To determine whether an increased frequency of MDSCs is observed in the circulation across different hepatobiliary malignancies, we investigated the frequency of these cells using the gating strategy provided in Fig. 1A. Consistent with earlier reports, the frequency of CD33+CD11b+HLA-DR−/low MDSCs was elevated in HCC patients compared to patients with benign liver lesions and healthy donors (Fig. 1B). This evidence concerns the gene CD33 and hepatocellular carcinoma.