The alterations of tyrosine and tryptophane residues along with the evolution of tumor: Determination by synchronous fluorescence spectra

Synchronous fluorescence spectra were applied to assess tyrosine (Tyr) and tryptophane (Trp) residues in the plasma of patients with hepatocellular carcinoma, tumor-bearing mice and in cultured cells (HepG2 and L-02). The results showed for the first time that the fluorescent intensities of Tyr and Trp residues increased significantly in the plasma proteins of patients suffering hepatocellular carcinoma. There is a correlation between the increase of murine plasma Tyr or Trp residues fluorescent intensities and the increasing time of tumor-bearing, indicating that the alterations of Tyr and Trp residues may be associated with tumor development. On the contrary, the fluorescent intensities of Tyr and Trp residues in tumor tissue or HepG2 cells decreased along with the increasing time of tumor-bearing or culture. These results suggested a profound imbalance of protein metabolism in tumor evolution process.