Tissue microarrays : a cross-over validation tool for research

Background: Genomic, transcriptomic, proteomic have increased the importance of tissues in the discovery and validation of prognostic, diagnostic and therapeutic biomarkers. Human tissue has become a strategic and unavoidable tool for all –omics technologies including high-throughput in situ proteomics to study signal transduction and protein-protein interactions. Tissue microarray (TMA) systems allow the study of hundreds of samples (paraffin embedded tissues or cells) on a single slide for hystochemical analysis. The “Galileo CK4500” (www.isenet.it) is a high-throughput semiautomatic and computer-assisted TMA platform with the unique feature of picking cores of interest in a tissue or cell block and extract nucleic acids for subsequent molecular biology analysis. Methods: Harvested and agarose re-suspended Neural Stem Cells (NSCs) were fixed in PFA (4%) and treated like the human glioblastoma xenografts tissue donor block selected for the specific study. Cores of cells or tissues (previously selected) from the donor blocks were placed by the arrayer either in a second paraffin block or in appropriate vessels to be processed for nucleic acid extraction. Results: TMA and CLMA (Cell Line Microarray) technology were used to analyse glioblastoma xenografts and NSCs, to verify stemness and tripotency. From the cores DNA, RNA and microRNAs were successfully extracted. Conclusions: The Galileo CK4500 platform is a powerful pathology tool to simultaneously screen a huge number of tissues or cell lines treated in different conditions or with different phenotypes. This technique will be particularly useful to obtain immunophenotypical information and to perform epigenetic studies in specific selected areas of a biological sample.