Cervical cancer patients that respond to chemoradiation therapy display an intense tumor infiltrating immune profile before treatment

Abstract

Cervical cancer (CC) is a major cause of death and suffering to women globally with 570,000 new cases in 2017. It disproportionately affects those living in resource-constrained countries such as Brazil, with 90% of the deaths from CC happening in low and middle-income countries. Early detection is still the best strategy for improving response to therapy and survival and cases detected in advanced stages show variable response rates to the standard chemoradiation therapy protocols. Both the genetic landscape and the immune status of patients can dramatically affect cancer progression and response to therapy, as well as disease recurrence. Here we performed a comprehensive sequencing analysis using the cancer gene panel - Ion AmpliSeq™ Cancer hotspot Panel V2 CHPv2, as well as determined the immune infiltrate composition of a group of locally advanced CC patients with the goal of identifying genetic and immune characteristics associated with a clinical response to therapy. The expression levels of CD68⁺ tumor-associated macrophages (TAMs) and CD8⁺ tumor-infiltrating lymphocytes (TILs), as well as the immune checkpoint molecules PD-1, PD-L1 and PD-L2 in stroma and in tumor regions were analyzed by immunohistochemistry (IHC). The HPV infection status with high-risk strains was also determined. Twenty-one samples from patients with squamous cell carcinoma segregated into responder (11) and non-responder (10) groups according to standard chemoradiation therapy response were studied. Our findings indicate that responder patients showed an increase of an inflammatory tumor microenvironment as indicated by higher numbers of CD8⁺ and PD-L2⁺ TILs, as well as higher expression of PD-L1 immunoreactive area, as compared to the non-responder group. Additionally, our results demonstrate a correlation between the number of gene mutations and PD-L2⁺ TILs in the responder group. The genes PIK3CA and KDR/VEGFR were the most mutated genes, corroborating past findings. Together, these findings indicate an inflammatory tumor microenvironment present in patients that will respond to future chemoradiation treatment as compared to those that will not. This points to possible future predictors of response to therapy in CC patients.