Correspondence to:
M C Boelens
Department of Pathology and Laboratory Medicine, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands;m.c.boelens{at}path.umcg.nl
Background: Changes in epithelial cell interactions have been implicated in carcinogenesis, tumour invasion and metastasis.
Aim: To screen for altered expression of epithelial adhesion genes in lung cancer development.
Methods: Gene expression profiles were assessed with cDNA expression arrays in eight non-small cell lung cancer (NSCLC) and eight normal bronchi obtained from the same patient. Immunohistochemistry (IHC) and RNA in situ hybridisation (ISH) were used to confirm the most prominently expressed adhesion molecules and to investigate their distribution at protein and mRNA levels.
Results: 43 differentially expressed cancer-related genes were identified in adenocarcinoma, squamous cell carcinoma (SCC) and normal bronchus. Five of these genes are related to epithelial adhesionthat is, integrin
3 (ITGA3), integrin ß4 (ITGB4), desmoplakin I and II (DSP), plakoglobin, and desmocollin 3 (DSC3). ITGA3 and ITGB4, showing predominantly cellmatrix staining, were up regulated in adenocarcinoma and SCC, respectively. ITGB4 also showed strong staining in SCC with IHC and ISH. Components of the desmosome adhesion complex DSP, plakoglobin and DSC3 were strongly up regulated in SCC and showed a distinct cellcell staining pattern. DSP and plakoglobin were predominantly present at central, more differentiated tumour cells, whereas DSC3 showed a stronger staining in the peripheral basal cells of SCC tumour areas.
Conclusions: Lack of cellular adhesion may have an important role in the metastatic potency of a primary tumour. A possible association of strong presence and normal-distributed desmosomal molecules in SCC with the less frequent and late pattern of metastasis in SCC as compared with adenocarcinoma is suggested.
Abbreviations: DSC3, desmocollin 3; DSP, desmoplakin I and II; IHC, immunohistochemistry; ISH, in situ hybridisation; ITGA3, integrin
3; ITGB4, integrin ß4; NSCLC, non-small cell lung cancer; PCR, polymerase chain reaction; SCC, squamous cell carcinoma
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