SELENIUM AND GSH-PX ACTIVITIES IN NPC PATIENTS BEFOREAND AFTER RADIOTHERAPY

The blood samples colleted from 68 nasoparyngeal carcinoma(NPC) patients in stage 11, 111, IV before and at the end of radiotherapy and from46 healthy persons were analysed for selenium (Se) and glutatione peroxidase (GSH-PXActivities No significant difference in selenium level was found between the NPC patients before radiotherapy and control group (P0.05). The selenium level in patients after radiotherapy was significantly lower than that in the normal control group (P P.05). The selen-iumlevel in NPC patients of different clinical stage after radiotherapy were lower than that in the control group. Furthermore, the selenium content of these patients decreased gradually with disease development However, the GSH-PX activities in NPC patients not only before radiotherapy, but also at the end of it were significantly lower than those of the normal control group(P0.01). The enzyme activities in patients before and after radiotherapy of different clinical stages were lower than those of control group(F = 9.76P 0.0001). In addition, it was found that the activities of GSH-PX in patients before and after radiotherapy decrease gradually with clinical stages of disease development. These suggested the determination of GSH-PX activities in NPC patients may be helpful in monitoring the clinical progression of the disease.