Chemometrics assisted investigation of variations in infrared spectra of blood samples obtained from women with breast cancer: a new approach for cancer diagnosis.

Fourier transform infrared spectra of blood samples obtained from healthy women and those affected by breast cancer have been analysed statistically. Several spectral differences were detected in the N-H stretching signals of amides I and II bands. The position of alpha-helix and beta-sheet amide I bands would shift in cancerous blood samples during stage development. Investigating the absorbance bands in the Fourier transform infrared spectra during the different stages of cancer, many changes are clearly observed in the intensity of a single band or the absorbance ratio of signals, indicating the changes that would occur in blood ingredients during cancer stages. These observations imply that the information is useful for diagnostic study of breast cancer and malignant abnormalities by infrared spectroscopy of whole blood samples. Finally, linear discriminant analysis was applied for classification of cancer case and normal case blood samples. The accuracy of the proposed method was 97.9%.