Raman spectroscopy for the diagnosis of unlabeled and unstained histopathological tissue specimens.

AIM: To investigate the possibility of diagnosing gastric cancer from an unstained pathological tissue using Raman spectroscopy, and to compare the findings to those obtained with conventional histopathology.

METHODS: We produced two consecutive tissue specimens from areas with and without cancer lesions in the surgically resected stomach of a patient with gastric cancer. One of the two tissue specimens was stained with hematoxylin and eosin and used as a reference for laser irradiation positioning by the spectroscopic method. The other specimen was left unstained and used for Raman spectroscopy analysis.

RESULTS: A significant Raman scattering spectrum could be obtained at all measurement points. Raman scattering spectrum intensities of 725 cm-1 and 782 cm-1 , are associated with the nucleotides adenine and cytosine, respectively. The Raman scattering spectrum intensity ratios of 782 cm-1 /620 cm-1 , 782 cm-1 /756 cm-1 , 782 cm-1 /1250 cm-1 , and 782 ​​cm-1 /1263 cm-1 in the gastric adenocarcinoma tissue were significantly higher than those in the normal stomach tissue.

CONCLUSION: The results of this preliminary experiment suggest the feasibility of our spectroscopic method as a diagnostic tool for gastric cancer using unstained pathological specimens.