Taken together, our findings revealed the impact of TPD52L2 on breast cancer patient survival and responses to radiation and targeted therapies, its association with pathological stages and lymph node metastasis, its enriched expression in BLBCs, and its important roles in maintaining malignant phenotypes and promoting tumor growth, establishing TPD52L2 as a novel biomarker in BLBC. Here, TPD52L2 is linked to metastatic malignant neoplasm in the lymph nodes.