provide a general overview of involved research methodologies and terminology. Moreover, we consider how germline genetics may influence neurosurgical practice.

RESULTS

Introduction of next-generation DNA sequencing has greatly increased our understanding of genetic predisposition to pediatric CNS tumors by enabling whole-exome/-genome sequencing of large cohorts. To date, the scientific literature has reported germline sequencing findings for more than 2000 children with CNS tumors. Although varying between tumor types, at least 10% of childhood CNS tumors can currently be explained by rare pathogenic germline variants in known cancer-related genes. Novel methodologies continue to uncover new mechanisms, suggesting that a much higher proportion of children with CNS tumors have underlying genetic causes. Understanding how genetic predisposition influences tumor biology and the clinical course in a given patient may mandate adjustments to neurosurgical treatment.

CONCLUSION

Germline genetics is becoming increasingly important to clinicians, including neurosurgeons. This review provides an updated overview of genetic predisposition to childhood CNS tumors with focus on aspects relevant to pediatric neurosurgeons.

ERK2 MAP kinase regulates SUFU binding by multisite phosphorylation of GLI1

Crosstalk between the Hedgehog and MAPK signaling pathways occurs in several types of cancer and contributes to clinical resistance to Hedgehog pathway inhibitors. Here we show that MAP kinase-mediated phosphorylation weakens the binding of the GLI1 transcription factor to its negative regulator SUFU. ERK2 phosphorylates GLI1 on three evolutionarily conserved target sites (S102, S116, and S130) located near the high-affinity binding site for SUFU; these phosphorylations cooperate to weaken the affinity of GLI1-SUFU binding by over 25-fold. Phosphorylation of any one, or even any two, of the three sites does not result in the level of SUFU release seen when all three sites are phosphorylated. Tumor-derived mutations in R100 and S105, residues bordering S102, also diminish SUFU binding, collectively defining a novel evolutionarily conserved SUFU affinity-modulating region. In cultured mammalian cells, GLI1 variants containing phosphomimetic substitutions of S102, S116, and S130 displayed an increased ability to drive transcription. We conclude that multisite phosphorylation of GLI1 by ERK2 or other MAP kinases weakens GLI1-SUFU binding, thereby facilitating GLI1 activation and contributing to both physiological and pathological crosstalk.

Congenital medulloblastoma in two brothers with SUFU-mutated Gorlin-Goltz syndrome: Case reports and literature review

Background

Congenital medulloblastoma is very rare, and many cases involve germline mutations that can lead to inherited syndromes. Here, we first report two brothers with congenital medulloblastoma who were diagnosed with Gorlin-Goltz syndrome caused by SUFU mutation.

Clinical presentation

Medulloblastoma was detected in two brothers at 2 and 3 months of age, with very similar imaging features. Genetic testing revealed that both children and their mother carried SUFU gene germline mutations, and both brothers were diagnosed with Gorlin-Goltz syndrome.

Conclusion

Gorlin-Goltz syndrome-associated congenital medulloblastoma with SUFU germline mutation is very rare. Pathological types mostly involve desmoplastic/nodular or extensive nodularity; chemotherapy is the main treatment, and studies revealing prognostic data are scarce.

Molecular mechanism(s) of regulations of cancer stem cell in brain cancer propagation

Brain tumors are most often diagnosed with solid neoplasms and are the primary reason for cancer-related deaths in both children and adults worldwide. With recent developments in the progression of novel targeted chemotherapies, the prognosis of malignant glioma remains dismal. However, the high recurrence rate and high mortality rate remain unresolved and are closely linked to the biological features of cancer stem cells (CSCs). Research on tumor biology has reached a new age with more understanding of CSC features. CSCs, a subpopulation of whole tumor cells, are now regarded as candidate therapeutic targets. Therefore, in the diagnosis and treatment of tumors, recognizing the biological properties of CSCs is of considerable significance. Here, we have discussed the concept of CSCs and their significant role in brain cancer growth and propagation. We have also discussed personalized therapeutic development and immunotherapies for brain cancer by specifically targeting CSCs.

