Conversely, malignant pleural mesothelioma with high CTLA-4 exhibits poor prognosis.818 Higher CTLA-4 mRNA levels in breast cancer indicate higher clinical stage and axillary lymph node metastasis.819 A combined analysis of 844 ESCC patients has found that patients with both a low CTLA-4 and platelet lymphocyte ratio (PLR) level have longer OS.820 In conclusion, CTLA-4 is a prognostic biomarker in cancers and its positive or negative effects depend on specific cancer conditions. Here, CTLA4 is linked to esophageal squamous cell carcinoma.