Basal cell carcinomas in gorlin syndrome: a review of 202 patients

Hedgehog Inhibitors Beyond Clinical Complete Response in Basal Cell Carcinoma: Should I Stop or Should I Go?

INTRODUCTION

In advanced basal cell carcinoma (BCC), the issue of whether Hedgehog inhibitors (HHIs) should be stopped or not after clinical complete response (cCR) achievement remains an unmet clinical need.

MATERIALS AND METHODS

We conducted a retrospective, multicenter study across 7 Italian dermato-oncology units including patients with BCC who continued vismodegib after cCR between 2012 and 2019. We assessed the relationship between the duration of vismodegib intake (days to cCR [DTCR], days to stop after cCR [DTS], total treatment days [TTD]), and disease-free survival (DFS). Reasons to stop vismodegib were (R1) toxicity and (R2) disease recurrence. The relationship between DTCR, DTS, TTD, and DFS in the whole population and in R1 subgroup was assessed by Pearson's correlation coefficient (P < .05) and Bayesian statistics (BF10).

RESULTS

Sixty-eight BCC patients with a median (m) age of 75.5 years (39-100) were included. Most patients were male (N = 43, 63%), without Gorlin syndrome (N = 56, 82%) and with head and neck area as primary site (N = 51, 75%). After cCR, out of 68 patients, 90% (N = 61/68) discontinued vismodegib: 82% (N = 50/61) due to toxicity (R1), and 18% (N = 11/61) due to recurrence (R2). Conversely, 10% (N = 7/68) continued vismodegib until last follow-up. In the whole population (N = 68), cCR was achieved with a mDTCR of 180.50 days. DFS showed a significant correlation with DTS (P < .01, BF10 = 39.2) and TTD (P < .01, BF10 = 35566), while it was not correlated to DTCR (BF10 < 0.1). The analysis of R1 subgroup (N = 50) confirmed these results. DFS correlated with DTS in all recurrent patients (N = 38, r = 0.44, P < .01) and in the recurrent patients who stopped vismodegib for toxicity (N = 26, r = 0.665, P < .01). DFS was longer when vismodegib was maintained for >2 months after cCR (mDFS > 2 months, N = 54 vs. ≤ 2 months, N = 14: 470 vs. 175 d, P < .01).

CONCLUSIONS

Our retrospective results suggest that HHIs should be continued after cCR to improve DFS in BCC.

Gorlin-Like Phenotype in a Young Girl With a De Novo PTCH2 Variant Mutation of Uncertain Significance

ABSTRACT

Gorlin syndrome, also known as basal cell nevus syndrome, is an autosomal dominant genetic disorder that predisposes humans to tumors. In most cases, this syndrome results from inactivating mutations in the patched homologue 1 gene. Basal cell carcinomas are one of the main characteristics of this syndrome and serve as a major diagnostic criterion. Gorlin syndrome shows a variable phenotype, and recently, other less common mutations in the suppressor of fused homologue or patched homologue 2 genes have been documented in individuals with this syndrome. We present the case of a patient with early-onset basal cell carcinomas and a mild Gorlin syndrome phenotype, attributed to a de novo patched homologue 2 variant of uncertain significance, which has not been previously reported in the literature.

Gorlin Syndrome: A Comprehensive Evaluation of Skin Findings

OBJECTIVE

Although Gorlin syndrome has rich skin findings, there is limited information about their subtypes, features specific to this genodermatosis, and relationships with each other.

MATERIALS AND METHODS

The demographic characteristics as well as cutaneous and extracutaneous findings of consecutive Gorlin syndrome patients diagnosed during 23 years were evaluated retrospectively. The relationship between palmoplantar pitting and basal cell carcinoma (BCC) in this localization and the relationship between odontogenic keratocysts (OKCs) and epidermoid cysts were investigated.

RESULTS

A total of 30 patients were diagnosed with Gorlin syndrome of whom 36.7% were children. BCC was the most common finding (90%) followed by OKCs (83.3%), skeletal system anomalies (76.7%), and palmoplantar pitting (76.7%). While classical BCC (63.3%) lesions were the predominant clinical subtype among all patients, acrochordon-like or small-sized papular BCCs were seen in 45.4% of pediatric patients. Three patients, 2 of whom were children, had BCC lesions in the palmoplantar region in association with palmoplantar pitting. Epidermoid cysts presenting clinically as solitary (n = 12) or a few nodules (n = 4) without punctum, located more commonly in acral areas (n = 10) were seen in 16 (53.3%) patients of whom 7 were children. Epidermoid cysts were seen in 60% of patients with OKCs, and the relationship between epidermoid cysts and OKCs was not statistically significant (P = .15). Extracutaneous tumors such as medulloblastoma (n = 3), cardiac fibroma (n = 1), and ameloblastoma (n = 1) were also recorded.

CONCLUSION

The awareness of papular or acrochordon-like BCCs, palmoplantar BCCs, and acral epidermoid cysts without punctum may facilitate early diagnosis of Gorlin syndrome in children.

