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Ann Thorac Surg 2002;73:933-937
© 2002 The Society of Thoracic Surgeons

Original article: general thoracic

Expression status of E-cadherin and {alpha}-, ß-, and {gamma}-catenins in thymoma

Ichiro Yoshino, MD*a, Shinichiro Kase, MDa, Tokujiro Yano, MDa, Kenji Sugio, MDa, Keizo Sugimachi, MD, FACSa

a Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

Accepted for publication October 20, 2001.

* Address reprint requests to Dr Yoshino, Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
e-mail: iyoshino{at}surg2.med.kyushu-u.ac.jp


   Abstract
Top
 Abstract
Introduction
 Patients and methods
 Results
 Comment
 Acknowledgments
 References
 
Background. A loss or dysfunction of E-cadherin or catenins, which maintain tissue integrity, is associated with an invasive phenotype of various solid tumors. Therefore, we analyzed the expression of E-cadherin and {alpha}-catenin, ß-catenin, and {gamma}-catenin in thymoma tissue specimens to investigate its clinical significance.

Methods. The expressions of E-cadherin and {alpha}-catenin, ß-catenin, and {gamma}-catenin in thymoma tissues were evaluated in 21 patients, including 9 epithelial predominant type, 5 lymphocytic predominant type, and 7 mixed type patients based on an immunohistochemical analysis using monoclonal antibodies, and the relationship between the expression status and clinicopathologic features was investigated.

Results. Reduced expressions were observed in 11 patients (52%) for E-cadherin, 10 (45%) for {alpha}-catenin, 6 (27%) for ß-catenin, and 10 (45%) for {gamma}-catenin. Such an expression status (reduced or preserved) of the molecules closely correlated with each other. The expression of E-cadherin was well preserved in 5 of 5 patients with lymphocyte predominant type whereas E-cadherin was reduced in 11 of 17 patients with other histologic subtypes. All of the 9 cortex type thymomas (B1 to 3) showed preserved expression of ß-catenin. There was no significant relationship among the expressions of the molecules and the Masaoka stage classification (I versus others).

Conclusions. The status of expressions for these molecules may affect the degree of lymphoid infiltration while not affecting the degree of invasiveness in thymoma.


   Introduction
Top
 Abstract
 Introduction
Patients and methods
 Results
 Comment
 Acknowledgments
 References
 
Thymoma is a highly curable disease by means of a complete resection in patients with noninvasive disease (Masaoka stage I) [1]. However, an incomplete resection or local recurrence is sometimes seen in an invasive type of the disease, which worsens the prognosis [2]. Because of the limited number of these patients, a molecular analysis for such a clinical aggressiveness has yet to be performed.

E-cadherin is the prime mediator of intercellular adhesion in epithelial cells [3, 4]. This transmembrane glycoprotein is mainly localized in adherent junctions and is mediated by extracellular domain cell-cell adhesion through calcium-dependent, homotypic interactions. Its carboxy cytoplasmic domain is associated with a group of undercoat proteins, termed catenins ({alpha}-catenin, ß-catenin, and {gamma}-catenin) [5, 6]. Both ß-catenin and {gamma}-catenin bind directly through Armadillo domains to the cytoplasmic domain of E-cadherin, and {alpha}-catenin links bound ß-catenin or {gamma}-catenin to the actin cytoskeleton and also regulate the adhesive function of E-cadherin [7]. ß-catenin demonstrates homology to human plakoglobin, a component of desmosomal plaque and adherence junctions [8].

A reduction of the E-cadherin and ß-catenin expressions plays an important role in both tumor progression and metastasis and has also been reported to be associated with a poor prognosis in malignancies of the esophagus [9], stomach [10], colon [11], liver [12], prostate [13], pancreas [14], and lung cancer [15]. Little has been reported so far regarding the immunohistochemical expression of these molecules in thymic tumors. We evaluated the expression of E-cadherin and {alpha}, ß-, and {gamma}-catenins in cases of clinical thymoma presenting with various histologic types.


