Prognostic significance of E-cadherin/catenin complex expression in gastric cancer

Abnormal expression of E-cadherin/catenin complex in cancer has been associated with poor differentiation and acquisition of invasiveness, suggesting a possible role of this protein as an invasion suppressor. In this study, we conducted an immunohistochemical investigation of all components of the E-cadherin/catenin complex in 65 gastric cancer patients. Abnormal expression of E-cadherin and, alpha- and gamma-catenin occurred more frequently in diffuse than in intestinal type of gastric cancer, and correlated with poor differentiation. Abnormal expression of E-cadherin and beta-catenin correlated with poor survival. Abnormal expression of all four components of the complex was associated with poorly differentiated and diffuse-type carcinoma, and poor survival. In the multivariate analysis, abnormal expression of the E-cadherin/catenin complex was not an independent prognostic factor. These results suggest that the E-cadherin/catenin complex may be a useful marker of differentiation and prognosis in gastric cancer. Further studies are warranted to clarify the impact of the E-cadherin/catenin complex on prognostic factor of gastric cancer.     

E-cadherin/catenin complex in benign and malignant melanocytic lesions

E-cadherin is a calcium-dependent cell-cell adhesion molecule expressed by melanocytes and responsible for their adhesion to keratinocytes in vitro. In this study, the expression of E-cadherin and its associated cytoplasmic proteins alpha-, beta-, and gamma-catenin was evaluated in melanocytic lesions by immunohistochemistry. E-cadherin expression was evaluated in 70 malignant melanomas and the catenins in 35 of these specimens. Twenty benign melanocytic naevi were also evaluated for E-cadherin and catenin expression. In normal epidermis, E-cadherin/catenin immunostaining was localized at the intercellular borders. In melanomas, a differential loss of E-cadherin expression was observed. Membranous E-cadherin staining was absent in dermal nests of melanomas in their radial growth phase and in Clark level II and III lesions, whereas it was present in a high proportion of melanomas in their vertical growth phase, in Clark level IV and V lesions and in metastasizing melanomas. In contrast, superficial compartments of naevi showed membranous E-cadherin immunoreactivity and junctional naevus cell nests displayed heterogeneous or diffuse cytoplasmic staining. Cytoplasmic alpha- and beta-catenin, but not gamma-catenin staining were detected in all benign and malignant lesions. These findings indicate that qualitative changes in the expression and cellular localization of E-cadherin and of alpha-, beta-, and gamma-catenin occur in melanocytic lesions and may reflect different stages in their progression.     

上皮钙黏素/链接素黏附复合体在鼻咽癌组织中的表达及意义

目的探讨鼻咽癌组织中上皮钙黏素(E-CAD)、β-链接素(β-CAT)和α-链接素(α-CAT)的表达情况及与临床病理特征的关系。方法应用免疫组化SP法检测52例鼻咽非角化癌及其癌旁黏膜组织中E-CAD、β-CAT和α-CAT的表达。结果鼻咽癌组织中E-CAD、β-CAT及α-CAT的异常表达率分别为48.1%、32.7%及34.6%,而全部52例癌旁黏膜上皮中均正常表达E-CAD、β-CAT和α-CAT,癌组织的异常表达率显著高于癌旁组织(P<0.05)。鼻咽癌的E-CAD、β-CAT、α-CAT表达之间呈正相关(P<0.05)。α-CAT正常表达的鼻咽癌患者外周血中抗EB病毒病毒壳抗原IgA(VCA-IgA)滴度高于异常表达者(P<0.01)。E-CAD、β-CAT、α-CAT的表达与其他临床病理特征无相关性。结论鼻咽非角化癌中E-CAD/β-CAT/α-CAT黏附复合体明显异常表达,三者表达具有一致性。E-CAD、β-CAT、α-CAT表达下调与鼻咽癌临床分期和淋巴结转移缺乏必然联系。     

Suppression of breast cancer invasion and migration by indole-3-carbinol: associated with up-regulation of BRCA1 and E-cadherin/catenin complexes

