H-1-NMR SPECTROSCOPY OF COLON TUMORS AND NORMAL MUCOSAL BIOPSIES - ELEVATED TAURINE LEVELS AND REDUCED POLYETHYLENEGLYCOL ABSORPTION IN TUMORS MAY HAVE DIAGNOSTIC-SIGNIFICANCE

Twenty-three pairs of normal mucosa and colonic adenocarcinoma biopsy specimens have been examined in this pilot study by H-1 NMR spectrosco py at 9.4 T to determine whether it was possible to find spectral mali gnancy markers. The 3.2 ppm (trimethylamine-containing compounds)/0.9 ppm (methyl of fatty acids) resonance intensity ratio in water suppres sed spectra, proposed by other authors as a malignancy marker, results in our hands, using resonance areas, in partial overlap between tumor and mucosa values, which reduces its diagnostic value. Furthermore, w e have found that submucosa contamination could mask the normal mucosa pattern and artifactually decrease the 3.2/0.9 ppm, ratio value by in creasing the 0.9 ppm resonance due to the known triglyceride content o f normal submucosa. On the other hand, we have observed in the Hahn sp in-echo spectra of intact biopsies resonances arising from taurine and exogenous polyethyleneglycol (PEG). Their assignment and quantificati on has been carried out in perchloric acid extracts of the tissue biop sies. The taurine (3.4 ppm)/creatine (3.0 ppm) area ratio produced an excellent discrimination between normal mucosa and tumour groups while the PEG (3.7 ppm)/creatine (3.0 ppm) area ratio presented a large ove rlap, although it was clearly higher in the mucosae than in the tumors for paired samples. These two NMR observable parameters are in our ha nds highly discriminating and are accordingly proposed as malignancy m arkers in tissue biopsies although their possible utility for in vivo studies remains to be demonstrated.