Electron spin resonance studies on normal human uterus and cervix and on benign and malignant uterine tumors

Electron spin resonance (ESR) studies at -130 degrees have been made on frozen samples of normal human cervix and uterus and on frozen samples of various pathological conditions of the cervix and uterus including fibroleiomyoma and carcinoma. Fifty-five samples of normal cervix and endometrium, 40 samples of nonmalignant disturbances, 15 benign tumor samples, and 20 malignant samples were studied. Very strong ESR signals were seen in frozen powders and frozen intact samples of normal cervix and endometrium and in nonmalignant gynecological conditions. In many cases, the ESR signal was greatly decreased or even undetectable in cancer samples. The substance(s) responsible for the ESR signal in frozen intact tissue (g = 2.11 to 2.15) is decreased in concentration when the sample is ground to powder under liquid nitrogen, and an anisotropic signal (g = 2.002 to 2.035) then becomes much more evident. The ESR signals in intact and in powder samples are sensitive to temperature variations; the signals disappear around 0 degrees, and only the intact samples show significant recovery of signal on recooling. The anisotropic g values and temperature sensitivity in the powders may result from an organic peroxy radical that is more strongly associated with a metal ion in intact samples.