Direct measurement of human lung cancerous and noncancerous tissues by fourier transform infrared microscopy: can an infrared microscope be used as a clinical tool?

We have analyzed very small amounts of human lung cancerous tissues directly by a Fourier transform infrared microscopy (FT-IR-MC). The corrected peak heights (H1045 and H1467) obtained from the bands at 1045 and 1467 cm(-1) due to glycogen and cholesterol were chosen for a quantitative evaluation of the malignancy. We found that the H1045/H1467 ratio is an exceptionally useful factor for discrimination of the cancerous tissues from the noncancerous tissues. If the H1045/H1467 ratio from the measured spectrum is larger than 1.4, we can say with confidence that the tissue contains squamous cell carcinoma or adenocarcinoma at least partially. Furthermore, we carried out the microscopic mapping of the tissues containing both cancerous and noncancerous sections, demonstrating that the color map reflects small changes in the spatial distribution of cancer cells in the tissues. The present method may also be applicable to analysis of other cancers, such as colorectal cancerous tissues in which glycogen level has a critical factor for their malignancy. In addition, since FT-IR-MC costs relatively little and does not require a special operator training for collecting and analyzing the spectra, it seems to be perhaps the apparatus best suited to clinical usage, especially in rather small hospitals.

Evaluation of glycogen level in human lung carcinoma tissues by an infrared spectroscopic method

Glycogen levels in the tissue samples obtained from carcinomas and normal sections of human lungs (26 patients) were studied by measuring the infrared band intensity at 1045 cm(-1) due to glycogen. As an internal standard peak, the band at 1545 cm(-1) (amide II) was chosen, and the ratios of these band areas (A1045/A1545) were compared with histological classification and differentiation of tumors. The glycogen level in the carcinoma tissues was significantly higher than that in the normal tissues (P < 0.01, n = 26). Further, the ratio of amounts of glycogen in the carcinomas and in the normal tissues for adenocarcinoma was higher than that for squamous cell carcinoma (P < 0.01). The increased degree of differentiation of the squamous cell carcinomas appeared to be correlated with an increase in the glycogen level. These results suggest that comparison of glycogen levels in the tumor and normal section of human lung may be used as a differentiating parameter for abnormality and histological classification of tumors. The present Fourier transform-infrared spectroscopy (FT-IR) method may become of wide application for studying various tissue samples.