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.     

Comparison of integrin,cadherin, and catenin expression in squamous cell carcinomas of the oral cavity

In addition to their role in maintenance of tissue integrity, cell adhesion molecules regulate the growth and differentiation of stratified squamous epithelia. Reduced expression of E-cadherin and the α₂β₁, α₃β₁ and α₆β₄ integrins is already reported to correlate with poor histological differentiation in oral squamous cell carcinomas. However, it is not clear how closely cadherin and integrin loss are related in any given tumour, nor whether cadherin loss is correlated with changes in expression of the cytoplasmic regulatory proteins known as catenins. Double-label immunofluorescence has been used to stain a panel of 22 oral squamous cell carcinomas with antibodies to ten proteins, including E- and P-cadherin, the major keratinocyte integrin subunits, and α-, β- and γ-catenin. Overall, E-cadherin expression and integrin expression correlated well with tumour grade, while P-cadherin staining was more variable. All tumours, regardless of differentiation status, showed reduced staining for at least two of the catenins, implying that the adhesive function of E- and P-cadherin could be impaired even when cadherin expression is normal. It is concluded that in all squamous cell carcinomas, regardless of degree of histological differentiation, there is some perturbed expression of cell adhesion molecules and that integrin and E-cadherin loss are closely related. © 1998 John Wiley & Sons, Ltd.     

Expression of classic cadherins type I in urothelial neoplastic progression

Loss or reduced expression of E-cadherin has been shown to be associated with poor survival in patients with bladder cancer. In numerous cases, loss of E-cadherin expression in bladder tumors has been accompanied by continued association of catenins with the membrane, suggestive of the expression of an alternative cadherin member. In this study we examined 75 bladder tumors using immunohistochemistry for the expression of E-, P-cadherin, and alpha-, beta-, and gamma-catenins. As reported previously, loss or reduced E-cadherin expression is a frequent event in late stage bladder cancer, accompanied by less frequent alterations associated with different catenin family members. Analysis of 51 tumors for expression of E-, P-, and N-cadherin showed P-cadherin localized to the basal cell layers of normal urothelium, with retention of expression in the majority of tumors. In low-grade tumors P-cadherin was found localized to an expanded basal cell compartment, contrasting with the more extensive staining observed in late stage tumors. Membranous P-cadherin staining was often found in the absence of E-cadherin staining. N-cadherin is not expressed in normal bladder mucosa, but detection of this cadherin member was recorded in 39% (20/51) of bladder tumors. Unlike P-cadherin, membranous N-cadherin was detected in focal regions within tumors, representing novel expression in urothelial neoplastic progression. Although focal N-cadherin staining was observed in 3 noninvasive lesions, the majority of tumors expressing N-cadherin were invasive (17/20). Coexpression of E-, P-, and N-cadherin was recorded in 5 grade 2 bladder tumors. Expression of P-cadherin is maintained throughout bladder tumorigenesis, accompanied by aberrant expression of N-cadherin. Clearly, neither P- nor N-cadherin act in an invasive-suppressor mode in bladder cancer, but whether they have a primary role to play in urothelial neoplastic progression has yet to be established.     

E-cadherin loss rather than beta-catenin alterations is a common feature of poorly differentiated thyroid carcinomas

AIMS: To investigate the immunohistochemical and molecular genetic features of the cadherins/catenins complex in thyroid carcinoma based on the hypothesis that poorly differentiated carcinoma of the thyroid represents an intermediate step between well-differentiated and undifferentiated carcinomas. METHODS AND RESULTS: Immunohistochemistry for E-, P- and N-cadherins and alpha-, beta- and gamma-catenins was performed in a series of 17 cases of poorly differentiated carcinoma of the thyroid. All cases showed absence of membranous expression of E-cadherin with no aberrant expression of P- or N-cadherins; regarding catenins there was heterogeneous loss of expression with membranous immunolocalization of the three catenins in most cases. Molecular analysis of the E-cadherin gene and exon 3 of the beta-catenin gene was also performed by polymerase chain reaction/single-strand conformation polymorphism and sequencing. No mutations in either gene were detected in any case. CONCLUSIONS: In contrast to previous reports, our results suggest that loss of E-cadherin rather than beta-catenin mutation is the crucial event in determining the differentiation 'level' of thyroid carcinomas.     

