zui近英國(guó)牛津大學(xué)科研人員進(jìn)行的一項(xiàng)研究確認(rèn)，遺傳因素和環(huán)境因素對(duì)乳腺癌發(fā)病風(fēng)險(xiǎn)的影響是相互獨(dú)立的，控制環(huán)境因素可有效降低乳腺癌的發(fā)病率。相關(guān)研究成果發(fā)表在zui近一期的《柳葉刀》雜志上。

乳腺癌的風(fēng)險(xiǎn)因素包括環(huán)境（生活方式和行為等）因素和遺傳因素兩大類，其中環(huán)境因素，如激素替代療法的使用、生育歷史、肥胖、飲酒等，是引發(fā)乳腺癌的主要原因。而遺傳因素是否會(huì)與環(huán)境因素相互作用，從而進(jìn)一步增加患病風(fēng)險(xiǎn)，學(xué)界一直沒(méi)有明確。

牛津大學(xué)癌癥疫學(xué)所的研究人員對(duì)英國(guó)7160名乳腺癌患者和10196名健康婦女的基因和環(huán)境因素信息進(jìn)行了研究。通過(guò)對(duì)12個(gè)和乳腺癌相關(guān)的常見(jiàn)基因變異與10個(gè)乳腺癌環(huán)境風(fēng)險(xiǎn)因素，包括生育次數(shù)、生育*胎時(shí)的年齡、是否母乳喂養(yǎng)、是否使用激素替代療法、肥胖、飲酒等，進(jìn)行比較研究后確認(rèn)，這兩類風(fēng)險(xiǎn)因素之間并不存在相互作用的情況，即使是激素替代療法也不會(huì)對(duì)遺傳因素產(chǎn)生影響。也就是說(shuō)，基因變異與不良生活方式都會(huì)增加罹患乳腺癌的風(fēng)險(xiǎn)，但二者互不相干。

需要指出的是，12個(gè)變異基因中不包括罕見(jiàn)的乳腺癌易感基因BRCA1和BRCA2。這兩個(gè)基因攜帶者罹患乳腺癌的風(fēng)險(xiǎn)很高，但有此基因變異的人也很少。

研究人員指出，確認(rèn)遺傳因素和環(huán)境因素這兩種風(fēng)險(xiǎn)因素間的關(guān)系可使醫(yī)生更好地理解它們對(duì)乳腺癌的影響。在罹患乳腺癌的婦女中，受遺傳因素影響發(fā)病的比例并不大，大多數(shù)婦女患病的原因要?dú)w罪于環(huán)境因素，而這些因素是可以人為控制的。因此，通過(guò)對(duì)環(huán)境風(fēng)險(xiǎn)因素的控制，就可以在很大程度上降低乳腺癌的發(fā)病率。

上海勁馬生物（）推薦原文出處：

The Lancet doi:10.1016/S0140-6736（10）60636-8

Gene—environment interactions in 7610 women with breast cancer: prospective evidence from the Million Women Study
Dr Ruth C Travis DPhil a , Gillian K Reeves PhD a, Jane Green MD a, Diana Bull a, Sarah J Tipper MSc a, Krys Baker a, Prof Valerie Beral FRS a, Prof Richard Peto FRS b, Prof John Bell FRS c, Diana Zelenika PhD d, Prof Mark Lathrop PhD d, for the Million Women

Background
Information is scarce about the combined effects on breast cancer incidence of low-penetrance genetic susceptibility polymorphisms and environmental factors （reproductive, behavioural, and anthropometric risk factors for breast cancer）. To test for evidence of gene—environment interactions, we compared genotypic relative risks for breast cancer across the other risk factors in a large UK prospective study.
Methods
We tested gene—environment interactions in 7610 women who developed breast cancer and 10 196 controls without the disease, studying the effects of 12 polymorphisms （FGFR2-rs2981582, TNRC9-rs3803662, 2q35-rs13387042, MAP3K1-rs889312, 8q24-rs13281615, 2p-rs4666451, 5p12-rs981782, CASP8-rs1045485, LSP1-rs3817198, 5q-rs30099, TGFB1-rs1982073, and ATM-rs1800054） in relation to prospectively collected information about ten established environmental risk factors （age at menarche, parity, age at first birth, breastfeeding, menopausal status, age at menopause, use of hormone replacement therapy, body-mass index, height, and alcohol consumption）.
Findings
After allowance for multiple testing none of the 120 comparisons yielded significant evidence of a gene—environment interaction. By contrast with previous suggestions, there was little evidence that the genotypic relative risks were affected by use of hormone replacement therapy, either overall or for oestrogen-receptor-positive disease. Only one of the 12 polymorphisms was correlated with any of the ten other risk factors: carriers of the high-risk C allele of MAP3K1-rs889312 were significantly shorter than non-carriers （mean height 162·4 cm [95% CI 162·1—162·7] vs 163·1 cm [162·9—163·2]; p=0·01 after allowance for multiple testing）.
Interpretation
Risks of breast cancer associated with low-penetrance susceptibility polymorphisms do not vary significantly with these ten established environmental risk factors.
Funding
Cancer Research UK and the UK Medical Research Council.