Nervous system (NS) Tumors in Cancer Predisposition Syndromes

Genetic syndromes which develop one or more nervous system (NS) tumors as one of the manifestations can be grouped under the umbrella term of NS tumor predisposition syndromes. Understanding the underlying pathological pathways at the molecular level has led us to many radical discoveries, in understanding the mechanisms of tumorigenesis, tumor progression, interactions with the tumor microenvironment, and development of targeted therapies. Currently, at least 7-10% of all pediatric cancers are now recognized to occur in the setting of genetic predisposition to cancer or cancer predisposition syndromes. Specifically, the cancer predisposition rate in pediatric patients with NS tumors has been reported to be as high as 15%, though it can approach 50% in certain tumor types (i.e., choroid plexus carcinoma associated with Li Fraumeni Syndrome). Cancer predisposition syndromes are caused by pathogenic variation in genes that primarily function as tumor suppressors and proto-oncogenes. These variants are found in the germline or constitutional DNA. Mosaicism, however, can affect only certain tissues, resulting in varied manifestations. Increased understanding of the genetic underpinnings of cancer predisposition syndromes and the ability of clinical laboratories to offer molecular genetic testing allows for improvement in the identification of these patients. The identification of a cancer predisposition syndrome in a CNS tumor patient allows for changes to medical management to be made, including the initiation of cancer surveillance protocols. Finally, the identification of at-risk biologic relatives becomes feasible through cascade (genetic) testing. These fundamental discoveries have also broadened the horizon of novel therapeutic possibilities and have helped to be better predictors of prognosis and survival. The treatment paradigm of specific NS tumors may also vary based on the patient's cancer predisposition syndrome and may be used to guide therapy (i.e., immune checkpoint inhibitors in constitutional mismatch repair deficiency [CMMRD] predisposition syndrome) [8]. Early diagnosis of these cancer predisposition syndromes is therefore critical, in both unaffected and affected patients. Genetic counselors are uniquely trained master's level healthcare providers with a focus on the identification of hereditary disorders, including hereditary cancer, or cancer predisposition syndromes. Genetic counseling, defined as "the process of helping people understand and adapt to the medical, psychological and familial implications of genetic contributions to disease" plays a vital role in the adaptation to a genetic diagnosis and the overall management of these diseases. Cancer predisposition syndromes that increase risks for NS tumor development in childhood include classic neurocutaneous disorders like neurofibromatosis type 1 and type 2 (NF1, NF2) and tuberous sclerosis complex (TSC) type 1 and 2 (TSC1, TSC2). Li Fraumeni Syndrome, Constitutional Mismatch Repair Deficiency, Gorlin syndrome (Nevoid Basal Cell Carcinoma), Rhabdoid Tumor Predisposition syndrome, and Von Hippel-Lindau disease. Ataxia Telangiectasia will also be discussed given the profound neurological manifestations of this syndrome. In addition, there are other cancer predisposition syndromes like Cowden/PTEN Hamartoma Tumor Syndrome, DICER1 syndrome, among many others which also increase the risk of NS neoplasia and are briefly described. Herein, we discuss the NS tumor spectrum seen in the abovementioned cancer predisposition syndromes as with their respective germline genetic abnormalities and recommended surveillance guidelines when applicable. We conclude with a discussion of the importance and rationale for genetic counseling in these patients and their families.

Medulloblastoma in the Modern Era: Review of Contemporary Trials, Molecular Advances, and Updates in Management

Critical discoveries over the past two decades have transformed our understanding of medulloblastoma from a single entity into a clinically and biologically heterogeneous disease composed of at least four molecularly distinct subgroups with prognostically and therapeutically relevant genomic signatures. Contemporary clinical trials also have provided valuable insight guiding appropriate treatment strategies. Despite therapeutic and biological advances, medulloblastoma patients across the age spectrum experience tumor- and treatment-related morbidity and mortality. Using an updated risk stratification approach integrating both clinical and molecular features, ongoing research seeks to (1) cautiously reduce therapy and mitigate toxicity in low-average risk patients, and (2) thoughtfully intensify treatment with incorporation of novel, biologically guided agents for patients with high-risk disease. Herein, we review important historical and contemporary studies, discuss management updates, and summarize current knowledge of the biological landscape across unique pediatric, infant, young adult, and relapsed medulloblastoma populations.

SUFU haploinsufficiency causes a recognisable neurodevelopmental phenotype at the mild end of the Joubert syndrome spectrum

BACKGROUND

Joubert syndrome (JS) is a recessively inherited ciliopathy characterised by congenital ocular motor apraxia (COMA), developmental delay (DD), intellectual disability, ataxia, multiorgan involvement, and a unique cerebellar and brainstem malformation. Over 40 JS-associated genes are known with a diagnostic yield of 60%-75%.In 2018, we reported homozygous hypomorphic missense variants of the SUFU gene in two families with mild JS. Recently, heterozygous truncating SUFU variants were identified in families with dominantly inherited COMA, occasionally associated with mild DD and subtle cerebellar anomalies.

