Comparison of gene expression data obtained by Affymetrix GeneChip analysis and real time RT-PCR. Linear regression analysis for IRF7 comparing fold change values for individual subjects as measured by Affymetrix analysis and real time RT-PCR analysis. The imiquimod response fold change, which is the maximum response from week 1, week 2 and week 4 treatment times was used. Fold change was calculated relative to sun-unexposed, nonlesional skin samples for 13 subjects treated with imiquimod. The R square value for the comparison was 0.83.