Tissue microarray for biomarkers studies in salivary gland tumors: Tissue microarray and salivary gland tumors

Abstract

Tissue microarray (TMA) modern methodology was first described by Wan et al. in 1987, being further adapted by Kononen et al. in 1998 after which the technique became quickly and widely accepted and described in the scientific literature worldwide. Its development took place at a time which demanded maximum results in a minimum period of time that followed the onset of other important methodological approaches like cDNA microarray and proteomics. Hence, with this new technique intended to be used in association with paraffin-embedded neoplastic or nonneoplastic human tissues, the biomarkers recently described with the use of cDNA microarray and proteomics could be clinicopath-ologically validated on a large-scale basis. The main advantage of TMA methodology is related to its ability of aggregating hundreds of tumor samples from different cases in a single paraffin block. Despite its possible limitations with regard to tissue representation, numerous validation studies have demonstrated its statistical equivalence with conventional tissue sections, further supporting its use in the study of molecular biomarkers at a DNA, RNA, or protein level. Because of the scarce knowledge currently available regarding the molecular pathogenesis of salivary gland tumors, the use of a high-throughput technology like TMA in the investigation of such group of tumors becomes extremely interesting. As a consequence, we have witnessed an increase in the number of studies looking for new potentially useful biomarkers using TMA sections for better understanding of the etiopathogenesis of salivary gland tumors. In this chapter the authors aim to describe the laboratory and scientific advantages that TMA methodology has brought in recent decades, describing its most important characteristics and potential limitations, especially related to the study of biomarkers in the highly morphologically heterogeneous group of salivary gland tumors.