The risk of malignant melanoma, internal malignancy and mortality in xeroderma pigmentosum patients

XPC multifaceted roles beyond DNA damage repair: p53-dependent and p53-independent functions of XPC in cell fate decisions

Xeroderma pigmentosum group C protein (XPC) acts as a DNA damage recognition factor for bulky adducts and as an initiator of global genome nucleotide excision repair (GG-NER). Novel insights have shown that the role of XPC is not limited to NER, but is also implicated in DNA damage response (DDR), as well as in cell fate decisions upon stress. Moreover, XPC has a proteolytic role through its interaction with p53 and casp-2S. XPC is also able to determine cellular outcomes through its interaction with downstream proteins, such as p21, ARF, and p16. XPC interactions with effector proteins may drive cells to various fates such as apoptosis, senescence, or tumorigenesis. In this review, we explore XPC's involvement in different molecular pathways in the cell and suggest that XPC can be considered not only as a genomic caretaker and gatekeeper but also as a tumor suppressor and cellular-fate decision maker. These findings envisage that resistance to cell death, induced by DNA-damaging therapeutics, in highly prevalent P53-deficent tumors might be overcome through new therapeutic approaches that aim to activate XPC in these tumors. Moreover, this review encourages care providers to consider XPC status in cancer patients before chemotherapy in order to improve the chances of successful treatment and enhance patients' survival.

Skin tumors in xeroderma pigmentosum: Evaluation of a large series and a literature review

BACKGROUND

Xeroderma pigmentosum (XP) is a rare genodermatosis with a lifelong propensity to develop malignant skin tumors.

METHODS

In this retrospective study, 24 XP patients were evaluated with regard to frequency and clinicopathological features of benign and malignant skin tumors.

RESULTS

Seventeen patients had at least one malignant skin tumor diagnosed: basal cell carcinoma (BCC) in 13 patients (n = 72), basosquamous carcinoma in three patients (n = 4), squamous cell carcinoma in six patients (n = 13), keratoacanthoma in three patients (n = 15), and melanoma in six patients (n = 18). Most melanomas (n = 15) were in situ lesions. Several benign skin tumors were noted such as tricholemmoma (n = 1), trichoepithelioma (n = 1), trichoblastoma (n = 1), follicular infundibulum tumor (n = 1), keratoacanthoma-like follicular lesion (n = 1), adnexal tumors with folliculosebaceous (n = 1) and tricholemmal differentiation (n = 1), and neurofibroma (n = 1). Benign vascular proliferations including pyogenic granulomas (n = 8), widespread telangiectasias, and senile angioma-like lesions were also observed in 3, 5, and 5 patients, respectively.

CONCLUSIONS

Similar to many reports, BCC was found to be the most common malignant skin tumor. The high prevalence of benign adnexal tumors of follicular differentiation, some of them showing mixed histopathological features and various vascular proliferations in our series raises the question of whether they indicate a formerly undescribed association with XP.

Xeroderma Pigmentosum in Children: Report of 4 Cases

: Xeroderma pigmentosum (XP) is a rare genetic disorder inherited in an autosomal recessive pattern. Patients with XP are extremely sensitive to ultraviolet (UV) radiation that leads to defective DNA repair. People with XP often suffer from problems in the eyes, face, neck, and other areas of the body, frequently exposed to sunlight. It is characterized by photosensitivity, dry skin, pigmentary changes of the skin, premature skin aging, and a considerable increase in incidence rates of malignant skin tumors. There is no cure for XP. In this article, we have described four patients from two families, three of whom had malignant skin tumors.

Utility of Computed Tomography-guided Biopsy in Evaluation of Metastatic Spinal Lesions

INTRODUCTION

Computed tomography (CT)-guided biopsy of spine is currently a valuable diagnostic tool and effective technique for diagnosing and planning a proper therapeutic strategy for certain spinal lesions. The reported diagnostic accuracy of core biopsy ranges from 77% to 97%.

