Cancer is difficult to cure because of its heterogeneity, metastasis, ability to escape immune responses, and the tumor microenvironment. Approximately 90% of cancer deaths are caused not by the primary tumor but by metastasis. In the stage of pre-metastasis, tumor cells in the primary focus lose their original polar epithelial cell characteristics (strong adhesion and lamellar structure) and transform, gaining stromal cell characteristics with migration and invasion ability (no cell polarity and loss of cell-to-cell tight junctions). During the process of epithelial-mesenchymal transition (EMT), these tumor cells undergo significant cytoskeleton reconstruction and altered expression of various EMT-related transcription factors and cell surface receptors. Together, these cellular and molecular changes also promote the occurrence of EMT processes and EMT phenotypes.

The molecular mechanism of tumor metastasis is a complex process. Tumor metastasis is regulated by a variety of special genes, which are activated or inhibited in the process of tumor metastasis and play synergistic or antagonistic roles, thus affecting the biological properties of tumor cells. The molecular mechanism of tumor metastasis is the intrinsic cause of tumor metastasis, and the key to treating cancer is controlling the spread and metastasis of tumors. Although some drugs can make the primary tumor shrink and metastasize, there are currently no drugs that can directly treat or prevent metastasis.

The purpose of this Special Issue is to further clarify the influence of EMT on tumor progression by publishing relevant research content, and to study the latest progress and new findings in anti-tumor drug therapy. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Molecular mechanisms of tumor metastasis
• The role of immune escape and exosomes or non-coding RNA in the process of tumor metastasis
• Drug therapy for tumor metastasis
• Studies on the structural biology of tumor metastasis-related proteins
• Drug design and screening based on tumor metastasis mechanisms
• Screening and detection of molecular markers for tumor metastasis
• Establishment of detection directions for molecular markers of tumor metastasis