ERBB2 and breast cancer: Given that triple-negative and HER2-positive breast cancer subtypes are highly aggressive and associated with poor prognosis and that CTCs serve as valuable prognostic and predictive biomarkers in these subtypes [26, 27], we selected two triple-negative breast cancer cell lines (BT549, MDA-MB-231) and two HER2-positive breast cancer cell lines (SKBR3, AU565) for subsequent functional studies, with triple-negative cell lines exhibiting the highest aggressiveness.