In vitro studies showedthat SpHL-D-S exhibits cytotoxic activity against various subtypesof human breast tumor cell lines, including MCF-7, MDA-MB-231, andSKBR3. MCF-7 is luminal A (ER+/PR+/HER2−), hormone-dependent, and less aggressive.MDA-MB-231 is triple-negative (ER–/PR–/HER2−),highly aggressive, with limited treatment options. Here, ERBB2 is linked to breast neoplasm.