"Clustering algorithms for microarray data: overview and comparative studies." Susmita Datta, Department of Mathematics and Statistics, Georgia State University Abstract Microarray chip has revolutionized the area of genomics. In the beginning, clustering was used to group genes according to the similarity of their expression profiles. Oftentimes, members in the same group had similar biological functions. The current emphasis of clustering seems to be in grouping tissue samples from the expression values. For example if microarray data are collected on different types of cancer cells then clustering those cells will provide information about the similarity of their gene expression profiles. This objective has the additional problem of dimensionality reduction of the underlying multivariate data. Given any of these clustering problems there are numerous clustering techniques to choose from. In this talk we will present an overview of some of these clustering algorithms. Their performances are examined on two well-known datasets for each of the two types of clustering problems. We introduce several validation measures to evaluate the performance of a clustering algorithm for a particular situation.