Indole-3-carbinol (I3C) is a compound occurring naturally in cruciferous vegetables and has been indicated as a promising agent in preventing breast cancer development and progression. In the present study we have investigated the effect of I3C on the cell migration and invasion behavior in estrogen receptor positive MCF-7 and estrogen receptor negative MDA-MB-468 human breast cancer cell lines. Both MCF-7 and MDA-MB-468 were poorly invasive cell lines and exhibited modest invasion and migration capacity in the presence of fibronectin as the chemoattractant. I3C (50 or 100 microM) elicited a significant inhibition of in vitro cell adhesion, migration, and invasion as well as in vivo lung metastasis formation in both cell lines. I3C also suppressed the 17beta-estradiol stimulated migration and invasion in estrogen-responsive MCF-7 cells. These results indicate that anti-invasion and antimigration activities of I3C occur via estrogen-independent and estrogen-dependent pathways. Moreover, I3C significantly caused a dose-dependent increase in E-cadherin, three major catenins (alpha, beta, and gamma-catenin) and BRCA1 expression. Our current finding is the first demonstration that I3C can activate the function of invasion suppressor molecules associated with the suppression of invasion and migration in breast cancer cells. Thus, clinical application of I3C may contribute to the potential benefit for suppression of breast cancer invasion and metastasis.     

Cadherin and catenin alterations in human cancer

Among the hallmarks of cancer are defective cell-cell and cell-matrix adhesion. Alterations in cadherin-catenin complexes likely have a major contributing role in cell-adhesion defects in carcinomas arising in many different tissues. E-cadherin, the prototypic member of the cadherin transmembrane protein family, regulates cell adhesion by interacting with E-cadherin molecules on opposing cell surfaces. E-cadherin's function in cell adhesion is also critically dependent on its ability to interact through its cytoplasmic domain with catenin proteins. A diverse collection of defects alter cadherin-catenin function in cancer cells, including loss-of-function mutations and defects in the expression of E-cadherin and certain catenins, such as alpha-catenin. Although there is much evidence that beta-catenin is deregulated in cancer as a result of inactivating mutations in the APC and AXIN tumor-suppressor proteins and gain-of-function mutations in beta-catenin itself, the principal consequences of beta-catenin deregulation in cancer appear to be largely distinct from the effects attributable to inactivation of E-cadherin or alpha-catenin. In this review, we highlight some of the specific genetic and epigenetic defects responsible for altered cadherin and catenin function in cancer, as well as potential contributions of cadherin-catenin alterations to the cancer process.     

Characterization of the E-cadherin/catenin complex in colorectal carcinoma cell lines

The E-cadherin/catenin complex is a prime mediator of cell-cell adhesion. APC mutations can result in loss of beta-catenin downregulation and an accumulation of beta-catenin in the cell. Beta-CATENIN mutations can have a similar effect. The aim of this study was to investigate the effect of beta-CATENIN and APC mutations on the expression and assembly of the E-cadherin/catenin complex. Five colorectal carcinoma cell lines with different APC and beta-CATENIN gene status were selected and mutations were confirmed. The expression of members of the E-cadherin/catenin complex was studied by immunohistochemistry and Western blotting. Complex assembly was investigated by immunoprecipitation. It is shown that E-cadherin and catenins are expressed in colorectal carcinoma cell lines with the predominant complex assembly being E-cadherin/beta-catenin/alpha-catenin. The subcellular distribution of the proteins is influenced by cell-cell contact, resulting in membranous localization. The expression and assembly of the E-cadherin/catenin complex does not appear to be affected by the presence of APC and or beta-CATENIN mutations.     

