TGFB1 and hepatocellular carcinoma: Furthermore, other blood-derived biomarkers such as cytokines (IL-6, IL-8 and TGF-β among others), ctDNA and CTCs have also been studied in some patients with HCC receiving immunotherapy, but their limited availability and high cost, could be a major drawback – at least for the time being – for using them in predictive scores for immunotherapy in advanced HCC (31–35).