Like the kind found in this example... "cnsexpressiondata"

At this URL - http://in.mathworks.com/help/bioinfo/examples/exploring-microarray-gene-expression-data.html

The file is found under - (I believe it is a demo file in the previous versions of matlab...)

Loading the Expression Data

Load the MAT file cnsexpressiondata containing three DataMatrix objects associated with the gene expression values preprocessed using RMA (expr_cns_rma), GCRMA with Maximum Likelihood Estimate (expr_cns_gcrma_mle), and GCRMA with Empirical-Bayes estimate (expr_cns_gcrma_eb).