恶性肿瘤转移机制研究新进展

肿瘤分为良性肿瘤和恶性肿瘤,两者的主要区别是后者有转移和复发倾向。转移是预后不良的征兆,也是癌症患者死亡的主要原因。肿瘤的转移是包括肿瘤细胞脱离原发灶侵入细胞外基质,侵袭附近血管和淋巴管而进入循环系统,并与血小板和靶点处内皮细胞黏附,并相互作用而穿出脉管系统,在靶点处形成新的克隆,有效地逃避机体免疫清除等事件在内的一系列"级联反应"。目前,已在少数实体瘤中分离出干细胞样细胞,即所谓的"肿瘤干细胞",这些细胞虽然数目极少,但有高度的成瘤性,有可能是肿瘤发生、发展及转移根源。

Update of the metastatic mechanisms of malignant tumors

Tumors are classified into two major categories,benign and malignant.One main difference between malignant and benign tumors is their tendency to metastasize and recur.The metastasis itself is an ominous sign for prognosis and responsible for most cancer deaths.The metastatic "cascade" comprises a lot of steps,including escape from the primary tumor site,penetration of local stroma,entry of local vascular or lymphatic vessels,aggregation with platelets,interaction with and adhesion to distant endothelia,extravasation,recolonization,and expansion,all the time avoiding effective immune clearance and being able to survive.It has now been shown to contain stem cell-like cells called cancer stem cells(CSC) in several solid tumors.Although generally rare,these cells appear to be highly tumorigenic and may drive tumor formation and mediate tumor metastasis.