KRAS and melanoma: Our results are concordant with several retrospective studies, generally including low number of samples, reporting good sensitivity (64–100%) for EGFR KRAS or BRAF mutation detection in the CSF (Ballester et al., 2018; Sasaki et al., 2016; Yang et al., 2014; Zhao et al., 2016) or PE (Kang et al., 2015; Liu et al., 2014; Liu et al., 2018; Shin et al., 2017) of NSCLC and melanoma patients with brain or pleural involvement, either baseline or after progression to targeted therapies.