TACSTD2 and breast carcinoma: When Trop-2 is overexpressed, it acts as an oncogene, interacting with many key cellular signaling pathways in tumor cells, potentially promoting the proliferation, growth, invasion, and metastasis of various malignant tumors such as breast cancer, colon cancer, papillary thyroid carcinoma, and esophageal squamous cell carcinoma, among others, playing a critical role in cancer development (5, 7).