Ultraviolet Radiation Biological and Medical Implications

Ultraviolet (UV) radiation plays a crucial role in the development of melanoma and non-melanoma skin cancers. The types of UV radiation are differentiated by wavelength: UVA (315 to 400 nm), UVB (280 to 320 nm), and UVC (100 to 280 nm). UV radiation can cause direct DNA damage in the forms of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs). In addition, UV radiation can also cause DNA damage indirectly through photosensitization reactions caused by reactive oxygen species (ROS), which manifest as 8-hydroxy-2'-deoxyguanine (8-OHdG). Both direct and indirect DNA damage can lead to mutations in genes that promote the development of skin cancers. The development of melanoma is largely influenced by the signaling of the melanocortin one receptor (MC1R), which plays an essential role in the synthesis of melanin in the skin. UV-induced mutations in the BRAF and NRAS genes are also significant risk factors in melanoma development. UV radiation plays a significant role in basal cell carcinoma (BCC) development by causing mutations in the Hedgehog (Hh) pathway, which dysregulates cell proliferation and survival. UV radiation can also induce the development of squamous cell carcinoma via mutations in the TP53 gene and upregulation of MMPs in the stroma layer of the skin.

Pediatric odontogenic keratocyst and early diagnosis of Gorlin syndrome: Clinicopathological aids

Odontogenic keratocysts (OKCs) are a common presentation in almost all patients with nevoid basal cell carcinoma syndrome (NBCCS) or Gorlin syndrome, irrespective of race. In most patients with NBCCS, OKC presents as multiple lesions affecting the jaws which makes it a signpost for the investigation of patients with the syndrome. In approximately 40% of pediatric patients, the initial presentation is that of a single OKC, which may often result in missing the diagnosis of NBCCS. This is particularly common in patients without clinically apparent NBCCS-related manifestations. This review examines the clinicopathological features that clinicians and oral pathologists may look for in pediatric patient with OKC and OKC surgical specimens that may serve as indicators for the diagnosis of NBCCS. Although these features do not diagnose NBCCS by themselves, they may significantly help in initiating the diagnostic process at an early stage with an obvious benefit to the child and relatives.

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.

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.

Modulation of Hedgehog Signaling for the Treatment of Basal Cell Carcinoma and the Development of Preclinical Models

Basal Cell Carcinoma (BCC) is the most commonly diagnosed cancer worldwide. While the survivability of BCC is high, many patients are excluded from clinically available treatments due to health risks or personal choice. Further, patients with advanced or metastatic disease have severely limited treatment options. The dysregulation of the Hedgehog (Hh) signaling cascade drives onset and progression of BCC. As such, the modulation of this pathway has driven advancements in BCC research. In this review, we focus firstly on inhibitors that target the Hh pathway as chemotherapeutics against BCC. Two therapies targeting Hh signaling have been made clinically available for BCC patients, but these treatments suffer from limited initial efficacy and a high rate of chemoresistant tumor recurrence. Herein, we describe more recent developments of chemical scaffolds that have been designed to hopefully improve upon the available therapeutics. We secondly discuss the history and recent efforts involving modulation of the Hh genome as a method of producing in vivo models of BCC for preclinical research. While there are many advancements left to be made towards improving patient outcomes with BCC, it is clear that targeting the Hh pathway will remain at the forefront of research efforts in designing more effective chemotherapeutics as well as relevant preclinical models.

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.

Cancer predisposition in pediatric neuro-oncology-practical approaches and ethical considerations

A genetic predisposition to tumor development can be identified in up to 10% of pediatric patients with central nervous system (CNS) tumors. For some entities, the rate of an underlying predisposition is even considerably higher. In recent years, population-based approaches have helped to further delineate the role of cancer predisposition in pediatric oncology. Investigations for cancer predisposition syndrome (CPS) can be guided by clinical signs and family history leading to directed testing of specific genes. The increasingly adopted molecular analysis of tumor and often parallel blood samples with multi-gene panel, whole-exome, or whole-genome sequencing identifies additional patients with or without clinical signs. Diagnosis of a genetic predisposition may put an additional burden on affected families. However, information on a given cancer predisposition may be critical for the patient as potentially influences treatment decisions and may offer the patient and healthy carriers the chance to take part in intensified surveillance programs aiming at early tumor detection. In this review, we discuss some of the practical and ethical challenges resulting from the widespread use of new diagnostic techniques and the most important CPS that may manifest with brain tumors in childhood.

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.

Review of the Molecular Genetics of Basal Cell Carcinoma; Inherited Susceptibility, Somatic Mutations, and Targeted Therapeutics

Simple Summary

Basal cell carcinoma is the most common human cancer worldwide. The molecular basis of BCC involves an interplay of inherited genetic susceptibility and somatic mutations, commonly induced by exposure to UV radiation. In this review, we outline the currently known germline and somatic mutations implicated in the pathogenesis of BCC with particular attention paid toward affected molecular pathways. We also discuss polymorphisms and associated phenotypic traits in addition to active areas of BCC research. We finally provide a brief overview of existing non-surgical treatments and emerging targeted therapeutics for BCC such as Hedgehog pathway inhibitors, immune modulators, and histone deacetylase inhibitors.

