Abstract
Single gene analysis looks to a single gene at a time and its relation to a specific phenotype such as cancer development. However, pathway analysis simplifies the analysis by focusing on group of genes at a time that involve in the same biological process. Pathway analysis has useful applications such as discovering diseases, diseases prevention and drug development. Different data mining approaches can be applied in pathway analysis. In this paper, we overview different pathway analysis techniques in analyzing gene expression and propose a classification for them. Pathway analysis can be classified into: detecting significant pathways and discovering new pathways. In addition, we summarize different data mining techniques that are used in pathway analysis.