Primary hepatocellular neoplasms in a MODY3 family with a novel HNF1A germline mutation.

Maturity onset diabetes of the young type 3 (MODY3) and hepatocellular adenomas (HCAs) are associated with mutations in the HNF1A gene. HNF1A codes for the transcription factor HNF1α, which interacts with DNA as a homodimer or a heterodimer with HNF1ß, to regulate multiple cellular functions including glucidic metabolism, lipidic transport, and detoxication. We report three members of one family with a novel germline in-frame deletion of HNF1A exons 2-3 identified initially using array CGH and direct sequence analysis. All three family members have MODY3 in association with primary liver cell tumours (HCA, liver adenomatosis (LA), and hepatocellular carcinoma (HCC)). Additionally, a high rate of infant mortality was observed in the family. The described family demonstrates a novel HNF1A mutation associated with both benign and malignant primary liver cell tumours and MODY3.

A non-syndrome form of neurosensory, recessive deafness maps to the pericentromeric region of chromosome 13q.

Non-syndromic, recessively inherited deafness is the most predominant form of severe inherited childhood deafness. Until now, no gene responsible for this type of deafness has been localized, due to extreme genetic heterogeneity and limited clinical differentiation. Linkage analyses using highly polymorphic microsatellite markers were performed on two consanguineous families from Tunisia affected by this form of deafness. The deafness was profound, fully penetrant and prelingual. A maximum two-point lod score of 9.88 (theta = 0.001) was found with a marker detecting a 13q locus (D13S175). Linkage was also observed to the pericentromeric 13q12 loci D13S115 and D13S143. These data map this neurosensory deafness gene to the same region of chromosome 13q as the gene for severe, childhood autosomal recessive muscular dystrophy.

Methylation of the CDH1 promoter as the second genetic hit in hereditary diffuse gastric cancer.

Aberrant promoter methylation and the associated loss of gene expression is a common accompaniment of human cancers. Nonetheless, it has been challenging to demonstrate in any given tumour that methylation of a specific gene was causal and not consequent to malignant transformation. In this regard, our attention was drawn to the genesis of gastric cancers in individuals with hereditary diffuse gastric cancer (HDGC). These individuals harbour germline mutations in the gene encoding E-cadherin, CDH1, but their cancers have consistently demonstrated absence of loss of heterozygosity at the CDH1 locus. These findings suggested the hypothesis that CDH1 promoter methylation might function as the 'second genetic hit' in the genesis of these cancers.

Adrenomedullin interacts with VEGF in endometrial cancer and has varied modulation in tumours of different grades.

OBJECTIVE: Endometrial cancer, in developed countries, is the most common malignancy of the female genital tract. Surgery and radiotherapy are successful in many patients but systemic and recurrent diseases have no consistently effective treatments, and for high grade advanced disease the prognosis is poor. The study investigated characteristics of adrenomedullin in endometrial cancer to assist in identifying targets for developing treatments. METHODS: Endometrial samples of women with and without cancer, and the Ishikawa cell line were used to investigate adrenomedullin mRNA regulation, peptide expression, adrenomedullin secretion and effects of adrenomedullin on VEGF secretion. RESULTS: Expression of adrenomedullin mRNA was upregulated compared to that in healthy post-menopausal endometria. Adrenomedullin secretion was increased by cobalt chloride in this study. Secretion was reduced by the naturally-occurring compounds, (-)-epigallocatechin gallate (EGCG) and 3,4',5-trihydroxystilbene (resveratrol), which we have previously demonstrated to also suppress VEGF secretion in endometrial tumour tissue. We noted, for the first time, that adrenomedullin enhanced VEGF secretion from tumour cells. CONCLUSIONS: Increased adrenomedullin expression may result in amplifying both tumorigenic and angiogenic activities. A substantial impact on growth of tumours may result in vivo as a consequence of the synergism between adrenomedullin and VEGF. Adrenomedullin, which has altered cellular characteristics in tumour compared to healthy tissue, offers an understudied target with potential to modify endometrial cancer behaviour, complementing other treatments.

