Novel microsatellite markers and single nucleotide polymorphisms refine the tylosis with oesophageal cancer (TOC) minimal region on 17q25 to 42.5 kb: sequencing does not identify the causative gene

The cytoglobin-dependent transcriptome in melanoma indicates a protective function associated with oxidative stress, inflammation and cancer-associated pathways

Cytoglobin (CYGB) is a member of the oxygen-binding globin superfamily. In this study we generated stable CYGB overexpressing A375 melanoma cells and performed RNA-sequencing to comprehensively explore the CYGB-dependent transcriptome. Our findings reveal that ectopic expression of CYGB dysregulated multiple cancer-associated genes, including the mTORC1 and AKT/mTOR signaling pathways, which are frequently overactivated in tumors. Moreover, several cancer-associated pathways, such as epithelial-mesenchymal transition (EMT) mediated by CSPG4, were downregulated upon CYGB overexpression. Intriguingly, ectopic expression suggested anti-inflammatory potential of CYGB, as exemplified by downregulation of key inflammasome-associated genes, including NLRP1, CASP1 and CD74, which play pivotal roles in cytokine regulation and inflammasome activation. Consistent with established globin functions, CYGB appears to be involved in redox homeostasis. Furthermore, our study indicates CYGB's association to DNA repair mechanisms and its regulation of NOX4, reinforcing its functional versatility. Additionally, multiple significantly enriched pathways in CYGB overexpressing cells were consistently dysregulated in opposite direction in CYGB depleted cells. Collectively, our RNA-sequencing based investigations illustrate the diverse functions of CYGB in melanoma cells, pointing to its putative roles in cellular protection against oxidative stress, inflammation, and cancer-associated pathways. These findings pave the way for further research into the physiological role of CYGB and its potential as a candidate therapeutic target in melanoma.

Lessons from the post-genomic era: Globin diversity beyond oxygen binding and transport

Vertebrate hemoglobin (Hb) and myoglobin (Mb) were among the first proteins whose structures and sequences were determined over 50 years ago. In the subsequent pregenomic period, numerous related proteins came to light in plants, invertebrates and bacteria, that shared the myoglobin fold, a signature sequence motif characteristic of a 3-on-3 α-helical sandwich. Concomitantly, eukaryote and bacterial globins with a truncated 2-on-2 α-helical fold were discovered. Genomic information over the last 20 years has dramatically expanded the list of known globins, demonstrating their existence in a limited number of archaeal genomes, a majority of bacterial genomes and an overwhelming majority of eukaryote genomes. In vertebrates, 6 additional globin types were identified, namely neuroglobin (Ngb), cytoglobin (Cygb), globin E (GbE), globin X (GbX), globin Y (GbY) and androglobin (Adgb). Furthermore, functions beyond the familiar oxygen transport and storage have been discovered within the vertebrate globin family, including NO metabolism, peroxidase activity, scavenging of free radicals, and signaling functions. The extension of the knowledge on globin functions suggests that the original roles of bacterial globins must have been enzymatic, involved in defense against NO toxicity, and perhaps also as sensors of O₂, regulating taxis away or towards high O₂ concentrations. In this review, we aimed to discuss the evolution and remarkable functional diversity of vertebrate globins with particular focus on the variety of non-canonical expression sites of mammalian globins and their according impressive variability of atypical functions.

Integrative analysis with expanded DNA methylation data reveals common key regulators and pathways in cancers

The integration of genomic and DNA methylation data has been demonstrated as a powerful strategy in understanding cancer mechanisms and identifying therapeutic targets. The TCGA consortium has mapped DNA methylation in thousands of cancer samples using Illumina Infinium Human Methylation 450 K BeadChip (Illumina 450 K array) that only covers about 1.5% of CpGs in the human genome. Therefore, increasing the coverage of the DNA methylome would significantly leverage the usage of the TCGA data. Here, we present a new model called EAGLING that can expand the Illumina 450 K array data 18 times to cover about 30% of the CpGs in the human genome. We applied it to analyze 13 cancers in TCGA. By integrating the expanded methylation, gene expression, and somatic mutation data, we identified the genes showing differential patterns in each of the 13 cancers. Many of the triple-evidenced genes identified in majority of the cancers are biomarkers or potential biomarkers. Pan-cancer analysis also revealed the pathways in which the triple-evidenced genes are enriched, which include well known ones as well as new ones, such as axonal guidance signaling pathway and pathways related to inflammatory processing or inflammation response. Triple-evidenced genes, particularly TNXB, RRM2, CELSR3, SLC16A3, FANCI, MMP9, MMP11, SIK1, and TRIM59 showed superior predictive power in both tumor diagnosis and prognosis. These results have demonstrated that the integrative analysis using the expanded methylation data is powerful in identifying critical genes/pathways that may serve as new therapeutic targets.

