Liquid Biopsy
Class II tumor suppressor genes (C2TSGs) are often epigenetically silenced very early in cancer development, which leads in several stages from initiated cancer cells to early tumors, then late (invasive) tumors and finally to metastasis. With the help of liquid biopsy diagnostics, methylated DNA originating from tumor cells can now be detected with very high technical sensitivity as cell-free DNA (cfDNA) in the bloodstream of affected patients. Of course, this requires highly developed techniques such as pyrosequencing, digital PCR or next generation sequencing. Cell free DNA from tumor cells is also referred to as ctDNA (tumor-derived cell free DNA). Since class II tumor suppressor genes are highly specifically methylated in tumor cells (compared to normal cells), the detection of methylated C2TSGs in blood-derived cfDNA is an indicator for the presence of tumor cells in the patient. Our research group has developed an experimental biomarker panel for the early detection of breast cancer, which consists of only four genes, the so-called SNiPER panel. However, further development into a product is no longer being pursued, as there are now more sensitive approaches, e.g. https://pubmed.ncbi.nlm.nih.gov/34176681/.
