Prognostic value of the proportion of the sclerosing component in fibrolamellar liver carcinoma

Introduction. Fibrolamellar hepatocellular carcinoma (FLC), which develops most often in the younger population. In FLC, variable histoarchitectonics are noted, possibly the presence of a sclerosing component, foci of necrosis and dystrophy of tumor cells.Objective. Assessment of the influence of the proportion of the sclerosing component in fibrolamellar carcinoma (FLC) of the liver on the course and prognosis of the disease. Determination of the relationship between the proportion of the sclerosing component in the tumor and the frequency of microvascular invasion.Materials and methods. A retrospective study included 34 patients with a diagnosis of FLC, who underwent radical surgical treatment at the first stage. A histological assessment of the proportion (%) of the sclerosing component in FLC was made. The effect of the proportion of the sclerosing component on overall (OS) and relapse-free (DFS) survival was assessed. The analysis of the relationship between the proportion of the sclerosing component in the tumor and the frequency of microvascular invasion was carried out.Results. Significantly worse RFS was achieved in the groups of patients with a sclerosing component in FLC > 5% than in the group of patients with a sclerosing component in FLC ≤ 5% (p = 0.0010; p = 0.024; log – rank test). Median DDS in group 1 is 107 (95% CI, 22–192) months; at 2 – 11 (95% CI, 8–14) months; in 3 – 21 (95% CI, 8–33). The frequency of histologically confirmed microvascular invasion in the compared groups was 29, 74, 87.5%, respectively. OS was significantly worse in 2 groups (27 patients in total) with a sclerosing component in FLC > 5% than in the group of patients with a sclerosing component in FLC ≤ 5%. Median OS in group 1 120 (95% CI, 60–180) months; at 2 – 41 (95% CI, 15–92) months; in 3 – 69 (95% CI, 35–103). A direct relationship was found between an increase in the proportion of the sclerosing component in a tumor and an increase in the frequency of microvascular invasion.Conclusions. We can assume that the severity of the sclerosing component in the FLK tumor can serve as an effective morphological marker of a less favorable prognosis for this HCC subtype and correlate with the frequency of microvascular invasion.

Chemical, molecular, and single cell analysis reveal chondroitin sulfate proteoglycan aberrancy in fibrolamellar carcinoma

Fibrolamellar carcinoma (FLC) is an aggressive liver cancer with no effective therapeutic options. The extracellular environment of FLC tumors is poorly characterized and may contribute to cancer growth and/or metastasis. To bridge this knowledge gap, we assessed pathways relevant to proteoglycans, a major component of the extracellular matrix. We first analyzed gene expression data from FLC and non-malignant liver tissue to identify changes in glycosaminoglycan (GAG) biosynthesis pathways. We then implemented a novel LC-MS/MS based method to quantify the abundance of different types of GAGs in patient tumors, followed by measurement of the levels of different GAG-associated proteins. Finally, we performed the first single-cell assay for transposon-accessible chromatin-sequencing on FLC tumors, to identify which cell types are linked to the most dominant GAG-associated protein in FLC. Our results reveal a pathologic aberrancy in chondroitin (but not heparan) sulfate proteoglycans in FLC and highlight a potential role for activated stellate cells.

DNAJB1-PRKACA in HEK293T cells induces LINC00473 overexpression that depends on PKA signaling

Fibrolamellar carcinoma (FLC) is a primary liver cancer that most commonly arises in adolescents and young adults in a background of normal liver tissue and has an poor prognosis due to lack of effective chemotherapeutic agents. The DNAJB1-PRKACA gene fusion (DP) has been reported in the majority of FLC tumors, however its oncogenic mechanisms remain unclear. Given the paucity of cellular models, in particular FLC tumor cell lines, we hypothesized that engineering the DP fusion gene in HEK293T cells would provide insight into the cellular effects of the fusion gene. We used CRISPR/Cas9 to engineer HEK293T clones expressing DP fusion gene (HEK-DP) and performed transcriptomic, proteomic, and mitochondrial studies to characterize this cellular model. Proteomic analysis of DP interacting partners identified mitochondrial proteins as well as proteins in other subcellular compartments. HEK-DP cells demonstrated significantly elevated mitochondrial fission, which suggests a role for DP in altering mitochondrial dynamics. Transcriptomic analysis of HEK-DP cells revealed a significant increase in LINC00473 expression, similar to what has been observed in primary FLC samples. LINC00473 overexpression was reversible with siRNA targeting of PRKACA as well as pharmacologic targeting of PKA and Hsp40 in HEK-DP cells. Therefore, our model suggests that LINC00473 is a candidate marker for DP activity.