METHODS

We reanalysed next generation sequencing (NGS) data in two cohorts comprising 1097 probands referred for genetic testing of JS genes.

RESULTS

Heterozygous truncating and splice-site SUFU variants were detected in 22 patients from 17 families (1.5%) with strong male prevalence (86%), and in 8 asymptomatic parents. Patients presented with COMA, hypotonia, ataxia and mild DD, and only a third manifested intellectual disability of variable severity. Brain MRI showed consistent findings characterised by vermis hypoplasia, superior cerebellar dysplasia and subtle-to-mild abnormalities of the superior cerebellar peduncles. The same pattern was observed in two out of three tested asymptomatic parents.

CONCLUSION

Heterozygous truncating or splice-site SUFU variants cause a novel neurodevelopmental syndrome encompassing COMA and mild JS, which likely represent overlapping entities. Variants can arise de novo or be inherited from a healthy parent, representing the first cause of JS with dominant inheritance and reduced penetrance. Awareness of this condition will increase the diagnostic yield of JS genetic testing, and allow appropriate counselling about prognosis, medical monitoring and recurrence risk.

Gorlin Syndrome Associated With a Solitary Circumscribed Retinal Astrocytic Proliferation in a Pediatric Patient

Gorlin syndrome is a rare autosomal dominant disorder with near complete penetrance. The underlying genetic mechanism is a mutation in a tumor suppressor gene. Thus far, mutations in patched homolog 1 and 2 genes (PTCH1 and PTCH2) and the suppressor of fused gene (SUFU) have been identified. The syndrome is characterized by neoplasms arising early in childhood as well as developmental abnormalities, including ophthalmic anomalies. We present the first case associating Gorlin syndrome with a rare retinal lesion known as solitary circumscribed retinal astrocytic proliferation (SCRAP). SCRAP is a benign, stable retinal tumor. For this reason, it is essential to differentiate it from similar retinal lesions that are associated with poor prognosis. [Ophthalmic Surg Lasers Imaging Retina 2022;53:514-516.].

PTCH1 mutant small cell glioblastoma in a patient with Gorlin syndrome: A case report

Gorlin syndrome or nevoid basal cell carcinoma syndrome is a rare genetic disease characterized by predisposition to congenital defects, basal cell carcinomas and medulloblastoma. The syndrome results from a heritable mutation in PATCHED1 (PTCH1), causing constitutive activation of the Hedgehog pathway. The present study described a patient with Gorlin syndrome who presented early in life with characteristic basal cell carcinomas and later developed a small cell glioblastoma (GBM), World Health Organization grade IV, associated with a Patched 1 (PTCH1) N97fs*43 mutation. Comprehensive genomic profiling of GBM tissues also revealed multiple co-occurring alterations including cyclin-dependent kinase 4 (CDK4) amplification, receptor tyrosine-protein kinase 3 (ERBB3) amplification, a fibroblast growth factor receptor 1 and transforming acidic coiled-coil containing protein 1 (FGFR1-TACC1) fusion, zinc finger protein (GLI1) amplification, E3 ubiquitin-protein ligase (MDM2) amplification and spectrin α chain, erythrocytic 1 (SPTA1) T1151fs*24. After the biopsy, imaging revealed extensive leptomeningeal enhancement intracranially and around the cervical spinal cord due to leptomeningeal disease. The patient underwent craniospinal radiation followed by 6 months of adjuvant temozolomide (150 mg/m²) with good response. She was then treated with vismodegib for 11 months, first combined with temozolomide and then with bevacizumab, until disease progression was noted on MRI, with no significant toxicities associated with the combination therapy. She received additional therapies but ultimately succumbed to the disease four months later. The current study presents the first documentation in the literature of a primary (non-radiation induced) glioblastoma secondary to Gorlin syndrome. Based on this clinical experience, vismodegib should be considered in combination with standard-of-care therapies for patients with known Gorlin syndrome-associated glioblastomas and sonic hedgehog pathway mutations.

Multidisciplinary approach to Gorlin-Goltz syndrome: from diagnosis to surgical treatment of jawbones

Background

Gorlin syndrome, also known as Gorlin-Goltz syndrome (GGS) or basal cell nevus syndrome (BCNS) or nevoid basal cell carcinoma syndrome (NBCCS), is an autosomal dominant familial cancer syndrome. It is characterized by the presence of numerous basal cell carcinomas (BCCs), along with skeletal, ophthalmic, and neurological abnormalities. It is essential to anticipate the diagnosis by identifying the pathology through the available diagnostic tests, clinical signs, and radiological manifestations, setting up an adequate treatment plan.

