2023

How fibrolamellar carcinoma differs from hepatocellular carcinoma in children – Creation of a multi-institutional database including central pathologic review

Goal: Understand the true incidence, accuracy of diagnosis, and optimal treatments for FLC

Principal Investigator: Roshni Dasgupta, MD of the Cincinnati Children’s Hospital Medical Center

Co-investigators:

  • Soo-Jin Cho, MD, PhD of the University of California, San Francisco
  • Kimberly Riehle, MD of the University of Washington
  • Dolores López-Terrada, MD, PhD of Texas Children’s Hospital

Grant length: Two years, plus extension

Study overview: In previous work, the Pediatric Surgical Oncology Research Collaborative (PSORC) collected and analyzed detailed records of 262 patients under age 20 diagnosed with hepatocellular cancers, assembled from 19 different hospitals and covering the years 1990 to 2017. This represents the richest available source of data on pediatric liver cancers. They found that 119 (45%) of the tumors had been classified as FLCs, 110 (42%) as conventional HCCs, and the remainder mainly as “hepatocellular neoplasms-not otherwise specified” (HcN-NOS) (12%). The latter tumors are generally hepatoblastomas (a distinct class of liver cancer most often seen in very young children), but with some features of HCC. However, the classification of each tumor in the collection was based on the diagnosis originally made at the treating hospital.

Because evidence suggests that FLC is frequently misdiagnosed in clinical practice, the PSORC team requested funding from FCF to carry out centralized pathology review of the 262 tumors to confirm the actual number of FLC cases versus other types of liver cancers. They also proposed to carry out molecular analyses of the tumors using methods that were not yet readily available in hospital labs when the bulk of the specimens were initially assessed.

The goals of the study are to:

  • Determine the accuracy of diagnosis of FLC vs HCC in pediatric patients. Expert pediatric liver pathologists, led by Dr. Soo-Jin Cho (UCSF), will carry out a centralized histopathologic review of specimens curated within the PSORC multi-institutional database, of which approximately 45% are FLC based on initial diagnoses at the contributing hospitals.
  • Perform molecular analysis of pediatric FLCs, HCC, and HCN-NoS. Studies led by Dr Lola López-Terrada (Texas Children’s Hospital/Baylor) will apply the current state-of-the-art standard for molecular pathology of FLC, including:
    • Immunohistochemistry for CK7 and CD68
    • Confirmation of the DNAJB1-PRKACA gene fusion by nucleic acid sequencing (primarily of spliced mRNA) and/or a microscopy-based method (fluorescence in situ hybridization).

If successful, the study could:

  • Confirm the histological classification of FLC versus other rare liver cancers found in the same age group, and correct errors likely to exist in the valuable Pediatric Surgical Oncology Research Consortium liver tumor collection and database. This will guide the standardization of identification of FLC by local pediatric pathologists. It also will reinforce the recognition of FLC as a distinct disease which should be clinically managed in that way.
  • Lay groundwork for personalized molecular analysis of FLC that is likely to provide more accurate prognoses and point to the most appropriate treatment strategy for each individual patient.
  • Provide important supporting evidence for ongoing efforts to obtain a unique ICD-10-CM code for FLC.

2020

DNAJB1-PKAc-β-catenin-ALCD-dependent activation of cancer genes plays an essential role in fibrolamellar hepatocellular carcinoma

Goal: Document mechanisms driving FLC and test if treatment with inhibitors of β-catenin may be a potential therapeutic approach for FLC

Principal Investigator:  Nikolai Timchenko, PhD

Grant length: One year

Study overview: In the course of studies of pediatric liver cancer, the team at CCHMC has identified chromosomal regions (Aggressive Liver Cancer Domains, ALCDs) in multiple liver cancer genes. Expression of the ALCD containing genes is increased in liver cancer. The project team has identified several regions within ALCDs that might be activated by transcription factors and chromatin remodeling proteins. One of these regions contains an ideal binding site for β-catenin-TCF4 complexes. Given recent reports showing that the mutant kinase DNAJB1-PKAc phosphorylates β-catenin, they hypothesized that DNAJB1-PKAc activates ALCD-containing cancer genes leading to FLC pathology. Preliminary studies of FLC patient tumor samples show that the DNAJB1-PKAc phosphorylates β-catenin at Ser675, leading to the formation of β-catenin-TCF4 complexes and that these complexes bind to the ALCDs. They also identified the ALCD-containing cancer genes that are specifically upregulated in patients with FLC.

Therefore, the main goal of this effort was to determine the role that the DNAJB1-PKAc-β-catenin-ALCD axis plays in the development of FLC. They:

  • Examined if the DNAJB1-PKAc-β-catenin-TCF4 pathway activates known ALCD-dependent cancer genes in FLC patients
  • Investigated new, FLC-specific ALCD-containing genes in FLC patients and determine mechanisms by which DNAJB1-PKAc-β-catenin pathway activates expression of these genes
  • Examined if the inhibition of the DNAJB1-PKAc-β-catenin-TCF4 pathway by using the β-catenin inhibitor PRI-724 inhibits development of FLC in a mouse model of FLC.

The project aimed to provide critical knowledge of the mechanisms of FLC and test if treatments with inhibitors of β-catenin might be considered a potential therapeutic approach for FLC.

Key findings: The study team determined that DNAJB1-PKAc phosphorylates β-catenin at Ser675 leading to the formation of β-catenin -TCF4 complexes and that these complexes bind to the Aggressive Liver Cancer Domains (ALCDs) in many oncogenes. The study also found new, FLC-specific ALCD-containing genes in FLC patients, the majority of which code for fibrotic genes and oncogenes.

Additionally, this research showed that the inhibition of the DNAJB1-PKAc-β-catenin-TCF4 pathway by the β-catenin inhibitor PRI-724 inhibits proliferation of cancer cells and the development of FLC in an organoid model of FLC. Interestingly, they also obtained evidence that DNAJB1-PKAc β-catenin -TCF4 pathway is preserved in lung metastases of FLC patients.

The results of the study were published in Hepatology Communications in September 2022. The complete journal article can be accessed here: https://aasldpubs.onlinelibrary.wiley.com/doi/10.1002/hep4.2055.

Implications: The results of the project provided critical knowledge of the mechanisms of FLC, and suggest that the inhibition of β-catenin might be considered as a therapeutic approach to treat FLC patients.