食管鳞癌catenin、E-cadherin和cyclinD1的表达及意义

目的：研究食管鳞状细胞癌中细胞周期素D1（cyclinD1)、钙粘附蛋白（E－cadherin,E-cad)、连接蛋白（cat)α，β，γ的表达及临床病理学意义。方法：采用免疫组织化学法检测62例食管癌手术标本的cyclinD1、E-cad、α-cat、β-cat、γ-cat蛋白表达，并结合临床随访资料进行分析。结果：cyclinD1、E-cad、α-cat、β-cat、γ-cat阳性病例分别为35例（56．5％）、39例（62．9％）、49例（79％）、59例（95．2％）和47例（75．8％）。其中α-cat与β-cat、E-cad蛋白表达呈正相关性，其相关系数分别为0．274和0．279（P＜0．05）。γ-cat蛋白缺失表达与淋巴结转移有显著相关性（P＜0．05）；E-cat、γ-cat蛋白缺失与保留表达和肿瘤分化程度、术后生存期长期，在统计学上有差异（P＜0．05）。结论：E-cat、γ-cat缺失表达是食管癌预后差的因素之一。     

HGF/SF modifies the interaction between its receptor c-Met, and the E-cadherin/catenin complex in prostate cancer cells

The effect of HGF/SF on the association between the E-cadherin/catenin complex and the tyrosine kinase receptor c-Met, was examined in prostate cancer cells LNCap FGC. Stimulation by HGF/SF showed E-cadherin and beta-catenin to be co-precipitated and located at areas of cell-cell contact with the HGF/SF receptor c-Met, as detected by immunoprecipitation and immunofluorescence respectively. Furthermore, continued exposure to this motogen increased the level of co-precipitations between the E-cadherin/catenin complex with c-Met, and also increased tyrosine phosphorylation of c-Met. In contrast, continued stimulation by HGF/SF decreased the level of co-localised peripheral staining and increased the level of cytoplasmic staining. In conclusion, the association between the E-cadherin/catenin complex with the HGF/SF receptor c-Met, may influence or regulate intercellular adhesion in prostate cancer following stimulation by HGF/SF.     

Immunocytochemical localization and expression of E-cadherin and {beta}catenin in the human corpus luteum

We have previously shown that the protein connexin-43 whichforms the connexons in gap junctions is present in the humancorpus luteum. Abundant expression of connexin-43 is seen inthe mid-luteal phase corpora lutea. Since the formation of gapjunctions in a tissue requires the presence of adherens junctionsformed by the cadherins, our aim in these studies was firstlyto localize immunocytochemically E-cadherin and ß-catenin(a cytoplasmic protein associated with E-cadherin) in the humancorpus luteum, and secondly to determine the concentrationsof these proteins in the early, mid- and late luteal phase humancorpora lutea. E-cadherin was localized to the periphery ofluteal cells and was not detected in non-luteal tissue. ß-cateninwas observed in the cytoplasm of the luteal cells. Abundantexpression of E-cadherin was observed by Western analysis inthe early luteal phase and the level of expression was significantlydifferent from that observed in the mid- and late luteal phasecorpora lutea. In contrast the concentrations of ß-cateninwere higher in the mid-luteal phase compared to the early lutealphase. The differential expression of the cell adhesion moleculeE-cadherin suggests that it may play a significant role in cell-to-cellcommunication in the corpus luteum, and in the cyclic developmentand demise of this tissue. ß-catenin/corpus luteum/E-cadherin/human/ovary     

Tspan8 is expressed in breast cancer and regulates E-cadherin/catenin signalling and metastasis accompanied by increased circulating extracellular vesicles

Tspan8 exhibits a functional role in many cancer types including pancreatic, colorectal, oesophagus carcinoma, and melanoma. We present a first study on the expression and function of Tspan8 in breast cancer. Tspan8 protein was present in the majority of human primary breast cancer lesions and metastases in the brain, bone, lung, and liver. In a syngeneic rat breast cancer model, Tspan8⁺ tumours formed multiple liver and spleen metastases, while Tspan8⁻ tumours exhibited a significantly diminished ability to metastasise, indicating a role of Tspan8 in metastases. Addressing the underlying molecular mechanisms, we discovered that Tspan8 can mediate up-regulation of E-cadherin and down-regulation of Twist, p120-catenin, and β-catenin target genes accompanied by the change of cell phenotype, resembling the mesenchymal–epithelial transition. Furthermore, Tspan8⁺ cells exhibited enhanced cell–cell adhesion, diminished motility, and decreased sensitivity to irradiation. As a regulator of the content and function of extracellular vesicles (EVs), Tspan8 mediated a several-fold increase in EV number in cell culture and the circulation of tumour-bearing animals. We observed increased protein levels of E-cadherin and p120-catenin in these EVs; furthermore, Tspan8 and p120-catenin were co-immunoprecipitated, indicating that they may interact with each other. Altogether, our findings show the presence of Tspan8 in breast cancer primary lesion and metastases and indicate its role as a regulator of cell behaviour and EV release in breast cancer. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Defective expression of FasL and Bax in human lung cancer

