Meta-analysis and Clinical Evaluation of the Relationship Between FAPalpha Expression and Malignant Degree of Solid Tumors

Background Aim This study aimed to identify the prognostic significance of Fibroblast activation protein alpha (FAPalpha) in solid tumor. Method A literature search was performed by using Pubmed, EMbase and CNKI for relevant articles published with the following key words “fibroblast activation protein” or “seprase”, “clinical” and “cancer” or “carcinoma”. Pooled effects with 95% confidence interval (CI) for outcomes (age, gender, positive ratio, histological differentiation, depth of tumor invasion, lymph node metastasis, clinical stage and overall survival) were calculated. Besides, immunohistochemical analysis was performed to evaluate FAPalpha positive ratio in normal, benign and malignant tumor tissues as well as in different degrees of differentiation, clinical stages and lymph node metastasis tissues. Results Finally, 28 articles with different types of solid tumors were included in the meta-analysis. Results revealed that solid tumors had a higher positive ratio of FAPalpha expression (OR: 39.51, P < 0.001), and FAPalpha overexpression also indicated higher degree of tumor depth invasion (OR: 2.82, P = 0.010), lymph node metastasis (OR: 2.52, P = 0.003), clinical stage (OR: 3.36, P = 0.003) and worse overall survival (HR: 2.03, P < 0.001). Results from immunohistochemistry demonstrated that FAPalpha expressed higher in malignant solid tumors than that in benign solid tumors ( P = 0.022), and it significantly overexpress in lymph node metastasis tissues ( P = 0.04). Conclusion Our findings indicate that FAP? expression is associated with worse prognosis in solid tumors and may be a promising prognosis predictor.