The MAL gene encodes a membrane proteolipid that is responsible for the formation and trafficking of apical transport vesicles in polarized epithelial cells. This apiral transportation is fundamental for the establishment and maintenance of polarity in epithelial cells. So MAL protein plays an essential role in the establishment of cell polarity. Defects in cell polarity are closely related with cancer occurrence and transformation. As a new growth -suppressor candidate for tumor. The MAL gene inactivation and ahnormalitv has certain relations with the cell signal transduction, the tumor occurrence development and the clinical prognosis. And a decrease of MAL expression mav be an important biomarker to define cancer cell subpopulations with metastatic ahility. Loss of heterozygosity and hypermethylation of the promoter region appear to be important mechanisms for inactivation of MAL function. Morever, further functional studies are needed to clarify the role of MAL in the metastatic process of carcinoma.%MAL基因编码一种膜脂蛋白,这种MAL蛋白在极化上皮细胞中负责形成和贩运顶端运输囊泡.而这种顶端运输是建立和维持上皮细胞极性的根本.因此MAL蛋白在建立细胞极性中发挥着重要作用.细胞极性的缺陷与癌症的发生和转移有关,目前的研究已经证明MAL基因是抑制肿瘤生长的新基因,MAL基因失活及异常与细胞信号转导、肿瘤的发生发展和临床预后等有一定关系.而且MAL表达减少可作为一个重要的生物标志物来界定有转移能力的癌症细胞亚群.杂合性丢失和启动子区甲基化似乎是MAL功能失活的重要机制.另外,还需要进一步的研究来阐明MAL在恶性肿瘤转移中的作用机制.
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