Transient P-cadherin expression in radiation proctitis; a model of mucosal injury and repair

Morphology at both cellular and glandular levels in the colon is dependent to an extent on cell-cell adhesion mediated by cadherin-catenin complexes. Alterations in the expression of E-cadherin, the cadherin normally present in colon, have been shown to be implicated in tissue remodelling within the gastrointestinal tract. Furthermore, it has previously been shown that P-cadherin, normally present only in stratified epithelia and placenta, is expressed in colitis and during neoplastic change in the colon. The morphological features of mucosal injury induced by pre-operative radiotherapy in the non-neoplastic rectal mucosa were studied in patients with rectal adenocarcinoma. Three characteristic phases of radiation proctitis were defined on histological grounds (acute injury, and early and late regenerative phases) essentially correlating with the time interval between radiotherapy and surgery; such features were mirrored by alterations in cadherin-catenin expression and localization in rectal crypts. On immunohistochemistry and western blotting, P-cadherin was highly expressed in the acute injury and early regenerative phases, with a decreased level of expression during late regeneration. E-cadherin and associated catenins were translocated from membrane to cytoplasm in degenerating crypts, with return of normal membranous expression in regenerating crypts. In conclusion, radiation-induced proctitis represents an in vivo model of mucosal injury and regeneration and provides a valid model in which to study events during epithelial injury and repair. Altered cadherin expression, in particular transient aberrant P-cadherin expression, is intimately associated with these processes.     

Identification of immunohistochemical biomarkers for papillary thyroid carcinoma using gene expression profiling

We report the successful validation of a combined gene expression profiling and tissue microarray approach to papillary thyroid carcinoma (PTC) biomarker identification. Our ultimate goal is the identification of protein biomarkers that can be effectively used in immunocytochemical assays applied to thyroid fine needle aspiration biopsy (FNAB) samples. To that end, we designed our approach to prioritize molecules that were minimally expressed in normal thyroid and highly expressed in PTC. We first generated gene expression profiles from 11 normal thyroid tissue samples and 9 samples of classic PTC. The results were segregated to rank most highly those molecules not expressed in normal thyroid and up-regulated at least 6-fold in PTC. From this list, we chose 2 molecules (P-cadherin and Bax) for immunohistochemical analysis for which commercial antibodies were available. These were compared with 2 other molecules that have been previously studied in thyroid cancer (cytokeratin-19 and galectin-3). For immunohistochemistry, a tissue microarray was generated that contained the following tissues: classic PTC (n = 20), follicular variant of PTC (n = 9), normal thyroid (n = 19), Hashimoto thyroiditis (n = 11), follicular adenoma (n = 15), and follicular carcinoma (n = 14). Immunohistochemical staining was scored and compared with the gene expression profiling. As anticipated, cytokeratin-19 and galectin-3 were highly expressed in PTC and less expressed in other tissues. Bax and P-cadherin were also expressed in PTC, but to a lower level than cytokeratin-19 and galectin-3; however, Bax and P-cadherin demonstrated virtually no staining of normal thyroid, unlike cytokeratin-19 and galectin-3. These results validate our approach for PTC biomarker discovery and identify several candidate biomarkers for further development.     

Integrins,cadherins, and catenins: molecular cross-talk in cancer cells

In the past decade, there have been major advances in the understanding of some of the mechanisms underlying tumour differentiation, invasion, and metastasis, in which cell–cell and cell–matrix adhesion molecules play a critical role. Cadherin/catenin complex and the integrins are the prime mediators of cell adhesion in normal and transformed cells, cadherin/catenin being largely responsible for intercellular adhesion and integrins for cell–extracellular matrix interactions. Intercellular and cell–matrix adhesion mediated by cadherin/catenin and integrins is likely to play a role in the control of both structural morphology and functional differentiation; hence, any loss of this control mechanism may well facilitate the neoplastic process. Indeed, in cancer cells, there is a co-ordinated down-regulation of both integrins and cadherins which correlates with tumour dedifferentiation. However, the expression and cellular localization of catenins do not always correlate with cadherin expression, since the catenins are rather promiscuous molecules which interact not only with E-cadherin, but also with growth regulatory and signalling molecules such as epidermal growth factor receptor and the adenomatous polyposis coli gene product. © 1998 John Wiley & Sons, Ltd.     

