OBJECTIVETo explore the features of DNA damage in nasopharyngeal carcinoma (NPC) patients of normal constitution and abnormal constitution and in high-risk population of NPC.

METHODSUsing single cell gel electrophoresis technique, the DNA damage of peripheral blood lymphocytes was detected in 28 healthy subjects, 27 in high-risk population of NPC, and 13 NPC patients at their first visits. The DNA damage was detected in the populations of normal constitution and of abnormal constitution. The tail length, the tail moment, and the tail DNA% were taken as the indices of DNA damage.

RESULTSThe tail length was (35.77 +/- 4.22) microm, the tail moment was (8.10 +/- 1.63) microm, and the tail DNA% was 57.48% +/- 4.63% in NPC patients. They were (15.25 +/- 4.15) microm, (5.01 +/- 1.92) microm, and 31.99% +/- 4. 11% in high-risk population of NPC. They were (14.31 +/- 3.64) microm, (4. 37 +/- 1.80) microm, and 29. 89% +/- 3. 15% in healthy subjects. There was statistical difference in the three indices among the three populations (P <0.05). In all the three populations, more DNA damage existed in those of abnormal constitution than in those of normal constitution (P <0.05).

CONCLUSIONSObvious instability of genetic materials exists in NPC patients, manifested as severe DNA damage of lymphocytes. In all the three populations, more DNA damage existed in those of abnormal constitution than in those of normal constitution.