circRNA_102990 and circRNA_103229 are candidate diagnostic biomarkers associated with T lymphocyte homeostasis in hepatocellular carcinoma

This study investigated the associations of circRNA_102990 and circRNA_103229 with T-lymphocyte subset homeostasis in hepatocellular carcinoma (HCC) and evaluated their diagnostic utility. Two previously uncharacterized circRNAs were screened from the GSE124850 dataset. A retrospective cohort comprising 88 patients with HCC (HCC group) and 44 healthy individuals (control group) was enrolled. The expression levels of the two circRNAs were measured in tissue and peripheral blood samples, and peripheral blood T-lymphocyte subset indices were assessed in parallel. Both circRNAs were downregulated in HCC tissues and in the blood of patients with HCC, and their expression levels were associated with tumor stage, degree of differentiation, and vascular invasion. Compared with controls, patients with HCC exhibited marked imbalance in T-lymphocyte subset distributions. Expression of the two circRNAs was positively correlated with the proportions of CD3 + and CD4 + T cells and with the CD4 + /CD8 + ratio, while showing negative correlations with the proportions of CD8 + T cells and regulatory T cells (Treg). For HCC diagnosis, combined detection of the two circRNAs achieved an area under the receiver operating characteristic curve (AUC) of 0.843, outperforming either marker alone. In vitro experiments confirmed that the overexpression of circRNA_102990 and circRNA_103229 could inhibit the invasion of HCC cells and promote their apoptosis. Collectively, circRNA_102990 and circRNA_103229 may represent candidate diagnostic biomarkers for HCC and may be linked to the regulation of immune homeostasis within the tumor microenvironment, thereby providing potential targets for future diagnostic and therapeutic strategies.