Microdissection, mRNA amplification and microarray: a study of pleural mesothelial and malignant mesothelioma cells

The studies of molecular alterations in tumor cells with microarrays are often hampered by inherent tissue heterogeneity. The emergence of Laser Capture Microdissection (LCM) allowed us to overcome this challenge since it gives selective access to cancer cells that are isolated from their native tissue environment. In this report, we microdissected mesothelial cells and malignant mesothelioma cells of ex vivo resected specimens using LCM. Amplified RNA from mesothelial and mesothelioma microdissected cells allowed us to measure global gene expression with 10 K-microarrays in four independent experiments. We screened 9850 annotated human genes, 1275 of which have satisfied our data analysis requirements. They included 302 overexpressed genes and 160 downregulated genes in mesothelioma microdissected cells as compared to mesothelial microdissected cells. Among them, the expression levels of eight genes, namely BF, FTL, IGFBP7, RARRES1, RARRES2, RBP1, SAT, and TXN according to HUGO nomenclature, were increased, whereas six: ALOX5AP, CLNS1A, EIF4A2, ELK3, REQ and SYPL, were found to be underexpressed in mesothelioma microdissected cells. The ferritin light polypeptide (FTL) gene overexpression was confirmed by real time quantitative PCR. Our approach allowed a comprehensive in situ examination of mesothelioma and provided an accurate way to find new marker genes that may be useful for diagnosis and treatment of malignant pleural mesothelioma.