Downregulation of ST6GALNAC1 is associated with esophageal squamous cell carcinoma development

Tylosis is an inherited disorder characterized by abnormal palmoplantar skin thickening and a highly elevated risk of esophageal squamous cell carcinoma (ESCC). Analyses of tylosis in families have localized the responsible gene locus to a region of chromosome 17q25.1. Frequent loss of heterozygosity (LOH) in 17q25.1 was also observed in the sporadic form of ESCC. A putative tumor suppressor gene for ESCC may exist at this locus. We investigated the expression patterns of genes on 17q25.1 in tumor and corresponding normal tissues from patients with sporadic ESCC using RNA sequence analysis. For candidate genes, quantitative real-time reverse transcription-PCR (qRT-PCR), direct sequence, LOH and methylation analyses were performed using 93 clinical ESCC samples and 10 cell lines. A significant downregulation of ST6GALNAC1 was demonstrated in ESCC tissues compared to its expression in normal tissues by qRT-PCR (n=93, p<0.0001). Frequent LOH (17/27, 62.9%) and hyper‑methylation in ST6GALNAC1 were also observed in all cell lines. Our results indicated that ST6GALNAC1 was downregulated in sporadic ESCC via hyper-methylation and LOH, and it may be a candidate responsible gene for ESCC. Furthermore, recent studies suggest that multiple genes on chromosome 17q25 are involved in ESCC development.

Selected telomere length changes and aberrant three-dimensional nuclear telomere organization during fast-onset mouse plasmacytomas

Mouse plasmacytoma (PCT) can develop within 45 days when induced by a v-abl/myc replication-deficient retrovirus. This fast-onset PCT development is always associated with trisomy of cytoband E2 of mouse chromosome 11 (11E2). Trisomy of 11E2 was identified as the sole aberration in all fast-onset mouse PCTs in [T38HxBALB/c]N congenic mice, with a reciprocal translocation between chromosome X and 11 (rcpT(X;11)) (Genes Cancer 2010;1:847-858). Using this mouse model, we have now examined the overall and individual telomere lengths in fast-onset PCTs compared with normal B cells using two-dimensional and three-dimensional quantitative fluorescent in situ hybridization of telomeres. We found fast-onset PCTs to have a significantly different three-dimensional telomere profile, compared with primary B cells of wild-type littermates with and without rcpT(X;11) (P < .0001 and P = .006, respectively). Our data also indicate for primary PCT cells, from the above mouse strain, that the translocation chromosome carrying 11E2 is the only chromosome with telomere lengthening (P = 4 x 10(-16)). This trend is not seen for T(X;11) in primary B cells of control [T38HxBALB/c]N mice with the rcpT(X;11). This finding supports the concept of individual telomere lengthening of chromosomes that are functionally important for the tumorigenic process.

Protection from intracellular oxidative stress by cytoglobin in normal and cancerous oesophageal cells

