More recently, Phase 1/2 trials (ClinicalTrials.gov Identifier: NCT02422979) of PIT using a conjugate of the silicon phthalocyanine PS derivative IRDye700DX with cetuximab (Cet, anti-EGFR) have been completed for recurrent HNSCC patients who cannot be effectively treated with chemotherapy, radiation therapy, or surgery. This evidence concerns the gene EGFR and head and neck squamous cell carcinoma.