Characteristics of immune-active and immune-silent phenotypes of early-stage cervical carcinoma as revealed by transcriptome sequencing

Abstract

Molecular classification, immuneheterogeneity, and the existence of distinct immunophenotypes of virus-associated cervical cancer (CeCa) remain as-yet weakly explored issues, and this is particularly true of its earliest clinical stages and pre-invasive forms: cervical intraepithelial neoplastic (CIN) lesions. The goal of the study was to identify transcriptomic landscapes of invasive CeCa at its initial progression that differ substantially in their immune-related characteristics, patterns of signaling pathways and composition of the microenvironment. Transcriptome profiling was carried out using RNA-sequencing on Illumina platform. A panel of surgical-derived tissue samples comprised human papillomavirus-positive CIN grade 1-3, cancer of FIGO IA1-IIB stages, and morphologically normal epithelium. Transcriptomic profiles were analyzed with the use of bioinformatics tools, such as gene set enrichment (GAGE) for signaling pathways, xCell enrichment for cell composition identification, and PREDA positional analysis of genomic data. Hierarchical clustering revealed heterogeneity of transcriptomic profiles within the early-stage CeCa, namely, the existence of two clusters of tumor samples and three functional patterns of genes showing coordinately altered expression. Pathway enrichment analysis on genes differently expressed between the two clusters/groups of CeCa samples (‘A' and ‘B') and CIN (group ‘C') suggested that invasive tumor progression in groups ‘A' and ‘B' might rely on immunologically dissimilar mechanisms. xCell analysis confirmed heterogeneity of changes in the abundancies of cell populations when comparing CeCa sample groups and CIN, along with differences in immune and stromal scores. PREDA demonstrated that these transcriptomic differences could be linked to different chromosomal regions and co-localized with particular gene families and potentially the reported virus integration hotspots. Overall, the existence and detectability of different transcriptomic immune-based phenotypes of invasive CeCa at its initial stages of progression is shown, which may provide new options to broaden the knowledge and applicability of target and immune anti-cancer therapy.

Keywords

• virus-associated cervical cancer
• transcriptome profiling
• tumor invasion
• tumor microenvironment
• pre-invasive lesions
• signaling pathways
• immune infiltration
• immune suppression