Long non-coding RNA（lncRNA）has become a research hotspot in recent years，and it has been proved that abnormal expressions of some certain lncRNAs are closely related to the occurrence and progression of tumors. Among many kinds of lncRNAs，the metastasis associated lung adenocarcinoma transcript 1（MALAT1）is upregulated in metastatic carcinoma cells. MALAT1 was widely expressed in normal tissues，and the expressions displayed significant differences in a variety of human tumor tissues，cells and peripheral blood，which suggests that MALAT1 may play an important role in the process of tumorigenesis，progression，invasion and metastasis. Herein we document the molecular characteristics and functions of MALAT1 with a reference to their implications in the molecular pathology of various cancers.