Identification of seven novel germline mutations in the human E-cadherin (CDH1) gene.

Hereditary diffuse gastric cancer (HDGC) is a cancer predisposition syndrome caused by germline mutation of the gene encoding the tumour-suppressor E-cadherin (CDH1). We describe the search for CDH1 mutations in 36 new diffuse gastric cancer families. All 16 CDH1 exons, neighbouring intronic sequence and an essential promoter region were screened by DNA sequencing. We detected nine different mutations, seven of which were novel. Of the seven novel mutations, five were identified in families who met the IGCLC clinical criteria for HDGC. Two mutations resulted in a premature stop codon and truncation of the protein. Three mutations affected splice sites; two of the splice-site mutations were shown by RT-PCR to disturb normal CDH1 splicing, while the third splice-site mutation was present in two unrelated HDGC families. The remaining two mutations resulted in amino acid substitutions and impaired the ability of E-cadherin protein to form cellular aggregates and suppress invasion in vitro. Together with the occurrence of extra-gastric tumours such as lobular breast and colorectal cancer, these findings further extend the types of CDH1 mutations and the spectrum of tumours associated with HDGC.

Single nucleotide polymorphisms (SNPs) at CDH1 promoter region in familial gastric cancer.

INTRODUCTION: Gastric cancer is the most frequent gastrointestinal malignancy in Mexico and the proportion of patients younger than 40 years is one of the highest reported in the world literature. Recently several families with familial diffuse gastric cancer have been identified at the National Institute of Medical Sciences and Nutrition. Germline mutations in the E-cadherin gene (CHD1) have been described that result in the development of diffuse hereditary gastric cancer in young patients. METHODS: The complete coding sequence at exons 1 to 16 and the promoter region of CDH1 was amplified by polymerase chain reaction in peripheral blood samples of two patients with early onset familial diffuse gastric cancer. RESULTS: No germline inactivating mutations of CHD1 were found on either patient. Single nucleotide polymorphisms -160 C->A were detected in the promoter region of CDH1 in both patients. CONCLUSIONS: The polymorphism -160 C->A theoretically confers an increased risk of developing diffuse gastric cancer. The relatives of these patients may an increased risk of gastric cancer among other tumors. There is presently not enough evidence to consider the -160 C->A polymorphism an etiologic factor of diffuse gastric cancer in these patients since the frequency and type of genetic alterations of CDH1 are largely unknown in the Mexican population. It will be necessary to conduct epidemiologic studies in the Mexican population to determine the influence that genetic alterations have on the genesis of diffuse gastric carcinoma.

Hereditary diffuse gastric cancer.

Hereditary diffuse gastric cancer (HDGC) is a cancer predisposition syndrome caused by germline mutation of the gene for the cell-to-cell adhesion protein E-cadherin. The syndrome is dominated by predisposition to the histologically diffuse, poorly differentiated form of gastric cancer. It is not associated with intestinal-type gastric cancer, but families may have an elevated risk of lobular breast cancer. Here, we review the identified families, mutations, and proposed mechanisms by which E-cadherin loss promotes tumorigenesis.

Side effects of short-term 10,000-lux light therapy.

OBJECTIVE: Previous reports of side effects from light therapy were mostly based on administration of 2,500-lux treatments. It has become common practice to use brighter, 10,000-lux exposure when treating seasonal affective disorder. The authors studied side effects produced by short-term 10,000-lux light therapy. METHOD: Seventy subjects with seasonal affective disorder who underwent brief 10,000-lux light therapy were asked to report side effects. RESULTS: Of the 70 subjects, 32 (45.7%) experienced side effects, and nine (12.9%) reported two or more apiece. Headaches and eye or vision problems were the most common. Almost all were mild, were transient, and did not interfere with treatment. CONCLUSIONS: Short-term 10,000-lux light therapy often produces side effects early in treatment. These are not serious or prolonged, however, confirming findings from earlier studies that used dimmer light.

