Evaluation of gallbladder lipid level during carcinogenesis by an infrared spectroscopic method

Background: Fourier transform infrared (FTIR) spectroscopy is sensitive to the molecular composition of tissue and has the potential to identify premalignant tissue. Our previous studies found that the lipids band of FTIR decreased in malignant tissues compared to normal tissue but increased in the cell line. Aim: To investigate the change of lipids during carcinogenesis in the gallbladder by FTIR spectroscopy. Methods: The tissue from 12 malignant samples and 10 normal samples together with their corresponding tissue plasma membrane and gallbladder cancer cell lines were observed by FTIR. Results: Specific changes of lipids were observed in the FTIR spectral features of tissue, cell, and plasma membrane. The CH₃ stretching band at 2,957 cm^-1 and the CH₂ stretching bands at 2,853 cm^-1 decreased in the malignant tissue but increased in the tissue plasma membrane; the C-O stretching band at 1,740 cm^-1 disappeared in the malignant tissue but significantly increased in the tissue plasma membrane. The intensity of these bands all increased in the cancer cell line. The ratio of intensity (I) of 1,460 cm^-1/1,398 cm^-1 was smaller in malignant tissue and the tissue plasma membrane. Conclusions: Lipids were increased in the plasma membrane during carcinogenesis of the gallbladder; the ratio of intensity (I) 1,460 cm^-1/1,398 cm^-1 could be a marker to diagnose cancer by FTIR.