CHARACTERIZATION OF MALIGNANT COLON TUMORS WITH P-31 NUCLEAR-MAGNETIC-RESONANCE PHOSPHOLIPID AND PHOSPHATIC METABOLITE PROFILES

Background. To further characterize selected pathologic features on a biochemical level, the authors analyzed the nuclear magnetic resonance metabolite and phospholipid spectra of 30 malignant colon tumors usin g (31)p magnetic resonance spectroscopy. Methods. Eleven individual ge neric phospholipids were identified in the spectra of 17 phospholipid extracts, and 31 individual phosphatic metabolites were identified in the spectra of 13 perchloric acid extracts. The metabolites and lipids were quantified for statistical intergroup comparisons based on tumor stage, lymph node status, differentiation, mucin production, blood ve ssel invasion (BVI), and lymphatic vessel invasion (LVI). Results. Sig nificant elevations in the relative concentration of a-glycerol phosph ate were noted when comparing AJCC tumor classification (T3 vs. T2, 0. 92 +/- 0.14 vs. 0.46 +/- 0.11, P < 0.009), tumor differentiation (mode rately vs. well differentiated, 0.92 +/- 0.14 vs. 0.46 +/- 0.11, P < 0 .099), and BVI (presence vs. absence, 1.03 +/- 0.04 vs. 0.68 +/- 0.10, P < 0.028) by elastic tissue stain. Among the tissue phospholipids an alyzed, the relative concentration of a choline phospholipid was signi ficantly different when comparing moderately and poorly differentiated tumors (6.26 +/- 0.56 vs. 3.29 +/- 0.30, P < 0.001), T2 and T3 tumors (3.90 +/- 0.45 vs. 6.31 +/- 0.56, P < 0.009), and mucin-positive vs. mucin-negative tumors (4.46 +/- 0.56 vs. 6.83 +/- 0.76, P < 0.028). Di fferences in lymph node status of the cases analyzed in this study (ly mph node positive vs. lymph node negative) were noted for tumors with elevated levels of sphingomyelin (8.13 +/- 0.40 vs. 6.88 +/- 0.16, P < 0.02), diminished levels of phosphatidylinositol (5.25 +/- 0.27 vs. 6 .38 +/- 0.34, P < 0.02), elevated levels of beta-glycerol phosphate (5 .30 +/- 0.70 vs. 1.20 +/- 0.06, P < 0.05), and elevated levels of glyc erol 3-phosphoserine (0.48 +/- 0.01 vs. 0.23 +/- 0.02, P < 0.002). Con clusions. The characteristic differences in the phospholipid and inter mediate phosphate metabolite profiles identified through magnetic reso nance spectroscopic and histopathologic analysis may provide important information regarding the nature of tumor and cell membrane metabolis m. Differences in these profiles may identify markers useful for biolo gic behavior, provide prognostic information, and characterize the imp act of the pathologic features of colon cancer.