Background <p>Hepatocellular carcinoma (HCC) often arises from chronic liver disease, but early biomarkers of malignant transformation are lacking. CD44, a transmembrane glycoprotein with multiple isoforms, has been implicated in cancer progression and immune modulation.</p> Methods <p>We analysed CD44 expression in mouse models of chronic and acute liver injury and assessed its clinical relevance in human HCC using bulk and single-cell transcriptomic datasets.</p> Results <p>CD44 and its isoforms v6 and v10 were progressively upregulated in chronic liver injury, peaking in HCC. CD44-positive hepatocytes increased with fibrosis severity and were abundant in murine liver tumours. In human HCC, CD44 expression was significantly elevated compared to non-tumorous liver and was associated with reduced overall survival. CD44^high tumours showed enrichment in oncogenic signalling pathways and greater infiltration of immunosuppressive cells, including M2 macrophages and Th2 cells. Single-cell RNA-seq confirmed CD44 expression in both tumour and immune cells, linking it to a protumor immune microenvironment.</p> Conclusions <p>CD44 is a promising early biomarker of hepatocarcinogenesis and a potential therapeutic target. Its expression reflects disease progression from fibrosis to cancer and is associated with poor prognosis and immune evasion in HCC.</p>