   Patients and methods
Top
 Abstract
 Introduction
 Patients and methods
Results
 Comment
 Acknowledgments
 References
 
Patients and tissue specimens
Between 1990 and 1998, 21 Japanese patients with thymoma were referred to Kyushu University Hospital for operations. None of these patients underwent chemotherapy or radiotherapy before operations. A complete resection was done in all patients. The patients consisted of 9 men and 12 women, ranging in age from 40 to 82 years of age (mean, 54 years old). Histologically, 9 patients were epithelial predominant type, 4 were lymphocytic predominant type, and 6 were mixed type [16], and 7 were medullary type (type A), 5 mixed type (type AB), 4 predominantly cortical type (type B1), 3 cortical type (type B2), and 2 atypical type (B3) [17]. According to the Masaoka staging classification, 9 patients were stage I (no capsular invasion), 4 were stage II (capsular invasion), 5 were stage III (invasion to adjacent tissues), and 1 was stage IVa (pleural dissemination).

Immunohistochemistry
Surgically resected tumor specimens were fixed with 10% formalin embedded in paraffin and then 3-µm-thick sections were prepared. The sections were deparaffinized in xylene three times for 5 minutes each and then placed in a graded series of ethanol (100%, 90%, 80%, and 70%). To enhance antigen retrieval, the sections were pretreated in an autoclave at 120°C for 5 minutes in 0.01 mol/L citrate buffer pH 6.0 and then cooled to room temperature. Thereafter, to quench the endogenous peroxidase activity, the sections were processed using 0.5% H2O2 in methanol for 30 minutes and then rinsed in phosphate buffered saline (PBS) three times for 5 minutes each. The sections were incubated with 10% rabbit normal serum for 20 minutes at room temperature. After this blocking, sections were incubated overnight at 4°C with primary antibodies at a 1:200 dilution that consisted of mouse monoclonal antibody against human E-cadherin (C20820), and human {alpha}-catenin, ß-catenin, and {gamma}-catenin antibodies (C19220, C19221, and C19222, respectively) purchased from Transduction Laboratories (Lexington, KY). Next the sections were rinsed three times with PBS for 5 minutes and then sequentially incubated with biotinylated secondary antibodies for 15 minutes at room temperature, rinsed three times with PBS for 5 minutes, and streptavidin-biotin-peroxidase for 5 minutes at room temperature, and then rinsed three times with PBS for 5 minutes. The peroxidase reaction was visualized by making use of a solution containing 3,3-diaminobenzidine tetrahydrochloride supplemented with 0.2% hydrogen peroxidase in PBS. The sections were then lightly counterstained with hematoxylin. Paraffin-embedded tissue specimens from normal colon epithelium of the homogeneous immunophenotype for the studied antigens were included as positive controls. These colon epithelium tissue specimens were obtained from patients undergoing operations for colon cancer.

Immunohistochemical assessment
The staining was mainly localized on membranes of the tumor cells. The rate of staining of the tumor cells was estimated to be a percentage of more than 500 tumor cells in five fields that were selected at random (x400) and scored in one of the following categories: (1) A preserved expression of more than 50% of the tumor cells were stained, or (2) A reduced expression equal to or less than 50% of the tumor cells were stained.

The distribution of the ratio of stained cells showed bipolarity and we separated the patients into two groups according to the above criteria. Necrotic areas were not taken into consideration. Heterogeneous staining was classified as a reduced expression when less than 50% of the tumor cells were stained. All tumor slides were examined at random by two investigators who were unaware of the clinical data.

Statistical analysis
Correlations between each antigen expression and clinicopathologic factors were evaluated using Fischer’s exact test, or Spearman’s method. A p value of less than 0.05 was considered to demonstrate statistical significance.


   Results
Top
 Abstract
 Introduction
 Patients and methods
 Results
Comment
 Acknowledgments
 References
 
Expression of E-cadherin and {alpha}-catenin, ß-catenin, and {gamma}-catenin
The expression status of each molecule is summarized in Table 1. E-cadherin was mainly localized on the membranes of the tumor cells (Fig 1a), and equal to or less than 50% of the staining for E-cadherin was observed in 11 patients (52%), in which 2 patients exhibited a total loss of expression (Fig 2a). The expressions of {alpha}-catenin, ß-catenin, and {gamma}-catenins were also localized mainly on the membranes of the tumor cells (Fig 1b, 1c, 1d). A reduced expression was observed in 10 patients for {alpha}-catenin (45%), 6 for ß-catenin (27%), and 7 for {gamma}-catenin (45%) as shown in Figure 2b–2d. As summarized in Table 2, degree of expression was positively correlated among each of the molecules. Therefore, among 12 patients in which at least one molecule was reduced for expression, 11 patients showed that two or more molecules were reduced.


