QUANTITATIVE AND QUALITATIVE CHARACTERIZATION OF H-1-NMR SPECTRA OF COLON TUMORS, NORMAL MUCOSA AND THEIR PERCHLORIC-ACID EXTRACTS - DECREASED LEVELS OF MYOINOSITOL IN TUMORS CAN BE DETECTED IN INTACT BIOPSIES

Sixteen colonic tumours and 10 normal mucosa biopsies have been examin ed by H-1 NMR spectroscopy at 9.4 T. A complete characterization and q uantification of the aliphatic region of PCA extract spectra and the a nalysis of the two dimensional COSY spectra of five pairs of intact bi opsies (tumor and control mucosa) has been carried out, The analysis o f the PCA extracts demonstrated a significant increase in the concentr ation of the endogenous compounds: lactate, glutamate, aspartate, taur ine, spermine, glutathione and glycerophosphoethanolamine, and a signi ficant decrease of myo- and scyllo-inositol, in tumours with respect t o mucosae, Among these metabolites, the high myo-inositol and taurine levels and the reciprocal changes Pound between them in tumours and mu cosae make their resonances interesting as possible malignancy markers if they are detectable in vivo. In contrast to the easy observation o f taurine in one-dimensional spectra of intact biopsies, the difficult y of observing myo-inositol prompted us to use two-dimensional COSY sp ectra for the detection and quantification of both these metabolites, In the two-dimensional spectra, the use of a ratio between the cross-p eak volumes of both metabolites permits an excellent differentiation b etween tumours and normal mucosa and suggests its potential to detect malignant changes in the healthy tissue, provided a two-dimensional ap proach is used.