Liquid Biopsy Paves the Way for Personalized Lung Cancer Treatment

However, critically ill lung cancer patients may not be able to undergo a surgical biopsy and may not have enough accessible tumor tissue. Liquid biopsy is a simple and noninvasive alternative to surgical biopsy in which traces of the cancer’s DNA in the blood can give clues about which treatments are most likely to work for that patient.

Genomic instability resulting in copy number variation is characteristic of malignant transformation and may be identified through next-generation massive parallel sequencing. Tumor-specific cell free DNA (cfDNA) is released by dying cancer cells into the serum and plasma where it provides a real-time, easily accessible target for this approach. Analysis of this type of liquid biopsy specimen is straightforward and not invasive so it can be easily repeated in order to monitor changes in the genetics of each lung cancer patient’s individual tumor.

Cancer cell genomics testing may be carried out with new generation assays such as the recently CE-marked Roche EGFR Mutation Test v2 for non-small-cell lung cancer (NSCLC), which allows clinicians to replace surgical biopsy specimens with readily accessible blood samples that contain tumor-specific cfDNA.

The EGFR Mutation Test v2 is the first oncology assay from Roche that utilizes either plasma or tumor tissue as a sample. The test identifies 42 mutations in the epidermal growth factor receptor (EGFR) gene, the most of any in vitro diagnostic (IVD) test on the market, and can also be used as an aid in selecting eligible patients with non-small-cell lung cancer (NSCLC) for therapy with an EGFR tyrosine kinase inhibitor (TKI). Additionally, Roche has developed a cfDNA sample preparation kit that is optimized for extracting the DNA from plasma. The EGFR Mutation Test v2 was designed to run on the cobas 4800 System, v2.1 or higher. The system can also be used for the detection of mutations in the KRAS and BRAF gene of tumor samples.

“Liquid biopsies could be a game-changer in cancer testing,” said Miro Venturi, global head diagnostics biomarkers at Roche. “In terms of patient acceptability and disease management, the benefits of noninvasive, quick and easily repeatable tests are clear. And in the longer term, liquid biopsies may ultimately be used to catch signs of cancer early, before symptoms arise. This could make a significant difference to the way we understand and treat cancer.”

A small number of liquid biopsy tests have already been approved and are available in some countries, and many more are in development. This new approach to cancer diagnostics is expected to revolutionize cancer detection and treatment.

Other types of diagnostic tests are also in development that can investigate tumor tissue or circulating tumor cells for multiple biomarkers at the same time or to determine whether there are multiple genetic defects present in the same tumor cell.

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