Transcriptomic immune profiling: a precision path forward for immunotherapy in patients with cervical cancer?

Abstract

<h3>Objectives:</h3> Immunotherapy has emerged as a promising intervention in metastatic or recurrent cervical cancer, but response rates have been modest, albeit with some durable responses. To date, immune profiling and pathway characterization via whole transcriptome sequencing (WTS) has been limited to sampled tumors from newly diagnosed, mostly early stage disease. In the current study, we sought to use WTS-based immune profiling to develop a more representative analysis of the cervical cancer population receiving immunotherapy. <h3>Methods:</h3> Cervical cancer tumor samples were analyzed using next-generation sequencing and whole exome sequencing (NGS: NextSeq, 592 Genes and NovaSEQ, WES), immune-histochemistry (IHC), and WTS (NovaSeq) (Caris Life Sciences, Phoenix, AZ). PD-L1 expression was tested by IHC using standard protocol (PD-L1+ threshold: CPS ≥1). Microsatellite instability (MSI) was tested by fragment analysis, IHC and NGS. Tumor mutational burden (TMB) was measured by counting all somatic mutations found per tumor (TMB-high: ≥10 mutations per MB). Immune cell infiltration was calculated by QuantiSeq. <i>TP53</i> mutations were used as a proxy indicator for non-HPV tumors. Statistical significance was determined using chi-square and Wilcoxon rank sum test and adjusted for multiple comparisons using Benjamini & Hochberg and Bonferroni, respectively (significance threshold: adjusted p-value < 0.01). <h3>Results:</h3> 930 patients with cervical cancer underwent profiling from 2008-2020. Median age was 52 years. 449 (48.3%) patients had metastatic disease. Among FDA-approved companion markers of response to immunotherapy, the most commonly present was PD-L1+ (83.5%). Compared to adenocarcinoma, squamous cell carcinoma (SCC) had a more robust immune signal, with increased: PD-L1+, TMB-high status, infiltration of multiple types of immune cells (neutrophils, CD8+ T cells, regulatory T cells), as well as increased expression of multiple immune checkpoint genes (see Table 1). PD-L1+ status was significantly associated with increased macrophage M1 (3.51% vs 2.04%), CD8+ T (0.7% vs. 0%) and regulatory T (2.4% vs 1.3%) cell infiltration, yet decreased NK (2.6% vs 3.2%) cell infiltration. TMB-high was associated with significantly increased infiltration of neutrophils and CD8+ T cells. Older (≥63 yrs;) patients had significantly more somatic <i>TP53</i> mutations (25.2% vs 10.1%, indicating more non-HPV tumors with increasing age) and dendritic cell infiltration compared to younger patients (Table 1). <h3>Conclusions:</h3> Cervical SCC had a higher immune signal than adenocarcinoma: increased immunotherapy biomarkers (PD-L1 and TMB), immune cell infiltration, and upregulation of immune checkpoint genes. Non-HPV status and dendritic cell infiltration increased with advanced age. The variety of signals noted in this analysis suggests that transcriptomic immune profiling should be further investigated in the push to better predict which patients with cervical cancer might benefit most from immunotherapy.