Main body

In the first part, we searched recent databases including MEDLINE (PubMed), Embase, and the Cochrane Library by analyzing the etiopathogenesis of the disease, identifying the genetic alterations underlying them. Subsequently, we defined what are, to date, the major and minor clinical diagnostic criteria, the possible genetic tests to be performed, and the pathologies with which to perform differential diagnosis. The radiological investigations were reviewed based on the most recent literature, and in the second part, we performed a review regarding the existing jawbone protocols, treating simple enucleation, enucleation with bone curettage in association or not with topical use of cytotoxic chemicals, and “en bloc” resection followed by possible bone reconstruction, marsupialization, decompression, and cryotherapy.

Conclusion

To promote the most efficient and accurate management of GGS, this article summarizes the clinical features of the disease, pathogenesis, diagnostic criteria, differential diagnosis, and surgical protocols. To arrive at an early diagnosis of the syndrome, it would be advisable to perform radiographic and clinical examinations from the young age of the patient. The management of the patient with GGS requires a multidisciplinary approach ensuring an adequate quality of life and effective treatment of symptoms.

Leiomyomatosis in an Infant With a SUFU Splice Site Variant: Case Report

Heterozygous loss-of-function variants in the suppressor of fused protein gene (SUFU) can result in Gorlin syndrome, which is characterized by an increased frequency of basal cell carcinoma, medulloblastoma, odontogenic keratocysts, as well as other tumors. We describe a case of a 5-month-old female who presented with multiple intra-abdominal leiomyomata and was found to have a likely pathogenic splice site variant in the SUFU gene. This is the first reported case of leiomyomatosis secondary to a pathogenic SUFU variant in an infant and may represent an early, atypical presentation of Gorlin syndrome.

Multiple Basal Cell Carcinomas in Immunocompetent Patients

Simple Summary

It is widely known that long-term treatment with immunosuppressive drugs represents a risk factor for the onset of malignancies, including multiple basal cell carcinomas. However, multiple basal carcinomas are ao found in the general population, and even in the absence of specific predisposing genetic mutations. This paper aims, through the retrospective evaluation of all patients diagnosed and surgically treated for basal cell carcinomas during 5 years at our Dermatological Division, to identify the characteristics of these subjects and any possible risk factors, useful for outlining specific surveillance programs. In our experience, multiple carcinomas were identified in over 24% of the subjects analyzed, with several lesions removed, ranging from 2 to 11, confirming the relevance of this phenomenon.

Abstract

Background: The onset of multiple BCCs is a relatively common condition, not only among patients undergoing chronic treatment with immunosuppressant drugs, but also in the general population, although specific risk factors for immunocompetent patients have not been identified. A putative role of somatic mutations in the hedgehog pathway should be considered. Methods: This study is a retrospective observation of all patients diagnosed and surgically treated for BCCs during 5 years at our Dermatological Division. For these patients, we evaluated clinical and histopathological characteristics and data about possible risk factors for BCC. Results: Five-hundred and six patients affected by multiple BCCs, accounting for the 24.2% of the entire sample, have been identified. In these patients, the total number of BCCs was 1516, ranging from 2 to 11. Subjects affected by multiple BCCs were more frequently males, with an older age at diagnosis; multiple BCCs developed mainly on the trunk and were often represented by a nodular histotype. The multivariate analysis highlighted that male gender, older age, nodular BCC, or face involvement at the first diagnosis are risk factors for the development of multiple BCCs. Conclusions: The frequency of multiple BCCs even among the non-immunocompromised population underlines the need to subject patients to a close surveillance program, to allow early diagnosis and treatment of additional cancers.

Cancer risk and tumour spectrum in 172 patients with a germline SUFU pathogenic variation: a collaborative study of the SIOPE Host Genome Working Group

BACKGROUND

Little is known about risks associated with germline SUFU pathogenic variants (PVs) known as a cancer predisposition syndrome.

METHODS

To study tumour risks, we have analysed data of a large cohort of 45 unpublished patients with a germline SUFU PV completed with 127 previously published patients. To reduce the ascertainment bias due to index patient selection, the risk of tumours was evaluated in relatives with SUFU PV (89 patients) using the Nelson-Aalen estimator.