Chromoendoscopic surveillance in hereditary diffuse gastric cancer: an alternative to prophylactic gastrectomy?

BACKGROUND: Hereditary diffuse gastric cancer (HDGC) is defined by germline mutations in the E-cadherin gene, CDH-1. The first family in which CDH-1 mutations were identified was a large Maori kindred, where lifetime penetrance is 70%. Prophylactic gastrectomy is an unacceptable option for many mutation carriers. The results of annual chromoendoscopic surveillance using the methylene blue/congo red technique in 33 mutation carriers over a five year period are described. PATIENTS AND METHODS: Thirty three confirmed CDH-1 mutation carriers (18 males, 15 females), median age 32 years (range 14-69), were enrolled in 1999-2003. Medical records, endoscopy, and pathology were reviewed retrospectively. RESULTS: Over five years, 99 surveillance endoscopies were performed, of which 93 were chromo-dye enhanced. Sixty nine chromoendoscopies were normal. In 24 procedures, 1-6 pale areas/stomach (size 2-10 mm) were detected post chromo-dye application (totalling 56 pale lesions). One biopsy was taken from each pale lesion: 23 lesions (41%) showed signet ring cell carcinoma (10 patients), 10 lesions (18%) gastritis (four patients), and 23 (41%) normal mucosa (10 patients). No chromo-dyes were used in six procedures with macroscopic lesions (two HDGC, four ulceration). Total gastrectomies from patients with carcinoma were macroscopically normal but pathological mapping showed multiple microscopic foci of early signet ring cell carcinoma. Correlation of chromoendoscopic and gastrectomy findings showed that congo red/methylene blue detected carcinoma foci 4-10 mm in size but not foci <4 mm. CONCLUSIONS: The use of chromoendoscopy following normal white light gastroscopy facilitated detection of early gastric carcinoma foci not visible with white light gastroscopy. If these findings are validated in other HDGC kindred, chromogastroscopy represents an improved surveillance technique that can be safely considered alongside prophylactic gastrectomy.

The inherited susceptibility to cancer.

The study of inherited cancer syndromes has led to the identification of over 25 genes directly involved in tumorigenesis. These genes have functions as diverse as signal transduction, cell cycle control, cell-to-cell adhesion, control of apoptosis, DNA repair and the maintenance of genome stability. Most cancer syndromes have a dominant pattern of inheritance, due to germline loss-of-function mutation of a tumour suppressor gene. All the recessively inherited genes have been implicated in the maintenance of genome stability. This review summarises our current understanding of the functions of the major cancer susceptibility genes.

E-cadherin downregulation in cancer: fuel on the fire?

The development, maintenance and repair of tissue requires an exquisite balance between cell proliferation, cell adhesion and cell motility. Equally, tumour initiation and progression are characterized by not only the abnormal expression of genes involved in cell proliferation and survival but also by genes responsible for the control of cell adhesion and cell motility. Central to the process of cell-cell adhesion in epithelial tissues is E-cadherin. Loss of E-cadherin function in tumours results in the rapid progression of relatively benign adenomas to invasive, metastatic carcinomas. Germline mutation of the E-cadherin gene predisposes to diffuse, poorly differentiated gastric cancer, and its downregulation in sporadic tumours is associated with poor clinical prognosis.

The role of the E-cadherin gene (CDH1) in diffuse gastric cancer susceptibility: from the laboratory to clinical practice.

