Correlations using amplified and total RNA isolated from U251 tumor. (A) Correlations between gene expression ratios for all genes using amplified RNA replicates 0.951 (n = 6,841 genes) and (B) total RNA replicates 0.919 (n = 6,981 genes). (D) and (E) represent scatter plots and correlations obtained for amplified 0.995 (n = 456 genes) and total replicates 0.995 (n = 274 genes), respectively, for outlier gene expression. (C) and (F) Representative correlation between total and amplified RNA from one sample 0.73 for all genes (n = 6,987 genes) and 0.945 for outliers (n = 203 genes). Extraction methods for all genes and outliers are found in the methods.