RESULTS

Overall, 117/172 (68%) SUFU PV carriers developed at least one tumour: medulloblastoma (MB) (86 patients), basal cell carcinoma (BCC) (25 patients), meningioma (20 patients) and gonadal tumours (11 patients). Thirty-three of them (28%) had multiple tumours. Median age at diagnosis of MB, gonadal tumour, first BCC and first meningioma were 1.5, 14, 40 and 44 years, respectively. Follow-up data were available for 160 patients (137 remained alive and 23 died). The cumulative incidence of tumours in relatives was 14.4% (95% CI 6.8 to 21.4), 18.2% (95% CI 9.7 to 25.9) and 44.1% (95% CI 29.7 to 55.5) at the age of 5, 20 and 50 years, respectively. The cumulative risk of an MB, gonadal tumour, BCC and meningioma at age 50 years was: 13.3% (95% CI 6 to 20.1), 4.6% (95% CI 0 to 9.7), 28.5% (95% CI 13.4 to 40.9) and 5.2% (95% CI 0 to 12), respectively. Sixty-four different PVs were reported across the entire SUFU gene and inherited in 73% of cases in which inheritance could be evaluated.

CONCLUSION

Germline SUFU PV carriers have a life-long increased risk of tumours with a spectrum dominated by MB before the age of 5, gonadal tumours during adolescence and BCC and meningioma in adulthood, justifying fine-tuned surveillance programmes.

Hedgehog signaling

Hedgehog (Hh) proteins constitute one family of a small number of secreted signaling proteins that together regulate multiple aspects of animal development, tissue homeostasis and regeneration. Originally uncovered through genetic analyses in Drosophila, their subsequent discovery in vertebrates has provided a paradigm for the role of morphogens in positional specification. Most strikingly, the Sonic hedgehog protein was shown to mediate the activity of two classic embryonic organizing centers in vertebrates and subsequent studies have implicated it and its paralogs in a myriad of processes. Moreover, dysfunction of the signaling pathway has been shown to underlie numerous human congenital abnormalities and diseases, especially certain types of cancer. This review focusses on the genetic studies that uncovered the key components of the Hh signaling system and the subsequent, biochemical, cell and structural biology analyses of their functions. These studies have revealed several novel processes and principles, shedding new light on the cellular and molecular mechanisms underlying cell-cell communication. Notable amongst these are the involvement of cholesterol both in modifying the Hh proteins and in activating its transduction pathway, the role of cytonemes, filipodia-like extensions, in conveying Hh signals between cells; and the central importance of the Primary Cilium as a cellular compartment within which the components of the signaling pathway are sequestered and interact.

Family history is key to the interpretation of exome sequencing in the prenatal context: Unexpected diagnosis of Basal Cell Nevus Syndrome

OBJECTIVE

To reach a molecular diagnosis for a family with two consecutive fetuses presenting with multiple congenital anomalies.

METHOD

The two fetuses underwent prenatal ultrasound, autopsy, radiologic and genetic investigation. Genetic analysis included karyotype and array-CGH for both fetuses and trio-based whole exome sequencing (WES) only for the second fetus.

RESULTS

WES results, initially focusing on recessive or dominant de novo variants, were negative. However, as a result of new relevant information regarding family history, the variant c.648_651dup in the PTCH1 gene was identified as causative of the fetal phenotype.

CONCLUSION

This case further highlights how WES data analysis and interpretation strongly rely on family history and robust genotype-phenotype correlation. This is even more relevant in the prenatal setting, where access to fetal phenotype is limited and prenatal recognition of many morbid genes is not fully explored. We also provide a detailed description of the prenatal manifestations of Basal Cell Nevus Syndrome. This article is protected by copyright. All rights reserved.

Gorlin Syndrome: Assessing Genotype-Phenotype Correlations and Analysis of Early Clinical Characteristics as Risk Factors for Disease Severity

PURPOSE

Gorlin syndrome (GS) is a rare genetic disorder characterized by lifetime risk of basal cell carcinomas (BCCs), skeletal anomalies (SAs), and other extracutaneous neoplasms. There is great variation in disease severity, and a genotype-phenotype correlation has not been well established. Here, we investigate whether patients' clinical characteristics predict disease severity to inform clinical decision making.

METHODS

Data of 248 patients with GS were collected between 2014 and 2021 from three institutions. Multivariable regression analyses were performed to investigate whether clinical characteristics predicted disease burden. Genotype-phenotype correlations were investigated in 40 patients.

