A study in humans demonstrated that the mir-34b was significantly decreased in the prefrontal cortex of depressed suicide subjects compared to non-psychiatric controls, with its expression measured at 0.672 of control levels [Smalheiser et al. DOI:10.1371/journal.pone.0033201]. A study in mice demonstrated that the mir-34b was differentially expressed in blood 24 hours after γ-irradiation [Jia & Wang DOI:10.3389/fcell.2022.861451]. In human studies, the mir-34b was downregulated in testicular biopsies of azoospermia patients and in subfertile men, showing high diagnostic value with an AUC of 0.944 and 0.852, respectively [Ahmed S. Doghish et al. DOI:10.1007/s00210-024-03594-7].