Abstract: Objective To establish a method for early diagnosis of gastric cancer using near-infrared Raman spectroscopy.
Methods A rapid near-infrared Raman system was used to examine the tissue specimens of pathologically confirmed gastric
cancer (33 cases), gastric precancerous lesions (27 cases), and normal gastric mucosa (45 cases). All the specimens were
obtained from 105 patients undergoing gastrectomy or endoscopic biopsy of suspected gastric lesions. Results High-quality
Raman spectra ranging from 700 to 1800 cm-1 were acquired from the gastric tissues within 5 s. The distribution pattern of
Raman spectra in gastric cancer differed significantly from those of gastric precancerous lesions and normal gastric mucosa,
particularly in the spectral ranges of 853 cm-1, 936 cm-1, 1003 cm-1, 1032 cm-1, 1174 cm-1, 1208 cm-1, 1323 cm-1, 1335 cm-1, 1450 cm-1,
and 1655 cm-1, which contained signals related to proteins, nucleic acids and lipids. The diagnostic decision algorithm based on
the Raman peak intensity ratios of I1003/ I1337, I1003/I1445, I1003/I1655, and I1156/I1655 yielded remarkable differences in gastric cancer from
gastric precancerous lesions and normal gastric mucosa, and the ratios were significantly higher in normal gastric tissues (P<
0.05). The discrimination based on near-infrared Raman spectroscopy using PCA-LDA algorithms associated with leaveone-
out and cross-validation method showed diagnostic sensitivities of 81.5%, 85.3%, and 100%, and specificities of 86.4%,
100%, and 97.4% for normal gastric mucosa, precancerous lesions and gastric cancer, respectively. Conclusion near-infrared
Raman spectroscopy in conjunction with intensity ratio algorithms shows the potential for noninvasive diagnosis and
detection of gastric malignancy at the molecular level.