Tumor circulome in the liquid biopsies for digestive tract cancer diagnosis and prognosis

Figure 1 The liquid biopsy markers commonly used for cancer screening and surveillance. With the rapid development of molecular biological technology, the liquid biopsy markers, including circulating free DNA, circulating tumor DNA, circulating tumor cells, microRNAs and exosomes can be clinically employed to detect early tumor generation and metastasis. cfDNA: Circulating free DNA; ctDNA: Circulating tumor DNA; CTCs: Circulating tumor cells; miRNA: MicroRNAs; dPCR: Digital polymerase chain reaction; FCM: The fuzzy c-means; LT-PCR: Long template polymerase chain reaction; TEC-Seq: Targeted error correction sequencing.