Abstract. The present studies investigated whether FasL and Bax genes are expressed in pleuro-pulmonary biopsies from patients with lung cancer. FasL, Bax, and TNF mRNAs were detected in 19 biopsies of primary or metastasic lung cancer by fluorescent in situ hybridization assays. Fluorescent probes were produced by polymerase chain reaction using a human spleen lambda gt11 library and specific primers for FasL, Bax, and TNF. Proteins were detected by immunohistochemistry using monoclonal anti- FasL, anti-Bax, and anti-TNF antibodies. Chromatin fragmentation was detected by TUNEL. Seven negative samples from subjects without lung pathology were obtained during legal autopsies and 12 positive control biopsies from patients with lung infections were also included. Sixty-eight percent of lung cancer biopsies exhibited FasL; Bax was expressed in 68% and TNF in 63%. FasL protein was detected in 21%, Bax protein in 26%, and TNF was present in 31% of cancer biopsies. A low degree of apoptosis in lung cancer was demonstrated by TUNEL assays. A defect in FasL, Bax, and TNF gene expression was found in lung cancer biopsies. Some tumors normally expressed the mRNA of FasL, Bax, or TNF, but their proteins were absent, or were non-functional, since TUNEL assays were negative. Such a failure would contribute to cancer cell survival and dissemination.     

Dynamic alteration of the E-cadherin/catenin complex during cell differentiation and invasion of undifferentiated-type gastric carcinomas

To examine qualitative alterations of the E-cadherin/catenin complex (CCC) during cell differentiation and invasion of undifferentiated-type gastric carcinoma, immunoreactivity for the intracytoplasmic domain and the extracellular domain (ECD) of E-cadherin, and that of beta-catenin, was analysed in the mucosal, submucosal, and deepest invasive parts of 20 early and 20 advanced cancers that had a component of intramucosal signet ring cell carcinoma. Histological subtype affected the mode of E-CCC alteration. The tumours with a tubular component and without organized differentiation of signet ring cells in a layered structure were associated with nuclear expression of beta-catenin and may derive from tubular adenocarcinomas through de-differentiation and de-regulation of the Wnt pathway. These tumours were characterized by relatively stable ECD expression throughout the course of tumour progression. On the other hand, the tumours with a layered structure, which may derive from signet ring cell carcinoma by de novo abnormality of E-cadherin, were characterized by dynamic alteration of ECD expression during cell differentiation and tumour progression; intramucosal spread (with a layered structure) as well as deep invasion (beyond the submucosa) commonly showed cellular dissociation with downregulation of ECD, whereas submucosal invasion and lymph node metastasis often showed cellular cohesion and retention (or 'reappearance') of ECD. Thus, cellular dissociation did not always reflect enhanced invasive activity but may be reversibly regulated during tumour progression.     

Abnormalities of the E-cadherin/catenin adhesion complex in classical papillary thyroid carcinoma and in its diffuse sclerosing variant.

