CDK4 and fibrolamellar hepatocellular carcinoma: Figure 7B shows the reduction in mRNAs for CYP3A4 and SLC22A1. Since the reduction in the expression for the CYP and SLC families is mediated by HDAC1-Sp5 complexes [28], we examined this pathway in our FLC samples and found the elevation of HDAC1 and Sp5 in tumor sections (Figure 7C). Consistent with data for fusion-positive HBLs, QRT-PCR also showed an elevation in cdk1, cdk4, and Col1A1 in FLC tumors (Figure 7D).