Squamous cell carcinoma in a family with dominant dystrophic epidermolysis bullosa: a molecular genetic study

Type VII Collagen Deficiency in the Oncogenesis of Cutaneous Squamous Cell Carcinoma in Dystrophic Epidermolysis Bullosa

Dystrophic epidermolysis bullosa is a rare genetic skin disorder caused by COL7A1 sequence variations that result in type VII collagen deficits and cutaneous and extracutaneous manifestations. One serious complication of dystrophic epidermolysis bullosa is cutaneous squamous cell carcinoma, a leading driver of morbidity and mortality, especially among patients with recessive dystrophic epidermolysis bullosa. Type VII collagen deficits alter TGFβ signaling and evoke multiple other cutaneous squamous cell carcinoma progression-promoting activities within epidermal microenvironments. This review examines cutaneous squamous cell carcinoma pathophysiology in dystrophic epidermolysis bullosa with a focus on known oncogenesis pathways at play and explores the idea that therapeutic type VII collagen replacement may reduce cutaneous squamous cell carcinoma risk.

Inherited epidermolysis bullosa and squamous cell carcinoma: a systematic review of 117 cases

BACKGROUND

Inherited epidermolysis bullosa (EB) comprises a highly heterogeneous group of rare diseases characterized by exacerbated skin and/or mucosal fragility and blister formation after minor mechanical trauma. Level of cleavage in the skin, clinical features with immunofluorescence antigen mapping and/or electron microscopy examination of a skin biopsy and/or gene involved, type(s) of mutation present and sometimes specific mutation(s), allow to define the EB type and subtype. This family of genodermatoses exposes patients to several complications, cutaneous squamous cell carcinoma (cSCC) being the most severe of them.

OBJECTIVE

The aim of this systematic review was to document patients with EB who developed cSCC.

METHODS

A systematic literature search was performed, from inception to March 2014, using Medline, Embase, Cochrane and ClinicalTrials.gov databases. Only articles published in English and French were selected. The diagnosis of EB had to be confirmed by EM and/or IFM and/or mutation analysis, while cSCC had to be confirmed by histological analysis.

RESULTS

Of 167 references in the original search, 69 relevant articles were identified, representing 117 cases. cSCCs were identified in all types of EB, though predominantly in recessive dystrophic EB (RDEB) forms (81 cases (69.2 %)). The median age at diagnosis was 36 years old (interquartile range (IQR), 27-48 years and range, 6-71 years) for all forms. Of those with measurements in the literature (88 cases (75.2 %)), tumor size was greater than 2 centimeters in 52 cases (59.1 %). The histopathological characteristics were specified in 88 cases (75.2 %) and well-differentiated forms predominated (73.9 %). No conclusion could be drawn on the choice of surgical treatment or the management in advanced forms.

LIMITATIONS

This study was retrospective and statistical analysis was not included due to various biases. This study design did not allow to infer prevalence, nor EB subtype risk for cSCC occurrence.

CONCLUSIONS

Our study correlated with historical data shows that most of the cSCCs occurred in subjects with the RDEB subtype, however reports also show that cSCCs can present in any patients with EB. The first signs of cSCC developed at a younger age in EB patients than in non-EB patients. Interestingly, the cSCC duration, before its diagnosis, was shorter in individuals with RDEB than with junctional EB (JEB) and dominant dystrophic EB (DDEB). This study further emphasizes the importance of regular monitoring of EB patients, particularly with the RDEB subtype as they developed cSCC at a younger age.

Management of cutaneous squamous cell carcinoma in patients with epidermolysis bullosa: best clinical practice guidelines

This article summarizes recommendations reached following a systematic literature review and expert consensus on the diagnosis and management of cutaneous squamous cell carcinomas in people with epidermolysis bullosa. The guidelines are intended to help inform decision making by clinicians dealing with this complex complication of a devastating disease.

Understanding the pathogenesis of recessive dystrophic epidermolysis bullosa squamous cell carcinoma

Patients with recessive dystrophic epidermolysis bullosa develop numerous life-threatening skin cancers. The reasons for this remain unclear. Parallels exist with other scarring skin conditions, such as Marjolin ulcer. We summarize observational and experimental data and discuss proposed theories for the development of such aggressive skin cancers. A context-driven situation seems to be emerging, but more focused research is required to elucidate the pathogenesis of epidermolysis bullosa-associated squamous cell carcinoma.

