Glutathione S-transferase P1 (GSTP1), a xenobiotic-metabolizing enzyme that plays an important role in the detoxification of chemotherapy agents through conjugating them with glutathione, has been shown that enriched in adriamycin-resistant breast cancer cell-derived exosomes and plasma-derived GSTP1-containing exosomes could predict response to chemotherapy drugs in breast cancer patients [136]. This evidence concerns the gene GSTP1 and breast cancer.