RESULTS

Patients with SAs had a mean increase of 120 lifetime BCCs (95% CI, 27.1 to 213) relative to patients without SAs. Those with ≥ 2 SAs had 2.45 increased odds (95% CI, 1.01 to 5.91) of advanced or metastatic BCCs. Moreover, the presence of multiple SAs was associated with 5.00 increased odds of having a keratocystic odontogenic tumor (95% CI, 2.22 to 11.3) and 2.79 increased odds of an ovarian fibroma (95% CI, 1.05 to 7.40). Genotype-phenotype analyses showed that missense/in-frame mutations were more likely to be hereditary compared with severe deleterious mutation types (100% v 27%; P = .004). In addition, heat map visualization illustrated that those with more deleterious variants, like large deletions, trended toward increased burden of SAs and BCCs per year.

CONCLUSION

GS patients with SAs may be at greater risk for developing more numerous and severe BCCs and other neoplastic growths including keratocystic odontogenic tumors and ovarian fibromas. Current clinical guidelines suggest yearly follow-up in individuals with GS. Since SAs are usually recognized at the time of diagnosis, our results suggest that more vigilant lifetime multidisciplinary surveillance should be considered for these patients starting in childhood.

The Immunogenetics of Non-melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy seen in Caucasians and includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The incidence of NMSC is showing an increasing trend which is attributed to the increased use of sunbeds, recreational sun exposure, aging population, and partly to improved screening and reporting. Ultraviolet (UV) radiation plays the most crucial role in the pathogenesis of both BCC and SCC by inducing DNA damage and mutagenic photoproducts. Other risk factors are fair skin, old age, genetic predisposition, immunosuppression, ionizing radiation, organic chemicals, and HPV infection. The role of genomic instability, genetic mutations/aberrations, and host immunity has been fairly illustrated in several studies. This chapter aims to discuss these aspects of NMSC in detail.

Hereditary gynecologic tumors and precision cancer medicine

Gynecologic cancers are more often caused by genetic factors than other cancers. Genetic testing has become a promising avenue for the prevention, prognosis, and treatment of cancers. This review describes molecular features of gynecologic tumors linked to hereditary syndromes, gives an overview of the current state of clinical management, and clarifies the role of gynecology in the treatment of hereditary tumors. Typical hereditary gynecologic tumors include hereditary breast and ovarian cancer, Lynch syndrome, Peutz-Jeghers syndrome, and Cowden syndrome. Multigene panel testing, which analyzes a preselected subset of genes for genetic variants, has recently become the first-choice test because it can provide more accurate risk assessment than a single test. Furthermore, comprehensive genomic cancer profiling enables personalized cancer treatment and aids in germline findings.

Sterol regulation of developmental and oncogenic Hedgehog signaling

The Hedgehog (Hh) family of lipid-modified signaling proteins directs embryonic tissue patterning and postembryonic tissue homeostasis, and dysregulated Hh signaling drives familial and sporadic cancers. Hh ligands bind to and inhibit the tumor suppressor Patched and allow the oncoprotein Smoothened (SMO) to accumulate in cilia, which in turn activates the GLI family of transcription factors. Recent work has demonstrated that endogenous cholesterol and oxidized cholesterol derivatives (oxysterols) bind and modulate SMO activity. Here we discuss the myriad sterols that activate or inhibit the Hh pathway, with emphasis on endogenous 24(S),25-epoxycholesterol and 3β,5α-dihydroxycholest-7-en-6-one, and propose models of sterol regulation of SMO. Synthetic inhibitors of SMO have long been the focus of drug development efforts. Here, we discuss the possible utility of steroidal SMO ligands or inhibitors of enzymes involved in sterol metabolism as cancer therapeutics.

Calcified Ovarian Fibromas Complicated with Basal Cell Nevus Syndrome

Basal cell nevus syndrome (BCNS) is a rare neurocutaneous syndrome characterized by tumorigeneses such as basal cell carcinomas, jaw cysts, ovarian fibromas, and cardiac fibromas. We present a 24-year-old female with calcified ovarian fibromas associated with BCNS. She had a surgical history of the maxillary cyst and was diagnosed with BCNS due to the cutaneous pits. Magnetic resonance imaging indicated an 8-cm mass and a 4-cm mass, which had been suspected to be a subserosal myoma and a fibroma, respectively. GnRH agonist was preoperatively administered; however, the size of the masses did not change. In laparoscopy, a tumor consisting of 8- and 5-cm masses in the right ovary was identified, and tumorectomy was performed. Because both tumors were extraordinarily rigid and could not be morcellated with scalpels or scissors, we removed them by the Luer Bone Rongeurs with minilaparotomy. The histopathological diagnosis was the ovarian fibromas with marked calcification.

