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remains unclear how and why cancer occurs and progresses. Using an evolutionary approach, the concept of a complex adaptive system (CAS) was developed to describe the behaviors of cancer tumorigenesis, [2] which may suggest a frameshift away from the limitations of current approaches that mainly address the importance of alteration in specific target molecules in cancer cells. This change in perspectives toward tumors, not simply as a disease to be cured but also as CAS, is expected to be the cornerstone of the paradigm shift toward innovative cancer therapies. [3] The human immune system can also be viewed as a CAS and therefore expected to initiate self-defense mechanisms against cancer in a complex adaptive manner as long as it recognizes the cancer cells as the non-self-signals. Consequently, the key to controlling cancer could lie in understanding how to manipulate the immune system and strengthen its defenses against cancer. The concept of facilitating the immune system to fight against cancer was first suggested in the late 1800s by Dr. Wiliam Coley, who was the first to observe anti-tumor effects after intratumoral injection of microbe-derived toxins. [4] Since then, the field of cancer immunotherapy research has flourished, resulting in clinical achievements such as immune checkpoint blockades and chimeric antigen receptor T cell (CAR-T) therapy. [5] However, immune suppression resistance mechanisms have simultaneously been identified that have impeded favorable response to cancer immunotherapy. [6,7] Exosome-based cancer therapies have emerged as a potential option for overcoming these limitations to the effects of current cancer therapies due to their pathophysiological efficacy against tumors. [8] Exosomes are secreted externally by cells and are found ubiquitously in blood, urine, saliva, cerebrospinal fluid, pleural fluid, and breast milk. [9,10] The distinction between different types of extracellular vesicles (EVs) is unclear; however, they are conventionally classified as either ectosomes (microvesicles or microparticles) or exosomes. [11] While ectosomes are formed by the outward budding of the plasma membrane, exosomes are formed from multivesicular bodies (MVB) containing intraluminal vesicles via inward budding of the late endosome, which later fuses to the membrane. The formed vesicles are then secreted via a process known as exocytosis (Figure 1). The two types of vesicle also differ in diameter, Exosomes are a class of extracellular vesicles of around 100 nm in diameter that are secreted by most cells and contain various bioactive molecules reflecting their cellular origin and mediate intercellular communication. Studies of these exosomal features in tumor pathogenesis have led to the development of therapeutic and diagnostic approaches using exosomes for cancer therapy. Exosomes have many advantages for conveying therapeutic agents such as small interfering RNAs, microRNAs, membrane-associated proteins, and chemotherapeutic compounds; thus, they are considered a prime candidate as a deliv...

An efficient system for direct delivery of integral membrane proteins is successfully developed using a new biocompatible exosome-based platform. Fusogenic exosomes harboring viral fusogen, vascular stomatitis virus (VSV)-G protein, can fuse with and modify plasma membranes in a process called "membrane editing." This can facilitate the transfer of biologically active membrane proteins into the target cell membranes both in vitro and in vivo.