ESR1 and breast carcinoma: A few preliminary studies have begun to explore sEV metabolomics in breast cancer models—for example, distinct diacylglycerol enrichment in sEVs from triple-negative breast cancer lines and elevated 27-hydroxycholesterol in sEVs from estrogen-receptor-positive cells [156]—while untargeted profiling has uncovered specific metabolites such as lysoPC 22:6 and N-acetyl-L-phenylalanine in sEVs from MDA-MB-231 versus non-tumorigenic cells [157].