A single gene variant predicts breast cancer survival after tamoxifen treatment, a new study finds.

    In the 46% of women with the "good" gene, tamoxifen works as well as newer drugs. For women with the gene variant linked to poor response to tamoxifen treatment, other treatment strategies would be a better choice.

    In the past 25 years, tamoxifen has prevented more than half a million deaths from breast cancer. The drug helps prevent breast cancer recurrence after surgery. Tamoxifen is still a useful drug, although newer drugs called aromatase inhibitors seem to work better in clinical trials.

    Now it appears that some women will do at least as well if they're treated with tamoxifen. Such women carry a version of a gene called CYP2D6 that makes tamoxifen work better.

    The gene encodes an enzyme crucial to tamoxifen activity. About 46% of women have a version of the gene that contributes to high enzyme activity. Others have genes that contribute to low or intermediate activity of the enzyme.

    Werner Schroth, PhD, of Germany's Fischer-Bosch Institute of Clinical Pharmacology, and colleagues analyzed CYP2D6 genes in 1,325 postmenopausal women treated with tamoxifen for early-stage breast cancer in Germany and in the U.S.

    They found that women with the highly active version of the gene were significantly less likely to have their breast cancer come back after five years of tamoxifen treatment. These women had outcomes similar to those seen in women treated with aromatase inhibitors.

    "[This] should provide new impetus to the medical and scientific community to revisit the issue of the relative efficacy of these two approaches in women with early breast cancer," Schroth and colleagues conclude.

    The researchers suggest that genetic testing could identify women who should not be treated with tamoxifen.

    最新發(fā)現(xiàn)表明，單個(gè)基因變異體可以預(yù)測(cè)經(jīng)過它莫西芬治療后乳腺癌患者的存活情況。

    在46%攜帶該"好"基因的婦女中，它莫西芬與新藥的治療效果相同。攜帶該基因變異體的婦女，對(duì)它莫西芬治療耐受，因此其他的治療方案會(huì)更好。

    在過去的25年中，它莫西芬使超過50萬(wàn)的患者免于死于乳腺癌。該藥物還阻止術(shù)后乳腺癌的復(fù)發(fā)。因此它莫西芬仍然是一個(gè)非常有效的藥物，雖然新的芳香酶抑制劑藥物在臨床試驗(yàn)上效果似乎更好。

    現(xiàn)在看起來(lái)一些婦女用它莫西芬治療的效果會(huì)很好。這些婦女?dāng)y帶有CYP2D6基因的一個(gè)變異體，該變異體使它莫西芬的作用效果更好。

    該基因編碼一個(gè)酶，這個(gè)酶在它莫西芬活性發(fā)揮過程中非常關(guān)鍵。大約46%的婦女?dāng)y帶該基因的一種變異體，這種變異使該酶的活性大大增強(qiáng)。而其他婦女?dāng)y帶的變異體的酶活性較低或中等。

    Werner Schroth是德國(guó)Fischer-Bosch臨床藥理研究所的博士。他和同事研究了1325例德國(guó)以及美國(guó)使用它莫西芬治療早期乳腺癌的絕經(jīng)后的婦女的CYP2D6基因。

    他們發(fā)現(xiàn)攜帶該基因高活性變異體的婦女在經(jīng)過5年它莫西芬治療后，乳腺癌復(fù)發(fā)率很低。其治療效果與使用芳香酶抑制劑治療的婦女的治療效果相似。

    Schroth及同事斷定說(shuō)："這將給醫(yī)學(xué)以及科學(xué)協(xié)會(huì)新的動(dòng)力去評(píng)價(jià)這兩種方法在治療婦女早期乳腺癌的作用。

    研究人員認(rèn)為遺傳檢測(cè)可以確定哪些婦女應(yīng)該用它莫西芬治療。