DNA sample quality and mutation status of study samples.

<p>A and B. Assessment of 200-bp (A) and 41-bp (B) amplifiable DNA in study samples. DNA samples isolated from cell line (control), FFPE reference standards and FFPE CRC tissues were evaluated. We included the control samples in every run to allow comparisons between runs. The amount of amplifiable DNA was compared to control by comparing the cycle thresholds (Ct) obtained from the quantitative PCR results. Error bars indicate the standard error of the mean. * = statistically significant t-test result (p< 0.01), NS = not statistically significant. Ref Std = FFPE reference standards, CRC = colorectal cancer tissue specimens, Ct = cycle threshold. C. Detection of <i>BRAF</i> mutation in poor-quality DNA obtained from FFPE CRC tissue (Sample 5 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198795#pone.0198795.t003" target="_blank">Table 3</a>). Genomic DNA sample from HEK-293 cells were used as negative control. D. <i>KRAS</i> and <i>BRAF</i> mutation status of 178 FFPE CRC tissues. The samples analyzed by methods other than cobas® KRAS Mutation Test, AmoyDx® <i>KRAS</i> Mutation Detection Kit and our AS-PCR assay were excluded from this study. mut^- = mutation not detected, mut⁺ = mutation detected, ND = not determined.