Abstract

Basal cell carcinoma (BCC) is a significant public health concern, with more than 3 million cases occurring each year in the United States, and with an increasing incidence. The molecular basis of BCC is complex, involving an interplay of inherited genetic susceptibility, including single nucleotide polymorphisms and genetic syndromes, and sporadic somatic mutations, often induced by carcinogenic exposure to UV radiation. This review outlines the currently known germline and somatic mutations implicated in the pathogenesis of BCC, including the key molecular pathways affected by these mutations, which drive oncogenesis. With advances in next generation sequencing and our understanding of the molecular genetics of BCC, established and emerging targeted therapeutics are offering new avenues for the non-surgical treatment of BCC. These agents, including Hedgehog pathway inhibitors, immune modulators, and histone deacetylase inhibitors, will also be discussed.

Basaloid follicular hamartomas in pediatric Basal Cell Nevus Syndrome: A diagnostic challenge

Basal Cell Nevus Syndrome (BCNS) is an autosomal dominant inherited disease caused by PTCH1 (9q22.3‐q31) germline mutations. Skin manifestations are mainly characterized by hyperkeratosis of the palms and soles, palmoplantar pits and a strong predisposition to develop multiple basal cell carcinomas (BCCs). Recently, it has been hypothesized that basaloid follicular hamartomas (BFH) could be included in BCNS skin features. We present three pediatric cases of GS with BCCs and BFHs. Clinical, dermoscopic and immunohistochemical tools are reported.

Current recommendations for cancer surveillance in Gorlin syndrome: a report from the SIOPE host genome working group (SIOPE HGWG)

Gorlin syndrome (MIM 109,400), a cancer predisposition syndrome related to a constitutional pathogenic variation (PV) of a gene in the Sonic Hedgehog pathway (PTCH1 or SUFU), is associated with a broad spectrum of benign and malignant tumors. Basal cell carcinomas (BCC), odontogenic keratocysts and medulloblastomas are the main tumor types encountered, but meningiomas, ovarian or cardiac fibromas and sarcomas have also been described. The clinical features and tumor risks are different depending on the causative gene. Due to the rarity of this condition, there is little data on phenotype-genotype correlations. This report summarizes genotype-based recommendations for screening patients with PTCH1 and SUFU-related Gorlin syndrome, discussed during a workshop of the Host Genome Working Group of the European branch of the International Society of Pediatric Oncology (SIOPE HGWG) held in January 2020. In order to allow early detection of BCC, dermatologic examination should start at age 10 in PTCH1, and at age 20 in SUFU PV carriers. Odontogenic keratocyst screening, based on odontologic examination, should begin at age 2 with annual orthopantogram beginning around age 8 for PTCH1 PV carriers only. For medulloblastomas, repeated brain MRI from birth to 5 years should be proposed for SUFU PV carriers only. Brain MRI for meningiomas and pelvic ultrasound for ovarian fibromas should be offered to both PTCH1 and SUFU PV carriers. Follow-up of patients treated with radiotherapy should be prolonged and thorough because of the risk of secondary malignancies. Prospective evaluation of evidence of the effectiveness of these surveillance recommendations is required.

Genomic profiling of late-onset basal cell carcinomas from two brothers with nevoid basal cell carcinoma syndrome

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant genetic disorder. It is commonly caused by mutations in PTCH1 and chiefly characterized by multiple basal cell carcinomas (BCCs) developing prior to the age of 30 years. In rare cases, NBCCS presents with a late onset of BCC development.

OBJECTIVE

To investigate BCC tumorigenesis in two brothers, who showed characteristic features of NBCCS but developed their first BCCs only after the age of 40 years. Two other siblings did not show signs of NBCCS.

RESULTS

We obtained blood samples from four siblings and nine BCCs from the two brothers with NBCCS. Whole exome sequencing and RNA sequencing revealed loss of heterozygosity (LOH) of PTCH1 in eight out of nine tumours that consistently involved the same haplotype on chromosome 9. This haplotype contained a germinal splice site mutation in PTCH1 (NM_001083605:exon9:c.763-6C>A). Analysis of germline DNA confirmed segregation of this mutation with the disease. All BCCs harboured additional somatic loss-of-function (LoF) mutations in the remaining PTCH1 allele which are not typically seen in other cases of NBCCS. This suggests a hypomorphic nature of the germinal PTCH1 mutation in this family. Furthermore, all BCCs had a similar tumour mutational burden compared to BCCs of unrelated NBCCS patients while harbouring a higher number of damaging PTCH1 mutations.

CONCLUSIONS

Our data suggest that a sequence of three genetic hits leads to the late development of BCCs in two brothers with NBCCS: a hypomorphic germline mutation, followed by somatic LOH and additional mutations that complete PTCH1 inactivation. These genetic events are in line with the late occurrence of the first BCC and with the higher number of damaging PTCH1 mutations compared to usual cases of NBCCS.

Cardiac Fibroma with Asymptomatic Ventricular Arrhythmia in an Adolescent with Gorlin's Syndrome

Nevoid basal cell carcinoma syndrome (NBCCS), also referred to as Gorlin's syndrome, is an autosomal dominant inherited condition that predisposes affected individuals to various tumors such as cardiac fibromas. Though technically benign, cardiac fibromas may result in malignant arrhythmias and sudden death. The pertinent literature pertaining to pediatric cases of cardiac fibromas and their clinical features were reviewed. We present the case of an asymptomatic teenage with de novo NBCCS who was diagnosed with both NBCCS and cardiac fibroma later in life. The patient was noted to have clinically significant ventricular arrhythmias that were eliminated with tumor resection. There are no established best practice guidelines for the management of cardiac fibromas in patients with NBCCS. Given the risk of sudden arrhythmic death, the presence of ventricular arrhythmias should prompt strong consideration of tumor resection.

