Decreased serum tryptophan in patients with cancer cachexia correlates with increased serum neopterin.
We investigated serum tryptophan (Trp), neopterin (NPT) and immunosuppressive acidic protein (IAP), one of tumor-associated tumor marker, concentrations in 28 patients with gastrointestinal tumors representing cancer cachexia and 10 healthy controls. NPT comes from activated macrophages presumably activated by tumor-sensitized T cells via gamma-interferon (IFN-gamma) excitation of the macrophages. We found that the NPT level was significantly higher than the control value. The negative correlation of NPT and Trp concentrations indicates activity of indoleamine 2,3-dioxygenase (IDO), a Trp degradating enzyme, in cancer-burden patients. The activity of IDO can be induced by cytokines such as IFN-gamma, and therefore low Trp levels may result from endogenous IFN-gamma production due to immune activation against tumors. We also found a positive correlation between NPT and IAP levels, suggesting that host immune activation against tumors played a role in the immunosuppression of cancer-burden states, followed by cancer-cachexia.
Iwagaki
H
H
First Department of Surgery, Okayama University Medical School, Japan.
Hizuta
A
A
Tanaka
N
N
Orita
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001708:Biopterins / Q000031:analogs & derivatives* / Q000097:blood; D002100:Cachexia / Q000097:blood* / Q000201:enzymology / Q000209:etiology*; D002272:Carcinoembryonic Antigen / Q000097:blood; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000737:chemistry / Q000150:complications*; D006801:Humans; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D008264:Macrophages / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood; D019798:Neopterin; D014364:Tryptophan / Q000097:blood*; D014366:Tryptophan Oxygenase / Q000097:blood
D002272:Carcinoembryonic Antigen; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D009363:Neoplasm Proteins; C030193:immunosuppressive acidic protein; D001708:Biopterins; D019798:Neopterin; D014364:Tryptophan; D014366:Tryptophan Oxygenase