Characterization of malignant colon tumors with 31p 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 using 31P magnetic resonance spectroscopy. Methods. Eleven individual generic 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 vessel invasion (BVI), and lymphatic vessel invasion (LVI). Results. Significant elevations in the relative concentration of α-glycerol phosphate were noted when comparing AJCC tumor classification (T3 vs. T2, 0.92 ± 0.14 vs. 0.46 ± 0.11, P < 0.009), tumor differentiation (moderately vs. well differentiated, 0.92 ± 0.14 vs. 0.46 ± 0.11, P < 0.009), 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 analyzed, the relative concentration of a choline phospholipid was significantly 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). Differences in lymph node status of the cases analyzed in this study (lymph 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 glycerol 3-phosphoserine (0.48 ± 0.01 vs. 0.23 ± 0.02, P< 0.002). Conclusions. The characteristic differences in the phospholipid and intermediate phosphate metabolite profiles identified through magnetic resonance spectroscopic and histopathologic analysis may provide important information regarding the nature of tumor and cell membrane metabolism. Differences in these profiles may identify markers useful for biologic behavior, provide prognostic information, and characterize the impact of the pathologic features of colon cancer. Cancer 1995; 76:1715–23.