An 84-year-old woman had a
squamous cell carcinoma on her left thigh. Before operation, half of the
tumor mass was irradiated with a microwave at 43 degrees C for an hour. After the
hyperthermia, the
tumor mass was removed, and the
DNA instability was investigated by microfluorocytometric measurement of the cells stained with
pararosaniline-Feulgen after hydrolysis with 2N HCl at 30 degrees C. The kinetic parameters k1, which is the rate constant for the generation of an
apurinic acid, k2, which is the rate constant for the depolymerization of the
apurinic acid and which reflects the degree of
DNA instability for
acid hydrolysis, and y0, which is the theoretical value of the
single-stranded DNA present initially and reflects the degree of DNA damage, were determined by a computer fitting of the Bateman function to the hydrolysis curve plotting of the fluorescence intensity of the
pararosaniline-Feulgen staining the
apurinic acid against the different hydrolysis times. The parameter values y0 and k2 of the cells treated by
hyperthermia were much higher than those of the cells treated without
hyperthermia. It is our conclusion that this microfluorometric detection would be valuable as an evaluation method for a
cancer therapy, although more data from other
cancers and treatments will be needed.