**2. Diagnosis of exosome-mediated cancer using liquid biopsies**

Liquid biopsy is a term generally used to describe the collection of body fluid and has been explored as a non-invasive complementary tool for the diagnosis of cancer. Non-invasive measurement of cancer biomarkers using liquid biopsy allows for patient stratification, screening, monitoring of response to treatment, and detecting minimal residual disease following recurrence. Extracellular vesicles are considered to be significant biomarkers in the liquid biopsy-based diagnosis of cancer, and profiling of these vesicles has the potential to improve the early detection of cancer.

#### **Figure 2.**

*Schema showing the liquid biopsy technique. Exosomes are released from cancer cells and enter blood vessels. Early diagnosis can be assisted by minimally invasive analysis of exosomes in blood vessels.*

Liquid biopsy can provide more comprehensive information on the genetic landscape and track genomic evolution during disease progression in patients. The main biological biomarkers used in liquid biopsy include circulating tumor cells, circulating tumor DNA, and exosomes originating from healthy tissue or tumor tissue [26]. Given that many tissues are difficult or impossible to biopsy or resect, conventional biopsies cannot provide information on the efficacy of treatment. Exosomes can be easily acquired from most types of body fluid; therefore, they are attracting attention as biomarkers in liquid biopsy for diagnosis (**Figure 2**).
