I am doing Cross-platform normalization and network-based data analysis of gene expression data to find out potential biomarker of cancer .I have merged 3 datasets without any treatment ( two of Affymetrix Human Genome U133A Array and one with Affymetrix Human Genome U133A Array plus 2, platform GPL96 AND GPL570) using insilicomerging package. I have 229 cancer samples and 74 normal one with i.e a ratio of about 3:1. I want to do the linear model analysis to find out differentially expressed genes.

please someone help me