Cytoglobin is an intracellular globin of unknown function that is expressed mostly in cells of a myofibroblast lineage. Possible functions of cytoglobin include buffering of intracellular oxygen and detoxification of reactive oxygen species. Previous work in our laboratory has demonstrated that cytoglobin affords protection from oxidant-induced DNA damage when over expressed in vitro, but the importance of this in more physiologically relevant models of disease is unknown. Cytoglobin is a candidate for the tylosis with oesophageal cancer gene, and its expression is strongly down-regulated in non-cancerous oesophageal biopsies from patients with TOC compared with normal biopsies. Therefore, oesophageal cells provide an ideal experimental model to test our hypothesis that downregulation of cytoglobin expression sensitises cells to the damaging effects of reactive oxygen species, particularly oxidative DNA damage, and that this could potentially contribute to the TOC phenotype. In the current study, we tested this hypothesis by manipulating cytoglobin expression in both normal and oesophageal cancer cell lines, which have normal physiological and no expression of cytoglobin respectively. Our results show that, in agreement with previous findings, over expression of cytoglobin in cancer cell lines afforded protection from chemically-induced oxidative stress but this was only observed at non-physiological concentrations of cytoglobin. In addition, down regulation of cytoglobin in normal oesophageal cells had no effect on their sensitivity to oxidative stress as assessed by a number of end points. We therefore conclude that normal physiological concentrations of cytoglobin do not offer cytoprotection from reactive oxygen species, at least in the current experimental model.

RHBDF2 mutations are associated with tylosis, a familial esophageal cancer syndrome

Tylosis esophageal cancer (TOC) is an autosomal-dominant syndrome characterized by palmoplantar keratoderma, oral precursor lesions, and a high lifetime risk of esophageal cancer. We have previously localized the TOC locus to a small genomic interval within chromosomal region 17q25. Using a targeted capture array and next-generation sequencing, we have now identified missense mutations (c.557T>C [p.Ile186Thr] and c.566C>T [p.Pro189Leu] in RHBDF2, which encodes the inactive rhomboid protease RHBDF2 (also known as iRhom2), as the underlying cause of TOC. We show that the distribution of RHBDF2 in tylotic skin is altered in comparison with that in normal skin, and immortalized tylotic keratinocytes have decreased levels of total epidermal growth factor receptor (EGFR) and display an increased proliferative and migratory potential relative to normal cells, even when normal cells are stimulated with exogenous epidermal growth factor. It would thus appear that EGFR signaling is dysregulated in tylotic cells. Furthermore, we also show an altered localization of RHBDF2 in both tylotic and sporadic squamous esophageal tumors. The elucidation of a role of RHBDF2 in growth-factor signaling in esophageal cancer will help to determine whether targeting this pathway in chemotherapy for this and other squamous cell carcinomas will be effective.

Cytoglobin: biochemical, functional and clinical perspective of the newest member of the globin family

Since the discovery of cytoglobin (Cygb) a decade ago, growing amounts of data have been gathered to characterise Cygb biochemistry, functioning and implication in human pathologies. Its molecular roles remain under investigation, but nitric oxide dioxygenase and lipid peroxidase activities have been demonstrated. Cygb expression increases in response to various stress conditions including hypoxia, oxidative stress and fibrotic stimulation. When exogenously overexpressed, Cygb revealed cytoprotection against these factors. Cygb was shown to be upregulated in fibrosis and neurodegenerative disorders and downregulated in multiple cancer types. CYGB was also found within the minimal region of a hereditary tylosis with oesophageal cancer syndrome, and its expression was reduced in tylotic samples. Recently, Cygb has been shown to inhibit cancer cell growth in vitro, thus confirming its suggested tumour suppressor role. This article aims to review the biochemical and functional aspects of Cygb, its involvement in various pathological conditions and potential clinical utility.

Duplication of Subcytoband 11E2 of Chromosome 11 Is Regularly Associated with Accelerated Tumor Development in v-abl/myc-Induced Mouse Plasmacytomas

Chromosome 11 aberrations constitute the second most frequent chromosomal aberration in mouse plasmacytomas (PCTs) in which both the myc and abl oncogenes are constitutively expressed. In these tumors, previous G-banding studies had revealed numerical aberrations including duplication of the entire chromosome 11 or segments of telomeric bands D and E. The trisomy of chromosome 11 was always associated with accelerated pristane + v-abl/myc-induced PCT development. In the present study, PCT development was studied in a unique BALB/c congenic mouse strain, (T38HxBALB/c) F1, carrying a reciprocal translocation between chromosomes X and 11. After v-abl/myc induction, PCTs in this strain had acquired a nonrandom duplication of subcytoband 11E2. This duplication was always associated with accelerated PCT development. Corresponding synteny regions in the human and rat are changed in many tumors and involved in duplication, amplification, or translocation events. Thus, together with these synteny data, our findings strongly suggest a causal involvement of 11E2 in the acceleration of v-abl/myc-induced PCTs.

