Raman Spectroscopy of Experimental Oral Carcinogenesis

Abstract

Oral cancers suffer from poor 5-year survival rates, owing to late detection of the disease. Current diagnostic/screening tools need to be upgraded in view of disadvantages like invasiveness, tedious sample preparation, long output times, and interobserver variances. Raman spectroscopy has been shown to identify many disease conditions, including oral cancers, from healthy conditions. Further studies in exploring sequential changes in oral carcinogenesis are warranted. In this Raman spectroscopy study, sequential progression in experimental oral carcinogenesis in Hamster buccal pouch model was investigated using 3 approachesex vivo, in vivo sequential, and in vivo follow-up. In all these studies, spectral changes show lipid dominance in early stages while later stages and tumors showed increased protein to lipid ratio and nucleic acids. On similar lines, early weeks of 7,12-dimethylbenz(a)anthracene-treated and control groups showed higher overlap and low classification. The classification efficiency increased progressively, reached a plateau phase and subsequently increased up to 100% by 14 weeks. The misclassifications between treated and control spectra suggested some changes in controls as well, which was confirmed by a careful reexamination of histopathological slides. These findings suggests Raman spectroscopy may be able to identify microheterogeneity, which may often go unnoticed in conventional biochemistry wherein tissue extracts are employed, as well as in histopathology. In vivo findings, quite comparable to gold-standard supported ex vivo findings, give further proof of Raman spectroscopy being a promising label-free, noninvasive diagnostic adjunct for future clinical applications.

Serum Raman spectroscopy in experimental carcinogenesis hamster buccal pouch model: Exploring early diagnostic capability

“…Similar trend in classification has also been stated by Kumar et al, wherein ex vivo and in vivo RS studies on epithelial HBP tissue were performed. [ 28,29 ]…”

“…[26,27] Previous RS studies from our laboratory have investigated experimental oral carcinogenesis in the HBP model using ex vivo, in vivo sequential and in vivo follow-up approaches. [28][29][30] Findings of the study demonstrated the efficacy of RS in identification of sequential biochemical changes occurring in HBP tissues. [28,29] The current study aims to identify the early events occurring during sequential oral carcinogenesis using hamster serum samples.…”

“…[28][29][30] Findings of the study demonstrated the efficacy of RS in identification of sequential biochemical changes occurring in HBP tissues. [28,29] The current study aims to identify the early events occurring during sequential oral carcinogenesis using hamster serum samples. This is the first study exploring the ex vivo sequential serum RS approach to gain insights into oral cancer progression.…”

Raman Spectroscopy: A Potential Diagnostic Tool for Oral Diseases

“…PCA presented a minor overlap between three clusters, indicating a large difference between three cell lines. Furthermore, Kumar et al explored the change in differentiation efficacy during the cancer-inducing process, and the accuracy of cancer identification increased during the first 7 weeks, remained steady from 8 to 11 weeks, and exceeded 80% by the 14th week (Kumar et al, 2016).…”

The Hamster Model of Sequential Oral Carcinogenesis: An Update

“…Heber et al evaluated five protocols of carcinogenesis based on different number of weeks of carcinogen application to hamsters and the 6-week carcinogenesis protocol was selected for long-term studies of therapeutic effects (33). Furthermore, for the detection of oral carcinogenesis in early stages, Raman spectroscopy method was used to evaluate the levels of lipids, proteins and nucleic acids in early and late stages of oral carcinogenesis (34). Another way to detect the transformation of normal epithelium to pre-cancerous and cancerous states in early stages is non-linear optical microscopy for direct characterization of the epithelial-connective tissue interface (35).…”