In vivo CRISPR screening identifies NF1/RASA1/TP53 co-mutations and downstream MEK signaling as a common key mechanism of sinonasal tumorigenesis - Whole Exome Sequencing of Nf1/Trp53 flox/flox

Here, we perform an in vivo loss-of-function screen using a pooled custom single-guide library delivered to the sinonasal cavity by adeno-associated virus vector to identify cancer driver genes across diverse sinonasal malignancies. This approach yielded sinonasal malignancies with diverse histologies, including sinonasal squamous cell carcinoma, adenocarcinoma, poorly differentiated sinonasal carcinoma, and sinonasal neuroendocrine tumors characteristic of olfactory neuroblastoma.

Surprisingly, rather than observing distinct sgRNA profiles across sinonasal tumor subtypes, common recurrent mutations were identified in Nf1 (79%), Rasa1 (74%), and Trp53 (68%) across malignancies with distinct histologies. Utilizing an orthogonal approach, we confirmed that Nf1/Trp53 were required for sinonasal tumorigenesis. Given that loss-of-function in NF1 and RASA1 may lead to increased Ras activity and downstream MEK signaling, we tested small molecule targeting of the RAS-MAPK pathway in sinonasal malignancies.