The glyoxalase system is modulated during cell division and differentiation and may also play an important role in cellular radiosensitivity. Glyoxalase I and glyoxalase II metabolize methylglyoxal to D-lactic acid, via D-lactoylglutathione.The glyoxalase enzymes activities were measured in erythrocytes of 17 healthy subjects and 41 patients with cancer of the larynx. The activities of glyoxalase I and glyoxalase II were decreased in the patients group in comparison to the control group and were as follows: 31.47±6.66 mU/mg protein and 11.73±3.21 mU/mg protein, respectively (control group: 42.40±7.28 and 19.66±2.62), (p< 0.0001). The activities of both glyoxalase I and glyoxalase II increased in patient erythrocytes following radiotherapy and in patients following combined therapy - surgery and radiotherapy. This was not so following surgery in comparison to enzymes activities in patients with cancer of the larynx cancer before therapy. The changes in glyoxalases activities following radiotherapy did not significantly differ from control group glyoxalase I and glyoxalase II activities.These results suggest that the glyoxalase system is affected by erythrocytes radiation.

Keywords: glyoxalases, cancer of the larynx, Radiotherapy