Characterization of a novel mutation in fibrolamellar hepatocellular carcinoma.

284 Background: Fibrolamellar hepatocellular carcinoma (FL-HCC) is a subtype of HCC occurring in children and young adults in the absence of underlying liver disease. Currently, there is no effective therapy for unresectable or metastatic FL-HCC. Recent genomic analysis identified a consistent mutation in FL-HCC involving a deletion on chromosome 19 resulting in a chimeric transcript containing the 5’-region of a heat shock protein (DNAJB1) fused to the catalytic subunit of protein kinase A (PRKACA). We sought to characterize the resultant protein and its effects on PKA activity in human FL-HCC. Methods: We prepared tissue lysates from four snap-frozen FL-HCC samples with paired, non-tumor liver as well as adult HCCs. PKA activity was determined via a radioactive kinase assay in the presence and absence of cAMP, a PKA activator. RNA was extracted using TRIZOL, and used for qRT-PCR. Triple immuno-fluorescent labeling was performed using antibodies to PRKACA, PKA RIIα, and a nuclear marker, DRAQ5. Results: ...