Defining the Spectrum, Treatment and Outcome of Patients With Genetically Confirmed Gorlin Syndrome From the HIT-MED Cohort

Gorlin syndrome is a genetic condition associated with the occurrence of SHH activated medulloblastoma, basal cell carcinoma, macrocephaly and other congenital anomalies. It is caused by heterozygous pathogenic variants in PTCH1 or SUFU. In this study we included 16 patients from the HIT2000, HIT2000interim, I-HIT-MED, observation registry and older registries such as HIT-SKK87, HIT-SKK92 (1987 – 2020) with genetically confirmed Gorlin syndrome, harboring 10 PTCH1 and 6 SUFU mutations. Nine patients presented with desmoplastic medulloblastomas (DMB), 6 with medulloblastomas with extensive nodularity (MBEN) and one patient with classic medulloblastoma (CMB); all tumors affected the cerebellum, vermis or the fourth ventricle. SHH activation was present in all investigated tumors (14/16); DNA methylation analysis (when available) classified 3 tumors as iSHH-I and 4 tumors as iSHH-II. Age at diagnosis ranged from 0.65 to 3.41 years. All but one patient received chemotherapy according to the HIT-SKK protocol. Ten patients were in complete remission after completion of primary therapy; four subsequently presented with PD. No patient received radiotherapy during initial treatment. Five patients acquired additional neoplasms, namely basal cell carcinomas, odontogenic tumors, ovarian fibromas and meningioma. Developmental delay was documented in 5/16 patients. Overall survival (OS) and progression-free survival (PFS) between patients with PTCH1 or SUFU mutations did not differ statistically (10y-OS 90% vs. 100%, p=0.414; 5y-PFS 88.9% ± 10.5% vs. 41.7% ± 22.2%, p=0.139). Comparing the Gorlin patients to all young, SHH activated MBs in the registries (10y-OS 93.3% ± 6.4% vs. 92.5% ± 3.3%, p=0.738; 10y-PFS 64.9%+-16.7% vs. 83.8%+-4.5%, p=0.228) as well as comparing Gorlin M0 SKK-treated patients to all young, SHH activated, M0, SKK-treated MBs in the HIT-MED database did not reveal significantly different clinical outcomes (10y-OS 88.9% ± 10.5% vs. 88% ± 4%, p=0.812; 5y-PFS 87.5% ± 11.7% vs. 77.7% ± 5.1%, p=0.746). Gorlin syndrome should be considered in young children with SHH activated medulloblastoma, especially DMB and MBEN but cannot be ruled out for CMB. Survival did not differ to patients with SHH-activated medulloblastoma with unknown germline status or between PTCH1 and SUFU mutated patients. Additional neoplasms, especially basal cell carcinomas, need to be expected and screened for. Genetic counselling should be provided for families with young medulloblastoma patients with SHH activation.

Molecular Bases of Human Malformation Syndromes Involving the SHH Pathway: GLIA/R Balance and Cardinal Phenotypes

Human hereditary malformation syndromes are caused by mutations in the genes of the signal transduction molecules involved in fetal development. Among them, the Sonic hedgehog (SHH) signaling pathway is the most important, and many syndromes result from its disruption. In this review, we summarize the molecular mechanisms and role in embryonic morphogenesis of the SHH pathway, then classify the phenotype of each malformation syndrome associated with mutations of major molecules in the pathway. The output of the SHH pathway is shown as GLI activity, which is generated by SHH in a concentration-dependent manner, i.e., the sum of activating form of GLI (GLIA) and repressive form of GLI (GLIR). Which gene is mutated and whether the mutation is loss-of-function or gain-of-function determine in which concentration range of SHH the imbalance occurs. In human malformation syndromes, too much or too little GLI activity produces symmetric phenotypes affecting brain size, craniofacial (midface) dysmorphism, and orientation of polydactyly with respect to the axis of the limb. The symptoms of each syndrome can be explained by the GLIA/R balance model.

Tumor Syndromes: Neurosurgical Evaluation and Management

There are multiple syndromes associated with tumors of the central nervous system (CNS). The most common CNS tumor syndrome is neurofibromatosis-1, with well-defined major and minor criteria needed for diagnosis. Other syndromes with variable degree of CNS and extra-CNS involvement that the neurosurgeon should be aware of include neurofibromatosis-2; Turcot syndrome; Cowden syndrome; Gorlin syndrome; Li-Fraumeni syndrome; ataxia-telangiectasia; multiple endocrine neoplasia type 1; von Hippel-Lindau syndrome; and tuberous sclerosis complex. Although most CNS tumor syndromes follow an autosomal dominant pattern of inheritance, the genetic underpinnings of each disease are complex and increasingly better understood.

