Small extracellular vesicles have been implicated in the regulation of neurodegenerative diseases, such as Huntington’s and Alzheimer’s diseases, and have been shown to promote metastasis via the Wnt, cadherin and integrin signalling pathways in various types of cancer [54,55,56,57,58]. This evidence concerns the gene CDH17 and early-onset autosomal dominant Alzheimer disease.