A New Era of Oncological Data

Transforming cancer care through liquid biopsy

For patients with cancer, regular monitoring of tumour-related genetic mutation is key to effective diagnostic, prognostic and therapeutic care. The current medical standard for molecular analysis of these mutations is tissue biopsy, an invasive and costly procedure that carries risk when used repeatedly and does not typically capture all relevant mutations in the tumour source. Eurofins Genomics and Clinical Diagnostics companies have been forerunners in sequencing tumour DNA obtained by non-invasive blood sampling and analysis, called liquid biopsy, providing specific oncological data that can have a significant impact on patient treatment decisions and outcomes.

Personalised cancer treatments targeted at particular molecular alterations in a patient can significantly improve their prognosis and quality of life, but these therapies require that genetic monitoring of the tumour is conducted regularly. In modern medicine, this usually depends on tissue biopsy, which involves extracting suspected cancerous tissue with a small needle or by surgically removing a larger portion. However, consecutively performing this invasive procedure carries risk for the patient and is oftentimes out of the question, as well as having shortcomings in the specificity of the data it produces; due to the heterogeneity of the tissue, a single sample does not typically represent all mutations at the tumour site. For this reason, in recent years, attention in the medical community has increasingly turned to the potential of circulating tumour DNA (ctDNA) in bodily fluids for cancer screening and diagnostics.

Just as healthy cells secrete DNA (called cell-free DNA, or cfDNA) into bodily fluids, such as blood, urine and cerebrospinal fluid, tumours secrete DNA in the same way. This ctDNA is characterised by genetic defects identical to and representative of the entire tumour genome. Scientists can therefore use ctDNA to genetically profile tumours with great accuracy by extracting fragments from blood plasma through a process known as liquid biopsy and using this to detect genetic mutations not represented in tissue samples. Though extracting DNA from plasma in a blood sample must be conducted very carefully and under specialised conditions, it is comparatively easier to do than extracting other circulating biomarkers. Liquid biopsy of ctDNA is thus a rapid, affordable and non-invasive innovation, providing important complementary medical information on cancer progress.

In 2015, realising the great diagnostic potential of cfDNA as a biomarker, GATC Biotech, now a Eurofins Genomics company, launched the first standardised sequencing service for cfDNA, based on their experience of detecting DNA traces in blood samples for prenatal testing (see page 6: New generation of non-invasive prenatal testing methods). Today, Eurofins Genomics offers the most comprehensive cancer gene panel for liquid biopsy in the world, at 597 genes, focusing on major cancer types.

In 2017, Eurofins Genoma, a Eurofins Clinical Diagnostics company, launched the first commercial liquid biopsy test, Oncotext™, validated and brought to market in collaboration with the Regina Elena National Cancer Institute. Later, a Eurofins Genoma project exploring how to best manage liquid biopsy in head and neck tumours was the first of its kind to make the technique available in daily clinical practice in Italy. Currently, there is no standard for the testing method, and Eurofins Genoma was the first to prove a developed method could detect minute traces of cfDNA from very small, non-metastatic tumours (a tumour that has not spread to other parts of the body), demonstrating the appropriateness of liquid biopsy for screening early-stage cancer, where a sensitivity at least tenfold to that of metastatic cancers is required. Today, Eurofins Genomics offers the most comprehensive cancer gene panel for liquid biopsy in the world, INVIEW Oncoprofiling at 728 genes, focusing on major cancer types.

The science behind