Brief report: High incidence of peridiagnosis thromboembolic events in patients with BRAF-mutant lung cancer.

INTRODUCTION: We aimed to determine if advanced BRAF-mutant NSCLC has a higher thromboembolic events (TEE) rate than the expected. METHODS: Between 2008 and 2021, 182 patients with BRAF-mutant advanced NSCLC (BRAF V600E, n = 70; BRAF non-V600E, n = 112) were retrospectively identified from 18 centers in Spain. Patients received chemotherapy (n = 147), immunotherapy (n = 69), targeted therapy (n = 42), and immunotherapy + chemotherapy (n = 26). RESULTS: Incidence rate of TEE was 26.4 % (95%CI: 19.9 %-32.9 %). A total of 72 TEE were documented among 48 patients, as 18 patients (37.5 %) developed more than one event. Median time to TEE onset was 2 months, 69 % of TEE occurred in the peridiagnostic period (+/- 90 days from cancer diagnosis), and in 16 pts. (33 %) TEE was the form of lung cancer presentation. Although most TEE were only venous (82 %; PE, n = 33; DVT, n = 16), arterial events were reported in 31 % and occurred earlier, or TEE presented in atypical locations (13.9 %). TEE were related to high hospitalization rate (59 %), recurrence (23 %), and mortality (10.4 %) despite appropriate anticoagulant/antiaggregant treatment. Median OS in patients without-TEE was 19.4 months (95%CI: 4.6-34.1), and significantly shorter in patients with arterial-TEE vs venous-TEE vs both of them: 9.9 months (95%CI: 0-23.5) vs 41.7 months (95%CI: 11.3-72.2 m) vs 2.7 months (95%CI: 2.1-3.3), p = 0.001. Neither clinical or molecular features (BRAF V600E/non-V600E), nor cancer treatment was associated to TEE occurrence. Khorana score underperformed to predict thrombosis at cancer diagnosis, as only 19.2 % of patients were classified as high-risk. CONCLUSIONS: Thrombotic events represent a new clinical feature of BRAF-mutant lung cancer. Patients with almost a 30 % incidence of TEE should be offered systematic anticoagulation.

The Hippo effector YAP promotes resistance to RAF- and MEK-targeted cancer therapies.

Resistance to RAF- and MEK-targeted therapy is a major clinical challenge. RAF and MEK inhibitors are initially but only transiently effective in some but not all patients with BRAF gene mutation and are largely ineffective in those with RAS gene mutation because of resistance. Through a genetic screen in BRAF-mutant tumor cells, we show that the Hippo pathway effector YAP (encoded by YAP1) acts as a parallel survival input to promote resistance to RAF and MEK inhibitor therapy. Combined YAP and RAF or MEK inhibition was synthetically lethal not only in several BRAF-mutant tumor types but also in RAS-mutant tumors. Increased YAP in tumors harboring BRAF V600E was a biomarker of worse initial response to RAF and MEK inhibition in patients, establishing the clinical relevance of our findings. Our data identify YAP as a new mechanism of resistance to RAF- and MEK-targeted therapy. The findings unveil the synthetic lethality of combined suppression of YAP and RAF or MEK as a promising strategy to enhance treatment response and patient survival.