Fibrolamellar hepatocellular carcinoma: Exploring molecular mechanisms and differentiation pathways to better understand disease outcomes and prognosis

Fibrolamellar hepatocellular carcinoma (FLC) is a rare but aggressive liver cancer of children that occurs predominantly in teenagers without a history of liver disease. Surgical resection remains the only therapeutic option, and the recurrence rate is extremely high (>50% within 3 years). A newly discovered chromosomal deletion that occurs in the majority of FLCs generates a novel kinase fusion between DnaJ heat shock protein family member B1 (DNAJB1) and protein kinase cAMP-activated catalytic subunit alpha (PRKACA) (DNAJB1-PRKACA). Despite its high penetrance and apparent specificity for FLC, the oncogenic role of this fusion event remains unclear. In this review article, we discuss the histology, presentation and diagnosis, current treatment, and roles of the DNAJB1-PRKACA as well as research models contributing to our understanding of this disease.