m5c RNA-seq
Circulating free DNA (cfDNA), a degraded DNA fragment released by human tissues into the circulatory system such as blood, is a novel molecular marker for tumors.These fragments, which can vary in length between 50 and 300 bp, are generally found at low concentrations in the blood of a healthy individual. The various types of cfDNA isolated from human blood for diagnostic and screening purposes include circulating tumor DNA (ctDNA), cell-free mitochondrial DNA (ccf mtDNA), and cell-free fetal DNA (cffDNA).
https://www.cd-genomics.com/epigenetics/cell-free-methylation-sequencing-service.html