P-cadherin expression is associated with high-grade ductal carcinoma in situ of the breast

Cadherins are calcium-dependent cell-cell adhesion glycoproteins, separated into several subclasses with distinct adhesive specificities and tissue distribution, which play an important role in many cellular events. We analyse the expression of E-, N- and P-cadherin in a series of ductal carcinoma in situ (DCIS) of the breast, since this disease represents a heterogeneous group, with different risks of progression to invasive breast carcinoma. We also studied the correlation between cadherin expression and DCIS classification systems, namely the Van Nuys and the Holland et al. classification, this latter based on cytonuclear differentiation and cell polarity. Our results showed that, regardless the classification applied, P-cadherin expression is strongly associated with high histological grade of DCIS (P=0.0047) and lack of estrogen receptors (P=0.0008). The use of Holland et al. classification showed a significant correlation between P-cadherin expression and decreased cell polarity (P=0.01). In conclusion, P-cadherin expression seems to be more relevant in DCIS pathogenesis than the altered expression of any other cadherin, including the decrease of E-cadherin expression.     

Alterations in cadherin and catenin expression during the biological progression of melanocytic tumours.

AIMS: Compelling evidence from cell culture studies implicates cadherins in the neoplastic progression of melanocytic tumours but few reports describe the expression of cadherins and the related transmembrane proteins, catenins, in a full range of benign and malignant excised melanocytic tumours. METHODS: Using immunohistochemistry and western blotting after tissue fractionation, the pattern of expression of cadherins/catenins was studied in a range of surgically excised melanocytic tumours, from dysplastic naevi to stage III cutaneous metastatic malignant melanoma. RESULTS: Appropriate membranous expression of E-cadherins and P-cadherins is seen in dysplastic naevocytes with an epithelioid phenotype and is largely maintained with malignant transformation to radial growth phase melanoma and primary vertical growth phase malignant melanoma. Loss of membranous E-cadherin is seen in a small number of vertical growth phase melanomas only when metastasis has occurred. However, there is a concomitant dramatic loss of membranous P-cadherin expression in all melanomas at the same stage. A minority of metastatic melanomas show de novo membranous N-cadherin expression in comparison with dysplastic naevi and primary melanoma. Membranous expression of the desmosomal cadherin, desmoglein, was not seen in any tumour studied. Frequently, beta catenin is aberrantly produced in the cytoplasm of cells in dysplastic naevi and metastatic malignant melanoma, with an implied compromise to adhesive function. Furthermore, membranous gamma catenin expression was not seen in any of the 70 melanocytic tumours studied, implying obligatory transmembrane binding of cadherins to beta catenin for maintenance of adhesive function. CONCLUSIONS: The most important alterations in membranous cadherin and catenin expression are seen late in the biological progression of melanocytic tumours at the stage of "in transit" or regional lymph node metastasis, with implications for tumour growth, invasion, and dissemination.     

Alterations in cadherin and catenin expression during the biological progression of melanocytic tumours.

AIMS: Compelling evidence from cell culture studies implicates cadherins in the neoplastic progression of melanocytic tumours but few reports describe the expression of cadherins and the related transmembrane proteins, catenins, in a full range of benign and malignant excised melanocytic tumours. METHODS: Using immunohistochemistry and western blotting after tissue fractionation, the pattern of expression of cadherins/catenins was studied in a range of surgically excised melanocytic tumours, from dysplastic naevi to stage III cutaneous metastatic malignant melanoma. RESULTS: Appropriate membranous expression of E-cadherins and P-cadherins is seen in dysplastic naevocytes with an epithelioid phenotype and is largely maintained with malignant transformation to radial growth phase melanoma and primary vertical growth phase malignant melanoma. Loss of membranous E-cadherin is seen in a small number of vertical growth phase melanomas only when metastasis has occurred. However, there is a concomitant dramatic loss of membranous P-cadherin expression in all melanomas at the same stage. A minority of metastatic melanomas show de novo membranous N-cadherin expression in comparison with dysplastic naevi and primary melanoma. Membranous expression of the desmosomal cadherin, desmoglein, was not seen in any tumour studied. Frequently, beta catenin is aberrantly produced in the cytoplasm of cells in dysplastic naevi and metastatic malignant melanoma, with an implied compromise to adhesive function. Furthermore, membranous gamma catenin expression was not seen in any of the 70 melanocytic tumours studied, implying obligatory transmembrane binding of cadherins to beta catenin for maintenance of adhesive function. CONCLUSIONS: The most important alterations in membranous cadherin and catenin expression are seen late in the biological progression of melanocytic tumours at the stage of "in transit" or regional lymph node metastasis, with implications for tumour growth, invasion, and dissemination.     

