Specific examples of proteins that are overexpressed in BC exosomes are alpha-1-antitrypsin (SERPIN1) and histone H2B type 1-K (HIST1H2BK), which were found at high concentrations in urinary EVs, with the presence of HIST1H2BK found to increase the risk of recurrence threefold [156]. This evidence concerns the gene H2BC12 and breast cancer.