Nevoid basal cell carcinoma syndrome: a case report and literature review

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS) is a rare genetic disorder associated with basal cell carcinomas (BCC), skeletal anomalies, and jaw cysts, and a number of ocular abnormalities. We describe a case of a 12-year-old boy diagnosed with NBCCS found to have several ophthalmic manifestations including a myelinated retinal nerve fiber. We conducted a literature review targeting the ocular and systemic manifestations of NBCCS, with a focus on the ophthalmic findings that have not been well characterized.

MATERIALS AND METHODS

We conducted a literature search from 1960 to 2021 utilizing specific keywords and criteria and excluded non-clinical articles. A total of 46 articles were ultimately used for the literature review.

RESULTS

In NBCCS, BCCs typically present before the age of 30 and gradually become numerous. Certain ocular features, less common in the general population, are much more common with NBCCS. Depending on the study, prevalence of these features in patients with NBCCS ranges from 26-80% for hypertelorism and 7-36% for myelinated retinal nerve fiber layer. Prevalence of nystagmus in patients with NBCCS was found to be approximately 6%. Systemic findings such as bilamellar calcification of the falx cerebri, palmar pits, and odontogenic keratocysts (OKCs) are also prevalent.

CONCLUSION

NBCCS may affect numerous organ systems, and thus requires a multidisciplinary team to manage. BCCs and jaw cysts are commonly occurring clinical features that have various surgical excisional options. The ocular anomalies of NBCCS are individually rare, and certain anomalies may present in the amblyogenic period of development and contribute to visual impairment.

Proposed criteria for nevoid basal cell carcinoma syndrome in children assessed using statistical optimization

Nevoid basal cell carcinoma syndrome (NBCCS) is a tumor predisposition condition, the cardinal features of which emerge in adolescence or adulthood. Using statistical optimization, this study proposes NBCCS criteria with improved sensitivity in children less than 18 years of age. Earlier detection may lead to improved surveillance and prevention of sequelae. A survey eliciting medical history was completed by, or on behalf of, individuals with NBCCS. Based on these findings, criteria for suspicion of NBCCS in children were suggested using information from a Bernoulli naïve Bayes classifier relying on the human phenotype ontology. The sensitivity and specificity of the existing and proposed diagnostic criteria were also assessed. Participants (n = 48) reported their first signs of NBCCS appeared at a median age of 8 months, but by our retrospective analysis, they did not fulfill the current diagnostic criteria until a median age of 7 years. This study delineates the early-onset features of NBCCS and proposes criteria that should prompt consideration of NBCCS. Additionally, we demonstrate a method for quantitatively assessing the utility of diagnostic criteria for genetic disorders.

Basal cell nevus syndrome: an update on clinical findings

Basal cell nevus syndrome, also known as Gorlin-Goltz syndrome, is a rare autosomal dominant disorder caused by mutations in the hedgehog signaling pathway, mainly in PTCH1. This pathway is involved in embryogenesis and tumorigenesis, and the loss of function of PTCH1 protein produces an aberrant increase in the hedgehog signaling pathway activity. Basal cell nevus syndrome is characterized by tumor predisposition, particularly with the development of multiple basal cell carcinomas at an early age, along with odontogenic keratocysts, palmoplantar pits, skeletal abnormalities, and an increased risk of medulloblastoma. Diagnosis is clinical, with gene mutation analysis confirming the suspicion. The striking phenotypic variability of the syndrome may lead to a delayed diagnosis, making it an uncommon but important entity to recognize. A high index of suspicion and an early diagnosis is crucial for prevention, surveillance, and the prompt establishment of multidisciplinary medical care.

A guideline for the clinical management of basal cell nevus syndrome (Gorlin-Goltz syndrome)

The overall objective of this guideline is to provide up-to-date, evidence-based recommendations for the diagnosis and surveillance of all symptoms of children and adults with either basal cell nevus syndrome (BCNS), a clinical suspicion of BCNS, or a parent with BCNS. In the last two groups the guidelines should be followed until the diagnosis of BCNS can be rejected with certainty. The guideline aims to: - Update and expand on the previous guidelines by an appraisal of all relevant literature from January 2011 up to January 2021 - Address important, practical, clinical questions relating to the primary guideline objective - Provide guideline recommendations - Discuss potential developments and future directions.