Recently our laboratory, as well as others, have been studying the non-water proton NMR signals of normal and malignant tissue. In many cases larger and more definitive differences are seen in the relaxation parameters of non-water resonances, arising largely from lipid components of tissue, making characterization of malignancy more reliable. We have been able to observe aliphatic proton resonances in all types of tissue and plasma studied and have begun the correlation of their NMR relaxation parameters with malignancy. It is the overall goal of the studies proposed in this application to further characterize the NMR properties of the non-water resonances of tumors and normal tissue and define certain aspects of both the biological and biophysical mechanism responsible for the unique features of these resonances in malignancy. The data from these studies will be used to test the hypotheses that: 1) the NMR signal and its relaxation parameters arising from resolvable aliphatic resonances is a more sensitive and specific indicator of malignancy than are the composite proton resonance or the water resonance itself; and 2) that an understanding of certain aspects of the mechanism which produces differences in these properties of the aliphatic resonance will be of value to the classification of stages of malignancy and its regression as well as, perhaps, offering new understanding of certain biophysical and biochemical aspects of the disease process itself.