Old proteins - new locations: myoglobin, haemoglobin, neuroglobin and cytoglobin in solid tumours and cancer cells

AIM

The unexpected identification of myoglobin (MB) in breast cancer prompted us to evaluate the clinico-pathological value of MB, haemoglobin (HB) and cytoglobin (CYGB) in human breast carcinoma cases. We further screened for the presence of neuroglobin (NGB) and CYGB in tumours of diverse origin, and assessed the O(2) -response of HB, MB and CYGB mRNAs in cancer cell lines, to better elicit the links between this ectopic globin expression and tumour hypoxia.

METHODS

Breast tumours were analysed by immunohistochemistry for HB, MB and CYGB and correlated with clinico-pathological parameters. Screening for CYGB and NGB mRNA expression in tumour entities was performed by hybridization, quantitative PCR (qPCR) and bioinformatics. Hypoxic or anoxic responses of HB, MB and CYGB mRNAs was analysed by qPCR in human Hep3B, MCF7, HeLa and RCC4 cancer cell lines.

RESULTS

78.8% of breast cancer cases were positive for MB, 77.9% were positive for HB and 55.4% expressed CYGB. The closest correlation with markers of hypoxia was observed for CYGB. Compared to the weakly positive status of MB in healthy breast tissues, invasive tumours either lost or up-regulated MB. Breast carcinomas showed the tendency to silence CYGB. HB was not seen in normal tissues and up-regulated in tumours. Beyond breast malignancies, expression levels of NGB and CYGB mRNAs were extremely low in brain tumours (glioblastoma, astrocytoma). NGB was not observed in non-brain tumours. CYGB mRNA, readily detectable in breast cancer and other tumours, is down-regulated in lung adenocarcinomas. Alpha1 globin (α1 globin) and Mb were co-expressed in MCF7 and HeLa cells; CYGB transcription was anoxia-inducible in Hep3B and RCC4 cells.

CONCLUSIONS

This is the first time that HB and CYGB are reported in breast cancer. Neither NGB nor CYGB are systematically up-regulated in tumours. The down-regulated CYGB expression in breast and lung tumours is in line with a tumour-suppressor role. Each of the screened cancer cells expresses at least one globin (i.e. main globin species: CYGB in Hep3B; α1 globin + MB in MCF7 and HeLa). Thus, globins exist in a wide variety of solid tumours. However, the generally weak expression of the endogenous proteins in the cancer argues against a significant contribution to tumour oxygenation. Future studies should consider that cancer-expressed globins might function in ways not directly linked to the binding and transport of oxygen.

Upper gastrointestinal cancer predisposition syndromes

Malignancies of the upper gastrointestinal tract form a heterogeneous group of cancers characterized by unique epidemiology and biology. Despite these differences, survival for advanced disease remains poor across the panel of diseases, from cancers of the esophagus, stomach, pancreas, and, until recently, even gastrointestinal stromal tumors. Genetic predisposition syndromes associated with these diseases comprise an emerging subset of these diseases that may provide valuable information on cause and etiology. They may provide insight into molecular drivers for the disease, or disease subtypes, and also insights into novel gene/environment interactions. This review summarizes the current understanding of genetic predisposition syndromes of cancers of the upper gastrointestinal tract.

[Hereditary tylosis syndrome and esophagus cancer]

Tylosis palmoplantaris is an autosomal dominant disorder characterized by hyperkeratosis of palms and soles. Lesions start during childhood and are more evident in areas of pressure. Familial tylosis palmoplantaris comprises two forms: epidermolytic and non-epidermolytic. Patients with the epidermolytic variant have up to 40% higher chance of developing squamous cell carcinoma of the esophagus. The association of tylosis palmoplantaris with esophageal cancer is called Howel-Evans syndrome.

