A phase 1 clinical trial (NCT01115790) of single-agent prexasertib in head and neck squamous cell carcinoma (HNSCC) and squamous cell carcinoma of the anus (SCCA) identified loss-of-function (LOF) mutations in the E3 ubiquitin ligase FBXW7 in patients with clinical benefit [12]. This evidence concerns the gene FBXW7 and head and neck squamous cell carcinoma.