Molecular Basis of Hyperammonemic Encephalopathy in Fibrolamellar Hepatocellular Carcinoma

Purpose hyperammonemic encephalopathy is a potentially fatal condition associated with fibrolamellar hepatocellular carcinoma. The mechanism involved in hyperammonemia in patients with fibrolamellar carcinoma was unclear until a possible physiopathological pathway was recently proposed. An ornithine transcarboxylase dysfunction was suggested as a result of increased ornithine decarboxylase activity induced by c-Myc overexpression. This c-Myc overexpression resulted from Aurora Kinase A overexpression derived from the activity of a chimeric kinase that is the final transcript of a deletion in chromosome 19, common to all fibrolamellar carcinomas. Methods we performed the analysis of the expression of all enzymes involved and tested for the mutation in chromosome 19 in fresh frozen samples of fibrolamellar hepatocellular carcinoma, non-tumor liver and hepatic adenomatosis. Results specific DNAJB-PRKACA fusion protein that results from the recurrent mutation on chromosome 19 common to all fibrolamellar carcinoma was detected only in the fibrolamellar carcinoma sample. Fibrolamellar carcinoma and adenomiomatosis samples presented increased expression of Aurora Kinase A, c-MYC and ornithine decarboxylase when compared to normal liver, while ornithine transcarbamylase was decreased. Conclusion The proposed physiopathological pathway is correct and that overexpression of c-Myc may also be responsible of hyperammonemia in patients with other types of rapidly growing hepatomas. This gives further evidence to apply new and adequate treatment to this severe complication.

Novel systemic therapies in the treatment of fibrolamellar carcinoma.

e16161 Background: Fibrolamellar carcinoma (FLC) is an exceedingly rare liver cancer affecting children and young adults without underlying liver disease. Complete surgical resection is the primary treatment option, but recurrence is common. There are currently no established systemic therapies. We have treated patients in both the neoadjuvant and adjuvant setting with three novel combination therapies: 5-fluorouracil/interferon/nivolumab (“Triple Therapy” or TT), gemcitabine/oxaliplatin/lenvatinib (GOL), and nivolumab/lenvatinib/quercetin (NLQ). The purpose of this study was to evaluate objective responses and tolerability of three multi-agent systemic therapies in the treatment of FLC. Methods: Data from all patients with FLC who received TT, GOL, or NLQ between May 2018 and February 2021 were reviewed. Patients who received a minimum of six cycles of systemic therapy with follow up scans at least two months after initiation were assessed based on objective response, survival, and toxicity. Results: Twenty-nine patients with FLC who were treated with novel multi-agent systemic therapy were evaluable based on the above criteria. Median age at start of treatment was 20 (7-52; 16F, 12M, 1 non-disclosed). Twenty-three patients received one combination therapy (13 TT, 8 GOL, 2 NLQ), five received two different lines (3 TT/NLQ, 2 TT/GOL), and one patient received all three novel combinations. Between our 29 patients, they had relapsed 36 total times, and 11 had already tried 2+ systemic therapies. Best RECIST 1.1 objective response (clinical remission + partial response) and tumor control rate (clinical remission + partial response + stable disease) were 58%/95%, 55%/100%, and 33%/83% for TT, GOL, and NLQ respectively. The median longest Progression Free Survival (PFS) on any novel multi-agent regimen was 9 months (2-29; 9.5 for TT, 7 for GOL, 6.5 for NLQ), with 18 patients still receiving the therapy extending their PFS. Of those with previous relapses, 56% have a PFS longer than their previous longest remission and 69% have a PFS longer than their previous shortest time to relapse. Half of patients with previous relapses are still receiving the treatment responsible for their longest PFS. Fever, chills, and nausea were the most common adverse effects experienced throughout all three regimens. Seven patients experienced 1+ grade 3 adverse event. There were no toxic deaths or organ failure. Two patients died as a result of disease; their longest PFS (1 on GOL, 1 on TT) were nine and 10 months. Conclusions: FLC is a devastating cancer with patients often relapsing even after successful surgical remission. There is a strong need for effective and tolerable systemic therapies for those with unresectable, relapsed, progressive, or metastatic disease. We have had promising results in treating FLC and prolonging survival with minimal toxicities using novel multi-agent regimens.