To investigate the specific binding affinity of CD44-mediated endocytosis, three different cell types were selected for cytotoxicity analysis: one normal fibroblast (low expression) and two different cancer cells, including triple-negative breast cancer (MDA-MB-231, CD44 positive) and liver cancer cells (HepG2, CD44 negative). The gene discussed is CD44; the disease is triple-negative breast carcinoma.