MATERIALS AND METHODS

We included all patients with spinal lesions suspicious of metastasis on magnetic resonance imaging, who presented between May 2012 and April 2014 and underwent CT-guided biopsy in our study. A total of thirty patients with spinal lesions were evaluated.

RESULTS

Majority presented in the seventh decade of their life (average age = 53.93; age range = 10-72 years). Male:female ratio was 1.5:1. Pain was the most common presenting symptom (100%). Lumbar spine was the most common site of lesion followed by dorsal spine. Biopsy is the gold standard in histopathological evaluation of spinal lesions. Metastatic lesion was diagnosed in 12 (40%) cases, plasmacytoma in 12 (40%) cases, non-Hodgkin's lymphoma in 2 (6.66%) cases, small round cell tumor in 1 (3.33%) case, nonspecific chronic inflammation in two patients, and necrosis with no viable cells in one patient. The most common malignancy to metastasize to spine was adenocarcinoma. The most common primary tumor of spine was plasmacytoma - multiple myeloma.

CONCLUSION

CCT-guided biopsy is a safe procedure, and no procedure-related complication was seen in any patient.

ERCC4 variants identified in a cohort of patients with segmental progeroid syndromes

Pathogenic variants in genes, which encode DNA repair and damage response proteins, result in a number of genomic instability syndromes with features of accelerated aging. ERCC4 (XPF) encodes a protein that forms a complex with ERCC1 and is required for the 5' incision during nucleotide excision repair. ERCC4 is also FANCQ, illustrating a critical role in interstrand crosslink repair. Pathogenic variants in this gene cause xeroderma pigmentosum, XFE progeroid syndrome, Cockayne syndrome (CS), and Fanconi anemia. We performed massive parallel sequencing for 42 unsolved cases submitted to the International Registry of Werner Syndrome. Two cases, each carrying two novel heterozygous ERCC4 variants, were identified. The first case was a compound heterozygote for: c.2395C > T (p.Arg799Trp) and c.388+1164_792+795del (p.Gly130Aspfs*18). Further molecular and cellular studies indicated that the ERCC4 variants in this patient are responsible for a phenotype consistent with a variant of CS. The second case was heterozygous for two variants in cis: c.[1488A > T; c.2579C > A] (p.[Gln496His; Ala860Asp]). While the second case also had several phenotypic features of accelerated aging, we were unable to provide biological evidence supporting the pathogenic roles of the associated ERCC4 variants. Precise genetic causes and disease mechanism of the second case remains to be determined.

Xeroderma pigmentosum and its dental implications

Xeroderma pigmentosum (XP) is a rare autosomal recessive genetic disorder characterized by defective DNA repair leading to clinical and cellular hypersensitivity to ultraviolet (UV) radiation and carcinogenic agents. Important clinical features are: Intense cutaneous photosensitivity, xerosis, poikiloderma, actinic keratosis, acute burning under minimal sun exposure, erythemas, hyperpigmented lentiginous macules, and malignant lesions in sun-exposed areas, including basocellular carcinoma, squamous cell carcinoma, and melanoma. There is a great involvement of many parts of the body, especially head and neck. Oral implications such as severe oral pain and mouth opening limitation were present due to perioral scars. The disorder is associated more commonly in populations where marriage of close blood relatives is common. Treatment of the disorder includes avoidance of UV radiation, topical application of 5-fluorouracil to treat actinic keratoses, and regular evaluation by an ophthalmologist, dermatologist, and neurologist. Genetic counseling is important aspects as an increased incidence of consanguineous marriages have been reported with this disorder. In addition, this paper discuss some important aspects concerning the role of the dental professional management of this entity, since XP patients require constant dental care and follow-up in order to control the occurrence of new lesions on the lips or inside oral cavity.

