Resumen de Cytotoxic T lymphocyte antigen-4 (CTLA-4) expression in chordoma and tumor-infiltrating lymphocytes (TILs) predicts prognosis of spinal chordoma

G. He, X. Liu, X. Pan, Y. Ma, X. Liu

• Purpose Chordoma is a rare tumor of the skeletal system that is characterized by a high recurrence rate and treatment resistance. Given the common finding of immune dysregulation in chordoma, immunotherapy has emerged as potential treatment option. As an important immune checkpoint regulator, we evaluated cytotoxic T-lymphocyte antigen-4 (CTLA-4) expression and its prognostic significance for patients with chordoma of the spine.

  Methods CTLA-4 expression was analyzed immunohistochemically in 32 chordoma tissues and 14 nucleus pulposus tissues to examine the specificity of CTLA-4 expression in chordoma. Univariate log-rank analysis was used to evaluate the association of CTLA-4 expression in tumor cells and tumor-infiltrating lymphocytes (TILs) with survival. Cox multivariate analysis was used to identify independent factors of survival.

  Results Positive CTLA-4 expression was observed in all of the TILs and tumor cell cytoplasm, and partial in the membrane or in both the membrane and nucleus, with a markedly higher positivity rate than that observed in normal nucleus tissues. Higher CTLA-4 expression in the tumor but not in TILs was significantly associated with shorter continuous disease-free survival (CDFS) and overall survival (OS). CTLA-4 expression in tumor cells and TILs were independent predictors for CDFS, whereas only tumor cell expression was a significant predictor of OS. Furthermore, the combination of CTLA-4 expression in the tumor and TILs had higher prognostic value.

  Conclusions Targeting CTLA-4 may be a potential novel therapeutic strategy for chordoma patients.