CUL3 and head and neck squamous cell carcinoma: NFE2L2 and CUL3 mutations have been identified in HNSCC at a frequency of 6% and 4%, respectively, with mutations in NFE2L2 mapping onto regions encoding the Neh2 domain of NRF2 and mutations in CUL3 occurring in regions encoding amino acids 33–66 in the CR1 domain.