Loss of function of the E-cadherin gene (CDH1) has been linked with diffuse gastric cancer susceptibility, and germline inactivating mutations in CDH1 characterise the hereditary diffuse gastric cancer (HDGC) syndrome. Hypermethylation in the CDH1 promoter region is a frequent phenomenon in poorly differentiated, diffuse gastric carcinomas and it was identified as the main mechanism for the inactivation of the remaining wild-type allele in HDGC cases. Specific criteria are used to identify patients with suspected HDGC and who should be investigated for CDH1 germline mutations. Accurate screening is mandatory for unaffected carriers of CDH1 mutations and selected high-risk individuals could be considered for prophylactic gastrectomy. Also, germline CDH1 mutations may predispose to lobular breast carcinoma and prostate cancer. Germline CDH1 mutations are not always detectable in patients who meet the HDGC criteria and the aetiological role of this gene is still under investigation. Families without recognised inactivating CDH1 mutations may have undisclosed CDH1 mutations or mutations in its regulatory sequences or germline mutations in unidentified genes that also contribute to the disease. In recent years, several germline missense CDH1 mutations have been identified, some of which showed a marked negative influence on E-cadherin function in experimental models. CDH1 promoter hypermethylation seems a key event in the carcinogenetic process of poorly differentiated, diffuse gastric cancer and it deserves further investigation as a new target for anticancer therapies with demethylating agents.

Tobacco rattle virus RNA-1 29K gene product potentiates viral movement and also affects symptom induction in tobacco.

In order to investigate the function of the 29K protein of tobacco rattle virus (TRV), we introduced different mutations in the 29K protein gene and analyzed the biological properties of the subsequent transcripts in tobacco plants. Although none of the mutant RNAs was able to accumulate to a detectable level, the defects in the 29K protein could be complemented by coinoculation with wild-type TRV or tobacco mosaic virus (TMV). Complementation was also achieved in transgenic plants expressing the homologous TMV 30K protein which is involved in cell-to-cell movement, but without inducing distinctive symptoms. Transcripts of chimeric TRV clones containing duplicate genes for the 29K protein initiated infections with formation of necrotic lesions and the progeny retained only one copy of the gene. These experiments demonstrate that the 29K protein is not required for viral RNA replication and, because the TRV transcripts do not encode the coat protein, that the 29K and 30K proteins act on nonencapsidated RNA. In addition to potentiating viral movement, the TRV 29K protein may also play a role in symptom induction on tobacco.

Influence of the poly(A) tail and putative polyadenylation signal on the infectivity of white clover mosaic potexvirus.

A series of mutations has been constructed in a cDNA clone of white clover mosaic virus (WCIMV) which decreases the poly(A) tail length of run-off transcripts from 74 to 27, 10 or zero 3'-terminal (A) residues. Although transcripts with short poly(A) tails were less infectious than wild-type RNA, complete removal of the (A) tail did not abolish infectivity. Addition of nonviral nucleotides to the 3' terminus of transcripts with no 3'-terminal (A) residues eliminated infectivity. Heterogenous-length poly(A) tails, indistinguishable from the wild type, were synthesized de novo in plants inoculated with transcripts with no 3'-terminal (A) residues, demonstrating the presence of a poly(A) polymerase activity in WCIMV-infected tissue. Mutation of a putative polyadenylation motif found in the 3' noncoding region of WCIMV decreased the efficiency of polyadenylation of the progeny of transcripts with 10 3'-terminal (A) residues. The same mutation in transcripts with no 3'-terminal (A) residues abolished infectivity.

Mutation and replacement of the 16-kDa protein gene in RNA-1 of tobacco rattle virus.

The function of the 16-kDa protein encoded by tobacco rattle virus (TRV) RNA-1 was investigated by a mutational analysis of the 16-kDa protein gene. Transcripts of TRV RNA-1 produced from a full-length cDNA clone of TRV RNA-1 (SYM strain) remained infectious when the 16-kDa protein gene was disrupted by premature termination codons and a deletion which removed 73% of the coding region. A deletion which included the intergenic region between the 29-kDa protein gene and the 16-kDa protein gene, the entire 16-kDa protein coding region, and 57% of the 3' noncoding region was not infectious. Transcripts in which the 16-kDa protein coding region was replaced by the tobacco mosaic virus (TMV) (L strain) coat protein gene were also infectious and expressed TMV coat protein in infected tissue. Inclusion of the TMV origin of assembly sequence in the chimaeric constructs resulted in the accumulation of TMV-like virus particles in infected tissue.

Incidence of gastric cancer and breast cancer in CDH1 (E-cadherin) mutation carriers from hereditary diffuse gastric cancer families.

