Multiple self-healing squamous epitheliomata (ESS1) mapped to chromosome 9q22-q31 in families with common ancestry

Multiple Self-Healing Squamous Epithelioma (MSSE): A Digenic Trait Associated with Loss of Function Mutations in TGFBR1 and Variants at a Second Linked Locus on the Long Arm of Chromosome 9

MSSE (Ferguson-Smith disease) is a rare familial condition in which multiple skin tumors resembling squamous carcinomas invade locally and then regress spontaneously after several months, leaving disfiguring scars. We review evidence from haplotype studies in MSSE families with common ancestry that the condition is caused by loss of function mutations in TGFBR1 interacting with permissive variants at a second linked locus on the long arm of chromosome 9. The spectrum of TGFBR1 mutations in MSSE and the allelic disorder Loeys Dietz syndrome (characterized by developmental anomalies and thoracic aortic aneurysms) differ. Reports of patients with both MSSE and Loeys Dietz syndrome are consistent with variants at a second locus determining whether self-healing epitheliomas occur in patients with the loss of function mutations found in most MSSE patients or the missense mutations in the intracellular kinase domain of TGFBR1 that characterize Loeys Dietz syndrome.

Digenic/multilocus aetiology of multiple self-healing squamous epithelioma (Ferguson-Smith disease): TGFBR1 and a second linked locus

Multiple self-healing squamous epithelioma (MSSE) is a rare familial skin cancer in which multiple tumours resembling crateriform squamous carcinomas are locally invasive but regress spontaneously after several months, leaving deep disfiguring facial scars and shallower scars on the limbs. First identified in a number of Scottish families, the condition has since been reported more widely. We review here the investigations leading to the discovery of loss of function mutations in TGFBR1 that are responsible for the disease. Loss of heterozygosity in tumours reveals that TGFBR1 acts as a tumour suppressor gene. TGFBR1 was initially excluded as the MSSE gene because it lies outside an extensive chromosome 9 haplotype shared by Scottish families. MSSE can now be regarded as a digenic/multilocus disease in view of the evidence of a second linked locus necessary for pathogenesis located within the Scottish haplotype. This article is part of a Directed Issue entitled: Rare Cancers.

Overexpression of Jumonji AT-rich interactive domain 1B and PHD finger protein 2 is involved in the progression of esophageal squamous cell carcinoma

Jumonji AT-rich interactive domain 1B (JARID1B) and PHD finger protein 2 (PHF2), members of the histone demethylases, have been found to be involved in many types of tumors. However, the expression and prognostic significance of JARID1B and PHF2 in esophageal squamous cell carcinoma (ESCC) still remains unclear. In this study, JARID1B and PHF2 expression were detected on tissue microarrays of ESCC samples in 120 cases using immunohistochemical staining. Our results showed that JARID1B and PHF2 were overexpressed in ESCCs. In addition, a significant correlation was observed between JARID1B nuclear expression level and histological grade (P=0.003). Kaplan-Meier survival analysis showed a tendency that high cytoplasmic expression of JARID1B and PHF2 was associated with decreased overall survival of ESCC patients, whereas JARID1B high expression in the nucleus was associated with high overall survival, although there was no statistical significance. Overall, our data suggest that JARID1B and PHF2 are overexpressed in ESCC and that they may play crucial roles in the course of ESCC initiation and/or progression.

Multiple self-healing squamous epithelioma is caused by a disease-specific spectrum of mutations in TGFBR1

Multiple self-healing squamous epithelioma (MSSE), also known as Ferguson-Smith disease (FSD), is an autosomal-dominant skin cancer condition characterized by multiple squamous-carcinoma-like locally invasive skin tumors that grow rapidly for a few weeks before spontaneously regressing, leaving scars. High-throughput genomic sequencing of a conservative estimate (24.2 Mb) of the disease locus on chromosome 9 using exon array capture identified independent mutations in TGFBR1 in three unrelated families. Subsequent dideoxy sequencing of TGFBR1 identified 11 distinct monoallelic mutations in 18 affected families, firmly establishing TGFBR1 as the causative gene. The nature of the sequence variants, which include mutations in the extracellular ligand-binding domain and a series of truncating mutations in the kinase domain, indicates a clear genotype-phenotype correlation between loss-of-function TGFBR1 mutations and MSSE. This distinguishes MSSE from the Marfan syndrome-related disorders in which missense mutations in TGFBR1 lead to developmental defects with vascular involvement but no reported predisposition to cancer.

Keratoacanthoma: facts and controversies

The keratoacanthoma and its variants are clinically and histologically heterogenous. Some consider the keratoacanthoma to be benign, whereas others classify it as a subtype of squamous cell carcinoma. The keratoacanthoma is generally treated rather than observed for spontaneous resolution. This hampers evaluation of the true natural history of lesions diagnosed as keratoacanthoma. In addition, studies have not found a reliable marker to differentiate keratoacanthoma from squamous cell carcinoma. It currently remains unclear how the keratoacanthoma relates to squamous cell carcinoma, and continued investigation is necessary.

Severe exacerbation of multiple self-healing squamous epithelioma (Ferguson-Smith disease) with radiotherapy, which was successfully treated with acitretin

We describe the challenging case of a patient presenting with extensive, eruptive mid-facial squamous cell carcinomas (SCCs) and keratoacanthomas (KAs) consequent to radiotherapy. Our patient had a personal and family history of multiple KAs and SCCs. Multiple self-healing squamous epithelioma, otherwise known as Ferguson-Smith disease, was diagnosed. This case presented a therapeutic challenge to preserve tissue and avoid severe facial disfigurement. We found oral acitretin to be the treatment of choice.

