Antitumor activity of tipifarnib and PI3K pathway inhibitors in HRAS-associated HNSCC.

e15658 Background: HRAS is an important driver oncogene in HNSCC and other squamous cell carcinomas (SCCs). HRAS mutations are observed in 6-10% of HNSCC cases and appear to define a unique subset of HNSCC associated with wild-type TP53, co-mutations in caspase 8 and a characteristic methylation pattern. RAS proteins undergo several posttranslational modifications that facilitate their attachment to membranes. The first and most critical...