BACKGROUND & AIMS: Germline mutations in CDH1 are known to cause hereditary diffuse gastric cancer (HDGC). Breast and colorectal cancer have also been reported in CDH1-associated HDGC. The purpose of this study was to estimate the cumulative risk of gastric and breast cancer in CDH1 mutation carriers. METHODS: Family data were collected by member groups of the International Gastric Cancer Linkage Consortium. Eligible families had at least 3 cases of diffuse gastric cancer, and at least 1 affected member had tested positive for a mutation in CDH1. Eleven families met these criteria. We used the pedigree information to estimate penetrance using the MENDEL program. The conditional likelihood of the pedigree was maximized given the phenotype of the pedigree and genotype of the index case at ascertainment. We parameterized the model in terms of log relative risks for mutation carriers compared with risks in the general population of the United Kingdom. Noncarriers of the gene were assumed to develop the disease at population incidence rates. RESULTS: The estimated cumulative risk of gastric cancer by age 80 years was 67% for men (95% confidence interval [95% CI], 39-99) and 83% for women (95% CI, 58-99). For women, the cumulative risk of breast cancer was 39% (95% CI, 12-84). The combined risk of gastric cancer and breast cancer in women was 90% by age 80 years. CONCLUSIONS: These penetrance estimates should be useful for genetic counseling in multiple-case families. However, they may not apply to individuals with a minimal family history, in whom the risks may be lower.

Hereditary diffuse gastric cancer: predominance of multiple foci of signet ring cell carcinoma in distal stomach and transitional zone.

BACKGROUND AND AIMS: Germline mutations in the CDH-1/E-cadherin gene are, to date, the only known cause of hereditary diffuse gastric cancer (HDGC). While two recent series of prophylactic gastrectomy described microscopic foci of signet ring cell carcinoma in sample sections from 10 macroscopically normal stomachs, whole stomach phenotype has not been mapped. We aimed to describe the size and distribution of foci in relation to mucosal zones and anatomical location. METHODS: Six patients (from three HDGC kindred) were referred for total gastrectomy via three different referral pathways. Following fixation, five stomachs were completely blocked and one extensively sampled. Histopathology was mapped to a mucosal photograph of each stomach, enabling precise localisation of carcinoma foci, benign pathology, and mucosal zones. RESULTS: There were 4-318 microscopic foci of intramucosal signet ring cell adenocarcinoma in the six macroscopically normal stomachs (foci size 0.1-10 mm in diameter). The distal third of the stomach contained 48% of total foci (range 29-75%). The body-antral transitional zone occupied 7.7% of mucosal area (range 3.6-11.8) but had 37% of foci (range 10%-75%). The largest foci were found in the transitional zone and foci density was five times greater in the transitional zone than in body or antral type mucosa. CONCLUSIONS: In germline CDH-1 mutation carriers, multiple microscopic foci of intramucosal signet ring cell carcinoma show a predilection for the distal stomach and the body-antral transitional zone. Targeting the transitional zone would maximise the likelihood of finding foci in macroscopically normal gastrectomies, and particular attention should be paid to this area during endoscopy.

Organization and interviral homologies of the coat protein gene of white clover mosaic virus.

The sequence of 1612 nucleotides of the 3'-terminal region of white clover mosaic virus (WCIMV) has been determined from cDNA clones. The viral sense RNA contains four open reading frames of Mr 20,684, Mr 7219, Mr 12,989, and at least Mr 17,000. The latter begins 5' to the sequence determined. The amino acid sequence of the open reading frame encoding the 20,684 polypeptide shows marked homology to the coat proteins of three other potexviruses. The putative coat protein gene was subcloned in a T7 transcription plasmid and RNAs produced by in vitro transcription were translated in the rabbit reticulocyte lysate system. The polypeptide products comigrated on SDS-polyacrylamide gels with one of those synthesized by the in vitro translation of viral RNA, and were immunoprecipitable with antiserum raised against WCIMV, confirming the location of the coat protein gene.