Diagnostic Approach to Macrocephaly in Children

Macrocephaly affects up to 5% of the pediatric population and is defined as an abnormally large head with an occipitofrontal circumference (OFC) >2 standard deviations (SD) above the mean for a given age and sex. Taking into account that about 2-3% of the healthy population has an OFC between 2 and 3 SD, macrocephaly is considered as "clinically relevant" when OFC is above 3 SD. This implies the urgent need for a diagnostic workflow to use in the clinical setting to dissect the several causes of increased OFC, from the benign form of familial macrocephaly and the Benign enlargement of subarachnoid spaces (BESS) to many pathological conditions, including genetic disorders. Moreover, macrocephaly should be differentiated by megalencephaly (MEG), which refers exclusively to brain overgrowth, exceeding twice the SD (3SD-"clinically relevant" megalencephaly). While macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, megalencephaly is most likely due to a genetic cause. Apart from the head size evaluation, a detailed family and personal history, neuroimaging, and a careful clinical evaluation are crucial to reach the correct diagnosis. In this review, we seek to underline the clinical aspects of macrocephaly and megalencephaly, emphasizing the main differential diagnosis with a major focus on common genetic disorders. We thus provide a clinico-radiological algorithm to guide pediatricians in the assessment of children with macrocephaly.

Photodynamic Therapy for Basal Cell Carcinoma: The Clinical Context for Future Research Priorities

Photodynamic therapy (PDT) is an established treatment option for low-risk basal cell carcinoma (BCC). BCC is the most common human cancer and also a convenient cancer in which to study PDT treatment. This review clarifies challenges to researchers evident from the clinical use of PDT in BCC treatment. It outlines the context of PDT and how PDT treatments for BCC have been developed hitherto. The sections examine the development of systemic and subsequently topical photosensitizers, light delivery regimens, and the use of PDT in different patient populations and subtypes of BCC. The outcomes of topical PDT are discussed in comparison with alternative treatments, and topical PDT applications in combination and adjuvant therapy are considered. The intention is to summarize the clinical relevance and expose areas of research need in the BCC context, ultimately to facilitate improvements in PDT treatment.

Cancer Predisposition Syndromes and Medulloblastoma in the Molecular Era

Medulloblastoma is the most common malignant brain tumor in children. In addition to sporadic cases, medulloblastoma may occur in association with cancer predisposition syndromes. This review aims to provide a complete description of inherited cancer syndromes associated with medulloblastoma. We examine their epidemiological, clinical, genetic, and diagnostic features and therapeutic approaches, including their correlation with medulloblastoma. Furthermore, according to the most recent molecular advances, we describe the association between the various molecular subgroups of medulloblastoma and each cancer predisposition syndrome. Knowledge of the aforementioned conditions can guide pediatric oncologists in performing adequate cancer surveillance. This will allow clinicians to promptly diagnose and treat medulloblastoma in syndromic children, forming a team with all specialists necessary for the correct management of the other various manifestations/symptoms related to the inherited cancer syndromes.

Basal cell nevus syndrome: From DNA to therapeutics

Basal cell nevus syndrome, also known as Gorlin syndrome, is a hereditary cancer syndrome associated with multiple basal cell carcinomas, congenital defects, and nondermatologic tumors. This disease is autosomal dominant with variable expressivity and is caused by abnormalities in the sonic hedgehog signaling pathway. Management requires a multidisciplinary approach and should include the biopsychosocial needs of patients and their families. Genetic testing is necessary to confirm an unclear diagnosis, evaluate at-risk relatives, and assist with family planning.

Wnt, Notch, and TGF-β Pathways Impinge on Hedgehog Signaling Complexity: An Open Window on Cancer

Constitutive activation of the Hedgehog (Hh) signaling pathway is associated with increased risk of developing several malignancies. The biological and pathogenic importance of Hh signaling emphasizes the need to control its action tightly, both physiologically and therapeutically. Evidence of crosstalk between Hh and other signaling pathways is reported in many tumor types. Here, we provide an overview of the current knowledge about the communication between Hh and major signaling pathways, such as Notch, Wnt, and transforming growth factor β (TGF-β), which play critical roles in both embryonic and adult life. When these pathways are unbalanced, impaired crosstalk contributes to disease development. It is reported that more than one of these pathways are active in different type of tumors, at the same time. Therefore, starting from a plethora of stimuli that activate multiple signaling pathways, we describe the signals that preferentially converge on the Hh signaling cascade that influence its activity. Moreover, we highlight several connection points between Hh and Notch, Wnt, or TGF-β pathways, showing a reciprocal synergism that contributes to tumorigenesis, supporting a more malignant behavior by tumor cells, such as in leukemia and brain tumors. Understanding the importance of these molecular interlinking networks will provide a rational basis for combined anticancer drug development.