Extracutaneous manifestations and complications of inherited epidermolysis bullosa: part II. Other organs

It is well known, primarily via case reports and limited case series, that nonepithelial tissues may become injured in patients with epidermolysis bullosa. Only recently, however, have there been data generated from large, well characterized cohorts. Our objective is to provide dermatologists with a comprehensive review of each of these major extracutaneous complications, with a summary of the pertinent literature and evidence-based recommendations for surveillance, evaluation, and management. Some epidermolysis bullosa subtypes are at risk for severe injury of the bone marrow, musculoskeletal system, heart, kidney, and teeth, and for the development of squamous cell carcinoma, basal cell carcinoma, or malignant melanoma. If untreated, significant morbidity or mortality may result.

Epidermolysis bullosa and the risk of life-threatening cancers: the National EB Registry experience, 1986-2006

BACKGROUND

Case series have demonstrated that potentially lethal cutaneous squamous cell carcinomas arise in patients with recessive dystrophic epidermolysis bullosa (RDEB), although the magnitude of this risk is undefined.

METHODS

Systematic case finding and data collection were performed throughout the continental United States (1986-2002) by the National EB Registry on 3280 EB patients to determine cumulative and conditional risks for squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and malignant melanoma (MM) within each major EB subtype, as well as the cumulative risk of death from each tumor. Study design was cross-sectional, with a nested randomly sampled longitudinal subcohort (N = 450).

RESULTS

SCCs arose primarily in RDEB, especially the Hallopeau-Siemens subtype (RDEB-HS), first beginning in adolescence. Less frequently, SCCs occurred in junctional EB (JEB). Cumulative risks rose steeply in RDEB-HS, from 7.5% by age 20 to 67.8%, 80.2%, and 90.1% by ages 35, 45, and 55, respectively. In Herlitz JEB, the risk was 18.2% by age 25. SCC deaths occurred only in RDEB, with cumulative risks in RDEB-HS of 38.7%, 70.0%, and 78.7% by ages 35, 45, and 55, respectively. MM arose in RDEB-HS, with a cumulative risk of 2.5% by age 12. BCCs arose almost exclusively in the most severe EB simplex subtype (Dowling-Meara) (cumulative risk = 43.6% by age 55).

LIMITATIONS

Mutational analyses were performed on only a minority of enrollees in the National EB Registry, preventing evaluation of the possible influence of specific genotypes on the risk of developing or dying from cutaneous SCCs.

CONCLUSIONS

SCC is the most serious complication of EB within adults, especially those with RDEB-HS. By mid-adulthood, nearly all will have had at least one SCC, and nearly 80% will have died of metastatic SCC despite aggressive surgical resection. When compared with SCCs arising within the normal population, the remarkably high risk of occurrence of and then death from SCCs among RDEB patients suggests likely differences in pathogenesis. Additional studies of EB-derived tumors and SCC cell lines may not only provide new insights into the mechanisms of carcinogenesis but also means whereby these particular tumors may be prevented or more effectively treated.

Epidermolysis bullosa. II. Type VII collagen mutations and phenotype-genotype correlations in the dystrophic subtypes

BACKGROUND

The dystrophic forms of epidermolysis bullosa (DEB), a group of heritable blistering disorders, show considerable phenotypic variability, and both autosomal dominant and autosomal recessive inheritance can be recognised. DEB is derived from mutations in the type VII collagen gene (COL7A1), encoding a large collagenous protein that is the predominant, if not exclusive, component of the anchoring fibrils at the dermal-epidermal junction.

METHODS

The Dystrophic Epidermolysis Bullosa Research Association Molecular Diagnostics Laboratory (Philadelphia, Pennsylvania, USA), established in 1996, has analysed more than 1000 families with different forms of epidermolysis bullosa, among them 332 families with DEB. DNA specimens were subjected to mutation analysis by polymerase chain reaction (PCR) amplification of all 118 exons and flanking intronic sequences of COL7A1, followed either by heteroduplex scanning and sequencing of the PCR products demonstrating heteroduplexes or by direct nucleotide sequencing.

RESULTS

355 mutant alleles out of the anticipated 438 (81.1%) were disclosed. Among these mutations, a total of 242 mutations were distinct and 138 were novel, previously unreported mutations. No evidence of mutations in any other gene was obtained.

DISCUSSION

Examination of the mutation database suggested phenotype-genotype correlations, contributing to the improved subclassification of DEB with prognostic implications. The mutation information also forms the basis for accurate genetic counselling and prenatal diagnosis in families at risk for recurrence.

