Numerous reports have now demonstrated that the epithelial-to-mesenchymal transition (EMT) process is involved in solid tumor progression, metastases, and drug resistance. Several transcription factors have been implicated as drivers of EMT and metastatic progression, including Twist, which has been shown to be associated with poor prognosis and drug resistance for many carcinomas and other tumor types. The role of a Twist vaccine in experimental cancer metastases has been principally studied in the 4T1 mammary tumor model, where there is a greater than 3-fold increase in Twist expression in lung metastases (shown) vs. the primary tumor. Vaccination of mice reduced the size of primary transplanted 4T1 tumors and had an even greater antitumor effect on lung metastases of the same mice, which was dependent on Twist-specific T cells. These studies provide the rationale for vaccine-induced T-cell-mediated therapy of transcription factors involved in driving the metastatic process. For details, see article by Ardiani and colleagues on page 1945.