Developments in Transduction, Connectivity and AI/Machine Learning for Point-of-Care Testing

We review some emerging trends in transduction, connectivity and data analytics for Point-of-Care Testing (POCT) of infectious and non-communicable diseases. The patient need for POCT is described along with developments in portable diagnostics, specifically in respect of Lab-on-chip and microfluidic systems. We describe some novel electrochemical and photonic systems and the use of mobile phones in terms of hardware components and device connectivity for POCT. Developments in data analytics that are applicable for POCT are described with an overview of data structures and recent AI/Machine learning trends. The most important methodologies of machine learning, including deep learning methods, are summarised. The potential value of trends within POCT systems for clinical diagnostics within Lower Middle Income Countries (LMICs) and the Least Developed Countries (LDCs) are highlighted.

Global gene expression of histologically normal primary skin cells from BCNS subjects reveals "single-hit" effects that are influenced by rapamycin

Studies of dominantly heritable cancers enabled insights about tumor progression. BCNS is a dominantly inherited disorder that is characterized by developmental abnormalities and postnatal neoplasms, principally BCCs. We performed an exploratory gene expression profiling of primary cell cultures derived from clinically unaffected skin biopsies of BCNS gene-carriers (PTCH1^+/-) and normal individuals. PCA and HC of untreated keratinocytes or fibroblasts failed to clearly distinguish BCNS samples from controls. These results are presumably due to the common suppression of canonical HH signaling in vitro. We then used a relaxed threshold (p-value <0.05, no FDR cut-off; FC 1.3) that identified a total of 585 and 857 genes differentially expressed in BCNS keratinocytes and fibroblasts samples, respectively. A GSEA identified pancreatic β cell hallmark and mTOR signaling genes in BCNS keratinocytes, whereas analyses of BCNS fibroblasts identified gene signatures regulating pluripotency of stem cells, including WNT pathway. Significantly, rapamycin treatment (FDR<0.05), affected a total of 1411 and 4959 genes in BCNS keratinocytes and BCNS fibroblasts, respectively. In contrast, rapamycin treatment affected a total of 3214 and 4797 genes in normal keratinocytes and normal fibroblasts, respectively. The differential response of BCNS cells to rapamycin involved 599 and 1463 unique probe sets in keratinocytes and fibroblasts, respectively. An IPA of these genes in the presence of rapamycin pointed to hepatic fibrosis/stellate cell activation, and HIPPO signaling in BCNS keratinocytes, whereas mitochondrial dysfunction and AGRN expression were uniquely enriched in BCNS fibroblasts. The gene expression changes seen here are likely involved in the etiology of BCCs and they may represent biomarkers/targets for early intervention.

Germline SUFU mutation carriers and medulloblastoma: clinical characteristics, cancer risk, and prognosis

Background

Germline mutations of suppressor of fused homolog (SUFU) predispose to sonic hedgehog (SHH) medulloblastoma. Germline SUFU mutations have been reported in nevoid basal cell carcinoma syndrome (NBCCS), but little is known about the cancer risk and clinical spectrum.

Methods

We performed a retrospective review of all patients with medulloblastoma and a germline SUFU mutation in France.

Results

Twenty-two patients from 17 families were identified with medulloblastoma and a germline SUFU mutation (median age at diagnosis: 16.5 mo). Macrocrania was present in 20 patients, but only 5 met the diagnostic criteria for NBCCS. Despite treatment with surgery and chemotherapy, to avoid radiotherapy in all patients except one, the outcome was worse than expected for SHH medulloblastoma, due to the high incidence of local relapses (8/22 patients) and second malignancies (n = 6 in 4/22 patients). The 5-year progression-free survival and overall survival rates were 42% and 66%. Mutations were inherited in 79% of patients, and 34 additional SUFU mutation carriers were identified within 14 families. Medulloblastoma penetrance was incomplete, but higher than in Patched 1 (PTCH1) mutation carriers. Besides medulloblastoma, 19 other tumors were recorded among the 56 SUFU mutation carriers, including basal cell carcinoma (BCC) in 2 patients and meningioma in 3 patients.

Conclusion

Germline SUFU mutations strongly predispose to medulloblastoma in the first years of life, with worse prognosis than usually observed for SHH medulloblastoma. The clinical spectrum differs between SUFU and PTCH1 mutation carriers, and BCC incidence is much lower in SUFU mutation carriers. The optimal treatment of SUFU mutation-associated medulloblastoma has not been defined.

Severe PATCHED1 Deficiency in Cancer-Prone Gorlin Patient Cells Results in Intrinsic Radiosensitivity

PURPOSE

Gorlin syndrome (or basal-cell nevus syndrome) is a cancer-prone genetic disease in which hypersusceptibility to secondary cancer and tissue reaction after radiation therapy is debated, as is increased radiosensitivity at cellular level. Gorlin syndrome results from heterozygous mutations in the PTCH1 gene for 60% of patients, and we therefore aimed to highlight correlations between intrinsic radiosensitivity and PTCH1 gene expression in fibroblasts from adult patients with Gorlin syndrome.

METHODS AND MATERIALS

The radiosensitivity of fibroblasts from 6 patients with Gorlin syndrome was determined by cell-survival assay after high (0.5-3.5 Gy) and low (50-250 mGy) γ-ray doses. PTCH1 and DNA damage response gene expression was characterized by real-time polymerase chain reaction and Western blotting. DNA damage and repair were investigated by γH2AX and 53BP1 foci assay. PTCH1 knockdown was performed in cells from healthy donors by using stable RNA interference. Gorlin cells were genotyped by 2 complementary sequencing methods.

