Therefore, to specifically evaluate the net effect of HERV-positive EVs on the innate immune response in zebrafish, we considered the association between HERV-K positive EV concentrations and expression levels of IL1-β or mpx. Interestingly, we found a strong association between these two variables, thereby supporting our hypothesis that the HERV-positive EVs might act as immunomodulators in tumor progression. Here, IL1B is linked to neoplasm.