Molecular epidemiology of hereditary epidermolysis bullosa in a Middle Eastern population

Epidermolysis bullosa (EB) encompasses a large group of inherited blistering skin disorders caused by mutations in at least 10 genes. Numerous studies, mainly performed in European and US families with EB, have revealed a number of characteristic epidemiological and genetic features, which form the basis for current diagnostic and counseling strategies. However, little is currently known about the molecular epidemiology of EB in Middle East populations. In the present study, we assessed 55 EB families for pathogenic sequence alterations in the 10 genes known to be associated with EB. Our results show unique EB subtype distribution and patterns of inheritance in our cohort. We also failed to detect recurrent mutations frequently encountered in Europe and the US, and did not consistently observe genotype-phenotype correlations formerly established in Western populations. Thus, the molecular epidemiology of EB in the Middle East is significantly different from that previously delineated in Europe and the US. Our data raise the possibility that similar differences may also be found in other genetically heterogeneous groups of disorders, and indicate the need for population-specific diagnostic and management approaches.

Increased risk of squamous cell carcinoma in junctional epidermolysis bullosa

Non-Herlitz junctional epidermolysis bullosa (JEB) is an autosomal recessive genodermatosis characterized by skin fragility and blistering. It is usually caused by mutations in the genes encoding the basement membrane proteins laminin 5 or type XVII collagen. Clinically, impaired wound healing and chronic erosions cause major morbidity in affected patients. Previously it was thought that these individuals, unlike patients with dystrophic EB, did not have an increased risk of developing skin cancer. However, we describe three patients with non-Herlitz JEB (aged 42, 56 and 75 years) who developed cutaneous squamous cell carcinomas (SCCs). The tumours were well-differentiated in two cases, but one patient had multiple primary SCCs that were either well- or moderately differentiated. Most cases of SCC in non-Herlitz JEB described have occurred in those with laminin 5 defects and on the lower limbs. These clinicopathological observations have important implications for the management of patients with this mechanobullous disorder as well as providing further insight into the biology of skin cancer associated with chronic inflammation and scarring.

Carcinome spinocellulaire compliquant une épidermolyse bulleuse héréditaire

The dystrophic form of hereditary epidermolysis bullosa is associated with an increased frequency of squamous cell carcinoma. We report a new case. An 18-year-old patient, carrying a Hallopeau Siemens hereditary epidermolysis bullosa, presented a subcutaneous nodular lesion, for 1 year that ulcerated and budded with inguinal lymphadenopathy. The histological study led to the conclusion of a well differentiated squamous cell carcinoma. The patient was treated surgically. Tumor and metastatic lymph nodes were excised. A radiotherapy was decided but the postoperative course was fatal due to an infection and to a deterioration of her general condition. Squamous cell carcinoma frequently occurs on the cicatricial lesion of hereditary epidermolysis bullosa and usually affects males with recessive hereditary epidermolysis bullosa. Metastases are frequent, precocious and multiple. The treatment may be surgical. The particularities of our observation are the young age of patient and the localization.

Squamous cell carcinoma developing in a 12-year-old boy with nonHallopeau-Siemens recessive dystrophic epidermolysis bullosa

We report a 12-year-old boy with nonHallopeau-Siemens recessive dystrophic epidermolysis bullosa (nHS-RDEB) who developed two skin lesions of squamous cell carcinoma (SCC) on the left foot. The incidence of SCC in nHS-RDEB is much lower than in the HS-RDEB subtype. Furthermore, this boy is the youngest among 92 previously described patients with DEB to develop SCC. This study emphasizes the importance of vigilance in monitoring the possible development of SCC in DEB patients regardless of age or clinical severity.

Targeted inactivation of the type VII collagen gene (Col7a1) in mice results in severe blistering phenotype: a model for recessive dystrophic epidermolysis bullosa

Dystrophic forms of epidermolysis bullosa (DEB) are associated with mutations in the type VII collagen gene (Col7a1) which encodes the major component of anchoring fibrils. To develop a DEB animal model, type VII collagen deficient mice were generated by targeted homologous recombination. The targeting vector replaced exons 46–69 of Col7a1 with the neomycin-resistance gene, in reverse transcriptional orientation, resulting in elimination of most of the collagenous domain 1. Col7a1 heterozygous (+/-) mice were phenotypically normal. Mating of Col7a1 +/- mice revealed that Col7a1 null (-/-) mice, which were born with extensive cutaneous blistering, died during the first two weeks of life probably due to complications arising from the blistering. Transmission electron microscopy revealed subepidermal blistering below the lamina densa and absence of anchoring fibrils. Immunohistochemical staining with anti-human type VII collagen antibody stained the dermal-epidermal junction in control mice, but did not stain the skin of Col7a1 null mice. Collectively, the DEB mice recapitulate the clinical, genetic, immunohistochemical and ultrastructural characteristics of recessive DEB in humans. These mice provide an animal model to study the pathomechanisms of DEB and serve as a system to test therapeutic approaches, including gene replacement, towards the cure of this devastating skin disease.