Figure 2

The schematic representation of an Activating KRAS Detection Chip and the analytic results in the peripheral blood specimen. (A) The schematic representation of an Activating KRAS Detection Chip with 22 candidate genes, one positive control (β-actin), one negative control (Oryza sativa sequence), and the blank control (dd water). Oligonucleotide fragments are blotted on membranes in triplicate. The expression levels of each gene spot were quantified and then normalized based on reference gene (β-actin) density which the spots are within the red circle of each image. We defined an overexpressed gene spot when the normalized spot density was 2 or more. Each overexpressed spot was then multiplied by respective weighted values ranging from 1 to 4 based on the performance after KRAS activation to calculate the total score of the chip. When the total score was higher than cutoff value 20, the chip result were considered to be positive. (B) Detectable KRAS oncogene from circulating RNA in the peripheral blood. (C) Undetectable KRAS oncogene from circulating RNA in the peripheral blood.