Khan SA et al. (2005) Proton and phosphorus-31 nuclear magnetic resonance spectroscopy of human bile in hepatopancreaticobiliary cancer. Eur J Gastroenterol Hepatol 17: 733–738

Early-stage diagnosis of hepatobiliary cancers is currently limited—biliary cytology is unreliable, and detection of early-stage disease using imaging techniques is often difficult. In vitro studies of liver tissue by nuclear magnetic resonance (NMR) spectroscopy have previously demonstrated alterations in phospholipid metabolism in patients with cancer. This prospective, UK pilot study therefore used NMR spectroscopy to study phospholipid metabolism in bile as a potential diagnostic marker for hepatobiliary cancer.

Bile samples were collected from 25 individuals (13 with underlying primary or secondary malignancy and 12 with nonmalignant pathology) either via aspiration at endoscopic retrograde cholangiopancreatography or at laparoscopic cholecystectomy. All samples underwent proton (1H) and phosphorus (31P) NMR analysis, although the 1H spectra from two samples (one from each group) were uninterpretable and were therefore excluded from further analysis.

The authors found 31P spectra more straightforward to interpret than 1H spectra, as they were not complicated by resonances from cholangiopancreatography contrast medium. Phosphatidylcholine levels were variable but significantly lower in bile from individuals with cancer than in bile from individuals without cancer. There are other potential causes for this reduction, however, which remain to be clarified, such as polymorphisms in the ABCB4 (previously MDR3) gene that is involved in phospholipid excretion, and reaction to radiotherapy. Although the ability of NMR spectroscopy to identify early-stage disease has not been specifically tested, these results are promising and the potential use of NMR spectroscopy as an adjunct to current diagnostic techniques is worthy of exploration.