Erasing the methyl mark: histone demethylases at the center of cellular differentiation and disease

The enzymes catalyzing lysine and arginine methylation of histones are essential for maintaining transcriptional programs and determining cell fate and identity. Until recently, histone methylation was regarded irreversible. However, within the last few years, several families of histone demethylases erasing methyl marks associated with gene repression or activation have been identified, underscoring the plasticity and dynamic nature of histone methylation. Recent discoveries have revealed that histone demethylases take part in large multiprotein complexes synergizing with histone deacetylases, histone methyltransferases, and nuclear receptors to control developmental and transcriptional programs. Here we review the emerging biochemical and biological functions of the histone demethylases and discuss their potential involvement in human diseases, including cancer.

Multiple self-healing squamous epithelioma in different ethnic groups: more than a founder mutation disorder?

Multiple self-healing squamous epithelioma (MSSE), also known as Ferguson-Smith Disease, is a rare cancer-associated genodermatosis with an autosomal dominant inheritance. Affected patients suffer from recurrent skin lesions, which clinically and histologically resemble keratoacanthomas or well-differentiated squamous cell carcinomas, but which, if left, undergo spontaneous regression, leaving pronounced scarring. The majority of MSSE cases previously described were of Scottish ancestry and all shared the same at-risk haplotype, suggesting that this disorder was caused by a founder mutation. The candidate locus for MSSE lies in a region of <4 cM in chromosome 9q22, between the markers D9S197 and D9S1809. We recently investigated MSSE families of non-Scottish origin. For every patient of these families, we obtained a detailed clinical history, with particular attention to the age of onset, distribution, and clinical course of their skin lesions. Once confirmed that they were really affected by MSSE, we performed haplotype analysis on them and their families. The haplotypes for polymorphic markers segregating with MSSE in non-Scottish and Scottish families differ, suggesting that MSSE is not caused by a founder mutation and might be more common than originally thought.

Multiple keratoacanthomas in a young woman: report of a case emphasizing medical management and a review of the spectrum of multiple keratoacanthomas

A 27-year-old white woman was referred for consultation with regard to the presence of extensive multiple keratotic lesions. She began to develop these lesions at the age of 9 years, with healing of the lesions resulting in scar formation. A biopsy was performed at the age of 16 years, but the patient was unsure of the results. Since then, she had not had any treatment or biopsies, and stated that she had not suffered from any health problems during the intervening period. She was most concerned about the tumors on her heels and soles, which caused difficulty with ambulation. The family history was negative for skin diseases, including melanoma, nonmelanoma skin cancer, psoriasis, and eczema, and positive for Type II diabetes mellitus. A relative reported that the patient's grandfather had similar lesions, but the patient's parents and siblings were healthy. She was married and had one child, a 9-year-old daughter. Her child had no skin lesions. The patient's only medication was Ortho-Tricyclene birth control pills. She had no known drug allergies. Physical examination revealed the presence of multiple lesions on her body (Fig. 1). Her left superior helix contained a well-demarcated, dome-shaped nodule with a rolled, mildly erythematous border with a central hyperkeratotic plug. A similar lesion was present in the scaphoid fossa of the left ear and smaller lesions were scattered on her face. Numerous lesions were present on the arms and legs bilaterally, with the majority of lesions being located on the anterior lower legs. There were also lesions present on the palms and soles. The lesions ranged in size from 5 mm to 3 cm, the largest being a verrucous exophytic nodule on the anterior aspect of her left leg. Overall, there appeared to be two distinct types of lesion. One type appeared round, oval, and symmetric with a central keratotic plug, similar to that on the ear. The other type was larger, more exophytic, and verrucous, including the lesions on the volar surfaces. Also present were numerous, irregularly shaped atrophic scars where previous lesions had healed spontaneously. There were no oral lesions or lesions on her fingernails or toenails, and her teeth and hair were normal. A biopsy was obtained from an early lesion on the right dorsal forearm. Histology revealed an exo-/endophytic growth having a central crater containing keratinous material (Fig. 2). The crater was surrounded by markedly hyperplastic squamous epithelium with large squamous epithelial cells having abundant glassy cytoplasm. Some cells were dyskeratotic. Within the dermis was a dense, chiefly mononuclear inflammatory infiltrate. A buttress of epidermis surrounded the crater. The clinical and pathologic data were consistent with keratoacanthomas. Initial laboratory screenings revealed elevated triglycerides and total cholesterol, 537 mg/dL (normal, < 150 mg/dL) and 225 mg/dL (normal, < 200 mg/dL), respectively, with all other laboratory results within normal limits. In anticipation of starting oral retinoid therapy for her multiple keratoacanthomas, she was referred to her primary care physician for control of hyperlipidemia. After her lipids had been controlled, she was placed on isotretinoin (Accutane) 40 mg/day. There was some interval improvement with regression of some lesions leaving atrophic scars. She was also started on topical application of tazarotene (Tazorac) for all nonresolving lesions. Possible side-effects from the isotretinoin occurred, including dry mouth and eyes. After 8 months of isotretinoin, the patient was switched to acitretin (Soriatane) 25 mg to determine whether it might have a more beneficial effect on the resistant lesions. Many of the larger lesions regressed leaving atrophic scars. The dose of acitretin was subsequently increased to 35 mg because the lesions on her heel and the ball of her foot persisted. Almost all of the lesions resolved, except those on her feet, which are slowly regressing. Currently, the patient is on a regimen of acitretin 25 mg once a day with tazarotene 0.1% gel applied directly to the few residual keratoacanthomas on her feet, which are slowly improving.

