An innovative diagnosis in gastrointestinal neuroendocrine neoplasms using Wax-Physisorption-Kinetics-based FTIR Imaging

Neuroendocrine neoplasm (NEN) is a common gastrointestinal (GI) tract tumor divided into the neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC) according to mitosis and Ki-67 index. However, the objective discordance between interobserver may cause unsuitable diagnosis and misleading treatment. Nowadays, aberrant glycosylation of glycoconjugates inducing further populations of elongated complex oligosaccharide covalent attached to glycoconjugates anchored in the cell membrane by neo-synthesis of cancer-associated alteration of carbohydrate determinants were observed during cancer development. This study aimed to demonstrate the wax physisorption kinetics coupled with Fourier transform infrared (WPK-FTIR) imaging between NET and NEC in the rectum, colon, and stomach by utilizing two wax reagents (beeswax and paraplast) as glycan adsorbents for physical binding glycans of glycoconjugates based on dipole-induced dipole interaction. Results showed greater physisorption with beeswax than that of paraplast, suggesting highly populated elongated glycans of glycoconjugates adhering onto the tumor surfaces of NETs than that of adjacent benign mucosa in the rectum and colon. Besides, the WPK results of gastric NEN tissue sections showed a higher infrared absorbance ratio of beeswax-remnant to paraplast-remnant remains onto the tissue sections referring to a higher population of elongated glycans in gastric NET as compared with that of gastric NEC. Based on our findings, different anatomical locations could share similar phenomena with minor variance. In conclusion, WPK-FTIR imaging may have the potential to be employed as an alternative diagnostic method in GI NENs in the future.