Comprehensive analysis of the immunological landscape of pituitary adenomas: implications of immunotherapy for pituitary adenomas.

PURPOSES

Immunotherapies for solid tumor are gaining traction in the clinic, however, the immunological landscape of pituitary adenomas (PAs) is not well defined. In the present study, we used the RNA-seq data of PAs to investigate the impact of immunological landscape on clinical features of pituitary adenomas and aim to evaluate the potential immunotherapy for PAs.

METHODS

We analyzed tumor-infiltrating immune cells in 115 PA samples using RNA-seq. Main immune cell types (B cells, CD8 T cells, CD4 T cells, macrophages and NK cells) were detected from the expression of genes. The association between immune cells abundance and immune checkpoint, as well as inflammatory factors were analyzed. 10 additional patients were enrolled for validation.

RESULTS

In RNA sequencing data, landscape of PAs were identified. Our computationally inferred immune infiltrates significantly associate with patient clinical features. Growth hormone-secreting adenomas (GHomas) were found with higher B cells and CD8 T cells infiltration. Moreover, GHomas showed relative different genetic background, significant invasive behavior and independently correlated with reduced progress-free time. Tumor progression was related to increased expression of PD-1/PD-L1 and was associated with higher immune infiltration. Analysis of cancer-testis antigen expression and CD8 T-cell abundance suggested CTAG2 and TSPYL6 were potential immunotherapeutic targets in GHomas and non-functioning adenomas, respectively.

CONCLUSIONS

Tumor-infiltrating immune cells confer important clinical and biological implications. Our results of immune-infiltrate levels in PAs may inform effective cancer vaccine and checkpoint blockade therapies and make it possible to take immunotherapy into invasive PAs.