Identification of susceptibility loci for cervical carcinoma by genome scan of affected sib-pairs

Cervical cancer is caused by a combination of environmental and genetic risk factors. Infection by oncogenic types of human papillomavirus is recognized as the major environmental risk factor and epidemiological studies indicate that host genetic factors predispose to disease development. A number of genetic susceptibility factors have been proposed, but with exception of the human leukocyte antigen CHLA, class II, have not shown consistent results among studies. We have performed the first genomewide linkage scan using 278 affected sib-pairs to identify loci involved in susceptibility to cervical cancer. A two-step qualitative non-parametric linkage analysis using 387 microsatellites with an average spacing of 10.5 cM revealed excess allelic sharing at nine regions on eight chromosomes. These regions were further analysed with 125 markers to increase the map density to 1.28 cM. Nominal significant linkage was found for three of the nine loci [9q32 (maximum lod-score, MLS) =1.95, P<0.002), 12q24 (MLS=1.25, P<0.015) and 16q24 (MLS=1.35, P<0.012)]. These three regions have previously been connected to human cancers that share characteristics with cervical carcinoma, such as esophageal cancer and Hodgkin's lymphoma. A number of candidate genes involved in defence against viral infections, immune response and tumour suppression are found in these regions. One such gene is the thymic stromal co-transporter (TSCOT). Analyses of TSCOT single nucleotide polymorphisms further strengthen the linkage to this region (MLS=2.40, P<0.001). We propose that the 9q32 region contains susceptibility locus for cervical cancer and that TSCOT is a candidate gene potentially involved in the genetic predisposition to this disease.

The elusive multiple self-healing squamous epithelioma (MSSE) gene: further mapping, analysis of candidates, and loss of heterozygosity

The MSSE gene predisposes to multiple invasive but self-healing skin tumours (multiple self-healing epitheliomata). MSSE was previously mapped to chromosome 9q22-q31 and a shared haplotype in affected families suggested a founder mutation. We have refined the MSSE critical region (<1 cM, <1 Mb) between the zinc-finger gene ZNF169 and the Fanconi anaemia gene FANCC. By genetic mapping we have excluded ZNF169 and FANCC as well as PTCH (PATCHED) and TGFBR1 (transforming growth factor beta receptor type-1) genes. The CDC14B cell cycle phosphatase gene also lies in the region but screening of the complete coding region revealed no mutation in MSSE patients. Somatic cell hybrids created by haploid conversion of an MSSE patient's cells enabled screening of the MSSE chromosome 9 and showed no CDC14B deletion or mutation that abrogates CDC14B mRNA expression. Thus, CDC14B is unlikely to be the MSSE gene. We also report the first molecular analysis of MSSE tumours showing loss of heterozygosity of the MSSE region, with loss of the normal allele, providing the first evidence that MSSE is a tumour suppressor gene.

Keratoacanthoma: A Clinico-Pathologic Enigma

BACKGROUND

Keratoacanthoma (KA) is an extraordinary entity. Once considered a benign neoplasm that resembled a highly malignant one (pseudomalignancy), it is now viewed in an opposite light as a cancer that resembles a benign neoplasm (pseudobenignity).

OBJECTIVE

The goal was to delineate the malignant potential of this neoplasm based on the author's experience and a review of recent data and research and to emphasize the KA as a possible part of an autosomal dominant familial cancer syndrome, the Muir-Torre syndrome.

METHODS

This is a review of the literature.

RESULTS

In this work, the KA is reviewed with recent advances emphasized.

CONCLUSION

KA is an abortive malignancy that rarely progresses into an invasive SCC. The KA may serve as a marker for the important autosomal dominant familial cancer syndrome, the Muir-Torre syndrome, as a result of a defective DNA mismatch repair gene.

Human herpes viruses in non-melanoma skin cancers

We examined the possible involvement of human herpes viruses in sporadic non-melanoma skin cancer of Greek patients. Polymerase chain reaction (PCR) based detection assays were utilized for the detection of viral cytomegalovirus (CMV), herpes simplex virus (HSV) and Epstein-Barr virus (EBV) genomes in 24 squamous cell carcinomas (SCC), five Bowen's disease, 72 basal cell carcinomas (BCC) specimens and eight premalignant lesions. Forty-two of 109 (38.5%) skin lesions were found positive for CMV DNA. The highest incidence was 6/8 (75%) observed in specimens with premalignant lesions. The incidence was 37.5% (27/72) in BCC, 33% (8/24) in SCC and 20% (1/5) in extragenital Bowen's disease. All samples were negative for HSV-1/2 and EBV DNA as assessed by our PCR based assay. The CMV infection showed no statistically significant correlation with the histological type, age, site of lesion or sex. Our results give a strong indication of the possible involvement of CMV in non-melanoma skin cancer development.

Mutational analysis of CDKN2A genes in patients with squamous cell carcinoma of the skin

BACKGROUND

Nonmelanoma skin cancers [squamous cell carcinomas (SCC) and basal cell carcinomas (BCC)] are the most common neoplasias of the Caucasian population.

