Rapid detection of superficial head and neck squamous cell carcinoma by topically spraying fluorescent probe targeting dipeptidyl peptidase‐IV

Abstract Background A fluorescent probe glutamylprolyl hydroxymethyl rhodamine green (EP‐HMRG), which becomes fluorescent after cleavage by dipeptidyl peptidase‐IV (DPP‐IV), has been reported to be useful for the detection of esophageal cancer. Thus, we investigated whether head and neck squamous cell carcinoma (HNSCC) can be detected by spraying EP‐HMRG. Methods Fluorescence imaging of 17 cases of HNSCCs resected using endoscopic or surgical resection was performed ex vivo after spraying EP‐HMRG, and then the fluorescence intensity of the tumors and normal mucosa were measured. Results Iodine‐voiding lesions became fluorescent within a few minutes after the application of EP‐HMRG in 12 resected tumors without a history of radiotherapy but this was not observed in the normal mucosa. Fluorescence intensity in tumor lesions was significantly higher than normal lesions. However, 5 other tumors that developed after radiotherapy did not have sufficient contrast against normal mucosa. Conclusion Fluorescence imaging with EP‐HMRG would be useful for rapid detection of superficial HNSCC without a history of radiotherapy.