SPP1 and hepatocellular carcinoma: Co-expression model analysis revealed strong positive correlations between 15 up-regulated hub genes (CCNB1, CDK1, BUB1B, ECT2, RACGAP1, ANLN, PBK, TOP2A, ASPM, RRM2, NEK2, PRC1, SPP1, HMMR, and DTL), suggesting their involvement in the same signaling pathway governing the occurrence of HBV-related HCC.