Liquid biopsy - This term is used to describe a new diagnostic tool. Since very recently it has raised great hopes, first especially in the scientific world and than
in clinics. Still it awaits its full appreciation and wide application.
What is behind liquid biopsy term? So liquid biopsy is the ability to detect diseases in the bloodstream, including literally slight traces of cancer occurring
anywhere in the body, at different times from the development of cancer, including its most early stages. Early detection of diseases, especially cancerous ones,
is sort of a Holy Grail in cancer research. Like the Holy Grail, so do diagnostics of the early stages of neoplasm causes lots of emotion and controversy.
Possibility of early diagnosis, monitoring the course of the disease and the response to treatment is undoubtedly also the dream of the modern doctor and
patient. Accurate diagnosis and early cancer treatment based on non-invasive techniques, for example, by testing body fluids such as blood and urine is higly
desiderable target. Liquid biopsy would greatly enable research and would introduce new therapeutic measures, i.e. implementing the idea of therapy
individualized.
Liquid biopsy is based on measureing/analysing the quantity of either circulating tumor cell (CTC) oraz sequencing circulating tumor DNA.
CTC, are epithelial cells derived from the primary or metastatic tumor that acquire the ability to detach and traverse the stromal tissue and then enter the
bloodstream. CTCs play an important role in tumor metastasis and their presence in the bloodstream is associated with the prognosis in many cancers. ctDNA
originates directly from the tumor or from CTCs. ctDNA after extraction is sequenced to look for mutations characteristic for particular type of the cancer.
Mutation detection in ctDNA has the potential to be used in early cancer detection, to determine the tissue of origin, prognosis, to monitor response and assess
potential resistance to the treatment, or to detect minimal residual disease.