The cadherin/catenin complex regulates cellular adhesion and motility and is believed to function as an invasion suppressor system. Several studies have identified alterations in the expression profiles of those molecules in different histotypes of thyroid carcinoma. The diffuse sclerosing variant (DSV) of papillary thyroid carcinoma (PTC) is a rare, highly invasive variant of PTC in which an impairment of cell-cell adhesion may play a major role. In an attempt to progress in the understanding of the clinicopathological features of DSV, this study examined eight cases of DSV, 18 cases of classical PTC and a control group of normal thyroid by immunohistochemistry (E-, P- and N-cadherins and beta-, gamma- and alpha-catenins). The E-cadherin gene was also studied by polymerase chain reaction/single strand conformation polymorphism (PCR/SSCP) and methylation-specific PCR (MSP). In contrast to classical PTC, which showed heterogeneous loss of E-cadherin expression, in almost every case of DSV a pronounced reduction was observed in its membranous expression, accompanied by a relocation to the cytoplasm. Inactivation of the E-cadherin/catenin complex appears to occur in DSV via two different pathways: E-cadherin alteration either through mutation (one out of the eight cases) or through methylation of the E-cadherin gene promoter (three out of five cases); and beta- and/or gamma-catenin alterations (three of the eight cases). Methylation of the E-cadherin gene promoter, abnormalities of E-cadherin expression and alterations of gamma-catenin were also detected in classical PTC. In DSV, as in classical PTC, there is neo-expression of P-cadherin in areas of squamous metaplasia and no N-cadherin expression. In conclusion, abnormalities of the E-cadherin/catenin complex appear to be more pronounced in DSV than in classical PTC. It remains to be shown whether or not such differences are associated with the more aggressive behaviour of DSV compared with classical PTC.     

Expression of the E-cadherin/catenin (alpha-, beta-, and gamma-) complex correlates with the macroscopic appearance of early gastric cancer

E-cadherin and its associated cytoplasmic proteins, alpha-, beta-, and gamma-catenins, play an essential role in the control of epithelial differentiation. We have previously shown that loss or down-regulation of E-cadherin/catenin correlates with poor survival in advanced gastric adenocarcinoma. The aim of this study was to assess the expression of E-cadherin and catenins in early gastric cancers (EGCs). Immunohistochemical staining for E-cadherin and alpha-, beta-, and gamma-catenins was performed on 41 paraffin-embedded gastrectomy specimens of EGC using an indirect immunoperoxidase technique. The pattern of expression and cellular localization of the E-cadherin/catenin complex in tumour cells were correlated with the macroscopic appearance of the tumour according to the Japanese Endoscopic Society classification. The tumours were classified as follows: three type I (protruding) and 38 type II (superficial), of which ten were type IIa (elevated), one was type IIb (flat), and 27 were type IIc (depressed). E-cadherin and alpha-, beta-, and gamma-catenins were expressed at the cell-cell junctions in normal mucosa. Forty out of 41 tumours showed abnormal expression (loss of membranous immunoreactivity and/or nuclear staining) of at least one component of the E-cadherin catenin complex. Loss of E-cadherin immunoreactivity was more frequently seen in type IIb (1/1, 100%) and type IIc (27/27, 100%) than in type I (1/3, 33%) and type IIa (1/10, 10%) (p<0.01). Abnormal expression of E-cadherin and alpha-catenin was more frequently seen in diffuse-type than in intestinal type tumours (p<0.05). Abnormal immunoreactivity of beta- and gamma-catenin, including nuclear localization, was observed in 34% and 7.3% of tumours, respectively, but there was no significant correlation with tumour type or endoscopic appearance. In conclusion, abnormal expression of the E-cadherin/catenin complex occurs in EGC and seems to correlate with macroscopic appearances.     

The spectrum of morphomolecular abnormalities of the E-cadherin/catenin complex in pleomorphic lobular carcinoma of the breast.

Pleomorphic lobular carcinoma of the breast is a high nuclear grade variant of lobular carcinoma. E-cadherin, a tumor-invasion suppressor gene, codes for a transmembrane protein that functions in intercellular adhesion. The E-cadherin protein internal domain binds with alpha, beta, gamma, and p120 catenins to anchor the E-cadherin complex to the actin cytoskeleton of the cell. The E-cadherin gene is routinely mutated in lobular neoplasia. This study examines the morphomolecular spectrum of the components of the E-cadherin-catenin complex in lobular neoplasia. Fifteen cases of pleomorphic lobular neoplasia, 8 cases of classic lobular neoplasia and 4 ductal carcinomas were studied. Normal breast epithelium and invasive ductal carcinomas all showed intense linear cell membrane immunostaining with antibodies to E-cadherin, alpha, beta, gamma, and P120 catenins. Membrane immunostaining of the catenin antibodies in lobular neoplasia was negative, except for rare cases that displayed beaded or dotlike patterns. Cytoplasmic immunostaining patterns for all lobular lesions included coarse paranuclear granules of beta catenin or diffuse intense cytoplasmic staining for P120 catenin. These immunostaining patterns demonstrate that catenins alpha, beta, gamma, and p120 are routinely dislocated from the cell membrane into the cytoplasm in lobular neoplasia and that the disrupted catenin patterns parallel absence of membrane E-cadherin in all cases. The diffuse cytoplasmic immunostaining of p120 in lobular neoplasia may be useful diagnostically as a positive marker for lobular neoplasia.     

