Infrared microscopy of epithelial cancer cells in whole tissues and in tissue culture, using synchrotron radiation.

Oral epithelial tumour tissue, and cultured cervical epithelial carcinoma cells have been studied using synchrotron infrared microspectroscopy. Mid infrared absorption spectra collected at cellular spatial resolution from within oral tumours were found to be sufficiently distinct, when analysed by principal component analysis, to distinguish between three different cell types within the tumour. The resulting data were sufficiently robust to allow correct classification of spectra from cells within subsequent tissue samples. These results go some way to demonstrate the potential of infrared spectroscopy as a tool in the post-operative screening of oral cancer patients by the examination of exfoliated epithelial cells. To gain a better understanding of the inherent variability in the infrared spectra of such epithelial cells, we have studied A431 carcinoma cells under the stimulus of the growth-stimulating hormone EGF. We have detected key changes in the infrared spectrum that relate to the activation of the growth factor signalling mechanism.