1. Introduction
The DNA microarray technology is emerging recently in the field of computational biology. This technology enables monitoring and measurement of expression levels for thousand of genes simultaneously through the hybridization process [1]. It is commonly used for comparing the gene expression levels in tissues under different conditions, such as wild-type versus mutant, or healthy versus diseased [2]. A typical DNA microarray study utilizes several DNA microarray chips on different tissue samples and generates a numerical array with thousands of rows (genes) and tens of columns (experiments/DNAchips) [4]. The gene expression indicates the approximate amount of protein contents in a given sample [1]. Microarray can be applied to a wide range of studies including gene regulation, disease diagnosis and prognosis, cancer classification, bio-marker discovery and drug development [5].