Association Between Clinicopathological Factors and Genomic Abnormalities Detected by FISH Analysis in Epithelioid Diffuse Malignant Pleural Mesothelioma

Background. Abnormality of genes including 9p21 is known in malignant mesothelioma and we have examined the frequency of gene deletion and amplification using the fluorescence in situ hybridization (FISH) method. We formerly reported that abnormality of the genes was more common in the sarcomatoid type than epithelioid type. In this study, we compared the clinicopathological factors including nuclear grade (NG) and genomic abnormality in epithelioid malignant pleural mesothelioma (MPM). Methods. Using paraffin-embedded tissues of 31 epithelioid MPMs, we investigated the presence of gene abnormalities in the genes 9p21, 1p36, 14q32, 22q12, 5p15, 6p, 8q24, and 7p12 by the FISH method, and compared the results with NG, clinical stage, and prognosis. Results. In the higher NG group of epithelioid MPM, more gene amplifications [in particular 5p15 and 8q24(MYC)] were observed, and clinical stage was more advanced. Cases with the amplification of 7p12(EGFR) tended to exhibit a worse prognosis. The significant correlation between histological differentiation and clinical features such as prognosis was not confirmed. Conclusions. NG status in epithelioid MPM may be related to gene alteration and clinical features.