SPP1 and hepatocellular carcinoma: Alpha fetoprotein is the most commonly used biomarker for HCC detection and some other new biomarkers such as glypican-3, osteopontin, Golgi protein 73, nucleic acids including microRNAs, Dickkopf-1 (DKK1), and midkine (MDK) will become clinically available in the near future [13, 14].