OBJECTIVES

The purpose of our study was to determine the involvement of CDKN2A genes in the development of sporadic nonmelanoma skin cancer in Greek patients.

PATIENTS AND METHODS

Allelic imbalance analysis was performed in 22 SCC and five Bowen's disease specimens. Mutational analysis was performed on exons 1alpha, 1beta and 2 of the CDKN2A locus in 22 SCC, five Bowen's disease and 39 BCC specimens. Exon 1alpha was additionally screened in 28 BCC specimens to complete the mutational analysis of a previous study.

RESULTS

Overall, 52% (14 of 27) of the SCC and Bowen's disease specimens exhibited loss of heterozygosity (LOH) in at least one microsatellite marker, whereas, only two of 27 (7%) exhibited microsatellite instability. LOH in 9p appears to be equally involved in both BCC and SCC tumours. Exons 1alpha, 1beta and 2 of the CDKN2A locus were screened for mutations. A Val28Gly substitution in exon 1alpha and a CCC-->TTT (Ala57Val and Arg58Ter) substitution in exon 2, resulting in a change in the amino acid sequence, are reported for the first time in two SCCs, the latter being indicative of a combination of an ultraviolet (UV) radiation-induced mutation and a point mutation. A previously described polymorphism of CDKN2A, the gene for p16INK4a, Ala148Thr, was also detected in an allelic frequency of 3.72%. No mutation was found in any of the five Bowen's disease specimens, or in exon 1beta of CDKN2A, also the gene for p14ARF.

CONCLUSIONS

Mutations and the high incidence of 9p LOH detected in our SCC samples imply that inactivation of CDKN2A genes, via allelic loss and/or mutation (probably UV-induced) may play a significant role in nonmelanoma skin cancer development, particularly in the more aggressive SCC type.

A review of inherited cancer syndromes and their relevance to oral squamous cell carcinoma

This paper examines the genetic defects associated with inherited cancer syndromes and their relevance to oral cancer. Tumour suppressor genes are now thought of as either gatekeepers or caretakers according to whether they control cell growth directly by inhibiting cell proliferation and/or promoting cell death (gatekeepers) or whether they maintain the integrity of the genome by DNA repair mechanisms (caretakers). In disorders such as xeroderma pigmentosum, ataxia telangiectasia, Bloom syndrome and Fanconi's anaemia, where there are defective caretaker genes, there is an increased incidence of second primary malignancies, including oral cancer. By contrast, with the exception of Li Fraumeni syndrome, abnormalities of gatekeeper genes do not predispose to oral cancer. Not only do Li Fraumeni patients develop second primary malignancies, but defects of the p53 pathway (p53 mutation, MDM2 over-expression, CDKN2A deletion) appear to be a ubiquitous feature of sporadic oral cancer as it occurs in the West. The findings suggest that genetic instability is of fundamental importance in the pathogenesis of oral cancer.

Loss of heterozygosity in human skin

Loss of heterozygosity (LOH) is a genetic mechanism by which a heterozygous somatic cell becomes either homozygous or hemizygous because the corresponding wild-type allele is lost. LOH has today been recognized as a major cause of malignant growth. This article gives a comprehensive review of skin disorders in which an origin from LOH has been either documented at the molecular level or postulated on the basis of clinical evidence. LOH has been shown to cause basal cell carcinoma, squamous cell carcinoma, and malignant melanoma, but this mechanism can likewise be taken as an important model to explain the origin of many other skin diseases such as benign hamartomas; type 2 segmental manifestation of autosomal dominant skin disorders; a pronounced segmental manifestation of acquired skin disorders with a polygenic background, superimposed on symmetric lesions of the usual type; paired mutant patches in the form of either allelic or nonallelic twin spotting; and the exceptional familial occurrence of some nevi, reflecting paradominant transmission. completion of this learning activity, readers should be familiar with the mechanism of LOH and its general significance for the biology of plants, animals, and humans. Participants should understand that this mechanism plays a crucial role not only in cutaneous malignant growth but also in the development of benign skin disorders, and they should be able to examine such diseases with a prepared mind to gain a better understanding of their origin.

The "sins" of the fathers: self-healing squamous epithelioma in Scotland

BACKGROUND

A review is presented of the recent progress made in mapping of the hereditary skin disease "Ferguson-Smith multiple self-healing squamous epithelioma."

METHODS

The use of founder effects in an autosomal dominant disease is reviewed as applied to gene mapping efforts.

RESULTS

A common haplotype among Scottish families segregating Ferguson-Smith disease allowed the narrowing of the candidate gene interval and the identification of several possible disease-associated genes.

CONCLUSION

The gene for Ferguson-Smith multiple self-healing squamous epithelioma lies in a narrow region on chromosome 9q, along with several other important hereditary skin disease loci.

Mutational analyses of candidate genes in human squamous cell carcinomas

OBJECTIVES AND STUDY DESIGN

Squamous cell carcinomas are common malignancies and a major cause of mortality. The molecular mechanisms involved in tumorigenesis remain largely unknown, but sequence alterations have been identified in coding regions of several genes. Primary squamous cell carcinomas of various tissues (skin, head and neck, esophagus, lung, penis, uterus, and vagina) from 52 patients were analyzed for the presence of mutations within several candidate genes presumably involved in tumorigenesis: Gsalpha, Gi2alpha, GTPase activating protein (GAP), and patched (PTCH) genes.

