The important role of Twist1 in promoting cell survival, cell invasion and immigration, and facilitating tumor angiogenesis. Both Twist1 and Twist2 are known to mediate EMT in human cancers. Twist1 is a key regulator of metastasis. It has been shown that Twist1 promotes EMT through down-regulation of E-cadherin in subsets of sporadic invasive human lobular breast cancer, but little is known about the expression pattern of Twist2. Twist2 activates EMT programs and facilitates a cancer stem cell phenotype in breast cancer. However, the role of Twist2 in promoting breast cancer invasion and metastasis has not been established in the context of the breast microenvironment. In addition, the identification and clinical relevance of Twist2 in breast cancer is not known. We showed that Twist2 was up-regulated in human primary breast carcinoma tissues compared with the matched normal breast tissues. Twist2 was expressed mostly in cytoplasm as demonstrated by immunohistochemical assay in tissue microarray. Cytoplasmic Twist2 was associated with tumor histological type, the TNM clinical stage and tumor metastasis. Our study showed that, in some cases of invasive ductal breast carcinoma, Twist2 were mainly localized in cytoplasm of cancer cells expressing E-cadherin at tumor center and the lymph metastases. In contrast, nuclear Twist2 were detected in cancer cells located at the invasive margins of primary breast cancer. In this study we report that Twist2 promotes breast cancer invasion through loss of E-cadherin. Our data suggested that there was a link between nuclear Twist2 and EMT and the EMT process depends on Twist2 cellular location. These results demonstrate an important role of Twist2 in breast cancer invasion and indicate that Twist2 may be a new EMT indicator for dissemination of breast cancer. It has been well recognized that EMT plays a critical role in cancer metastasis. However, the difficulty to directly demonstrate the role of EMT in metastasis in vivo is to validate cancer cells that have undergone an EMT in primary human tumor specimens. The molecular mechanism associated with the involvement of EMT in tumor metastasis is still highly debated. As clinical observations showed that the majority of human breast carcinoma cells in metastases express E-cadherin and maintain their epithelial morphology, cancer cells may have disseminated without switching to a mesenchymal phenotype. The master regulators of tumor invasion and metastasis were largely unknown. Twist1 is one of essential factors to promote tumor metastasis. The hypothesis that cancer cells routinely undergo a complete EMT program is likely to be simplistic. In breast cancer, Twist1 only partially induced an EMT program. Twists belong to bHLH transcription factor family which form either homo-or-heterodimers with other bHLH proteins to bind to a core E-box sequence on the promoter region of target genes such as E-cadherin. It has been reported that Twist2 could activate EMT programs to facilitate a cancer stem cell phenotype in breast cancer recently. But how Twist2 participates in EMT of breast cancer in vivo remains poorly understood. The present data indicate that Twist2 staining was a reliable Temozolomide predictor in the prognosis of breast cancer patients. Twist2 increased significantly with tumor metastasis, especially in cytoplasm of ductal carcinoma of breast cells. Additionally, cytoplasm Twist2 expression was mainly in ductal carcinoma of breast relative to lobular carcinoma. Twist1 has also been shown to be expressed in cytoplasm but not nucleus of human hepatocellular carcinoma, whereas E-cadherin was localized on membranes. Twist2 overexpression was significantly linked to cervical cancer progression recently.