Four human NSCLC cell lines with differing KRAS and EGFR mutational status, H292 (KRASwt; EGFRwt), H358 (KRASG12C; EGFRwt), H1650 (KRASwt; EGFRΔE746-A750) and H1975 (KRASwt; EGFRL858R + T790M), were assessed for RAS-GTP activity by a Raf ‘pull down assay’ using the RAS-binding domain of Raf-1. Here, RAF1 is linked to non-small cell lung carcinoma.