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  		Table 1. Profile of Expression of E-Cadherin, {alpha}-Catenins, ß-Catenins, {gamma}-Catenins in Thymoma

 


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  		Fig 1. Expression of E-cadherin and {alpha}-catenin, ß-catenin, {gamma}-catenin based on an immunohistochemical analysis. (a) The preserved expression of E-cadherin, (b) {alpha}-catenin, (c) ß-catenin, (d) and {gamma}-catenin in a lymphocytic predominant type case (each x400).

 


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  		Fig 2. Reduced expression of E-cadherin and {alpha}-catenin, ß-catenin, and {gamma}-catenin based on an immunohistochemical analysis. (a) A reduced expression of E-cadherin, (b) {alpha}-catenin, (c) ß-catenin, and (d) {gamma}-catenin in an epithelial predominant type case (each x400).

 

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  		Table 2. Relationship of Expression Level of E-Cadherin and {alpha}-Catenin, ß-Catenin, {gamma}-Catenin

 
Histologic subtypes, masaoka stage, and reduced expression of each molecule
A reduced expression of each molecule was frequently observed in epithelial predominant type and mixed type. However, all the molecules were expressed in tumor cells of 50% or more in lymphocytic predominant type (Table 3). Statistical significance was seen regarding the expression of E-cadherin, {alpha}-catenin, and {gamma}-catenin. As to cellular morphologic subtypes, all of nine B1 to 3 thymomas showed preserved expression of ß-catenin (Table 4), although they included no lymphocytic predominant type. Statistical significance was seen regarding the expression of E-cadherin, {alpha}-catenin, and {gamma}-catenin. To investigate the relationship between the invasiveness of thymoma and the expression of E-cadherin and {alpha}-catenin, ß-catenin, and {gamma}-catenin, Masaoka stage I and II–IVa were compared (Table 5). The expression status of whether it was preserved or decreased was not statistically different among the subgroups classified by the Masaoka stage.


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  		Table 3. Expression Status of E-Cadherin, {alpha}-Catenin, ß-Catenin, {gamma}-Catenin in Each Subtype of Thymoma

 

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  		Table 4. Expression Status of E-Cadherin, {alpha}-Catenin, ß-Catenin, {gamma}-Catenin in Each Morphological Subgroup

 

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  		Table 5. Expression Status of E-Cadherin, {alpha}-Catenin, ß-Catenin, {gamma}-Catenin in Each Stage

 

   Comment
Top
 Abstract
 Introduction
 Patients and methods
 Results
 Comment
Acknowledgments
 References
 
In this study, we immunohistochemically evaluated the expression of E-cadherin and the catenins of thymoma in formalin-fixed, paraffin-embedded tissue specimens, and we analyzed a relationship between the expression status and invasiveness, and between the expression status and the histologic subtype. In several types of solid malignancies, a reduced expression of E-cadherin or catenins is associated with invasiveness and metastasis, as well as with a poor prognosis [18–20]. In a similar analysis for nonsmall cell lung cancer, we recently reported that a reduced ß-catenin expression, but not E-cadherin, significantly correlated with a poor prognosis [21]. Patients in which both were reduced showed a significantly unfavorable prognosis compared with those in which either of the molecules was reduced. However, in the present study for thymoma there was no positive relationship regarding the Masaoka stage classification, which is well known to accurately reflect prognosis [22]. The adhesion of lymphocytes and epithelial cells has recently been shown to be mediated by E-cadherin of epithelial cells and alpha E beta 7 integrin of lymphocytes [23]. Using the clinically obtained intestinal mucosa, Cepek and colleagues [24] found infiltrating lymphocytes to express alpha E beta 7 integrin and adhere to epithelial cells through their E-cadherin. Kroneld and colleagues [25] also demonstrated the expression of alpha E beta 7 on lymphocytes infiltrating the salivary gland of patients with Sjogren’s syndrome, and as a result, the expression of E-cadherin was found to be associated epithelial cells. Our data presented in this study can be explained by such a mechanism. The histologic subtypes classified according to the degree of lymphoid infiltration has been reported to affect postoperative prognosis; 5-year and 10-year survival rates were 96.3% and 87.9%, respectively, in lymphocyte predominant type, 89.5% and 86.3%, respectively, in mixed type, and 76.3% and 65.5%, respectively, in epithelial predominant type [26]. The expression of E-cadherin on tumor cells may induce lymphoid reaction that exerts anti-tumor effect as mentioned before in other tumors [27–29].