Genetic heterogeneity of oesophageal cancer in high-incidence areas of southern and northern China

BACKGROUND AND OBJECTIVE

Oesophageal cancer is one of the most common and deadliest cancers worldwide. Our previous population-based study reported a high prevalence of oesophageal cancer in Chaoshan, Guangdong Province, China. Ancestors of the Chaoshan population migrated from the Taihang Mountain region of north-central China, which is another high-incidence area for oesophageal cancer. The purpose of the present study was to obtain evidence of inherited susceptibility to oesophageal cancer in the Chaoshan population, with reference to the Taihang Mountain population, with the eventual goal of molecular identification of the disease genes.

METHODS

We conducted familial correlation, commingling, and complex segregation analyses of 224 families from the Chaoshan population and 403 families from the Taihang population using the FPMM program of S.A.G.E. version 5.3.0. A second analysis focused on specific families having large numbers of affected individuals or early onset of the disease.

RESULTS

For the general population, moderate sib-sib correlation was noticed for esophageal cancer. Additionally, brother-brother correlation was even higher. Commingling analyses indicated that a three-component distribution model best accounts for the variation in age of onset of oesophageal cancer, and that a multifactorial model provides the best fit to the general population data. An autosomal dominant mode and a dominant or recessive major gene with polygenic inheritance were found to be the best models of inherited susceptibility to oesophageal cancer in some large families.

CONCLUSIONS

The current results provide evidence for inherited susceptibility to oesophageal cancer in certain high-risk groups in China, and support efforts to identify the susceptibility genes.

Cytoglobin is upregulated by tumour hypoxia and silenced by promoter hypermethylation in head and neck cancer

BACKGROUND

Cytoglobin (Cygb) was first described in 2002 as an intracellular globin of unknown function. We have previously shown the downregulation of cytoglobin as a key event in a familial cancer syndrome of the upper aerodigestive tract.

METHODS

Cytoglobin expression and promoter methylation were investigated in sporadic head and neck squamous cell carcinoma (HNSCC) using a cross-section of clinical samples. Additionally, the putative mechanisms of Cygb expression in cancer were explored by subjecting HNSCC cell lines to hypoxic culture conditions and 5-aza-2-deoxycitidine treatment.

RESULTS

In clinically derived HNSCC samples, CYGB mRNA expression showed a striking correlation with tumour hypoxia (measured by HIF1A mRNA expression P=0.013) and consistent associations with histopathological measures of tumour aggression. CYGB expression also showed a marked negative correlation with promoter methylation (P=0.018). In the HNSCC cell lines cultured under hypoxic conditions, a trend of increasing expression of both CYGB and HIF1A with progressive hypoxia was observed. Treatment with 5-aza-2-deoxycitidine dramatically increased CYGB expression in those cell lines with greater baseline promoter methylation.

CONCLUSION

We conclude that the CYGB gene is regulated by both promoter methylation and tumour hypoxia in HNSCC and that increased expression of this gene correlates with clincopathological measures of a tumour's biological aggression.

Cytoglobin, the newest member of the globin family, functions as a tumor suppressor gene

Cytoglobin (CYGB) is a recently discovered vertebrate globin distantly related to myoglobin with unknown function. CYGB is assigned to chromosomal region 17q25, which is frequently lost in multiple malignancies. Previous studies failed to detect evidence for mutations in the CYGB gene. Recent studies provided preliminary evidence for increased methylation of the gene in lung cancer. Our study was aimed at investigating the role of CYGB as a tumor suppressor gene. By nested methylation-specific DNA sequencing analysis of lung and breast cancer cell lines and bronchial and mammary epithelial cell lines, we identified that methylation of a 110-bp CpG-rich segment of the CYGB promoter was correlated with gene silencing. We specifically targeted this sequence and developed a quantitative methylation-specific PCR assay, suitable for high-throughput analysis. We showed that the tumor specificity of CYGB methylation in discriminating patients with and without lung cancer, using biopsies and sputum samples. We further showed the tumor specificity of this assay with multiple other epithelial and hematologic malignancies. To show tumor suppressor activity of CYGB, we performed the following: (a) RNA interference-mediated knockdown of CYGB gene on colony formation in a CYGB expression-positive lung cancer cell line, resulting in increased colony formation; (b) enforced gene expression in CYGB expression-negative lung and breast cancer cell lines, reducing colony formation; and (c) identification of potential proximate targets down-stream of the CYGB genes. Our data constitute the first direct functional evidence for CYGB, the newest member of the globin family, as a tumor suppressor gene.