Immunohistochemical evaluation of E-cadherin adhesion molecule expression in human gastric cancer

Summary E-cadherin (ECD) is one of subclasses of the cadherin family which plays a major role in the maintenance of intercellular adhesion in epithelial tissues. An immunohistochemical study of ECD expression was performed on gastric adenocarcinoma from 103 patients using our monoclonal antibody for human ECD (HECD-1). ECD was strongly expressed in normal gastric epithelium without exception; however, various staining patterns were observed in cancer tissues. The frequency of tumours with preserved ECD expression (Pre-type) and reduced ECD expression (Rd-type) was 42% and 58% respectively. Tumours with a high frequency of Rd-type expression particularly included: undifferentiated tumours (85%, 46/54), Borrmann's type 4 (90%, 9/10), tumours larger than 2.6 cm in diameter (65%, 53/81), tumours invading beyond the subserosa layer (78%, 46/59), and tumours with infiltrative growth (87%, 41/47). Furthermore, the frequency of Rd-type expression in cases with peritoneal dissemination (82%, 9/11) or lymph node metastasis (73%, 43/59) was significantly higher than that in cases without dissemination or metastasis. These results suggest that ECD might play a key role in the genesis of histological differentiation, and that the reduction of ECD expression may affect the mode of invasion and metastasis of human gastric cancer cells.     

Differential expression of E-cadherin and beta catenin in primary and metastatic Wilms's tumours.

BACKGROUND: The E-cadherin-catenin adhesion complex is crucial for intercellular adhesiveness and maintenance of tissue architecture. Its impairment is associated with poorly differentiated phenotype and increased invasiveness of carcinomas. AIMS: To evaluate E-cadherin, beta catenin, gamma catenin, and ezrin expression and its relation to histopathological features of primary and metastatic Wilms's tumours. METHODS: Immunohistochemistry was used to determine the expression and cellular distribution of E-cadherin, beta catenin, gamma catenin, and ezrin in primary and metastatic Wilms's tumours. Western blotting was used to determine polypeptide size and expression of E-cadherin and beta catenin in Wilms's tumours compared with normal kidney. RESULTS: Moderate expression of E-cadherin was found mainly in cytoplasm and occasionally cell membranes of dysplastic tubules, whereas low expression was seen in cytoplasm of blastemal cells. Primary and metastatic tumours showed moderate to high beta catenin expression in blastemal and epithelial cells, with predominantly membranous and cytoplasmic staining. Occasional nuclear staining was noted in metastatic tumours. Low to high gamma catenin and ezrin expression was seen in cytoplasm of blastemal and epithelial cells of primary and metastatic tumours. Higher amounts of 92 kDa beta catenin were detected in tumours than in normal kidney. Low expression of 120 kDa E-cadherin was seen in moderately differentiated tumours, whereas expression was lacking in poorly differentiated tumours. CONCLUSIONS: Compared with primary tumours, metastatic tumours showed lower expression of E-cadherin and gamma catenin, with nuclear staining for beta catenin. Low E-cadherin was associated with poorly differentiated tumours. These results suggest that abnormal expression of adhesion proteins correlates with the invasive and metastatic phenotype in Wilms's tumours.     

CDH1/E-cadherin germline mutations in early-onset gastric cancer

Background

Gastric cancer remains a leading cause of cancer deaths worldwide. Genetic factors, including germline mutations in E‐cadherin (CDH1, MIM#192090) in hereditary diffuse gastric cancer (HDGC, MIM#137215), are implicated in this disease. Family studies have reported CDH1 germline mutations in HDGC but the role of CDH1 germline mutations in the general population remains unclear.