METHODS

Mutational analysis scheme included polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), single stranded conformational polymorphism (SSCP), and selected sequence analysis.

RESULTS AND CONCLUSION

No tumor had any evidence of mutations in any of these analyzed genes. Mutations within these genes do not occur frequently in an unselected population of patients with squamous cell carcinomas.

Mutation analysis of the human homologue of Drosophila patched and the xeroderma pigmentosum complementation group A genes in squamous cell carcinomas of the skin

The human homologue of Drosophila patched (PTCH), located at chromosome 9q22.3, was recently identified as a candidate tumor suppressor gene for familial and sporadic basal cell carcinomas. Squamous cell carcinomas (SCCs) of the skin display allelic loss in this chromosomal region, which, in addition to the PTCH gene, contains the DNA repair gene xeroderma pigmentosum complementation group A (XPA). Patients with xeroderma pigmentosum are predisposed to non-melanoma skin tumors because of deficient excision repair of ultraviolet-induced DNA damage. Mutation analysis by single-strand conformation analysis and direct DNA sequencing of all 23 exons of the PTCH gene and all six exons of the XPA gene in 14 SCCs did not reveal structural alterations in any of these genes. Additionally, analysis of PTCH expression by in situ hybridization in SCCs revealed no evidence of upregulation of PTCH mRNA, confirming the lack of mutations in this gene. These findings suggest that another, yet to be identified gene or genes on chromosome 9q are involved in SCC tumorigenesis.

The human homologue of the ninjurin gene maps to the candidate region of hereditary sensory neuropathy type I (HSNI)

The human ninjurin gene was isolated from a cDNA library enriched for transcripts from band 9q22. A 1.2-kb message was detected for ninjurin in all human tissues studied. The full-length sequence codes for a putative 152-amino-acid protein with 89% identity to the rat ninjurin protein. The mouse homologue was isolated and showed 98% amino acid identity to the rat protein. Mapping by FISH localized mouse ninjurin to mouse chromosome 13, a region that shows synteny with human chromosome 9q22. Genomic characterization of the human gene revealed four exons covering less than 10 kb. The map position of the human gene is between the genetic markers D9S196 and D9S197 on human chromosome band 9q22. This places the gene within the candidate regions for the degenerative neurological disorder hereditary sensory neuropathy type I and the cancer predisposition syndrome multiple self-healing squamous epitheliomata.

Mechanism of homophilic binding mediated by ninjurin, a novel widely expressed adhesion molecule

Ninjurin is a novel protein that is up-regulated after nerve injury both in dorsal root ganglion (DRG) neurons and in Schwann cells. We previously reported that ninjurin demonstrates properties of a homophilic adhesion molecule and promotes neurite outgrowth from primary cultured DRG neurons. We have now found that ninjurin is widely expressed in both adult and embryonic tissues, primarily in those of epithelial origin. Aggregation assays were used to demonstrate that ninjurin-mediated adhesion requires divalent cations and is an energy-dependent process. The critical domain for ninjurin-mediated homophilic adhesion was localized to an 11-residue region (between Pro26 and Asn37) by mutagenesis and by employing synthetic oligopeptides as competitive inhibitors of ninjurin-mediated adhesion. Of particular importance are the Trp residue at position 29 and the 3 arginines in the region. Furthermore, we show that the peptide which inhibits aggregation of Jurkat cells expressing ninjurin is also capable of blocking the ability of ninjurin to promote neurite extension from DRG neurons. Using FISH analysis, the ninjurin gene was localized to human chromosome 9q22. Several genetic diseases of unknown etiology have been mapped to this region, including hereditary sensory neuropathy type 1, self-healing squamous epithelioma, split-hand/foot deformity type 1, and familial dilated cardiomyopathy.

FKHL15, a new human member of the forkhead gene family located on chromosome 9q22

FKHL15 was isolated from a cDNA library enriched for transcripts from 9q22. Isolation and sequencing of a 3.5-kb cDNA clone identified a putative 376-amino-acid protein with greater than 80% homology over a 100-amino-acid stretch to the forkhead DNA-binding domain. The FKHL15 gene contains a region rich in alanine residues, frequently associated with transcriptional repression. The forkhead genes are believed to play important roles in development and differentiation in many different organisms and have also been implicated in the development of some tumors. The map position of FKHL15 on 9q22 places the gene within the candidate regions for the cancer predisposition syndrome multiple self-healing squamous epitheliomata and the degenerative neurological disorder hereditary sensory neuropathy type I. This is a region frequently lost in squamous cell cancer.

No evidence of mutation in the human PTC gene, responsible for nevoid basal cell carcinoma syndrome, in human primary squamous cell carcinomas of the esophagus and lung

The high frequency of loss of heterozygosity that has been observed on the distal region of the long arm of chromosome 9 in squamous cell carcinomas of esophagus, lung, uterus, and head and neck indicates the presence of a tumor suppressor gene(s) in this region. To investigate the possible role of the PTC gene on chromosome 9q22.3, that was identified as the cause of nevoid basal cell carcinoma syndrome, during carcinogenesis in esophagus and lung, we examined 20 esophageal squamous cell carcinomas and 10 squamous cell carcinomas of the lung for mutations in any coding exon of PTC. Using single-strand conformation polymorphism and direct sequencing, we detected no mutations other than two non-deleterious polymorphisms. Our results suggest that inactivation of some tumor suppressor gene(s) on 9q other than PTC contributes to the development of squamous cell carcinomas in these tissues.

