分化染色技术的进展,使检出培养细胞内姊妹染色单体互换(SCE)较为容易进行。最近研究结果表明电离辐射、紫外线和各种致变剂——致癌剂可使SCE发生率增高,有时在低剂量时即能引起染色体明显损伤。已经发现,Bloom氏综合征病人的细胞中自发的SCE率较高,而且提出,接触已知的或可疑的致癌物质或恶性发展时,可能与SCE发生率增高有关。本文报告急性淋巴细胞性白血病(ALL)患儿在发病前、 Advances in differentiation and staining techniques have made it easier to detect sister chromatid exchange (SCE) in cultured cells. Recent studies have shown that ionizing radiation, ultraviolet light, and various types of mutagens, carcinogens, can increase the incidence of SCE, and sometimes can cause significant chromosome damage at low doses. It has been found that the spontaneous SCE rate in patients with Bloom’s syndrome is high, and it is suggested that exposure to known or suspected carcinogens or malignant development may be associated with an increased incidence of SCE. This article reports on children with acute lymphoblastic leukemia (ALL)