Beta- and gamma-catenin expression in thyroid carcinomas

Cadherins are calcium-dependent cell–cell adhesion molecules whose intracellular domain forms a complex with proteins required for their function, called catenins. Down-regulation of cadherins has frequently been detected in many types of human carcinomas, being associated with tumour progression. The present study investigates the immunohistochemical expression of E-cadherin and beta- and gamma-catenin in 27 human thyroid carcinomas. E-cadherin immunoreactivity was found to be decreased at cell–cell contacts in 8/15 (53 per cent) papillary, 5/7 (71 per cent) follicular, and 5/5 (100 per cent) anaplastic carcinomas. Beta-catenin membrane localization was found to be decreased in 6/15 (40 per cent) papillary, 2/7 (28 per cent) follicular, and 5/5 (100 per cent) anaplastic carcinomas. Gamma-catenin expression was partially or totally lost in 13/15 (86 per cent) papillary, 6/7 (85 per cent) follicular, and 5/5 (100 per cent) anaplastic carcinomas. A normal pattern of expression for these three molecules was observed in areas of normal tissue in each sample. These data indicate that in addition to E-cadherin, catenins are also down-regulated at cell–cell junctions in thyroid tumours and could represent potentially useful differentiation and/or transformation markers. The high frequency of alterations of gamma-catenin expression found in thyroid carcinomas suggests an important role for this gene product in thyroid carcinogenesis. © 1998 John Wiley & Sons, Ltd.     

P-cadherin expression in canine mammary tissues

P-cadherin is a classical cadherin expressed by myoepithelial cells in mammary tissue. Its expression in human breast cancer has been associated with aggressive tumour behaviour. To analyse the possible role of P-cadherin in canine mammary carcinogenesis, its expression was examined immunohistochemically in 82 samples of normal (n=2), hyperplastic (n=11) and neoplastic (n=69) canine mammary tissues. In normal and hyperplastic canine mammary glands, P-cadherin was restricted to myoepithelial cells, usually at sites of cell-to-cell contact. In tumour tissues, however, P-cadherin expression was observed in both epithelial and myoepithelial cells, with a cytoplasmic pattern of cellular distribution. Aberrant epithelial P-cadherin immunolabelling was found in 19/44 (43%) benign tumours and in 16/25 (64%) malignant tumours (P<0.001). In malignant tumours, a significant correlation between P-cadherin expression intensity and histological type was observed (P<0.05).     

Nuclear localization of E-cadherin expression in Merkel cell carcinoma

CONTEXT: Cadherins are cell-cell adhesion proteins that act as tumor suppressor genes and have a critical role in cell sorting and tissue formation during organogenesis. The pattern of cadherin expression constitutes a useful diagnostic and prognostic tool in the evaluation of tumors and for determining the histogenesis of tumor cells. We have previously characterized the cell types of several tumors based on the expression of individual cadherins. OBJECTIVE: To investigate the expression of cadherins in Merkel cell carcinomas. DESIGN: Paraffin immunohistochemical analysis of the 3 best-studied cadherins was performed on 35 cases of Merkel cell carcinoma. RESULTS: E-cadherin was expressed in 34 (97%) of 35 Merkel cell carcinomas examined, N-cadherin was expressed in 22 (63%) of 35 cases, and P-cadherin was expressed in 15 (43%) of 35 cases. This frequency of cadherin expression was similar to a group of small cell and neuroendocrine tumors from other primary sites. Interestingly, the localization of E-cadherin expression was unique in Merkel cell carcinomas compared with other primary neuroendocrine tumors. Merkel cell carcinomas showed marked preference for nuclear versus membrane localization, whereas small cell tumors from other sites showed fewer cases of nuclear E-cadherin expression. The nuclear localization of E-cadherin did not correlate with cadherin-associated protein beta-catenin nuclear expression. CONCLUSIONS: Our findings show that E-cadherin is the most frequently expressed cadherin in Merkel cell carcinoma, followed in frequency by N-cadherin then P-cadherin. The pattern of nuclear E-cadherin expression is more frequent for Merkel cell carcinoma than small cell tumors of other primary sites. These observations suggest that E-cadherin expression and function are altered in Merkel cell carcinoma, and this finding has potential use in the differential diagnosis of these tumors.     

