Background: Activated eosinophils have been deemed to affect carcinogenesis and tumor progression via various mechanisms in tumor microenvironment. However, the prognostic role of tumor-associated tissue eosinophilia (TATE) in human cancers remains controversial. Therefore, we performed the meta-analysis to better understand the role of TATE in prognosis prediction for cancer patients.
Methods: We searched PubMed, Embase and EBSCO to identify the studies evaluating the association between TATE and overall survival (OS) and/or disease-free survival (DFS) in cancer patients, then computed extracted data into hazard ratios (HRs) for OS, DFS and clinicopathological features such as lymph node metastasis etc with STATA 12.0.
Results: A total of 6384 patients from 26 published studies were incorporated into this meta-analysis. We found that the presence of TATE was significantly associated with improved OS, but not with DFS in all types of cancers. In stratified analyses based on cancer types, pooled results indicated that the infiltration of eosinophils was significantly associated with better OS in esophageal carcinoma and colorectal cancer. In addition, TATE significantly inversely correlated with lymph node metastasis, tumor stage and lymphatic invasion of cancer.
Conclusion: TATE leads to a favorable clinical outcome in cancer patients, implicating that it is a valuable biomarker for prognostic prediction for human cancers and clinical application of biological response modifiers or agonists promoting TATE may be the novel therapeutic strategy for patients.