[Detection of novel driver mutations in liquid biopsy: case report of a RET-positive lung adenocarcinoma treated with pralsetinib.].

Advances in cancer biology research led to the identification of new molecular drivers in non-small cell lung cancer. These alterations should be searched especially in young and never-smoker patients, in order to ensure access to targeted therapies. In particular, RET mutations occur in 1-2% of lung adenocarcinomas and represent the molecular target of innovative treatments such as pralsetinib. The Next Generation Sequencing provides a comprehensive genomic profiling both on tissue and blood sampling. The liquid biopsy could be extremely advantageous, as it is a simple, non-invasive and repeatable test. We report the case of a non-smoker woman with metastatic lung adenocarcinoma unresponsive to chemotherapy and immunotherapy. RET mutation (RET-KIF5B fusion) was found by liquid biopsy. The patient started therapy with pralsetinib obtaining an early radiological response and a significant clinical benefit.