Molecular profiling and analysis of genetic aberrations aimed at identifying potential therapeutic targets in fibrolamellar carcinoma of the liver

Current Advances in the Treatment of Fibrolamellar Carcinoma of Liver

Fibrolamellar carcinoma (FLC) of the liver is a rare type of liver cancer that is prevalent in children and young adults, often less than 40 years old. The etiology is unclear. It presents without underlying liver disease with distinctive histological features such as fibrous collagen bands surrounding the tumor cells. Fusion protein DNAJB1-PRKACA is found in most of the cases. The prognosis of FLC is poor. Even though curative treatment option is surgery for a certain patient population, other treatment modalities including radiation, chemotherapy are currently being used without significant improvement of overall survival. Recently, targeted therapy and immunotherapy have been studied which may provide survival advantage in the future. This review sought to compile data from clinical trials and case reports/series to outline the current state of FLC treatment.

Organoid models of fibrolamellar carcinoma mutations reveal hepatocyte transdifferentiation through cooperative BAP1 and PRKAR2A loss

Fibrolamellar carcinoma (FLC) is a lethal primary liver cancer, affecting young patients in absence of chronic liver disease. Molecular understanding of FLC tumorigenesis is limited, partly due to the scarcity of experimental models. Here, we CRISPR-engineer human hepatocyte organoids to recreate different FLC backgrounds, including the predominant genetic alteration, the DNAJB1-PRKACA fusion, as well as a recently reported background of FLC-like tumors, encompassing inactivating mutations of BAP1 and PRKAR2A. Phenotypic characterizations and comparisons with primary FLC tumor samples revealed mutant organoid-tumor similarities. All FLC mutations caused hepatocyte dedifferentiation, yet only combined loss of BAP1 and PRKAR2A resulted in hepatocyte transdifferentiation into liver ductal/progenitor-like cells that could exclusively grow in a ductal cell environment. BAP1-mutant hepatocytes represent primed cells attempting to proliferate in this cAMP-stimulating environment, but require concomitant PRKAR2A loss to overcome cell cycle arrest. In all analyses, DNAJB1-PRKACA^fus organoids presented with milder phenotypes, suggesting differences between FLC genetic backgrounds, or for example the need for additional mutations, interactions with niche cells, or a different cell-of-origin. These engineered human organoid models facilitate the study of FLC.

Fibrolamellar hepatocellular carcinoma that was successfully treated with surgical resection: a case report

Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare malignant hepatic cancer with characteristics that differ from those of typical hepatocellular carcinoma (HCC). Unlike conventional HCC, FLHCC is common in young patients without any underlying liver disease and is known to be associated with a unique gene mutation. This cancer type is rare in Asia, with only a few cases being reported in Korea. We report a case of FLHCC in a young woman that successfully underwent surgical resection. The efficacy of alternative treatments, such as transarterial chemoembolization or systemic chemotherapies, has not yet been established. To conclude, early diagnosis and appropriate surgical resection are important for the treatment of FLHCC.

A framework for fibrolamellar carcinoma research and clinical trials

Fibrolamellar carcinoma (FLC), a rare, lethal hepatic cancer, occurs primarily in adolescents and young adults. Unlike hepatocellular carcinoma, FLC has no known association with viral, metabolic or chemical agents that cause cirrhosis. Currently, surgical resection is the only treatment demonstrated to achieve cure, and no standard of care exists for systemic therapy. Progress in FLC research illuminates a transition from an obscure cancer to one for which an interactive community seems poised to uncover fundamental mechanisms and initiate translation towards novel therapies. In this Roadmap, we review advances since the seminal discovery in 2014 that nearly all FLC tumours express a signature oncogene (DNAJB1-PRKACA) encoding a fusion protein (DNAJ-PKAc) in which the J-domain of a heat shock protein 40 (HSP40) co-chaperone replaces an amino-terminal segment of the catalytic subunit of the cyclic AMP-dependent protein kinase (PKA). Important gains include increased understanding of oncogenic pathways driven by DNAJ-PKAc; identification of potential therapeutic targets; development of research models; elucidation of immune mechanisms with potential for the development of immunotherapies; and completion of the first multicentre clinical trials of targeted therapy for FLC. In each of these key areas we propose a Roadmap for future progress.