LIquid BIopsies in Patients Presenting Non-small Cell Lung Cancer

Lung cancers are the first cause of death by cancer in the world. The majority of these patients are diagnosed at a late stage, non-eligible to a curative treatment. Due to tumoral genomic identification, it has been possible to classify NSCLC in molecular subtypes according to molecular abnormalities detection called "drivers" which can be targeted using an appropriate treatment. This change modifies the standard treatments from the very first line of treatment particularly for patients having an EGFR mutation or an ALK or ROS1 rearrangement, with a significant benefit of progression free survival. The French NCI (INCa) recommends to identify genomic alterations of a genes panel including EGFR, KRAS, BRAF, HER2, ALK and ROS1 as well as mutations in MET exon 14. However, all the patients who benefit from a targeted therapy develop resistance after a mean duration of 10-12 months after starting the treatment. In case of progression, the tumour genetic analysis through new biopsies, enables to identify these mechanisms and then to determine if the patient can benefit or not from a third generation molecule active on these mechanisms, and to have a better understanding of the disease evolution. The detection of these alterations is routinely performed using tissular biopsies but in 10 to 20% of the cases, it is not possible. The detection of these molecular abnormalities in the plasma, called " liquid biopsy " is a valuable non-invasive complementary approach for these patients. It is presently used in routine for detecting the EGFR mutations at diagnosis as well as for searching EGFR T790M mutation for resistant patients. The liquid biopsies enable to detect circulating tumoral DNA.