活化白细胞黏附分子、E-钙黏蛋白和β-连环蛋白在甲状腺乳头状癌中的表达及意义

目的通过对甲状腺乳头状癌(PTC)、结节性甲状腺肿和癌旁正常组织中活化白细胞黏附分子(ALCAM)、E-钙黏蛋白(E-cadherin)和β-连环蛋白(β-catenin)蛋白表达水平的检测,分析三者在PTC发生、发展过程中的作用及三者之间的相关性,探讨ALCAM、E-cadherin和β-catenin在PTC中的作用机制。方法采用免疫组织化学法、Western blotting法检测ALCAM、E-cadherin和β-catenin在PTC中的表达并分析三者的变化与临床病理特征的关系。结果 PTC组织中ALCAM的阳性率明显高于结节性甲状腺肿和癌旁正常组织(P0.05);PTC组织中E-cadherin的阳性表达率明显低于结节性甲状腺肿和癌旁正常组织(P0.05);PTC样本中β-catenin的异位表达率明显高于结节性甲状腺肿和癌旁正常组织(P0.05)。三者的阳性率在结节性甲状腺肿和癌旁正常组织中无明显差异(P0.05)。三者的异常表达与PTC淋巴结转移有关(P0.05),与患者年龄、性别、肿瘤大小无关(P0.05)。结论在PTC组织中ALCAM、β-catenin高表达,E-cadherin呈现低表达,三者的异常表达与淋巴结转移相关。三者在PTC的发生、发展和转移的过程中起重要的作用。     

Simultaneous loss of E-cadherin and catenins in invasive lobular breast cancer and lobular carcinoma in situ

Loss of expression of the intercellular adhesion molecule E-cadherin frequently occurs in invasive lobular breast carcinomas as a result of mutational inactivation. Expression patterns of E-cadherin and the molecules comprising the cytoplasmic complex of adherens junctions, α-, β- and γ-catenin, were studied in a series of 38 lobular breast carcinomas with known E-cadherin mutation status. The effect of loss of E-cadherin by mutational inactivation (or other mechanisms) on the expression of catenins was investigated. Complete loss of plasma membrane-associated E-cadherin expression was observed in 32 out of 38 invasive lobular carcinomas, for which in 21 cases a mutation was found in the extracellular domain of E-cadherin. In total, 15 frameshift mutations of small deletions or insertions, ranging from 1 to 41 bp, three non-sense mutations, and three splice mutations were identified. Mutations were scattered over the whole coding region and no hot spots could be detected. In all cases, simultaneous loss of E-cadherin and α- and β-catenin expression was found; in 50 per cent of these cases, additional loss of γ-catenin was observed. In six invasive lobular carcinomas, expression of both E-cadherin and catenins was retained. In none of these carcinomas was an E-cadherin mutation detected. Lobular carcinoma in situ adjacent to invasive lobular carcinoma showed simultaneous loss of E-cadherin and catenins in all the cases studied—remarkably, also, in four cases positive for E-cadherin and catenin expression in the invasive component. These results indicate that simultaneous loss of E-cadherin and α-, β- and γ-catenin may be an important step in the formation of lobular carcinoma in situ, as a precursor of invasive lobular breast cancer. Events additional to E-cadherin inactivation must be involved in the transition of lobular carcinoma in situ to invasive lobular carcinoma. © 1997 John Wiley & Sons, Ltd.     

Expression of P-cadherin, but not E-cadherin or N-cadherin, relates to pathological and functional differentiation of breast carcinomas.

AIMS: To compare the expression of the cell adhesion molecules P-cadherin, N-cadherin, and E-cadherin in invasive and in situ breast carcinomas relative to clinicopathological features (size, node status, type, grade, and receptors) to determine whether expression patterns relate to specific tumour characteristics. METHODS: Using immunohistochemistry, 110 invasive and in situ breast carcinomas were examined for the presence, extent, and localisation of all three cadherins. Findings were related to tumour size, type, grade, node status, oestrogen (ER), progesterone, and epidermal growth factor receptor (EGFR) expression for invasive carcinomas and to grade and receptors for in situ carcinomas. RESULTS: P-cadherin was detected in 40% of invasive carcinomas, N-cadherin in 30%, and E-cadherin in 81%. For invasive carcinomas, the presence of P-cadherin significantly correlated with high grade, lack of ER and presence of EGFR, but not tumour size or node status. Carcinomas containing P-cadherin could be put into three categories dependent upon receptor and E-cadherin profile. There were no correlations between E/N-cadherin and size, grade, node status, or receptors. Three of 16 infiltrating lobular carcinomas expressed cytoplasmic but none membranous E-cadherin, and P-cadherin and N-cadherin were present in four carcinomas of this type. E-cadherin was found in all ductal carcinomas in situ, P-cadherin in a proportion of high grade tumours, and N-cadherin in a mixture of grades. CONCLUSION: P-cadherin but not E/N-cadherin expression in breast carcinomas shows a strong correlation with higher grade (poorer differentiation), lack of ERs, and presence of EGFR, and its expression may aid in the further subdivision of high grade carcinomas.