A number of cellular processes are necessary for the growth and the spread of cancer. The great successes in fighting cancer that we’ve seen in the past decade are a direct result of our growing knowledge of these aberrant developments. New research pathways continue to reveal themselves and researchers from every major country are actively pursing these new avenues. Researchers from Austria have recently released the results of their work studying the relationship between integrin-linked kinase (ILK) expression and malignant pleural mesothelioma. ILK has been found to be significantly overexpressed in a number of other cancers, so its expression in pleural mesothelioma may give doctors another tool in the diagnosis of this difficult disease.

Introduction to the Study

Integrin-linked kinase (ILK) is an essential protein involved in multiple cellular processes, including cell migration, cell proliferation and cell-adhesion, as well as in signal transduction. Functionally, it links integrins and growth factors to a number of signaling pathways. Whereas properly regulated ILK is known to regulate tumor angiogenesis, dysregulated ILK has been implicated in tumor growth and seems to impair apoptosis among affected cells. ILK is overexpressed in a number of different cancers, including “prostate, colon, gastric and ovarian cancers, malignant melanomas and...non-small cell lung cancer.” Immunohistochemical analysis (IHC) can be used to identify its expression in these cancers.

To study what, if any, relationship ILK has with mesothelioma incidence, researchers from Austria analyzed 34 tissue samples taken from people who underwent surgery for pleural mesothelioma between 1999 and 2006. They analyzed this tissue for ILK expression, as well as for epidermal growth factor receptor (EGFR) expression. EGFR is the surface receptor for epidermal growth factor protein ligands and mutations of it are a known co-factor in the development of cancer.

The demographics of the sample population were as follows: mean age of 68.1 years, with a mostly male population (30 vs. 4 females). As would be expected, epitheloid mesothelioma was the most common histological subtype of the tissue samples (19), with sarcomatoid mesothelioma the least common (2).

Conclusion

Using immunohistochemical analysis, 29 of the mesothelioma tissue samples tested positive for ILK, which is a percentage of 87.9. In these tissues, the actual tumor area stained at more than 50% coverage, while normal mesothelial tissue, as well as normal lung parenchyma, did not show any ILK expression at all. At 75.8% of cases, EGFR expression was seen in a plurality of the tissue samples as well, but not to the extent that ILK was seen.

The researchers note their work is the first to establish a correlation between ILK expression and mesothelioma and they conclude that ILK is an important biomarker in the diagnosis of the disease. With a diagnostic potential approaching 90%, the authors state that not only is ILK effective in identifying mesothelioma as such, it’s useful to differentiate it from other malignancies, such as lung adenocarcinoma where ILK expression is seen in less than 30% of cases. The authors also state that other studies have noted that ILK inhibition has been associated with improved apoptosis and inhibition of metastasis, so the identification of ILK expression in malignant pleural mesothelioma may also provide a future avenue of treatment for this disease.

Labels: mesothelioma