A New Approach to the Study of Human Solid Tumor Cells by Means of FT-IR Microspectroscopy

Abstract

Cells coming from normal and neoplastic human lung tissue were analyzed by means of FT-IR microspectroscopy. Among the various methods tested to isolate the cells, mechanical treatment alone was found to yield the best results. Monolayers of cells were homogeneously distributed by cytocentrifuge preparation on BaF₂ windows, and several spectra were obtained for different circular micro-areas of the order of one hundred microns in diameter. This procedure made it possible to obtain reliable spectra and to reject those containing additional bands due to impurities arising from the isolation treatment. Spectral differences between normal and neoplastic cells reflect an increase in the intensity of the bands corresponding mainly to PO₂⁻ symmetrical and asymmetrical vibrations of DNA in pathological samples with respect to normal ones. The value of the ratio of the integrated areas of the bands at 1080 and 1540 cm⁻¹ due to DNA and proteins, respectively, makes it possible to differentiate between normal and abnormal cells, thus suggesting the use of this parameter as an original approach in the recognition of early neoplastic transformation undetectable by means of traditional procedures.