Tryptophan as the fingerprint for distinguishing aggressiveness among breast cancer cell lines using native fluorescence spectroscopy.

Tryptophan is investigated as the key native marker in cells to determine the level of metastasis competence in breast cell lines using native fluorescence spectroscopy. The ratio of fluorescence intensity at 340 nm to intensity at 460 nm is associated with aggressiveness of the cancer cells. We found that the fluorescence of aggressive breast cancer cell has a much higher contribution from tryptophan compared with that from the normal cells and nonaggressive breast cancer cell.