Characterization of a YAC contig containing the NBCCS locus and a novel Kruppel-type zinc finger sequence on chromosome segment 9q22.3

Gorlin's syndrome or nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by a familial or hereditary predisposition to basal cell carcinomas (generally multiple and of early onset), odontogenic keratocysts (jaw cysts), palmar and plantar pits, a wide variety of developmental defects, as well as cancers such as medulloblastomas and ovarian fibromas. The gene for NBCCS has been mapped to human chromosome region 9q22.1-q31 by linkage analysis and by cytogenetic evidence of deletions in this region in patients with the syndrome. This is supported by loss of heterozygosity in tumors of polymorphic marker loci flanked by D9S197 and D9S180. We have utilized sequence tagged site (STS) mapping and somatic cell hybrid panel analysis to construct two overlapping yeast artificial chromosome (YAC) contigs spanning this region of the genome. We used the YAC contigs to identify a new zinc finger gene containing a highly informative microsatellite locus.

A gene for a novel zinc-finger protein expressed in differentiated epithelial cells and transiently in certain mesenchymal cells

We have identified a novel zinc-finger protein whose mRNA is expressed at high levels in the epidermal layer of the skin and in epithelial cells in the tongue, palate, esophagus, stomach, and colon of newborn mice. Expression in epithelial cells is first detected at the time of their differentiation during embryonic development. In addition, during early embryonic development there is expression in mesenchymal cells of the skeletal primordia and the metanephric kidney which is later down-regulated. The expression pattern suggests that the protein could be involved in terminal differentiation of several epithelial cell types and could also be involved in early differentiation of the skeleton and kidney. The carboxyl terminus of the protein contains three zinc fingers with a high degree of homology to erythroid krüppel-like factor and binds to DNA fragments containing CACCC motifs. The amino-terminal portion of the protein is proline and serine-rich and can function as a transcriptional activator. The chromosomal location of the gene was mapped using mouse interspecific backcrosses and was shown to localize to mouse chromosome 4 and to cosegregate with the thioredoxin gene.

Differential allele loss on chromosome 9q22.3 in human non-melanoma skin cancer

Familial predisposition to basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin are apparent in the autosomal dominant syndromes naevoid basal cell carcinoma syndrome (NBCCS) and multiple self-healing squamous epitheliomata (MSSE) respectively. The gene responsible for NBCCS has been proposed to be a tumour-suppressor gene and is mapped to the same 2 Mb interval on 9q22.3 as the MSSE gene ESS1. In an attempt to further map the NBCCS gene, we have examined loss of heterozygosity (LOH) in 16 sporadic BCCs and two familial BCCs using microsatellite markers located within the candidate gene region. The overall frequency of LOH observed was 67% in the BCCs and partial or interstitial deletions were found in eight tumours, with the highest LOH frequency at markers D9S280, D9S287 and D9S180. To determine if the same genomic region also shows frequent LOH in tumours with a squamous phenotype, we have examined 11 SCCs, four actinic keratoses and 13 cases of Bowen's disease for LOH at 9q22.3. An overall LOH frequency of 50% was observed at D9S180, and occurred in all types of squamous tumours. In contrast, a much lower LOH frequency of only 6% was found at the D9S287 locus. Our observation of different patterns of LOH at 9q22.3 in sporadic BCCs and SCCs implies that more than one tumour-suppressor gene might be located in this genomic region.

The gene for multiple familial trichoepithelioma maps to chromosome 9p21

Multiple familial trichoepithelioma (MFT) is an autosomal dominant skin disease characterized by the presence of many small tumors predominantly on the face. To map the causative gene, we performed linkage analysis with microsatellite markers in three American families. We found a significant linkage of a gene for MFT to chromosome 9p2l. The maximum combined lod score was 3.31 at D9S171 at theta = 0. The disease locus was defined to a 4-cM region between IFNA and D9S126. Because several tumor suppressor genes including p16 and p15 have been mapped to this region, the gene for MFT may also be a tumor suppressor.

Genetic alterations in esophageal cancer and their relevance to etiology and pathogenesis: a review

Cancer of the esophagus exists in 2 main forms with different etiological and pathological characteristics-squamous cell carcinoma (SCC) and adenocarcinoma (ADC). This review focuses on the occurrence of genetic alterations in SSC and ADC of the esophagus and on their possible implications for the elucidation of the etiology and pathogenesis of these cancers. The most common alterations found in esophageal cancers include allelic losses at chromosomes 3p, 5q, 9p, 9q, 13q, 17p, 17q and 18q, as well as mutations of p53 (mostly missense), Rb (deletions), cyclin DI (amplifications) and c-myc (amplifications). The sequence of occurrence of these alterations with respect to histopathological tumor progression is discussed. Our findings underscore the different etiology and pathogenesis of SCC vs. ADC and suggest that the genetic alterations observed may represent molecular fingerprints of critical risk involved in the development of these 2 cancers.

