Monoclonal antibody anti-N-cadherin (clone 13A9) and anti-E-cadherin (clone E9) (Soler et al, 1995). Accurate (6F9), American Research Products (6F9), Calbiochem (HybEcad#1), Coulter (67A4), Eurodiagnostica/Accurate (5H9), Immunotech (67A4), Lab Vision Corp (HybEcad#1), Sanbio/Monosan/Accurate (5H9), Urodiagnostica/Accurate (5H9) and Zymed (HECD1, ECCD1, ECCD2, SHE78-7).

Applied primarily to frozen sections, both antibodies are now applicable to formalin-fixed, paraffin-embedded tissue with heat pretreatment in citrate buffer.

It has long been recognized that cancer cells have differences in their adhesive properties when compared with non-transformed cells (Hedrick et al, 1993). There is evidence that among the different cell adhesion molecules, the cadherin family of calcium-dependent cell-cell adhesion molecules and their associated proteins are indeed tumor suppressors. The cadherin family includes several distinctive members, two of which include E(epithelial)-cadherin (Gumbiner and Simons, 1986), a 120 kD protein expressed in epithelial cells and concentrated in cell-cell adherens junctions, and N (nerve)-cadherin (Redies et al, 1993), a 135 kD protein expressed in nerve cells, developing skeletal muscle (Knudsen et al, 1990), embryonic and mature cardiac muscle cells (Soler & Knudsen, 1994) and pleural mesothelial cells (Hatta et al, 1987). During embryonic development, expression of distinctive members of the cadherin family determines the aggregation of cells into specialized tissues as they interact with identical cadherins within the same tissue. Hence, the mesoderm-derived mesothelial cells that form the pleura express N-cadherin, whilst epithelial cells of the lung express E-cadherin (Hatta et al, 1987). Therefore, the development of well-characterized monoclonal antibodies that recognize N-cadherin without crossreactivity with E-cadherin provided an opportunity for its application to immunohistology.

In 1995, Soler et al found a high level of expression of N-cadherin in all mesotheliomas and E-cadherin in all pulmonary adenocarcinomas on fresh-frozen sections. The same group of investigators recently confirmed these findings using antibodies to N-cadherin and E-cadherin that reacted with fixation and paraffin-embedding-resistant epitopes in a series of malignant mesotheliomas and adenocarcinomas (Han et al, 1997). Although one case of mesothelioma was negative for N-cadherin and one adenocarcinoma was weakly positive for N-cadherin (but strongly positive for E-cadherin), these antibodies appeared to offer a sufficient degree of sensitivity and specificity for use in the differential diagnosis of mesothelioma and adenocarcinoma.
The application of antibodies to N- and E-cadherin to ovarian epithelial tumors has revealed interesting findings (Soler et al, 1997). Both E- and N-cadherins were expressed in serous and endometrioid tumors, whilst mucinous tumors strongly expressed E-cadherin only. The expression of N-cadherin in serous and endometrioid tumors traces their origin to the mesoderm-derived ovarian surface epithelium. Another recent study (Dara et al, 1997) demonstrated both E- and N-cadherins in benign but not malignant ovarian tumors, whilst only N-cadherin was present in borderline tumors. Further, negative E-cadherin ovarian carcinomas presented a shorter survival. These workers suggest that the E- and N-cadherin differential expression may be involved in ovarian carcino-genesis and may have diagnostic and prognostic value.
Reduction in E-cadherin expression has been associated with lack of cohesiveness, high malignant potential and invasiveness in epithelial neoplasms of the colon (Kinsella et al, 1993), ovary (Hashimoto et al, 1989), stomach (Matsuura et al, 1992), pancreas (Moller et al, 1992), lung (Williams et al, 1993), breast (Gamallo et al, 1993; Sormunen et al, 1998) and head/neck (Schipper et al, 1991). In contrast, N-cadherin has also been demonstrated in astrocytomas/glioblastomas (Shinoura et al, 1995) and rhabdomyosarcomas (Soler et al, 1993).

Confirmation of data reported by Han et al (1997) and availability of anticadherin antibodies, represent a breakthrough in the study and diagnosis of malignant mesothelioma. Malignant mesothelioma and pulmonary adenocarcinoma tissue are recommended for use as positive controls for N- and E-cadherin respectively. We have found trypsin predigestion followed by HIER to produce the greatest immunoreactivity for these antigens, particularly E-cadherin.

