X-ray fluorescence analysis of elemental concentrations in human tongue tissues: Distinguishing healthy from carcinoma profiles

This study explores the feasibility of Wavelength Dispersive X-ray Fluorescence (WDXRF) to distinguish between healthy and carcinoma tongue tissues based on elemental concentration profiles. The concentrations of six chemical elements (phosphorus, sulphur, calcium, iron, zinc and copper) were determined in formalin-fixed and paraffin-embedded tissue samples from both tumour regions and histologically validated healthy margins in 31 patients with tongue squamous cell carcinoma. Mean concentrations for every sample were calculated from three replicate measurements and analysed using discriminant analysis and mixed linear models. Although the discriminant model lacked statistical relevance, the structural matrix suggested iron, copper and zinc contributed the most to the differentiation between tissue types. These elements were subsequently investigated further by using mixed linear models, which confirmed they had significantly reduced concentrations in carcinoma tissues (p ' 0.001), having maintained significant results after Bonferroni correction. Furthermore, a decreased iron concentration in carcinoma tissue of patients who reported frequent alcohol consumption was observed (p = 0.003), while tobacco use showed no significant effect on the element’s concentrations. Although exploratory, our results show changes in specific elemental concentrations, something that may help define oral cancer and support the incorporation of X-ray fluorescence into complementary diagnostic means.