RESULTS

Only cells from patients with Gorlin syndrome who presented severe deficiency in PATCHED1 protein exhibited a significant increase in cellular radiosensitivity, affecting cell responses to both high and low radiation doses. For 2 of the radiosensitive cell strains, heterozygous mutations in the 5' end of PTCH1 gene explain PATCHED1 protein deficiency. In all sensitive cells, DNA damage response pathways (ATM, CHK2, and P53 levels and activation by phosphorylation) were deregulated after irradiation, whereas DSB repair recognition was unimpaired. Furthermore, normal cells with RNA interference-mediated PTCH1 deficiency showed reduced survival after irradiation, directly linking this gene to high- and low-dose radiosensitivity.

CONCLUSIONS

In the present study, we show an inverse correlation between PTCH1 expression level and cellular radiosensitivity, suggesting an explanation for the conflicting results previously reported for Gorlin syndrome and possibly providing a basis for prognostic screens for radiosensitive patients with Gorlin syndrome and PTCH1 mutations.

Cancer Surveillance in Gorlin Syndrome and Rhabdoid Tumor Predisposition Syndrome

Gorlin syndrome and rhabdoid tumor predisposition syndrome (RTPS) are autosomal dominant syndromes associated with an increased risk of childhood-onset brain tumors. Individuals with Gorlin syndrome can manifest a wide range of phenotypic abnormalities, with about 5% of family members developing medulloblastoma, usually occurring in the first 3 years of life. Gorlin syndrome is associated with germline mutations in components of the Sonic Hedgehog pathway, including Patched1 (PTCH1) and Suppressor of fused (SUFU)SUFU mutation carriers appear to have an especially high risk of early-onset medulloblastoma. Surveillance MRI in the first years of life in SUFU mutation carriers is, therefore, recommended. Given the risk of basal cell carcinomas, regular dermatologic examinations and sun protection are also recommended. Rhabdoid tumors (RT) are tumors initially defined by the descriptive "rhabdoid" term, implying a phenotypic similarity with rhabdomyoblasts at the microscopic level. RTs usually present before the age of 3 and can arise within the cranium as atypical teratoid/rhabdoid tumors or extracranially, especially in the kidney, as malignant rhabdoid tumors. However, RTs of both types share germline and somatic mutations in SMARCB1 or, more rarely, SMARCA4, each of which encodes a chromatin remodeling family member. SMARCA4 mutations are particularly associated with small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). The outcome following a diagnosis of any of these tumors is often poor, and the value of surveillance is unknown. International efforts to determine surveillance protocols are underway, and preliminary recommendations are made for carriers of SMARCB1 and SMARCA4 mutations. Clin Cancer Res; 23(12); e62-e67. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

A Novel PTCH1 Frameshift Mutation Leading to Nevoid Basal Cell Carcinoma Syndrome

Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is a rare multisystemic autosomal dominant disorder typically presenting with cutaneous basal cell carcinomas, multiple keratocysts, and skeletal anomalies. NBCCS is caused by heterozygous mutations in the PTCH1 gene in chromosome 9q22, in the PTCH2 gene in 1p34, or the SUFU gene in 10q24.32. Here, we report on an 18-month-old boy presenting with medulloblastoma, frontal bossing, and multiple skeletal anomalies and his father who has basal cell carcinomas, palmar pits, macrocephaly, bifid ribs, calcification of falx cerebri, and a history of surgery for odontogenic keratocyst. These clinical findings were compatible with the diagnosis of NBCCS, and a novel mutation, c.1249delC; p.Gln417Lysfs*15, was found in PTCH1 causing a premature stop codon.

Gorlin Syndrome

Gorlin syndrome is a rare autosomal dominant disease caused by mutations in the sonic hedgehog signaling pathway. Of particular importance is the PTCH1 gene. The disease is characterized by the development of multiple basal cell carcinomas at young ages. These tumors may present with other skin manifestations such as palmoplantar pits and with extracutaneous manifestations such as odontogenic keratocysts and medulloblastoma. Although the dermatologist may be key for recognizing clinical suspicion of the syndrome, a multidisciplinary team is usually necessary for diagnosis, treatment, and follow-up. Skin treatment may be complicated due to the large number of basal cell carcinomas and the extent of involvement. In recent years, new drugs that inhibit targets in the sonic hedgehog pathway have been developed. Although these agents appear promising options for patients with Gorlin syndrome, their efficacy is limited by adverse effects and the development of resistance.

