【摘要】 <正> 细胞姐妹染色单体交换 (SCE)频率的改变能真实地反映出DNA损害和/或修复,其灵敏性(或出现率)超过染色体或染色单体断裂二百倍,所以自1957年发现其观察方法以来逐渐已成为检测致变剂、致畸剂和致癌剂的细胞遗传学效应的一种新的重要技术。近年来又发现了一些有并发恶性肿瘤倾向的染色体不稳定性综合征,例如Bloom氏综合征,病人体细胞的SCE成倍地多于正常人~1。因此,国内外学者在SCE与恶性肿瘤的关联方面也作了许多研究。虽然,到目前为止,尚未观察到周围血淋巴细胞SCE频率增加肯定地导致了遗传缺陷或产生一种更多还原

【Abstract】 Studies and counts of sister chromatid exchange(SCE) in peripherat lymphocytes were carried out in 60 cancer patients, including 20 colo-rectal cancer, 20 nasopharyn-geal and 20 gastric cancer patients. Twenty age-matched normal adults served as con-trol. The mean frequency of SCEs/cell was 12.44, 11.06, 10.92 and 7.15, resoectivelv. There was statistically significant difference in SCE level between every group of patients and the controls(p<0.01). Exempted the influence of the factor of smok-ing, comparative studies on rate of SCE in non-smoker patients and non-smoker con-trnlc shnwped that the former had a higher leveI(p<0.01) too. Concerning the mechanism of statistically significant elevation of SCE frequency in cancer patients, the article related the results to three factors: environmental, meta- bolic and/or chromosome instability. Increased DNA damage induced by these factors led to increase of SCE rates. The SCE process has also been considered to reflect mi-totic recombination which may play a role in the predisposition to cancer formation. Recent aata in or out of this country showed that a“spontaneous”elevation of the SCE level in the lymphocytes might occur in some types of cancer patient. However, opinions were controversial. Further researches are needed to clarify this point.更多还原