In all the molecules examined, statistical significance between type A/AB and type B1 to 3 (World Health Organization classification) was only observed in the expression of ß-catenin (Table 4). Preserved expression of ß-catenin was associated with such relatively aggressive thymomas (B1 to 3). It could not be explained that the preserved expression of ß-catenin was associated with relatively aggressive tumor (B1 to 3). It was reported that the APC3 tumor suppresser gene product forms a complex ß-catenin [30, 31]. As a consequence, mutation in either APC or ß-catenin leads to the accumulation of cytoplasmicß-catenin, which binds to T-cell factor (Tcf) and lymphoid enhancer factor (Lef) transcription factors [32, 33]. Mutation of ß-catenin would be further examined for thymomas.

In conclusion, the reduced expression of a cadherin-catenin complex is therefore considered to be associated with histologic subtype, especially with lymphoid infiltration, but not with invasiveness.


   Acknowledgments
Top
 Abstract
 Introduction
 Patients and methods
 Results
 Comment
 Acknowledgments
References
 
This work was supported in part by a Grant-in-Aid for cancer research from the Ministry of Education, Science, Sports and Culture, Tokyo, Japan.


   References
Top
 Abstract
 Introduction
 Patients and methods
 Results
 Comment
 Acknowledgments
 References
 

  1. Lewis J.E., Wick M.R., Scheithauer B.W., Bernatz P.E., Taylor W.F. Thymoma: a clinicopathologic review. Cancer 1987;60:2727-2743.[Medline]
  2. Hejna M., Haberl I., Raderer M. Nonsurgical management of malignant thymoma. Cancer 1999;85:1871-1884.[Medline]
  3. Takeichi M. Cadherin cell adhesion receptors as a morphogenetic regulator. Science 1991;251:1451-1455.[Abstract/Free Full Text]
  4. Ozawa M., Baribault H., Kemler R. The cytoplasmic domain of the cell adhesion molecule uvomorulin associates with three independent proteins structurally related in different species. EMBO J 1989;8:1711-1717.[Medline]
  5. Butz S., Stappert J., Weissig H., Kemler R. Plakoglobin and beta-catenin: distinct but closely related. Science 1992;257:1142-1144.[Free Full Text]
  6. Cowin P., Kapprell H.P., Franke W.W., Tamkun J., Hynes R.O. Plakoglobin: a protein common to different kinds of intercellular adhering junctions. Cell 1986;46:1063-1073.[Medline]
  7. McCrea P.D., Turck C.W., Gumbiner B. A homolog of the armadillo protein in D rosophila (plakoglobin) associated with E-cadherin. Science 1991;254:1359-1361.[Abstract/Free Full Text]
  8. Butz S., Stappert J., Weissig H., Kemler R. Plakoglobin and beta-catenin: distinct but closely related. Science 1992;257:1142-1144.
  9. Kadowaki T., Shiozaki H., Inoue M., et al. E-cadherin and alpha-catenin expression in human esophageal cancer. Cancer Res 1994;54:291-296.[Abstract/Free Full Text]
  10. Matsuura K., Kawanishi J., Fujii S., et al. Altered expression of E-cadherin in gastric cancer tissues and carcinomatous fluid. Br J Cancer 1992;66:1122-1130.[Medline]
  11. Hiscox S., Jiang W.G. Expression of E-cadherin, alpha, beta, and gamma-catenin in human colorectal cancer. Anticancer Res 1997;17:1349-1354.[Medline]
  12. Ihara A., Koizumi H., Hashizume R., Uchikoshi T. Expression of epithelial cadherin and alpha- and beta-catenins in nontumoral livers and hepatocellular carcinomas. Hepatology 1996;23:1441-1447.[Medline]
  13. Cheng L, Nagabhushan M, Pretlow TP, Amini S, Pretlow TG. Expression of E-cadherin in primary and metastatic prostate cancer. Am J Pathol 11996;48:1375–80.
  14. Gunji N., Oda T., Todoroki T., et al. Pancreatic carcinoma: correlation between E-cadherin and alpha-catenin expression status and liver metastasis. Cancer 1998;82:1649-1656.[Medline]
