Tumor-Infiltrating Podoplanin+ Fibroblasts Predict Worse Outcome in Solid Tumors

Background/Aims: Tumor-infiltrating fibroblasts are a heterogeneous population, and different subpopulations play differential roles in tumor microenvironment. However, the prognostic role of podoplanin+ fibroblasts in human solid tumors still remains controversial. Therefore, we performed the meta-analysis to better understand the role of this subpopulation in prognosis prediction for patients with solid tumor. Methods: We searched PubMed and EBSCO to identify the studies evaluating the association of intratumoral podoplanin+ fibroblast density detected by immunohistochemical method and overall survival (OS) and/or disease-free survival (DFS) in patients with solid tumor, then computed extracted data into hazard ratios for OS, DFS and clinicopathological features with STATA 12.0. Results: A total of 4883 patients from 29 published studies were incorporated into this meta-analysis. We found that podoplanin+ fibroblast infiltration significantly decreased OS and DFS in all types of solid tumors. In stratified analyses, podoplanin+ fibroblast infiltration was significantly associated with worse OS in cholangiocarcinoma, breast, lung and pancreatic cancer. And these cells were inversely associated with DFS in breast, lung and pancreatic cancer. In addition, high density of these cells significantly correlated with unfavorable clinicopathological features such as lymph node metastasis, TNM stage, lymphatic and vascular invasion of solid tumor. Conclusion: Podoplanin+ fibroblast infiltration leads to worse clinical outcome in solid tumors, implicating that it is a valuable prognostic biomarker and targeting it may have a potential for effective treatment.