HRAS and head and neck squamous cell carcinoma: Recent and emerging clinical data using tipifarnib in patients with HRAS-mutant HNSCC [55], salivary gland cancer [35], and metastatic urothelial carcinoma [36, 56] suggest that higher rates of clinical activity will be realized in a molecularly-defined population, which led to renewed interest in examining the efficacy of tipifarnib in tumors with hotspot HRAS mutations.