Genetic mechanisms in esophageal carcinogenesis: frequent deletion of 3p and 17p in premalignant lesions

Although dysplasia of the esophagus is thought to be the precursor lesion of esophageal squamous cell carcinoma (ESC), the sequence of genetic events during esophageal carcinogenesis is unclear. Using the polymerase chain reaction, we examined allelic losses at microsatellite loci in DNAs isolated from 106 lesions among 32 patients with ESC. Allelic losses on 3p or 17p occurred frequently even in dysplastic lesions (9 of 21 and 13 of 24 samples, respectively) including lesions with mild dysplasia (3p, 4 of 10 samples; 17p, 6 of 14 samples, respectively), and allelic losses on these chromosomal arms were also observed in cancerous tissues. We also detected allelic losses of the short and long arms of chromosome 9 at a low frequency in lesions with mild dysplasia and often in lesions with severe dysplasia and in intraepithelial cancers. Our results suggested that inactivation of tumor suppressor genes on 3p and 17p occurs at a very early stage of esophageal carcinogenesis and that genes on 9p and 9q are likely to play important roles in malignant changes. Comparison of the genetic alterations in precancerous dysplastic lesions with those in carcinomas supports the idea that ESC arises from the dysplastic lesion.

Loss of heterozygosity analysis of keratoacanthoma reveals multiple differences from cutaneous squamous cell carcinoma

Keratoacanthomas (KAs) resemble squamous cell carcinomas (SCCs) except that, unlike SCCs, after a period of rapid growth over a few months they involute completely. The basis of their regressing natural history is not known. We have examined keratoacanthomas and another benign cutaneous tumour, the basal cell papilloma (BCP), for loss of heterozygosity (LOH) at a number of loci that are frequently lost in SCCs and other skin tumours. The frequency of LOH for both KAs and BCPs was low, with only isolated losses identified at 9p, 9q and 10q in KAs [fractional allelic loss (FAL) was 1.3%], and at 9p and 17p in BCPs (FAL was 0.4%). This contrasts with previous work showing a FAL of 32% in SCC and 46% in actinic keratoses. The results show a clear difference between KA and SCC and do not support the hypothesis that KAs are SCCs that regress as a result of external (host) influences but rather suggest that KAs and SCCs are different de novo. LOH around the locus implicated in the multiple self-healing epitheliomata of Ferguson-Smith (9q22-q31) was shown in only 1 of 11 KAs.

Cloning and chromosomal localization of the human TRK-B tyrosine kinase receptor gene (NTRK2)

There is increasing evidence that neutrophins and their receptors play an important role in regulating development of both the central and the peripheral nervous systems. Human TRK-A (NTRK1) and TRK-C (NTRK3) have been cloned and sequenced, but only a truncated form of human TRK-B has been published. Therefore, we isolated complementary DNAs spanning the entire coding region of both human full-length and truncated forms of TRK-B from human brain cDNA libraries. Human full-length TRK-B codes for a protein of 822 amino acid residues. The putative mature peptide sequence is 49% homologous to human TRK-A and 55% to full-length human TRK-C, with 40% amino acid identify among TRK-A, -B, and -C. Nine of 13 cysteine residues, 4 of 12N-glycosylation sites in the extracellular domain, and 10 of 13 tyrosine residues in the intracellular domain are conserved among human TRK-A, -B, and -C. There is a cluster of 10 serine residues in the juxtamembrane region of TRK-B that is absent in TRK-A. Two major sizes of TRK-B transcripts were expressed in human brain. Northern blot analysis using probes specific for the extracellular or the tyrosine kinase domain revealed that the 9.5-kb band encodes the full-length TRK-B mRNA and the 8.0-kb band encodes the truncated form of TRK-B mRNA. By fluorescence in situ hybridization and somatic cell hybrid mapping, the human TRK-B gene was localized to chromosome 9q22.1.

Comparative mapping of 50 human chromosome 9 loci in the laboratory mouse

We have set out to produce a comprehensive comparative map between human chromosome 9 (HSA9) and the laboratory mouse. The mouse homologues of 50 loci that were known to map to HSA9 were mapped by interspecific backcross linkage analysis. Ten loci from the short arm of HSA9 were mapped, and 40 from HSA9q, with 24 markers coming from the HSA9q33-q34 region--a part of the chromosome known to be very gene rich. Fifteen new assignments have been made--Ak3, Ctsl, Cntfr, C8g, D2H9S46E, Eng, Gcnt1, Irebp, Pappa, Ptgds, Snf212, Tal2, Tmod, Vav2, and Vldlr, the human homologues of which all map to HSA9. In addition, the assignment of Snf212 and Vldlr to MMU19 has defined a new region of synteny between the proximal portion of the short arm of HSA9 and the mouse.

Delineation of two distinct deleted regions on chromosome 9 in human non-melanoma skin cancers

The mapping of the naevoid basal cell carcinoma syndrome (NBCCS) and the Ferguson-Smith syndrome to the same region on chromosome arm 9q has led to speculation that the two conditions may reflect different mutations within the same gene. Loss of heterozygosity of 9q alleles in both familial and sporadic basal cell carcinomas (BCCs) suggests that the NBCCS gene on 9q is acting as a tumour suppressor gene. Although LOH of 9q markers has not been studied in squamous cell neoplasms from patients with the Ferguson-Smith syndrome, chromosome 9 allele loss has been reported in sporadic squamous cell carcinomas (SCCs) of the skin. In order to characterise further the deleted region on chromosome 9 in BCCs and SCCs of the skin we have examined a series of non-melanoma skin cancers using a panel of highly informative microsatellite markers. Forty-four BCCs and 49 SCCs were studied. Loss of heterozygosity of one or more 9q markers was seen in 33 of the 44 BCCs. Only 4 of the 33 BCCs with 9q loss showed loss of 9p markers. Twenty-two BCCs showed loss of all informative 9q markers. Partial or interstitial 9q deletions were seen in 5 BCCs, and in 3 of these 5 BCCs the breakpoint occurred within the currently defined NBCCS locus. Chromosome 9 loss was seen in 16 of 49 SCCs. In contrast to the low frequency of 9p loss in BCCs, LOH of 9p markers was a common finding in SCCs, occurring in 15 of the 16 SCCs with chromosome 9 loss. In 5 SCCs 9p loss occurred with retention of 9q alleles.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic alterations in non-melanoma skin cancer

