We sought to find novel biomarkers for precision diagnosis and focused on serum exosomes, which is useful for liquid biopsy.

The concept of precision medicine is "an emerging approach for diagnosis, treatment and prevention of various diseases with individual variability in genes, environment, and lifestyle for each person." This approach will allow to predict, treat and prevent a particular disease more accurately. It is in contrast to a one-size-fits-all approach, in which drug development strategy for the average person without consideration between individual variations.

Cells secrete various type of extracellular vesicle (EV). EVs can be broadly divided into two categories, ectosomes and exosomes. Ectosomes are vesicles that budding out the surface of the plasma membrane. Ectosomes include microvesicles, microparticles, and large vesicles in the size range of ~50 nm to 1 ￬m in diameter. Exosomes are EVs with a size range of 50 to 150 nm (average ~100 nm) in diameter with an endosomal origin. EVs, including exosomes, can contain many constituents of a cell, including DNA, RNA, lipids, metabolites, and cytosolic and cell-surface proteins. The physiological purpose of generating exosomes remains largely unknown but most people have been believed that exosome cargo can remove excess and/or unnecessary constituents from cells to maintain cellular homeostasis. Recent studies reviewed here also indicate a functional, targeted, mechanism-driven accumulation of specific cellular components in exosomes, suggesting that they have a role in regulating intercellular communication.

In our laboratory, we investigate that the usage of serum exosomes to diagnosis various diseases including cancers, diabetic complications and Alzheimer.

We sought to understand how epithelial clusters become invasive during metastasis. We focused on the non-EMT dissemination, which is crucial for dissemination of epithelial cells without EMT.

Most human cancers arise in epithelial tissues, which progress to metastasis when epithelial cells manage to invade their surroundings and become migratory. The epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells; these are multipotent stromal cells that can differentiate into a variety of cell types. EMT has also been shown to occur in wound healing, in organ fibrosis and in the initiation of metastasis in cancer progression. Initiation of metastasis requires invasion, which is enabled by EMT. Carcinoma cells in a primary tumor lose cell-cell adhesion mediated by E-cadherin repression and break through the basement membrane with increased invasive properties, and enter the bloodstream through intravasation. Later, when these circulating tumor cells (CTCs) exit the bloodstream to form micro-metastases, they undergo MET for clonal outgrowth at these metastatic sites. Thus, EMT and MET form the initiation and completion of the invasion-metastasis cascade.

We investigate that the tumor may undergo metastasis without EMT. Epithelial cells can disseminate primary site without EMT. Later, epithelial clusters undergo EMT at the metastatic sites. These findings provides a new concept for metastasis and a clue for developing anti-metastatic drug.