High-quality, high-resolution,
proton-decoupled natural-abundance 13C NMR spectra have been obtained in vitro at 100.6 MHz from unprocessed human pathology specimens of
tumors and adjacent nonneoplastic control tissues from lung, colon, and prostate. In these preliminary studies, specific molecular parameters were identified from the spectra that distinguished neoplastic from nonneoplastic tissue of a given organ in all sites studied. The NMR results were congruent with data derived from histochemical and biochemical examinations of the tissues and with previous studies using non-NMR methods. In particular, a comparison of the spectra of prostatic
adenocarcinoma with that of adjacent hyperplastic tissue revealed the following differences: The
tumors contained (1) larger amounts of
triacylglycerols, (2) smaller amounts of
citrate, and (3) acidic
mucins. These transformation-associated deviations from the normally high amounts of
citrate and low amounts of
lipids in the prostate are consistent with an alteration in either the concentration or the activity of
ATP-citrate lyase in the
tumors. The 13C NMR spectra of colonic
adenocarcinoma tissue showed that this
tumor type contained (1) smaller signals from
triacylglycerols, (2) larger signals from
phospholipids and
lactate, and (3) decreased
lipid fatty acyl chain saturation, when compared to spectra from adjacent normal colon.
Colloid carcinoma, another variant of colonic
carcinoma, showed prominent 13C resonances from
glycoproteins, which were absent from the spectra of normal colon, and from spectra from the more common pattern of colonic
adenocarcinoma. Smaller 13C NMR signals from
mucins and other
proteins, and the presence of
triacylglycerol signals distinguished poorly differentiated lung
carcinoma and from nonmalignant lung tissue. These results indicate that natural-abundance 13C NMR spectroscopy may constitute a unique, nondestructive method, for the simultaneous measurement of a large number of tissue metabolites and structural components of significance to the study and diagnosis of a wide range of human
tumors.