To demonstrate the infrared (IR)-based bile analysis as a reliable screening tool for gall bladder (GB)
cancer, we analyzed a sample set of 37 diverse bile samples (five normal, 18 GB
polyp, six
hepatocellular carcinoma (HCC), and eight GB
cancer subjects). Bile samples of normal subjects (control) and HCC patients were newly included to examine if IR-based bile analysis could be expanded to identify HCC. Concentrations of three
bile acids and eight
bile salts in the aqueous phase samples were determined in parallel and lipidomic analysis of nine
lipid classes in the organic phase samples was performed using liquid chromatography-mass spectrometry. Concentrations of
bile salts were lower and relative abundances of
bile salts were dissimilar between GB
cancer samples and remained group samples. Also, the levels of
lipids such as
phosphatidylcholines and
phosphatidylethanolamines were again lower and their relative abundances in the organic phase of GB
cancer samples were different from those of other samples. IR spectral features of the aqueous, organic, and amphiphilic aggregate phases were individually characteristic, while not descriptive enough for the thorough identification of GB
cancer. Nonetheless, since they were mutually complementary to represent different metabolites in bile, the use of three phase-merged spectra was synergetic to yield the superior discrimination of GB
cancer.