HORMONALLY INDUCED MODULATION IN THE PHOSPHATE METABOLITES OF BREAST-CANCER - ANALYSIS OF IN-VIVO P-31 MRS SIGNALS WITH A MODIFIED PRONY METHOD

A modified Prony method (MPM) was applied to analyze the main signals present in spatially resolved P-31 NMR spectra of MCF7 breast tumors i mplanted in nude mice, First, the method was tested on synthetic data to establish its limits of reliability, Its performance with respect t o peak identification and quantification of signal intensities was the n exploited on data from three implanted tumors during hormonal manipu lation with estrogen and the antiestrogenic drug tamoxifen, The phosph omonoester peak was resolved into phosphocholine (PC) and phosphoethan olamine (PE), Treatment with tamoxifen led to a significant reduction in the PE to PE+PC peak amplitude ratio in the tumors under considerat ion, MPM analysis also revealed the presence of two different inorgani c phosphate pools: a larger acidic pool and a smaller alkaline pool du ring estrogen-induced growth and the reverse during tumor regression.