Clinical significance of simultaneous determination of serum tryptophan and tyrosine in patients with lung cancer

Background: To explore the clinical significance of serum tyrosine (Tyr) and tryptophan (Trp) in patients with lung cancer, we used a simple and efficient method of high‐performance liquid chromatography with fluorescence detection (HPLC‐FD) that simultaneously measured serum Trp and Tyr contents. Methods: The concentrations of Tyr and Trp were measured simultaneously by HPLC‐FD in the sera of 80 patients with lung cancer and 120 healthy controls. Results: Trp concentrations were significantly lower in patients with lung cancer than in healthy controls (39.26±5.44 vs. 49.93±5.43 µmol/l, respectively; P0.05). In addition, patients in the adenocarcinoma group had significantly lower Trp and Tyr concentrations than those in squamous cell carcinoma group. There was no difference between the early stage and advanced stage of lung cancer. Conclusions: Determination of serum Trp and Tyr concentrations can be employed to assist the diagnosis of the histotypes of lung cancer and tumor stage. Tyr and Trp as indexes on the lung cancer diagnostic sensitivity, specificity were 54.9, 62.9% and 82.4, 92.1%, Trp is an important and special index for lung cancer diagnosis of which the specificity of diagnosis of lung cancer is more than 92%. J. Clin. Lab. Anal. 25:246–250, 2011. © 2011 Wiley‐Liss, Inc.