Figure 2.

Study workflow on an in vivo model system to validate liquid biopsy protocols. Three human colorectal cancer cell lines can be selected as proxies of clinical cancers and cultured in vitro (top left panel) or used to establish tumor xenografts (top right panel). DNA and RNA can be isolated from cells, supernatants and tumor xenografts. Circulating tumor DNA (ctDNA) and microRNAs (miRNAs) can be isolated from blood plasma and droplet digital PCR (ddPCR), reverse transcription (RT)-ddPCR and RT-quantitative PCR (qPCR) can be performed to detect KRAS mutations and miRNA analysis. Examples of published studies are reported within the boxes. Blue and orange arrows indicate positive events associated with miR-221 and mutG13D content.