Establishment of three novel human malignant pleural mesothelioma cell lines: morphological and cytogenetical studies and EGFR mutation status.

UNLABELLED: The incidence of mesothelioma is estimated to rise sharply worldwide, including Japan, in the next two decades. Molecular and proteomic studies are urgently required to elucidate the pathobiology of malignant mesothelioma. This paper describes the characterization of novel human malignant pleural mesothelioma cell lines representing the sarcomatoid, epithelioid and biphasic subtypes.
MATERIALS AND METHODS: Established pleural effusion fluid cell lines were observed using phase-contrast microscopy and transmission electron microscopy. The immunoreactivity of the cells was evaluated using immunohistochemistiy, FACS analysis and Western blotting. The expression of SV40 large cell antigen and the EGFR mutation status were also analyzed.
RESULTS: The cell lines had different morphological and immunophenotypic characteristics. All cell lines showed immunophenotypic marker expression of vimentin, mesothelin and N-cadherin, but no expression of CEA or E-cadherin. At the electron microscopic level, a cell surface rich in microvilli confirmed mesothelial origin of the cell lines. Karyotype analyses showed complex abnormalities in all cell lines. Neither EGFR mutations relevant to tyrosine kinase inhibitor responsiveness nor the expression of SV40 large cell antigen was detected in any of the cell lines.
CONCLUSION: FACS analysis is more sensitive for evaluating mesothelin expression than immunohistochemistry of cut specimens. Irrespective of the expression of EGFR on FACS analysis, no EGFR mutation was detected. These three cell lines may be useful for studying cellular, molecular and genetic aspects of mesothelioma.