Aims

To examine the frequency of CDH1 germline mutations in a population‐based series of early‐onset gastric cancer (EOGC <50 years old).

Methods

211 cases of EOGC were identified in Central‐East Ontario region from 1989 to 1993, with archival material and histological confirmation of non‐intestinal type gastric cancer available for 81 subjects. Eligible cases were analysed for CDH1 germline mutations by single‐strand conformation polymorphism, variants were sequenced, and tumours from cases with functional mutations were stained for E‐cadherin (HECD‐1) using immunohistochemistry.

Results

1155 (89%) of 1296 polymerase chain reactions amplified successfully. One new germline deletion (nt41delT) was identified in a 30‐year‐old patient with isolated cell gastric cancer. The overall frequency of germline CDH1 mutations was 1.3% (1/81) for EOGC and 2.8% (1/36) for early‐onset isolated cell gastric cancer.

Conclusion

This is the first population‐based study, in a low‐incidence region, of genetic predisposition to gastric cancer. Combined with our previous report of germline hMLH1 mutations in two other subjects from this series, it is suggested that 2–3% of EOCG cases in North Americans may be owing to high‐risk genetic mutations. These data should inform cancer geneticists on the utility of searching for specific genetic mutations in EOGC.Gastric cancer is the second most common cause of cancer deaths worldwide.¹ Despite an overall decline in the incidence of gastric cancer in older people, the incidence of early‐onset (⩽50 years old) gastric cancer (EOGC) and familial clustering of gastric cancer remains stable in frequency.² Genetic predisposition to gastric cancer caused by known genes such as CDH1 and the mismatch repair genes may have an important role in the development of gastric cancer in these cases.³ Autosomal dominant gastric cancer is estimated to account for about 1–3% of all cases.⁴ We have previously reported two new germline mutations (2 of 139 cases) in the hMLH1 gene in our population‐based series of EOGC.⁵In 1998, Guildford et al⁶ first described inactivating germline mutations in E‐cadherin (CDH1 gene) responsible for the development of diffuse‐type gastric cancer (DGC) in three families of Maori origin. Additional family studies have shown that E‐cadherin is responsible for some families presenting with DGC, according to the Lauren classification.⁷ In 1999, the International Gastric Cancer Linkage Consortium (IGCLC) provided the first clinical management guidelines for this autosomal dominant hereditary predisposition syndrome, hereditary diffuse gastric cancer (HDGC, MIM#137215), as defined by Guildford et al earlier that year.^8,9 HDGC is caused by germline inactivating mutations in E‐cadherin (CDH1, MIM# 192090). However, other genes are likely to cause HDGC, as only 30% of families with HDGC meeting the primary criteria for HDGC have been found to have CDH1 germline mutations. To date, 57 distinct functional CDH1 germline mutations have been reported. Of these, 50 are listed in the Human Gene Mutation Database (http://www.hgmd.cf.ac.uk/ac/gene.php?gene = CDH1), an additional five functional mutations were reported by Suriano et al,¹⁰ and a further two splice mutations associated with cleft lip/palate and HDGC were more recently reported by Frebourg et al.¹¹ Most of these mutations result in a truncated, non‐functional protein. Although primary criteria are fairly well established for screening of CDH1 germline mutations in kindreds with gastric cancer, the IGCLC recognise the need for large population‐based studies of genetic predisposition to gastric cancer to determine the role of germline mutations in sporadic EOGC. Here, we report the first population‐based study of EOGC to determine the frequency of CDH1 germline mutations in a population at a low risk for gastric cancer.

Keypoints

• This is the first and largest population‐based study of genetic predisposition to gastric cancer in a low‐incidence region reporting a new germline CDH1 mutation.
• 2–3% of cases of early‐onset gastric cancer (EOGC) in North America may be owing to high‐risk genetic mutations.
• Informs geneticists on the use of searching for genetic mutations in EOGC.