Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP Brazil.
Genet Mol Biol. 2010 Oct;33(4):637-40. doi: 10.1590/S1415-47572010005000082. Epub 2010 Dec 1.
Breast cancer (BC) is the most prevalent type worldwide, besides being one of the most common causes of death among women. It has been suggested that sporadic BC is most likely caused by low-penetrance genes, including those involved in DNA repair mechanisms. Furthermore, the accumulation of DNA damage may contribute to breast carcinogenesis. In the present study, the relationship between two DNA repair genes, viz., XRCC1 (Arg399Gln) and XRCC3 (Thr241Met) polymorphisms, and the levels of chromosome damage detected in 65 untreated BC women and 85 healthy controls, was investigated. Chromosome damage was evaluated through micronucleus assaying, and genotypes determined by PCR-RFLP methodology. The results showed no alteration in the risk of BC and DNA damage brought about by either XRCC1 (Arg399Gln) or XRCC3 (Thr241Met) action in either of the two groups. Nevertheless, on evaluating BC risk in women presenting levels of chromosome damage above the mean, the XRCC3Thr241Met polymorphism was found to be more frequent in the BC group than in the control, thereby leading to the conclusion that there is a slight association between XRCC3 (241 C/T) genotypes and BC risk in the subgroups with higher levels of chromosome damage.
乳腺癌（BC）是世界上最常见的类型，也是女性死亡的最常见原因之一。有人认为散发性 BC 很可能是由低外显率基因引起的，包括参与 DNA 修复机制的基因。此外，DNA 损伤的积累可能导致乳腺癌的发生。本研究调查了两个 DNA 修复基因 XRCC1（Arg399Gln）和 XRCC3（Thr241Met）多态性与 65 名未经治疗的 BC 女性和 85 名健康对照者中检测到的染色体损伤水平之间的关系。通过微核测定评估染色体损伤，通过 PCR-RFLP 方法确定基因型。结果表明，在两组中，XRCC1（Arg399Gln）或 XRCC3（Thr241Met）作用均未改变 BC 和 DNA 损伤的风险。然而，在评估染色体损伤水平高于平均值的女性的 BC 风险时，发现 XRCC3Thr241Met 多态性在 BC 组中比对照组更为频繁，从而得出结论，在染色体损伤水平较高的亚组中，XRCC3（241 C/T）基因型与 BC 风险之间存在轻微关联。