Seltene Tumordispositionssyndrome mit Manifestation im Kindesalter

Bei etwa 7–10 % der pädiatrischen Krebspatienten werden zugrunde liegende Tumordispositionssyndrome (TDS) vermutet. Das Erkennen von TDS hat klinische Implikationen für die Krebsprävention und -früherkennung, die Krebstherapie und -nachsorge, die psychosoziale Unterstützung sowie die Beratung von Angehörigen und Identifizierung weiterer Anlageträger in den betroffenen Familien. Hinweise auf das Vorliegen eines TDS anhand von Eigen- und Familienanamnese, Untersuchungsbefund sowie gegebenenfalls Tumorhistologie und -genetik müssen daher möglichst früh erkannt werden, um bei Verdacht auf Vorliegen eines TDS eine humangenetische Beratung und gegebenenfalls genetische Diagnostik zu veranlassen. Wissenschaftliche Untersuchungen zu TDS liefern Einblicke in die Biologie der Gewebe- und Tumorentwicklung und weisen auf mögliche Ansatzpunkte zielgerichteter Therapien hin. Die vorliegende Arbeit gibt eine Übersicht über TDS mit erhöhtem Risiko für Wilms-Tumoren (Nephroblastome), Neuroblastome oder Medulloblastome. Zusätzlich werden zwei vergleichsweise neu beschriebene Syndrome mit breitem Neoplasiespektrum erläutert: die konstitutionelle Mismatch-Reparatur-Defizienz (CMMRD) und das DICER1-Syndrom. Neben der Erläuterung der klinischen Charakteristika und der genetischen Grundlagen werden für die tägliche Praxis Hinweise zur Indikation von genetischen Untersuchungen und Früherkennung bei TDS aufgeführt. Die Betreuung der Betroffenen und ihrer Angehörigen sollte möglichst interdisziplinär erfolgen. Forschung zu TDS, zum Beispiel im Rahmen von Registern für TDS, ist essenziell, um langfristig die medizinische Versorgung von Menschen zu verbessern, die bedingt durch konstitutionelle genetische Veränderungen ein erhöhtes Krebsrisiko haben.

First evidence of genotype-phenotype correlations in Gorlin syndrome

BACKGROUND

Gorlin syndrome (GS) is an autosomal dominant syndrome characterised by multiple basal cell carcinomas (BCCs) and an increased risk of jaw cysts and early childhood medulloblastoma. Heterozygous germline variants in PTCH1 and SUFU encoding components of the Sonic hedgehog pathway explain the majority of cases. Here, we aimed to delineate genotype-phenotype correlations in GS.

METHODS

We assessed genetic and phenotypic data for 182 individuals meeting the diagnostic criteria for GS (median age: 47.1; IQR: 31.1-61.1). A total of 126 patients had a heterozygous pathogenic variant, 9 had SUFU pathogenic variants and 46 had no identified mutation.

RESULTS

Patients with variants were more likely to be diagnosed earlier (p=0.02), have jaw cysts (p=0.002) and have bifid ribs (p=0.003) or any skeletal abnormality (p=0.003) than patients with no identified mutation. Patients with a missense variant in PTCH1 were diagnosed later (p=0.03) and were less likely to develop at least 10 BCCs and jaw cysts than those with other pathogenic PTCH1 variants (p=0.03). Patients with SUFU pathogenic variants were significantly more likely than those with PTCH1 pathogenic variants to develop a medulloblastoma (p=0.009), a meningioma (p=0.02) or an ovarian fibroma (p=0.015), but were less likely to develop a jaw cyst (p=0.0004).

CONCLUSION

We propose that the clinical heterogeneity of GS can in part be explained by the underlying or SUFU variant.

Autotransplantation of a Strange Positioned Impacted Central Incisor in a surgically Prepared Socket: A Miracle Esthetic Concept

Esthetics is a prime concern for a young lady. Any anomaly in the anterior tooth may create anxiety and depression. This anxiety and depression may hamper her married life and overall personality. This case report reveals an unerupted right central incisor situated in a strange position, creating space in the maxillary anterior region and giving an unesthetic appearance. Autotransplantation is a method of choice for a strangely positioned impacted central incisor in a new appropriate site. This method offers a new treatment option for some clinical situations if orthodontic approach is not possible. It permits tooth movement to a distant or the opposite side of the same dental arch as well as to the opposite jaw. This procedure also offers potential benefits of reestablishment of normal alveolar process development, esthetics, functions, and arch integrity. This procedure has the potential to become a viable alternative treatment plan for young patients of low socioeconomic status, allowing the reestablish-ment and restoration of a missing tooth and their functions. This article discusses methods of auto-reimplantation of a tooth in a fresh surgically prepared socket, its biological principle, and establishment of functions, esthetics, and phonetics.

Gorlin-Goltz Syndrome: A Rare Case Report of a 11-Year-Old Child

Gorlin-Goltz Syndrome, also known as nevoid basal cell carcinoma syndrome (NBCCS), is an autosomal dominant trait caused due to mutations in the patched tumor suppressor gene (PTCH) gene found on the long arm of chromosome 9. The syndrome is characterized by the presence of odontogenic keratocysts (OKCs), basal cell carcinomas, and skeletal malformations. Early diagnosis of the syndrome can be done by pedodontist as OKC is one of the early manifestations of the syndrome. Early diagnosis and treatment is important for long-term prognosis of the syndrome by reducing the severity of cutaneous carcinomas and deformities due to jaw cyst. The present case describes an 11-year-old patient with some typical features of NBCCS, which were diagnosed through its oral and maxillofacial manifestations. This case emphasizes the importance of pedodontist in early recognition of the syndrome.

HOW TO CITE THIS ARTICLE

Tandon S, Chauhan Y, Sharma M, Jain M. Gorlin-Goltz Syndrome: A Rare Case Report of a 11-Year-Old Child. Int J Clin Pediatr Dent 2016;9(3):264-268.