Genetics of gastroesophageal cancer: paradigms, paradoxes, and prognostic utility

Hereditary diffuse gastric cancer and tylosis are autosomal dominant cancer susceptibility syndromes. Accumulating evidence also suggests a genetic contribution to Barrett's esophagus and adenocarcinoma, traditionally considered acquired disorders. In this article we review the current knowledge on the genetic mechanisms underlying hereditary diffuse gastric cancer, tylosis, and Barrett's esophagus. Hereditary diffuse gastric cancer is a paradigm for hereditary cancer susceptibility syndromes with E-cadherin implicated as the dominant oncogene in up to one-third of cases. Tylosis in contrast remains the paradox as whilst the putative abnormality has been localized to the long arm of chromosome 17, sequencing of this region has failed to reveal a disease causing mutation. In the case of Barrett's esophagus and adenocarcinoma, although a validated specific disease-associated gene is yet to be identified, the increasing body of evidence of a possible genetic link is paving the way for subsequent prognostic studies such as AspECT (Aspirin Esomeprazole Chemoprevention Trial). For the clinician these advances in understanding are already having implications for practice in terms of improved screening and the stratification of management strategies. As the mechanisms continue to be defined, there is the real possibility that these mechanisms could be exploited or subverted in the design of new therapies. In the meantime, however, clinicians should undertake rigorous biopsy programs to ensure early invasive lesions are detected.

Allogeneic transplantation and the risk for transmission of genetic disease: the heritable cancer disorders

With the development of new approaches to transplantation therapy, such as those building upon the potential found in stem cells, it is vital to pursue a clear understanding of transplantation risks. Allogeneic transplantation presents risk for the transmission of disease of various types, including genetic disease. Predisposition to develop cancer is a feature of numerous genetic disorders, and it may be transmissible by transplantation. Some genetic disorders predisposing to cancer are remarkably common, either worldwide or in specific populations, and they could pose significant risk. Hence, to reduce risk to recipients, there is reason to exclude from donation those potential donors (including embryos) harboring certain germ-line mutations. However, the frequent absence of readily identifiable features might confound the effort to exclude those who harbor mutation. Thus, it is also important to consider the magnitude of risk that they represent. For some disorders, life-threatening cancer is highly likely to develop in those individuals born with germ-line mutation, but whether recipients would face the same risk from transplanted mutation is not always evident. Given the diversity of pathways that lead to cancer, there may be diverse factors that impact the likelihood for cancer to develop in the recipient, with some factors decreasing and others increasing the risk. One factor of special concern is the possibility that manipulation of donor cells, prior to transplantation, might introduce additional genetic or epigenetic abnormality, thereby increasing the risk.

Frequent genetic and epigenetic abnormalities contribute to the deregulation of cytoglobin in non-small cell lung cancer

Lung cancer demonstrates the highest mortality in the UK. Previous studies have implicated allelic loss at chromosome 17q in the development of non-small cell lung carcinoma (NSCLC), and a number of known and putative tumour-suppressor genes reside within this region. One candidate tumour-suppressor gene is cytoglobin (CYGB), which is contained entirely within the 42.5 kb tylosis with oesophageal cancer (TOC) minimal region. CYGB abnormalities have been demonstrated only in sporadic head and neck cancers. In this study, we investigated the expression, promoter methylation and allelic imbalance status of this gene in 52 paired (normal/tumour) surgically excised lung tissue samples from patients with NSCLC. CYGB expression in tumour tissue was significantly reduced compared with corresponding adjacent normal in 54% of the examined cases (paired t-test, P<0.001). The CYGB promoter was shown by pyrosequencing to be significantly hypermethylated [2-fold increase of methylation index (MtI) in tumours] in 25/52 (48%) tumour samples compared with normal samples. MtI of the CYGB promoter was associated with CYGB mRNA expression (linear regression analysis, P=0.009), suggesting a primary role for the epigenetic events in CYGB silencing. In addition, frequent LOH was detected at the locus 17q25 in 32/48 (67%) tumours examined. It is of note that the loss of expression intensified when both LOH and hypermethylation coincided in samples (Mann-Whitney, P=0.049). These findings provide the first evidence to suggest the implication of CYGB in the pathogenesis of NSCLCs.