Xeroderma pigmentosum: clinicopathological review of the multiple oculocutaneous malignancies and complications

Multiple oculo-cutaneous malignancies are a common manifestation on sun-exposed facial areas in patients with Xeroderma pigmentosum (XP). Commonly seen are the basal cell carcinoma and the squamous cell carcinomas which manifest in the early first decade in contrast to fifth and sixth decade in the general population. XP manifests as photosensitivity, hyperpigmentation, premature skin aging and malignant changes like squamous cell carcinoma, basal cell carcinoma, fibrosarcoma and rarely malignant melanoma as well as internal malignancies. We report 11 cases of Xeroderma pigmentosa managed in our institute which included sex males and five females. All had photosensitivity, hyperpigmentation and consanguinity with facial malignant lesions like SCC and BCC. Ocular signs of photophobia and excessive lacrimation was seen in all the cases while blurring of vision due to corneal clouding, corneal injection, pterygium and limbal SCC were seen in 5 cases. SCC of the lids were seen in 7 cases while BCC seen in 8 cases and limbal and conjunctival SCC seen in one case. All were managed with excision while one case of melanoma with neck secondaries needed radical neck dissection while the other orbital exenteration. Oculo-cutaneous malignancies occur in the sun exposed areas so patients are advised regular follow up with speciality care. Awareness about the rare condition and importance of early detection and prevention of UV rays induced skin damage should be propagated. The disease is ultimately fatal, life can be prolonged by simple preventive measures to minimize sun exposure and early detection of the skin lesions and management.

Exploiting the nucleotide substrate specificity of repair DNA polymerases to develop novel anticancer agents

The genome is constantly exposed to mutations that can originate during replication or as a result of the action of both endogenous and/or exogenous damaging agents [such as reactive oxygen species (ROS), UV light, genotoxic environmental compounds, etc.]. Cells have developed a set of specialized mechanisms to counteract this mutational burden. Many cancer cells have defects in one or more DNA repair pathways, hence they rely on a narrower set of specialized DNA repair mechanisms than normal cells. Inhibiting one of these pathways in the context of an already DNA repair-deficient genetic background, will be more toxic to cancer cells than to normal cells, a concept recently exploited in cancer chemotherapy by the synthetic lethality approach. Essential to all DNA repair pathways are the DNA pols. Thus, these enzymes are being regarded as attractive targets for the development of specific inhibitors of DNA repair in cancer cells. In this review we examine the current state-of-the-art in the development of nucleotide analogs as inhibitors of repair DNA polymerases.

How sunlight causes melanoma

The incidence of melanoma has continued to rise dramatically over the past few decades, especially in young females. Due to the deadly nature of this disease, melanoma has become an important public health problem. It is generally accepted that ultraviolet light radiation (UVR) from sunlight is a major risk factor for melanoma skin cancer development. However, the mechanistic details of how sunlight via UVR causes melanoma are still being elucidated. Currently, it is thought that carcinogenic, inflammatory, and immunosuppressive properties of UVR all contribute to initiation, progression, and metastasis of primary melanoma. We review current findings on how sunlight-generated UVR generates DNA damage, inflammation, and immune suppression, thus leading to melanoma.

Two extreme conditions of xeroderma pigmentosum

Two atypical cases of xeroderma pigmentosum are reported. One of these cases with lung metastasis of squamous cell carcinoma in the first decade of life and the other with late onset disease (XP) in fifth decade of life. Lung metastasis of squamous cell carcinoma in first decade of life in patients with xeroderma pigmentosum has never been reported in the literature to our knowledge. Late onset of the disease in fifth decade is also a rare condition. Clinicians should be more alert for the internal organ metastases to improve the survival of the patients and should never forget that xeroderma pigmentosum has got a wide range of clinical presentation.

