背景介紹
循環(huán)腫瘤細(xì)胞(circulating tumor cell, CTC)是指由原發(fā)灶脫落，侵入血液循環(huán)的腫瘤細(xì)胞。CTC能逃避機(jī)體免疫，在原發(fā)或遠(yuǎn)處臟器駐留，從而形成復(fù)發(fā)、轉(zhuǎn)移病灶。原發(fā)腫瘤生長到一定階段，會侵襲周圍血管，腫瘤細(xì)胞會首先通過整聯(lián)蛋白附著在血管基底膜處生長；當(dāng)腫瘤細(xì)胞數(shù)量逐漸增多，其分泌的基質(zhì)金屬蛋白酶也逐漸增加，通過逐步消化掉IV型膠原蛋白，突破基底膜屏障，進(jìn)入血液，即被稱為CTC；CTC進(jìn)入血液后，會隨著血液循環(huán)游走全身，形成復(fù)發(fā)轉(zhuǎn)移，不同腫瘤的遠(yuǎn)處轉(zhuǎn)移與血流分布有很大關(guān)系。例如乳腺癌一般會在肺部有繼發(fā)性病灶，而結(jié)腸癌則常形成肝轉(zhuǎn)移。
循環(huán)腫瘤細(xì)胞是近30年來研究應(yīng)用的僅有的幾個(gè)新型腫瘤分子標(biāo)志物之一。通過檢測CTC數(shù)量和蛋白表達(dá)可對腫瘤進(jìn)行確診、判斷預(yù)后、監(jiān)控療效。例如，當(dāng)CTC出現(xiàn)上皮間質(zhì)轉(zhuǎn)換（EMT）、過表達(dá)上皮細(xì)胞粘附分子往往提示腫瘤患者預(yù)后不佳；通過對比手術(shù)或放化療前后血液中CTC數(shù)量，可以判斷治療是否有效，具有重要的臨床研究及應(yīng)用價(jià)值。
參考文獻(xiàn)：
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