Biochemical identification of pre-malignant changes in oral mucosal lesions

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Objectives: To establish whether infra-red (IR) microscopy could be used as a diagnostic tool by looking for biochemical markers indicative of change in state from normal to dysplasia in oral mucosal biopsies. Methods: Oral mucosal biopsies were categorised into four groups, namely, non-dysplastic, mild, moderate, and severe dysplasia. Five biopsies per group were selected and 10 mm thick sections were cut and mounted on BaF₂ slides for IR analysis. Areas for analysis were identified using parallel H & E stained sections and spectra were taken from the basal epithelium for each specimen. Using an IR microscope interfaced to a synchrotron source (Daresbury, UK) spectra were taken from 10 x 10 mm area in transmission mode from 25 individual cells for each specimen. Results: We were able to show that there are differences between the spectral responses of basal keratinocytes in specimens from each of the categories; the mean spectra for each group are summarised in Fig 1. With increasing epithelial dysplasia there was a reduction in the intensity of peaks related to the concentrations of RNA (1121 cm^-1), DNA (1020 cm^-1), carbohydrates (900-1185 cm^-1) and nucleic acid phosphates (1185-1300 cm^-1). One-way ANOVA revealed that there were no statistically significant differences in intensities of these peaks between the non-dysplastic and mild dysplasia samples. There were significant differences between all of the other samples and the moderate and severe dysplasia samples for the RNA, DNA and carbohydrate peaks (p<0.05). Conclusion: We have shown a correlation between the biochemical properties of oral keratinocytes and conventional histological grading of dysplastic lesions. This suggests that IR spectroscopy may be a useful tool in the objective assessment of oral dysplastic lesions. Figure 1: Mean spectra for the four groups