Incidence of xeroderma pigmentosum in Larkana, Pakistan: a 7-year study

Xeroderma pigmentosum (XP) is a rare autosomal recessive inherited disorder caused by a defect in the normal repair of DNA of various cutaneous cell types damaged by exposure to ultraviolet radiation. We present our 7-year experience with 36 XP patients who either visited the Department of Dermatology or were seen in the medical camps arranged in remote areas for patients' welfare, from 1995 to 2001. For ease of discussion we classified all cases into the following subgroups on clinical grounds only: mild, those with light brown freckles on the face alone; moderate, those with dark brown freckles with burning on the face, neck, ears, chest, hands and photophobia but without other associated obvious cutaneous and ocular changes; severe, those with extensive dark brown freckles with burning on the exposed parts as well as on the unexposed parts of the body, i.e. the chest, back, abdomen and arms including other associated cutaneous and ocular changes such as ulcers and malignancy. Of 36 patients, three (8.3%) were classified as mild, nine (25%) moderate and 24 (66.7%) severe; there were 18 males and 18 females, age range 2-30 years (mean 8.9 years). Seventeen patients had cutaneous changes: actinic keratosis, keratoacanthoma, fissures and ulcerative nodules on the exposed parts of the body. Four patients had wide ulcers, along with mass formation and severe pigmentation on the face, neck and head. Twenty-nine patients developed ocular symptoms: photophobia, conjunctivitis, corneal keratitis and lid ulcer. One patient had complete loss of vision. Histopathological findings revealed that six patients had squamous cell carcinoma (SCC) on the face, head, ear or lip. More than one sibling (two to four) was affected in four families. The majority of cases (20/36, 55.6%) were from the Brohi tribe (skin type III), while the remaining cases (16/36, 44.4%) were from the Sindhi population (skin type IV). The large number of XP patients seen in those with skin type III (Brohi tribe) compared with skin type IV (Sindhi population) indicates that the skin type and the race has a considerable value in the pathogenesis of XP. Furthermore, 24 of 36 patients were in the severe group and six of these had SCC. Moreover, no neurological abnormalities were observed in our patients. All patients were treated according to disease severity by prescribing oral antibiotics, local steroids, sunscreens and/or chemotherapy followed by irradiation in malignant cases. Two patients died because of extensive SCC.

Tumeurs cutanées au cours du xeroderma pigmentosum au Maroc

INTRODUCTION

Xeroderma pigmentosum is a rare recessive and autosomically transmitted genodermatosis. Its cutaneous manifestations are dominated by skin cancers. This investigation aims at studying the epidemiologic, clinic, histologic, therapeutic and evolutive aspects of the skin tumors during xeroderma pigmentosum.

PATIENTS AND METHODS

A retrospective monocentric study was carried out in the Dermatology and Veneorology Department of Ibn Rochd University Hospital of Casablanca, Morocco. It included all the xeroderma pigmentosum admitted to hospital or followed-up from 1990 to 2000. All the dossiers were included. The anatomopathologic study was carried out in all the skin tumor cases.

RESULTS

One hundred and twenty xeroderma pigmentosum were admitted in 10 Years. Fifty-four percent of the cases were females and 46 p. 100 were males. The mean apparition of the first tumor was 7.7 Years. One hundred and fifty-three skin tumors were diagnosed in 96 patients (80 p. 100). These tumors were of basocellular carcinoma type in 32.6 p. 100, of squamous cell carcinoma type in 33.9 p. 100 and of melanoma type in 11 p. 100. Ocular tumors were found in 31 cases (25.8 p. 100) and buccal in 8 cases. Therapeutically, the surgical exeresis of one or many tumors was performed in all cases. Electrocoagulation was associated in 42 p. 100 of the cases and skin graft in 52 p. 100. Cutaneous relapses after surgery were noticed in 55 cases (57.2 p. 100). Twenty-five patients died and 31 were lost to follow-up.

DISCUSSION

Our series is characterized by a large frequency of mainly cutaneous tumors (80 p. 100) in comparison with the largest review of literature (45 p. 100). These tumors were mainly represented by basocellular and squamous cell carcinoma with onset at an early age (7.7 Years). Our series is also characterized by a large frequency of cutaneous relapses after surgery (51.6 p. 100). Neglecting advice on photoprotection and the lack of regular control visits lead to the proliferation of large size tumors, making therapeutic strategies difficult or even impossible.

