MALAT1 and breast cancer: MALAT1 expression levels inbreast cancer cells are significant: MDA-MB-231 exosomes substantially increasethe proliferation of MDA-MB-231 and ZR-75-1 cells; however, exosomes fromMDA-MB-231 cells treated with MALAT1-siRNA (small interfering RNA or siRNAtargeting MALAT1) reduce cell proliferation in breast cancer patients.