Promoter methylation of P16, RARbeta, E-cadherin, cyclin A1 and cytoglobin in oral cancer: quantitative evaluation using pyrosequencing

Methylation profiling of cancer tissues has identified this mechanism as an important component of carcinogenesis. Epigenetic silencing of tumour suppressor genes through promoter methylation has been investigated by a variety of means, the most recent of which is pyrosequencing. We have investigated quantitative methylation status in oral squamous cell carcinoma patients. Fresh tumour tissue and normal control tissue from resection margin was obtained from 79 consecutive patients undergoing resection of oral squamous cell carcinoma. DNA was extracted and bisulphite treated. PCR primers were designed to amplify 75-200 bp regions of the CpG rich gene promoters of p16, RARbeta, E-cadherin, cytoglobin and cyclinA1. Methylation status of 4-5 CpG sites per gene was determined by pyrosequencing. Significant CpG methylation of gene promoters within tumour specimens was found in 28% for p16, 73% for RARbeta, 42% for E-cadherin, 65% for cytoglobin and 53% for cyclinA1. Promoter methylation was significantly elevated in tumours compared to normal tissue for p16 (P = 0.048), cytoglobin (P = 0.002) and cyclin A1 (P = 0.001) but not in RARbeta (P = 0.088) or E-cadherin (P = 0.347). Concordant methylation was demonstrated in this tumour series (P = 0.03). Significant differences in degree of methylation of individual CpG sites were noted for all genes except RARbeta and these differences were in a characteristic pattern that was reproduced between tumour samples. Cyclin A1 promoter methylation showed an inverse trend with histological grade. Promoter methylation analysis using pyrosequencing reveals valuable quantitative data from several CpG sites. In contrast to qualitative data generated from methylation specific PCR, our data demonstrated p16 promoter methylation in a highly tumour specific pattern. Significant tumour specific methylation of cyclin A1 promoter was also seen. Cytoglobin is a novel candidate tumour suppressor gene highly methylated in upper aero-digestive tract squamous cancer.

Association of palmoplantar keratoderma, cutaneous squamous cell carcinoma, dental anomalies, and hypogenitalism in four siblings with 46,XX karyotype: A new syndrome

The association of palmoplantar keratoderma (PPK) with the development of cutaneous squamous cell carcinomas (SCCs), dental anomalies, severe hypogenitalism with hypospadias, abnormal development of gonads with ambiguous external genitalia, gynecomastia, altered plasma sex hormones levels, and hypertriglyceridemia has not, to our knowledge, been reported previously. We describe it in 4 brothers with 46,XX karyotype, whereas the 5 sisters of their consanguineous parents were unaffected. This family may represent a new syndrome. The PPK was of the classical nonepidermolytic histologic type. The proband also had a laryngeal carcinoma diagnosed in his early forties and nodular testicular hyperplasia of Leydig cells.

Rearrangements of the telomeric region of mouse chromosome 11 in Pre-B ABL/MYC cells revealed by mBANDing, spectral karyotyping, and fluorescence in-situ hybridization with a subtelomeric probe

Previous work has demonstrated that chromosome 11 is trisomic or shows a duplicated region encompassing the E1/E2 band of chromosome 11 in 90% of v-abl/myc-induced plasmacytomas (Wiener et al. 1995). In the present report, we have studied BALB/c PreB lymphocytes that were immortalized by v-abl and stably transfected with a conditional MycER vector (Mai et al. 1999). These cells, termed PreB ABL/MYC, showed changes in the E1/E2 bands of chromosome 11 that are similar to those reported previously for v-abl/myc-induced plasmacytomas. This was shown by the use of chromosome painting, SKY, FISH and mBAND. Our findings suggest that the Pre-B ABL/MYC cells may be used to analyse the genetic changes affecting chromosome 11 that are associated with v-abl/myc-dependent tumorigenesis in mouse B cells.