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.

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.

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.

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.

Somatic mutations of KIT in familial testicular germ cell tumours.

Somatic mutations of the KIT gene have been reported in mast cell diseases and gastrointestinal stromal tumours. Recently, they have also been found in mediastinal and testicular germ cell tumours (TGCTs), particularly in cases with bilateral disease. We screened the KIT coding sequence (except exon 1) for germline mutations in 240 pedigrees with two or more cases of TGCT. No germline mutations were found. Exons 10, 11 and 17 of KIT were examined for somatic mutations in 123 TGCT from 93 multiple-case testicular cancer families. Five somatic mutations were identified; four were missense amino-acid substitutions in exon 17 and one was a 12 bp in-frame deletion in exon 11. Two of seven TGCT from cases with bilateral disease carried KIT mutations compared with three out of 116 unilateral cases (P=0.026). The results indicate that somatic KIT mutations are implicated in the development of a minority of familial as well as sporadic TGCT. They also lend support to the hypothesis that KIT mutations primarily take place during embryogenesis such that primordial germ cells with KIT mutations are distributed to both testes.

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.

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.

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.

Germline E-cadherin gene mutations: is prophylactic total gastrectomy indicated?

BACKGROUND: The CDH1 gene encodes E-cadherin, an epithelial cell adhesion molecule. Germline CDH1 mutations recently were identified in families with hereditary diffuse gastric carcinoma in a pattern suggestive of autosomal dominant inheritance with incomplete penetrance. METHODS: The proband was a woman age 47 years with a strong family history of diffuse gastric carcinoma. A germline E-cadherin gene mutation was identified in this patient, her brother, and three first cousins. All five family members underwent endoscopic evaluations, which were negative for malignancy, and elected to undergo a prophylactic total gastrectomy with Roux-en-Y esophagojejunostomy. RESULTS: Pathologic examination of the proband's stomach revealed several microscopic foci of intramucosal signet ring cell adenocarcinoma in the cardia and proximal gastric body. Postgastrectomy specimens from the proband's brother and three first cousins all showed intramucosal signet ring cell adenocarcinoma in various regions of the stomach. Immunoperoxidase studies performed on gastric tissue from these five patients demonstrated diminished or absent E-cadherin reactivity in the cancerous mucosa. CONCLUSIONS: Although total gastrectomy was performed as a prophylactic intervention, occult gastric carcinoma was discovered in all five patients. Thus, total gastrectomy should be curative for gastric carcinoma in these patients. Based on their successful outcomes and the lack of efficacious surveillance methods for diffuse gastric carcinoma, prophylactic total gastrectomy may be the management of choice for germline E-cadherin gene mutation carriers. However, prophylactic total gastrectomy should be undertaken cautiously because the procedure may be associated with considerable morbidity.

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.

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.

E-cadherin germline mutations define an inherited cancer syndrome dominated by diffuse gastric cancer.

To extend earlier observations of germline E-cadherin mutations in kindreds with an inherited susceptibility to diffuse gastric cancer, we searched for germline E-cadherin mutations in five further families affected predominantly by diffuse gastric cancer and one family with a history of diffuse gastric cancer and early-onset breast cancer. Heterozygous inactivating mutations were found in the E-cadherin gene in each of these families. No mutation hotspots were identified. These results demonstrate that germline mutation of the E-cadherin gene is a common cause of hereditary diffuse gastric cancer and suggest a role for these mutations in the incidence of breast cancer.

Familial gastric cancer: clinicopathological characteristics, RER phenotype and germline p53 and E-cadherin mutations.

Gastric cancer frequently occurs in family members with hereditary non-polyposis colorectal cancer (HNPCC) and Li-Fraumeni syndrome (LFS) and germline E-cadherin mutations were recently identified in a subset of familial gastric cancers. Thus, families with an aggregation of gastric cancers were recruited by reviewing the genealogical trees of 3632 patients with gastric cancer. The criteria for recruiting such families were the following: at least three relatives should have gastric cancer and one of them should be a first degree relative of the other two; at least two successive generations should be affected; in one of the relatives gastric cancer should be diagnosed before age 50. Thirty-one cases (0.9%) fitted all three of these criteria. There were only gastric cancer patients in 18 of the 31 families and there were no families that fitted clinical criteria of HNPCC or LFS. Paraffin-embedded tissues were available in 29 probands and DNA was successfully isolated for molecular analyses in 13 probands. RER phenotype was detected in three (23%) cases, whereas germline p53 mutations were detected in none of 13 cases. A germline E-cadherin mutation was detected in one of three diffuse types and none of 10 intestinal types, however, a mutation resulting in the replacement of Gly by Val was detected in the precursor sequence. Thus, although familial clustering of gastric cancer occurs in approximately 1% of gastric cancer patients, germline mutations of the DNA mismatch repair, p53 and E-cadherin genes do not significantly contribute to such a clustering.

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.

Absence of PAX2 gene mutations in patients with primary familial vesicoureteric reflux.

Vesicoureteric reflux (VUR) is a common childhood condition characterised by regurgitation of urine from the bladder to the kidney. It is the commonest cause of end stage renal failure in children and an important cause in adults. Primary VUR is often familial, suggesting that genetic factors play an important role in its aetiology. Recently, VUR was observed as part of a syndrome, involving optic nerve colobomas and renal anomalies, caused by mutations of the PAX2 gene. PAX2 is a member of the paired box family of genes and is expressed in the ureteric bud and differentiating nephrogenic mesenchyme of the developing kidney. PAX2 has been shown to play a critical role in the development of both the kidney and the ureter. The occurrence of VUR in one family with the PAX2 mutation, and the expression pattern of PAX2 in developing ureteric bud, strongly suggested that PAX2 could be the cause of primary familial VUR. Single strand conformational polymorphism (SSCP) analysis of 23 affected subjects in eight families with primary familial VUR showed no alterations in exons 2-5 of the PAX2 gene. In addition, a polymorphic dinucleotide repeat marker located within the PAX2 gene segregated independently of the disease trait in one large family who primarily had VUR or reflux nephropathy. These results suggest that PAX2 is not a major cause of primary familial reflux.

E-cadherin germline mutations in familial gastric cancer.

The identification of genes predisposing to familial cancer is an essential step towards understanding the molecular events underlying tumorigenesis and is critical for the clinical management of affected families. Despite a declining incidence, gastric cancer remains a major cause of cancer death worldwide, and about 10% of cases show familial clustering. The relative contributions of inherited susceptibility and environmental effects to familial gastric cancer are poorly understood because little is known of the genetic events that predispose to gastric cancer. Here we describe the identification of the gene responsible for early-onset, histologically poorly differentiated, high grade, diffuse gastric cancer in a large kindred from New Zealand (Aotearoa). Genetic linkage analysis demonstrated significant linkage to markers flanking the gene for the calcium-dependent cell-adhesion protein E-cadherin. Sequencing of the E-cadherin gene revealed a G --> T nucleotide substitution in the donor splice consensus sequence of exon 7, leading to a truncated gene product. Diminished E-cadherin expression is associated with aggressive, poorly differentiated carcinomas. Underexpression of E-cadherin is a prognostic marker of poor clinical outcome in many tumour types, and restored expression of E-cadherin in tumour models can suppress the invasiveness of epithelial tumour cells. The role of E-cadherin in gastric cancer susceptibility was confirmed by identifying inactivating mutations in other gastric cancer families. In one family, a frameshift mutation was identified in exon 15, and in a second family a premature stop codon interrupted exon 13. These results describe, to our knowledge for the first time, a molecular basis for familial gastric cancer, and confirm the important role of E-cadherin mutations in cancer.