Abstract: The normal, benign and malignant human breast tissues have been studied by means of infrared spectroscopy. Some remarkable spectral differences (shape, peak positions and relative intensities) are observed among these three types of the samples. In the malignant breast tissues, these mainly characteristic changes involve: (1) In comparison with the normal breast tissues, the band near 1162 cm^-1 from the stretching modes of C—O(H) group in proteins evidently shifts to a higher wavenumber, which suggests that the intermolecular hydrogen bonds are almost broken; The band near 3310 cm^-1 from the stretching modes of the hydrogen bonded N—Hin protein molecules shifts to a lower wavenumber, which indicates that the intensity of the hydrogen bonds on the NH…O=Cis stronger in protein molecules of malignant breast tissues. (2) The intensity of the symmetric stretching modes of νPO₂^- at 1080 cm^-1 from the phosphodiester groups in cellular nucleic acids is remarkably stronger, which suggests that the relative contents of DNAin cancer cellular increase. The symmetric stretching modes of PO₃^- at 970 cm^-1 from the phosphorylated proteins become stronger, which suggests that the relative contents of phosphorylated protein increase. (3) The change of the intensity of collagen bands indicates the increase of its relative contents. This investigation shows that Infrared spectrometry can represent the characteristic of the breast tumor at the molecular level.

Key words: Infrared spectrometry, Breast cancer, Study on tumor