Tumor-associated neutrophils: an emerging player in the immune microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), comprising the majority of primary liver cancers, is one of the leading causes of cancer-related death worldwide, responsible for approximately 746,000 cases or 9.1% of total cancer deaths in 2012 (1). HCC is commonly associated with chronic hepatitis and liver cirrhosis. Great advances have been made in the prevention, screening, and diagnosis of HCC for the past few decades. However, progress in HCC treatments has been relatively slower. Surgical resection, local ablation, and liver transplantation provide opportunities to cure early-stage diseases, but such curative treatments are associated with high recurrence rates. Sorafenib, a multikinase inhibitor mainly targeting RAF kinase and vascular endothelial growth factor receptor, is the standard therapeutic agent for advanced diseases, but shows a modest antitumor efficacy and short duration of tumor control (2,3). Thus, novel therapeutic strategies are needed (4,5).