Xeroderma Pigmentosum: Mondscheinkinder. Xeroderma Pigmentosum: Children of the Moon

Xeroderma pigmentosum is based on a genetic defect in the DNA repair system, which is diagnosed in early childhood. Xeroderma pigmentosum is a rare disorder, which is transmitted in an autosomal recessive manner. Children with xeroderma pigmentosum display hypersensitivity to ultraviolet (UV) radiation. These patients experience serious sunburns with minimal exposure and then develop poikiloderma in the sun-exposed areas. Squamous cell carcinomas, basal cell carcinomas and malignant melanomas all appear during childhood. The majority of patients do not reach adult, but die from metastatic cutaneous malignancies. Genetically, xeroderma pigmentosum is differentiated into 7 complementation groups (XP-A to XP-G) and the xeroderma pigmentosum variants (XP-V). The assignment to the specific complementation group is made by fusing of xeroderma pigmentosum fibroblasts. Xeroderma pigmentosum must be distinguished from other so-called DNA repair deficiency syndromes, including Cockayne syndrome and trichothiodystrophy. A topical DNA repair enzyme appears to be helpful. A recombinant liposomal encapsulated T4 endonuclease V repairs UV-induced cyclobutane-pyrimidine dimers. Direct curative treatment of xeroderma pigmentosum could be achieved with gene therapy in future. Transfection of an intact repair gene which specifically codes for the missing repair protein could open new possibilities in the therapy of xeroderma pigmentosum.

Molecular analysis of glioma and skin-tumour alterations in a xeroderma-pigmentosum child

Xeroderma pigmentosum (XP) is a rare hereditary disease characterized by a very high frequency of skin tumours due to a defect in the nucleotide-excision-repair process. Some of these patients have also been reported to develop internal tumours with higher frequency than the normal population. Reported here are the clinical features and molecular analysis of an XP patient who developed multiple skin cancers as well as a thalamic glioma. Complementation analysis with recombinant retrovirus, cloning efficiency and unscheduled DNA synthesis after UV-C indicate that the patient belongs to the C group. Characterization of the p53 mutations in the 2 tumours of the patient leads to speculation on the aetiological agents involved in tumour initiation. The skin tumour is clearly induced by the presence of unrepaired UVB-induced DNA damage on the non-transcribed strand of the p53 gene, while the glioma may be induced by unrepaired DNA lesions produced by free radicals.

Neurocutaneous syndromes associated with pigmentary skin lesions

Tremendous strides have been made in our understanding of genetic disorders, including those that involve both the skin and the nervous system. The list of well-established neurocutaneous syndromes has increased during a few decades from a few classical phakomatoses to more than 30 entities. The dermatologist has the opportunity to facilitate precise diagnosis and optimal care for these patients by recognition of the cutaneous markers for these diseases. We have attempted to provide an overview of some recent advances in those syndromes manifested by pigmentary skin changes, emphasizing the clinical spectrum of each disorder and providing guidelines for an approach to management.

Expression of mitochondrial genes and DNA-repair-related nuclear genes is altered in xeroderma pigmentosum fibroblasts

Differential hybridization was used to detect repair defects in xeroderma pigmentosum (XP) that are not amenable to current analyses. cDNA libraries were constructed from cytoplasmic RNA of normal and XP fibroblast strains (complementation groups A and D) and analyzed for differential gene expression. More than 40,000 lambda gt10 cDNA clones were differentially screened with in vitro transcripts made from cDNA in the pBluescript vector. Six differential clones were detected in the libraries of the XP group A and D strains which caused stronger or weaker signals when probed with transcripts from XP strains than with those from the normal strains. Two clones coded for mitochondrial genes: mitochondrial 16 S rRNA and ATPase 6L. Overexpression of mitochondrial genes in XP may indicate that functions of the ATP-generating system are impaired since such functions are intensified whenever they become insufficient, for example as a consequence of DNA damage. It is tempting to assume that abnormal mitochondria are one of the causes for the neurological malfunctions in XP. Furthermore, densitometric analysis of Northern blots revealed that mRNA of lactate dehydrogenase, chain M, was less abundant in four XP group A strains (extent of reduction: 70%) and in two XP group D strains (extent of reduction: 58%). Enzyme activity was also diminished. In addition, mRNA of the gene for glyceraldehyde-3-phosphate dehydrogenase was less expressed in the same XP group A and D fibroblast strains investigated (reduction in both complementation groups: 50%). Both glycolytic enzymes have nuclear functions apart from their role in sugar metabolism. Lactate dehydrogenase, chain M, is identical to a helix-destabilizing protein; it is closely associated with chromatin and unfolded DNA, suggesting a role in DNA synthesis and transcription. The 37-kDa subunit of glyceraldehyde-3-phosphate dehydrogenase is involved in transcription and was shown to be identical to uracil-DNA glycosylase, a base-excision repair enzyme. We presume that the nuclear functions of these glycolytic enzymes may be thwarted in the XP strains investigated and may account for malfunctions in XP, particularly for neurological disturbances.

