Serum Raman spectroscopy: evaluation in hamster buccal pouch models

Oral cancer is one of the major cancers worldwide with >50% 5-year survival-rates owing to lack of early diagnosis. In view of this, in-vivo, exfoliative cells, and serum Raman spectroscopy have been actively pursued as theranostic solution. These studies successfully demonstrated stratification of healthy, malignant and premalignant oral conditions. In the present study, Serum Raman spectroscopy (SRS) which enables minimal invasiveness and distant diagnosis is rigorously evaluated in the experimental oral carcinogenesis, hamster buccal-pouch model. Sequential spectral variations have been observed across 14 weeks in controls and carcinogen (DMBA) treated hamster sera. Processed Raman spectra of sera (Weeks 1, 4, 8, 10, 12 and 14) were subjected to PCA and PC-LDA, both week-wise and group-wise. Serum spectra of untreated and physical injury controls showed misclassification as tumor/DMBA treated group at later weeks. Also misclassifications between injury and tumor spectra (12 and 14 weeks) have been observed suggesting chronic mechanical irritations/injuries as an important etiological factor in oral carcinogenesis. On the other hand, spectra of DMBA treated and physical injury group do not classify as untreated or vehicle control spectra, suggesting the significance of SRS as a rapid and objective diagnostic adjunct tool.