Delayed diagnosis of Gorlin syndrome: Learning from mistakes!

Gorlin syndrome (GS) is a rare inherited multisystem disorder with predisposition to basal cell carcinomas and various other neoplasms. Characteristic features include falx calcification, multiple odontogenic keratocysts (OKCs), early onset medulloblastoma, craniofacial and skeletal malformations, cardiac and ovarian fibroma. We present a case of GS in a 9-year-old girl with recurrent dental infections which was overlooked for 8 years. Diagnosis was finally suggested by the incidental detection of multiple OKCs and ovarian fibromas on follow-up magnetic resonance imaging performed for surveillance of previous operated brain tumor.

Skeletal stigmata as keys to access to the composite and ancient Gorlin-Goltz syndrome history: The Egypt, Pompeii and Herculaneum lessons

There are several genetic diseases with a wide spectrum of congenital bone stigmata in association to cutaneous and visceral benign and malignant neoplasms. Gorlin-Goltz syndrome, also named nevoid basal cell carcinoma syndrome, is an autosomal dominant systemic disease with almost complete penetrance and high intra-familial phenotypic variability, caused by germline mutations of the gene PTCH1. The syndrome is characterized by unusual skeletal changes and high predisposition to the development of multiple basal cell carcinomas, odontogenic keratocysts tumors and other visceral tumors. The Gorlin syndrome, clinically defined as distinct syndrome in 1963, existed during Dynastic Egyptian times, as revealed by a costellation of skeletal findings compatible with the syndrome in mummies dating back to 3000years ago and, most likely, in the ancient population of Pompeii. These paleogenetic and historical evidences, together with the clinical and biomolecular modern evidences, confirm the quite benign behavior of the syndrome and the critical value of the multiple and synchronous skeletal anomalies in the recognition of these rare and complex genetic disease.

Diagnosis and Management of Hereditary Basal Cell Skin Cancer

Basal cell carcinoma (BCC) is the most common cancer in Caucasians worldwide and its incidence is rising. It is generally considered a sporadic tumour, most likely to affect fair-skinned individuals exposed to ultraviolet (UV) radiation. This chapter focusses on the approach to recognising the relatively few individuals in whom a high-risk hereditary susceptibility may be present. Gorlin syndrome is the main consideration and the gene most commonly mutated is PTCH1, a key regulator of the Hedgehog developmental pathway. Recently, loss of function of another gene in the same pathway, SUFU, has been found to explain a subset of families. Understanding the pathogenesis of familial BCCs has advanced the understanding of the biology of sporadic tumours and led to targeted therapy trials. The management of familial BCCs remains a challenge due to significant unmet needs for non-surgical treatments and a high burden of disease for the individual. Together with the prospect of advances in gene discovery and translation, these challenges highlight the need for ongoing review of at-risk and affected individuals by a multidisciplinary team.

DICER1 syndrome can mimic different genetic tumor predispositions

DICER1, a RNAse endonuclease involved in the processing of siRNA and microRNA, is known to play a pivotal role in the post-transcriptional regulation of gene expression. Germ line mutations in the DICER1 gene increase the risk for different types of tumors. At present, DICER1 syndrome is an established, though not well defined, member of the group of genetic tumor predisposition syndromes. Here, we report a DICER1 syndrome family with a medical history of different rare tumors mostly occurring at a young age. The tumor spectrum in this family included both DICER1 syndrome-typical forms, such as pleuropulmonary blastoma, multinodular goiter, and cystic nephroma, and not previously reported manifestations, such as pilomatrixoma, and juvenile basal cell carcinoma. The latter tumor types are usually considered to be indicators of familial adenomatous polyposis and basal cell nevus syndrome.

Vismodegib hedgehog-signaling inhibition and treatment of basal cell carcinomas as well as keratocystic odontogenic tumors in Gorlin syndrome

Vismodegib hedgehog signaling inhibition treatment has potential for reducing the burden of multiple skin basal cell carcinomas and jaw keratocystic odontogenic tumors. They are major criteria for the diagnosis of Gorlin syndrome, also called nevoid basal cell carcinoma syndrome. Clinical features of Gorlin syndrome are reported, and the relevance of hedgehog signaling pathway inhibition by oral vismodegib for maxillofacial surgeons is highlighted. In summary, progressed basal cell carcinoma lesions are virtually inoperable. Keratocystic odontogenic tumors have an aggressive behavior including rapid growth and extension into adjacent tissues. Interestingly, nearly complete regression of multiple Gorlin syndrome-associated keratocystic odontogenic tumors following treatment with vismodegib. Due to radio-hypersensitivity in Gorlin syndrome, avoidance of treatment by radiotherapy is strongly recommended for all affected individuals. Vismodegib can help in those instances where radiation is contra-indicated, or the lesions are inoperable. The effect of vismodegib on basal cell carcinomas was associated with a significant decrease in hedgehog-signaling and tumor proliferation. Vismodegib, a new and approved drug for the treatment of advanced basal cell carcinoma, is a specific oncogene inhibitor. It also seems to be effective for treatment of keratocystic odontogenic tumors and basal cell carcinomas in Gorlin syndrome, rendering the surgical resections less challenging.