Spurdle A B, Dite G S, Chen X, Mayne C J, Southey M C, Batten L E, Chy H, Trute L, McCredie M R, Giles G G, Armes J, Venter D J, Hopper J L, Chenevix-Trench G
Cancer Unit, Joint Experimental Oncology Programme, Queensland Institute of Medical Research, and The University of Queensland, Brisbane, Australia.
J Natl Cancer Inst. 1999 Jun 2;91(11):961-6. doi: 10.1093/jnci/91.11.961.
We conducted a population-based, case-control-family study to determine whether androgen receptor (AR) exon 1 polymorphic CAG repeat length (CAGn) was a risk factor for early-onset breast cancer in the Australian population.
Case subjects under 40 years of age at diagnosis of a first primary breast cancer and age-matched control subjects were interviewed to assess family history and other risk factors. AR CAGn length was determined for 368 case subjects and 284 control subjects. Distributions in the two groups were compared by linear and logistic regression, allowing adjustment for measured risk factors. All statistical tests were two-tailed.
When analyzed as either a continuous or a dichotomous variable, there was no association between CAG, length and breast cancer risk, before or after adjustment for risk factors. Mean (95% confidence interval [CI]) CAGn lengths were 22.0 (21.8-22.2) for case subjects and 22.0 (21.7-22.3) for control subjects (P = .9). The frequency (95% CI) of alleles with 22 or more CAGn repeats was 0.531 (0.494-0.568) for case subjects and 0.507 (0.465-0.549) for control subjects (P = .4). After adjustment, the average effect on log OR (odds ratio) per allele was 0.16 (95% CI = -0.03 to 0.40; P = .2), and the effect of any allele was equivalent to an OR of 1.40 (95% CI = 0.94-2.09; P = .1). Stratification by family history also failed to reveal any association. Similar results were obtained when alleles were defined by other cutoff points.
We found no evidence for an association between AR exon 1 CAGn length and breast cancer risk in women under the age of 40, despite having 80% power to detect modest effects.
我们开展了一项基于人群的病例对照家系研究，以确定雄激素受体（AR）外显子1多态性CAG重复长度（CAGn）是否为澳大利亚人群早发性乳腺癌的一个风险因素。
对诊断为原发性乳腺癌的40岁及以下病例受试者和年龄匹配的对照受试者进行访谈，以评估家族史和其他风险因素。测定了368例病例受试者和284例对照受试者的AR CAGn长度。通过线性回归和逻辑回归比较两组的分布情况，并对测量的风险因素进行校正。所有统计检验均为双侧检验。
无论是将CAG长度作为连续变量还是二分变量进行分析，在对风险因素进行校正前后，CAG长度与乳腺癌风险之间均无关联。病例受试者的平均（95%置信区间[CI]）CAGn长度为22.0（21.8 - 22.2），对照受试者为22.0（21.7 - 22.3）（P = 0.9）。CAGn重复次数为22次或更多的等位基因频率（95%CI），病例受试者为0.531（0.494 - 0.568），对照受试者为0.507（0.465 - 0.549）（P = 0.4）。校正后，每个等位基因对log OR（比值比）的平均影响为0.16（95%CI = -0.03至0.40；P = 0.2），任何一个等位基因的影响相当于OR为1.40（95%CI = 0.94 - 2.09；P = 0.1）。按家族史分层也未发现任何关联。当通过其他切点定义等位基因时，获得了类似结果。
我们没有发现证据表明40岁以下女性中AR外显子1 CAGn长度与乳腺癌风险之间存在关联，尽管有80%的把握度可检测到中等程度的效应。
