Reactivity of integrin-linked kinase in human mesothelial cell proliferation.

Integrin-linked kinase (ILK) is a protein kinase that links integrins and growth factors to a range of signalling pathways. ILK expression and activity are increased in a variety of human cancers. However, little is known regarding the role of ILK in malignant pleural mesothelioma (MPM). In this study, we assessed the expression of ILK in samples of human MPM, and compared it with the expression of epidermal growth factor receptor (EGFR). Thirty-four samples of human malignant mesothelioma were stained with a polyclonal antibody against ILK. Two independent observers evaluated the morphological pattern and intensity of staining. The findings have been compared with the patient's characteristics. Most MPM and mesothelial cell proliferation samples (87.9%) showed cytoplasmic ILK staining of varying intensity. Normal mesothelial cells and normal lung parenchyma did not stain for ILK at all. Conversely, the percentage of positive EGFR staining was somewhat lower (75.8%). The ILK-positive patients were significantly older than the ILK-negative patients. Here we report for the first time that ILK is indeed expressed in malignant mesothelioma. For further validation of a causal association between ILK and neoplastic mesothelial transformation, these immunohistochemical results should be supplemented with clinical and molecular biological data.