Tryptophan and its metabolites in patients with oral squamous cell carcinoma: preliminary study

It has been showed that tryptophan (TRP) degradation has been linked to modulation of cancer cell proliferation. The aim of our study was to estimate the concentration of TRP and its derivatives, such as anthranilic (AA) and kynurenic acid (KYNA) in plasma, saliva, squamous cell carcinoma (SCC) tissues and healthy oral mucosa in patients with oral SCC.

The study was performed on plasma, non-stimulated, mixed saliva and squamous cell carcinoma tissues and healthy oral mucosa in patients with oral SCC. The concentration of TRP and its metabolites were determined by high-performance liquid chromatography (HPLC).

In plasma the concentration of TRP was 33.73 +/- 2.52 microM, of KYNA was 26.97 +/- 5.35 nM and of AA was 32.40 +/- 2.30 nM. In saliva the concentration of TRP was 3.81 +/- 0.62 microM, of KYNA was 8.06 +/- 1.86 nM and of AA was 20.41 +/- 10.77 nM. In cancer tissues the levels of TRP (30.21 +/- 5.88 microM), KYNA (15.85 +/- 1 .82 nM) and AA (265.32 +/- 1 51.45 nM) were higher in respect to the concentration of TRP (13.28 +/- 0.62 microM), KYNA (12.75 +/- 2.28 nM) and AA (31.68 +/- 8.89 nM) in normal tissues. The increase in the content of TRP, KYNA and AA in cancer tissues reached 127.48 +/- 5.95%, 24.31 +/- 4.35% and 737.50 +/- 206.96%, respectively.

Our study has demonstrated the change of TPR metabolism, which is reflected by the increase TRP, AA and KYNA concentrations in patients with oral squamous cell carcinoma. We can suppose that these substances may be one of many factors responsible for cancer development.