A large-scale meta-analysis including 12 clinical studies with 2694 participants by Zeng et al. demonstrated a strong and significant association between high MCAM expression and poor prognosis in several malignancies, including hepatocellular carcinoma, leiomyosarcoma, esophageal squamous cell carcinoma, lung cancer, colorectal cancer, clear cell renal cell carcinoma, gastric cancer, gallbladder adenocarcinoma, breast cancer, and epithelial ovarian cancer [159]. Here, MCAM is linked to breast cancer.