FLIM as an identification tool for analyzing mouse esophageal squamous cell carcinoma tissue sections

Esophageal carcinoma is a common clinical cancer and with sixth occurrence frequency in the world, has a low five-year survival rate. Among different types of esophageal carcinoma, esophageal squamous cell carcinoma (ESCC) has the highest incidence rate and has a poor prognosis after surgery. For clinical diagnosis, hematoxylin and eosin (H&E) stained sections of diseased tissues are considered as the “golden standard”. However, determination of the tumor regions is usually relied on professional experience, which is time consuming and has a high misdiagnosis rate. Currently, novel optical imaging tools such as multi-photon excitation imaging and fluorescence lifetime imaging microscopy (FLIM) have been applied in clinical diagnosis. FLIM contains advantages of accurate measurement and high sensitivity to microenvironment. In this work, we constructed mice orthotopic esophageal cancer model to investigate the characteristics of esophageal tumor cells. Then FLIM technique were used to investigate H&E stained sections from both healthy control mice and ESCC mice, providing difference between the fluorescence lifetime values of normal tissues and those of the pathological tissues. Results also revealed an alteration of the fluorescence lifetime values of esophageal stratum corneum, which might be generated through tumor extrusion. Furthermore, the fluorescence lifetime values of tumor cells are distinctly smaller than those of the surrounding stroma, indicating an accurate identification the lesion area. In conclusion, the fluorescence lifetime images obtained by FLIM could provide a quantitative method in future pathological identification.