FAP and medullary thyroid gland carcinoma: In a meta-analysis that analyzed the clinical implication of FAP overexpression in solid tumors of colorectal cancer, pancreatic adenocarcinoma, non-small cell lung cancer, breast cancer, medullary thyroid carcinoma, and oral squamous cell carcinoma, high FAP expression was related to the risk of distant metastasis (OR: 2.56) [34], showing similar results to our study.