Cutaneous markers of internal malignancy. I. Malignant involvement of the skin and the genodermatoses

Cutaneous findings often reflect the presence and course of an internal disease. Recognition of external clues is important to facilitate both early diagnosis and prompt treatment of the internal disorder. Early recognition is especially valuable in a patient with an internal malignant disease because intervention may significantly affect survival. In this two-part series, we review the spectrum of cutaneous markers of internal malignancy. Part I focuses on malignant involvement of the skin caused by either direct extension or metastases and the genodermatoses with malignant potential. Part II will be devoted to the paraneoplastic skin manifestations of internal malignancy as well as environmental carcinogens that produce cutaneous features. We also discuss some proposed but controversial associations between skin disease and internal malignancy.

A child with xeroderma pigmentosum and bone marrow failure

The case of a child with both xeroderma pigmentosum and bone marrow failure is reported. It is suggested that this is not a chance association, and that the bone marrow hypoplasia may reflect an increased susceptibility of this patient's haemopoietic stem cells to non-UV mutagens.

Co-recessive inheritance: A model for DNA repair and other surveillance genes in higher eukaryotes

The co-recessive inheritance hypothesis proposes that certain recessively inherited diseases require homozygosity and/or hemizygosity for defective alleles at more than one locus simultaneously for the trait to be expressed. Although this hypothesis was originally proposed in the context of defective alleles for genes coding for DNA-repair functions, it need not be limited to this context, and genetic selection pressure may favor this model for genes involved in surveillance of any type. The co-recessive inheritance hypothesis also predicts extremely high carrier frequencies, likely affecting much of the general population, for defective alleles associated with these rare recessive diseases. The model predicts much lower rates of consanguinity between the parents of affected individuals than autosomal recessive inheritance, allowing it to be tested epidemiologically, and recent data suggest that the hypothesis may be valid for some cases of ataxia telangiectasia and xeroderma pigmentosum. The model provides possible explanations for a number of otherwise puzzling findings in several diseases associated with defective DNA repair.

Cell-cycle defect of DNA repair in progeria skin fibroblasts

We examined the temporal regulation of DNA repair during synchronous cell proliferation in normal and progeroid human fibroblasts. Ultraviolet light-induced (254 nm, 20 J/m2) unscheduled DNA synthesis was measured at 4-h intervals after serum stimulation, for up to 32 h. Normal cells regulated DNA repair in a defined temporal sequence, showing a peak in the induction of DNA repair just before DNA synthesis. Progeroid skin fibroblasts failed to show an increase in nucleotide excision repair before scheduled DNA synthesis, but the background level of DNA repair was not significantly different from that in controls. Regulation of repair in progeroid human fibroblasts appeared similar, but not identical to that previously reported by Gupta and Sirover (1984b) for xeroderma pigmentosum complementation group C. Our results suggest that patients with Hutchinson-Gilford progeria may have a defect in DNA repair; the results offer nominal evidence that the average level of UV-induced DNA is decreased, and that individuals with this disease lack both the normal enhancement of DNA repair before scheduled DNA synthesis and the temporal control of DNA repair.