A recent study into the analysis of cf-DNA performed on more than 8300 late stage NSCLC patients showed that gene fusions (on ALK, RET, ROS1) were identified at baseline in more than 2.3% cases, underlying that LB testing in these patients could be a powerful tool to detect some genomic alterations, and so could be a primary option, at least for patients with an incomplete tissue biopsy analysis [37]. This evidence concerns the gene RET and non-small cell lung carcinoma.