title: Tumor-induced changes in host metabolism: a possible role for free tryptophan as a marker of neoplastic disease.
abstract: Tumor growth is associated with a number of metabolic abnormalities. Glucose metabolism is deranged as frequently revealed by an impaired oral glucose tolerance test. Lipoprotein lipase activity is depressed, resulting in hypertrigliceridemia after an exogenous lipid load. Also protein metabolism is deranged in cancer patients, as revealed by changes of plasma amino acid profile. Our previous studies on plasma amino acids have shown that increased plasma free tryptophan levels are a frequent finding in cancer patients. To sustain a possible role for free tryptophan as a marker of neoplastic disease, we measured its plasma concentrations in 241 patients with cancer. Plasma free tryptophan concentrations were found to be significantly elevated with respect to healthy controls in patients with breast, lung, colon, stomach, and cancer from various origin. The sensitivity of this marker in predicting the presence of the tumor was highest for stomach and lung cancer patients. High plasma free tryptophan concentrations seem to be directly related to the presence of the tumor, since in breast cancer patients they returned to within normal range after eradicative surgery.
authors.affiliation: Department of Clinical Medicine, University of Rome La Sapienza, Rome, Italy. alessandro.laviano@uniroma1.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Laviano
authors.forename: Antonia
authors.initials: A
authors.lastname: Cascino
authors.forename: Maurizio
authors.initials: M
authors.lastname: Muscaritoli
authors.forename: Francesca
authors.initials: F
authors.lastname: Fanfarillo
authors.forename: Filippo
authors.initials: F
authors.lastname: Rossi Fanelli
mesh_terms: D000596:Amino Acids / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood*; D050260:Carbohydrate Metabolism; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism; D009369:Neoplasms / Q000097:blood* / Q000378:metabolism; D014364:Tryptophan / Q000097:blood*
chemical_list: D000596:Amino Acids; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D014364:Tryptophan