Non-melanoma skin cancer is common and offers unrivaled opportunities to relate genetic changes to clinical and biologic behavior. Recent technical advances in molecular biology render genetic analysis of even the smallest skin cancers possible. In this review I will discuss the role of p53 gene in skin carcinogenesis, the relation between p53 immunostaining and p53 mutation, and recent evidence for the involvement of putative tumor suppressor genes both on chromosome 9 and other chromosomes in non-melanoma skin cancer.

Genetic mapping of the FACC gene and linkage analysis in Fanconi anaemia families

Fanconi anaemia is an autosomal recessive disorder associated with increased chromosome breakage and progressive bone marrow failure. The gene for complementation group C (FACC) has been cloned and mapped to chromosome 9q22.3, but neither its genetic location nor the proportion of patients belonging to group C is known. We have used a polymorphism within the FACC gene to localise it within a 5 cM interval on chromosome 9q, bounded by D9S196/D9S197 and D9S176. The genes for Gorlin's syndrome and multiple self-healing squamous epitheliomata have also been mapped to this interval. Linkage analysis with the three highly informative microsatellite polymorphisms flanking FACC in 36 Fanconi anaemia families showed that only 8% of families were linked to this locus. This indicates that the genes for the other Fanconi anaemia complementation groups must map to one or more different chromosomal locations. The markers also allowed rapid exclusion of 56% of the families in our panel from complementation group C, thus substantially reducing the number of patients who need to be screened for FACC mutations.

Fine mapping of the locus for nevoid basal cell carcinoma syndrome on chromosome 9q

The nevoid basal cell carcinoma syndrome is an autosomal dominant disorder characterized primarily by multiple basal cell carcinomas, odontogenic keratocysts, and pits of the palms and soles. Tumor deletion studies and linkage analysis in Caucasians have revealed that the gene is on chromosome 9q. To further refine the location of the nevoid basal cell carcinoma syndrome locus, we tested linkage to this region in three families. Evaluation of recombinants suggested that the nevoid basal cell carcinoma syndrome locus lies in the interval defined distally by D9S127. Our data, together with existing published data defining D9S12 as a proximal flanking marker, refine the location of nevoid basal cell carcinoma syndrome to an 8.3-cM interval. Two of the families studied were African-American and show a notable variation in phenotypic expression in which affected individuals developed few skin cancers. However, despite clinical heterogeneity, our data are consistent with the hypothesis that the same locus is involved in these African-American families.

Chromosome 9 allele loss occurs in both basal and squamous cell carcinomas of the skin

Linkage studies of kindreds with the nevoid basal cell carcinoma syndrome and the high frequency of chromosome 9 allele loss in sporadic basal cell carcinomas indicate that chromosome 9 may contain tumor suppressor genes important in the development of sporadic and familial basal cell carcinomas. The recent mapping of the Ferguson-Smith syndrome, which predisposes affected individuals to the development of multiple lesions histologically indistinguishable from squamous cell carcinomas, suggests that tumor suppressor genes on 9q may also be important in the development of squamous cell neoplasms of the skin. Fifty-four non-melanoma skin cancers (24 basal cell carcinomas, 14 squamous cell carcinomas, and 16 cases of Bowen's disease) were examined for loss of heterozygosity on chromosome 9. Allelic loss at one or more loci on chromosome 9 was observed in 14 of 24 basal cell carcinomas, four of 14 squamous cell carcinomas, and three of 16 cases of Bowen's disease. Allelic deletion of one or more 9q markers was seen in 14 basal cell carcinomas, three squamous cell carcinomas, and three cases of Bowen's disease. Five basal cell carcinomas had interstitial deletions and in one the breakpoint mapped within the nevoid basal cell carcinoma syndrome locus. 9p loss occurred in three of nine informative squamous cell carcinomas. Allelic deletion of 9p markers was not seen in 19 basal cell carcinomas and seven cases of Bowen's disease. These findings suggest that chromosome 9 contains one or more tumor suppressor genes important in the development of both basal and squamous cell carcinomas of the skin.

Coincidence painting: a rapid method for cloning region specific DNA sequences

We have developed a novel coincidence cloning strategy, termed Coincidence Painting, which enables the rapid generation of large numbers of region specific sequences. Coincidence Painting utilises Degenerate Oligonucleotide Primed PCR (DOP-PCR) amplification of flow sorted derivative translocation chromosomes. The PCR products are hybridised in situ onto specific flow sorted chromosomes for coincident sequence selection. Eluted and reamplified material is then cloned using a novel insert end revelation and ligation technique. Cloned inserts range in size from 150-1300 bps of which approximately 54% appear to be single copy sequences. The cloning method permits the excision of vector free probe for library hybridisation screening and the small insert size facilitates analysis for the generation of sequence tagged sites (STSs). We have used such clones successfully for YAC screening by PCR and for cosmid screening by filter hybridisation. This new methodology should allow the rapid saturation with probes of regions defined by specific translocation breakpoints.