Gene expression profiling of rheumatoid arthritis synovial tissues

Spots were selected that had an expression level higher than 1.6 the local background. The use of a common reference sample allows the comparison of the relative expression levels across the tissue samples. All genes were expressed relative to their median expression level across the arrays of the same microarray platform, allowing us to combine the data from the 2 platforms. Data from Lymphochip and Stanford Human cDNA arrays was combined per patient. Only genes with reliable datapoints in at least 80% of the samples were used. Subsequently, genes with the same unigene identifier were averaged in SMD. For all further analysis genes were selected that showed at least a two-fold difference in expression level in at least one array. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Keywords: disease_state_design Using regression correlation