•Dara E, Scoazec Y-Y, Walker-Combrouze F et al 1997. Expression of cadherins in benign, borderline, and malignant ovarian epithelial tumors: a clinicopathologic study of 60 cases. Human Pathology 28: 922-928.

•Gamallo C, Palacios J, Suarez A et al 1993. Correlation of E-cadherin expression with differentiation grade and histological type in breast carcinoma. American Journal of Pathology 142: 987-993.

•Gumbiner B, Simons K 1986. A functional assay for proteins involved in establishing an epithelial occluding barrier: identification of a uyomorulin-like peptide. Journal of Cell Biology 102: 457-468.

•Han AC, Soler AP, Knudsen KA et al 1997. Differential expression of N-cadherin in pleural mesotheliomas and E-cadherin in lung adenocarcinomas in formalin-fixed, paraffin-embedded tissues. Human Pathology 28: 641-645.

•Hashimoto M, Niwa O, Nitta Y, et al 1989. Unstable expression of E-cadherin adhesion molecules in metastatic ovarian tumor cells. Japanese Journal of Cancer Research 80: 459-463.

•Hatta K, Takgari S, Fujisawa H et al 1987. Spatial and temporal expression pattern of N-cadherin cell adhesion molecules correlated with morphogenetic processes of chicken embryos. Developmental Biology 120: 215-227.

•Hedrick L, Cho KR, Vogelstein B 1993. Cell adhesion molecules as tumor suppressors. Trends in Cell Biology 3: 36-39.

•Kinsella AR, Green B, Lepts GC et al 1993. The role of the cell-cell adhesion molecule E-cadherin in large bowel tumor cell invasion and metastasis. British Journal of Cancer 67: 904-909.

•Knudsen KA, Myers L, McElwee SA 1990. A role for the Ca2+- dependent adhesion molecule, N-cadherin in myoblast interaction during myogenesis. Experimental Cell Research 188: 175-184.

•Matsuura K, Kawanishi J, Jujii S et al 1992. Altered expression of E-cadherin in gastric cancer tissues and carcinomatous fluid. British Journal of Cancer 66: 1122-1130.

•Moller CJ, Christgau S, Williamson MR et al 1992. Differential expression of neural cell adhesion molecules and cadherins in pancreatic islets, glucagonomas, and insulinomas. Molecular Endocrinology. 6: 1332-1342.

•Redies C, Engelhardt K, Takeichi M 1993. Differential expression of N-and R-cadherin in functional neuronal systems and other structures of the developing chicken brain. Journal of Comparative Neurology 333: 398-416.

•Schipper JH, Frixen UH, Behrens J et al 1991. E-cadherin expression in squamous cell carcinoma of head and neck: inverse correlation with differentiation and lymph node metastasis. Cancer Research 51: 6328-6337.

•Shinoura N, Paradies NE, Warnick RE, et al 1995. Expression of N-cadherin anda-catenin in astrocytomas and glioblastomas. British Journal of Cancer 72: 627-633.

•Soler AP, Knudsen KA 1994. N-cadherin involvement in cardiac myocyte interaction and myofibrillogenesis. Developmental Biology 162:9-17.

•Soler AP, Johnson KR, Wheelock MJ et al 1993. Rhabdomyosarcoma-derived cell lines exhibit aberrant expression of the cell-cell adhesion molecules N-CAM, N-cadherin, and cadherin-associated proteins. Experimental Cell Research 208: 84-93.

•Soler AP, Knudsen A, Jaurand M-C, et al 1995. The differential expression of N-cadherin and E-cadherin distinguishes pleural mesotheliomas from lung adenocarcinomas. Human Pathology 26: 1363-1369.

•Soler AP, Knudsen KA, Tecson-Miguel A 1997. Expression of E-cadherin and N-cadherin in surface epithelial-stromal tumors of the ovary distinguishes mucinous from serous and endometrioid tumors. Human Pathology 28:734-739.

•Sormunen RT, Leong AS-Y, Varaaniemi JP, et al. Fodrin, E-cadherin andb-catenin immunolocalization in infiltrating ductal carcinoma of the breast correlated with selected prognostic indices. Journal of Pathology (submitted).

•Williams CL, Hayes VY, Hummel AM et al 1993. Regulation of E-cadherin-mediated adhesion by muscarinic acetylcholine receptors in small cell lung carcinoma. Journal of Cell Biology 121: 643-654.

Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.