KRAS and squamous cell lung carcinoma: In Calu-3 (HER2-amplified, KRAS-wt, lung squamous cell carcinoma), dabrafenib-induced paradoxical ERK activation could not be abrogated by simultaneous MEK inhibition (Fig. 7a-b) and pharmacological interactions between the two drugs were highly antagonistic (CI: 19.3; Fig. 7c).