大量研究證實(shí)上皮-間質(zhì)轉(zhuǎn)化（EMT）是與癌癥的侵襲和轉(zhuǎn)移有牽連的關(guān)鍵事件,。腫瘤細(xì)胞經(jīng)過血液循環(huán)傳播后，腫瘤細(xì)胞會發(fā)生間質(zhì)上皮轉(zhuǎn)化（MET）,，形成繼發(fā)性的腫瘤轉(zhuǎn)移灶。

然而,，腫瘤細(xì)胞的這種形態(tài)學(xué)上的變化并沒有從人類腫瘤標(biāo)本組織中得到很有力的證據(jù),。在上皮癌組織中,，上皮型細(xì)胞形態(tài)和基因表達(dá)在一定程度上得到了保留。雖然轉(zhuǎn)化成間質(zhì)型腫瘤細(xì)胞可能涉及許多癌癥類型包括肉瘤,，但在某些腫瘤中，分化成間質(zhì)型的腫瘤細(xì)胞并不利于轉(zhuǎn)移的發(fā)生發(fā)展,。

事實(shí)上,，有些類型的癌癥細(xì)胞是通過上皮-間質(zhì)轉(zhuǎn)化以及間質(zhì)上皮轉(zhuǎn)化過程侵入周圍組織并遷移，而不是通過淋巴管和血管發(fā)生轉(zhuǎn)移,。EMT的基因表達(dá)也與腫瘤組織學(xué)分級相關(guān),，而轉(zhuǎn)錄因子Snail、Slug和Twist傳統(tǒng)上被認(rèn)為是EMT的誘導(dǎo)因素,，在一定條件下,，他們也調(diào)解腫瘤細(xì)胞的去分化和維持干細(xì)胞狀態(tài)。

在各種惡性腫瘤包括基底細(xì)胞樣乳腺癌和大腸癌中上述基因經(jīng)常不穩(wěn)定,，未分化型腫瘤細(xì)胞可用來預(yù)測早期轉(zhuǎn)移擴(kuò)散以及預(yù)后差,。這項(xiàng)最新研究從臨床角度討論了一些腫瘤細(xì)胞分化和轉(zhuǎn)移的爭論，提出證據(jù)表明上皮型癌細(xì)胞在整個轉(zhuǎn)移過程是一直維持其上皮型形態(tài)的,。（生物谷：Bioon.com）

編譯自：Insights into cancer metastasis from a clinicopathologic perspective: Epithelial mesenchymal transition is not a necessary step

doi:10.1002/ijc.27745
PMC:
PMID:
Insights into cancer metastasis from a clinicopathologic perspective: Epithelial mesenchymal transition is not a necessary step

Michael Herman Chui*

Epithelial-mesenchymal transition (EMT) has been implicated as the critical event initiating cancer invasion and metastasis. After disseminating through the circulation, the malignant cells have been proposed to undergo subsequent mesenchymal-epithelial transition (MET) to form secondary tumours. However, strong evidence from human tumour specimens for this paradigm is lacking. In carcinomas, cancers derived from epithelial tissues, epithelial morphology and gene expression are almost always retained to some degree. While mesenchymal transdifferentiation may be involved in the pathogenesis of carcinosarcomas, even in these neoplasms, as well as in germ cell tumours capable of multi-lineage differentiation, the mesenchymal phenotype does not facilitate metastatic progression. Indeed, most cancers invade and travel through lymphatic and blood vessels via cohesive epithelial migration, rather than going through the EMT-MET sequence. EMT gene expression is also consistently associated with high histologic grade and while the transcription factors, Snail, Slug and Twist have traditionally been thought of as inducers of EMT, under certain conditions, they also mediate de-differentiation and maintenance of the stem cell state. In various malignancies, including basal-like breast cancer and colorectal cancer, the genetically unstable, undifferentiated phenotype predicts early metastatic spread and poor prognosis. This paper discusses some of the controversies surrounding differentiation and metastasis from a clinicopathologic perspective and presents evidence that the epithelial phenotype is maintained throughout the process of cancer metastasis.