  15. Retera J.M., Leers M.P., Sulzer M.A., Theunissen P.H. The expression of beta-catenin in non-small-cell lung cancer: a clinicopathological study. J Clin Pathol 1998;51:891-894.[Abstract]
  16. Rosai J., Levine G.D. Tumors of the thymus. Atlas of tumor pathology. Washington D.C: Armed Forces Institute of Pathology, 1976:55-99.
  17. Fritz A., Percy C., Implementing ICD—3: Impact of the new edition. training.seer.cancer.gov/moduleicdo3/downloadables/ICDO3%20abstract%20n%20article%20NEW%20PDF.pdf.
  18. Umbas R., Isaacs W.B., Bringuier P.P., et al. Decreased E-cadherin expression is associated with poor prognosis in patients with prostate cancer. Cancer Res 1994;54:3929-3933.[Abstract/Free Full Text]
  19. Jawhari A., Jordan S., Poole S., Browne P., Pignatelli M., Farthing M.J. Abnormal immunoreactivity of the E-cadherin-catenin complex in gastric carcinoma: relationship with patient survival. Gastroenterology 1997;112:46-54.[Medline]
  20. Shimazu T., Schalken J.A., Giroldi L.A., et al. Prognostic value of cadherin-associated molecules (alpha-, beta-, and gamma-catenins and p120cas) in bladder tumors. Cancer Res 1996;56:4154-4158.[Abstract/Free Full Text]
  21. Kase S., Sugio K., Yamazaki K., Okamoto T., Yano T., Sugimachi K. Expression of E-cadherin and ß-catenin in Human Non-Small Cell Lung Cancer and the Clinical Significance. Clin Cancer Res 2000;6:4789-4796.[Abstract/Free Full Text]
  22. Masaoka A., Monden Y., Nakahara K., Tanioka T. A follow-up study of thymomas with special reference to their clinical stage. Cancer 1981;48:2485-2492.[Medline]
  23. Higgins J.M., Mandelebrot D.A., Shaw S., et al. Direct and regulated interaction of integrin alphaEbeta 7 with E-cadherin. J Cell Biol 1998;140:197-210.[Abstract/Free Full Text]
  24. Cepek K.L., Shaw S.K., Parker C.M., et al. Adhesion between epithelial cells and T lymphocytes mediated by E-cadherin and the alpha E beta 7 antigen. Nature 1994;372:190-193.[Medline]
  25. Kroneld U., Jonsson R., Carlsten H., Bremell T., Johnnessen A.C., Tarkowski A. Expression of the mucosal lymphocyte integrin alphaEbeta7 with Sjogren’s syndrome. Scand J Rheumatol 1998;l27:215-218.[Medline]
  26. Nakahara K., Ohno K., Hashimoto J., et al. Thymoma: results with complete resection and adjuvant postoperative irradiation in 141 consecutive patients. J Thorac Cardiovasc Surg 1988;95:1041-1047.[Abstract]
  27. Underwood J.C.W.E. Lymphoreticular infiltration in human tumors: prognostic and biological implications: a review. Br J Cancer 1974;30:538-548.[Medline]
  28. Conder I., Aderne W. The significance of lymphocytic infiltration in neuroblastoma. Br J Cancer 1972;26:321-327.[Medline]
  29. Shimokawara I., Imamura M., Yamanaka N., Ishii Y., Kikuchi K. Identification of lymphocytic subpopulation in human breast cancer tissue and its significance: an immunoperoxidase study with anti-human T- and B-cell sera. Cancer 1982;49:1456-1464.[Medline]
  30. Rubinfeld B., Souza B., Albert I., et al. Association of the APC gene product with beta-catenin. Science 1993;262:1731-1734.[Abstract/Free Full Text]
  31. Su L.K., Vogelstein B., Kinzler K.W. Association of the APC tumor suppressor protein with catenins. Science 1993;262:1734-1736.[Abstract/Free Full Text]
  32. Morin P.J., Sparks A.B., Korinek V., et al. Activation of beta-catenin-Tcf signaling in colon cancer by mutations in beta-catenin or APC. Science 1997;275:1787-1790.[Abstract/Free Full Text]
  33. Rubinfeld B., Robbins P., El-Gamil M., Albert I., Porfiri E., Polakis P. Stabilization of beta-catenin by genetic defects in melanoma cell lines. Science 1997;275:1790-1792.[Abstract/Free Full Text]




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