The immune landscape during the tumorigenesis of cervical cancer

Abstract

Objective: Deciphering the determinants of the intralesional immune reaction in cervical carcinogenesis may be conducive to improving the understanding of the disease and then improve outcomes.

Methods: Public gene-expression data and full clinical annotation were searched in Gene Expression Omnibus in the joint analysis of the array-based four eligible cohorts. The infiltrating estimation was quantified using microenvironment cell populations-counter algorithm and absolute-mode CIBERSORT and verified by flow cytometry analysis. An unsupervised classification on immune genes strongly associated with progression, designated by linear mixed-effects regression. We determined immune response and signaling features of the different developmental stages and immune phenotypes by functional annotation and systematically correlated the expression of immune checkpoints with cell-infiltrating characteristics.

Results: We identified the lesion-intrinsic immunosuppression mechanism was triggered at precancerous stages, such as genome instability and mutation, aerobic glycolysis, activation of proto-oncogene pathways and so forth. Predominant innate and adoptive cells were increasing from normalcy to cancer (B cell, total T cell, regulatory T cells [Tregs], monocytes, neutrophils, and M2-like macrophages) together with the decrease of CD4⁺ T cell and CD8⁺ T cell through the development of cervical cancer. Immune escape initiated on the expression of immunosuppressive molecules from high-grade squamous intraepithelial lesions (HSIL) and culminated in squamous cell carcinoma (SCC). Of note, the expression of immune checkpoints was escalated in the immune-hot and immune-warm phenotype largely encompassed by HSIL and SCC under the stress of both activated and suppressive immune responses.

Conclusions: Immune surveillance is unleashing from low-grade squamous intraepithelial lesions onwards and immune-suppression mechanisms are triggered in HSIL. Thorough knowledge of the immune changing pattern during cervical tumorigenesis contributes to finding the potential therapeutic targets to susceptive patients towards immune checkpoints inhibitors.

Keywords: cervical carcinogenesis; immune checkpoint; immune evasion; immunotherapy; tumor environment.