Fibrolamellar hepatocellular carcinoma: a rare but distinct type of liver cancer

Fibrolamellar hepatocellular carcinoma treated with chemotherapy and immunotherapy: a rare entity with unique characteristics

We present the case of a 21-year-old male diagnosed with stage IV fibrolamellar hepatocellular carcinoma, studied by the Oncomine Comprehensive Assay genomic sequencing panel with the finding of the DNAJB1-PRKACA fusion and treated with a combination of chemotherapy and immunotherapy based on cisplatin, 5-fluorouracil, adriamycin and nivolumab.

Fibrolamellar Hepatocellular Carcinoma: Comprehensive Review of Diagnosis, Imaging, and Management

BACKGROUND

Fibrolamellar hepatocellular carcinoma (FLC) is a rare malignancy that primarily affects patients in late adolescence and young adulthood. FLC tumors are characterized by their unique histologic features and a recently discovered genomic alteration, a chimeric fusion protein found in nearly all tumors. This review article provides the latest advancements in diagnosing, imaging, and managing FLC.

STUDY DESIGN

A comprehensive systematic review was performed using MEDLINE/PubMed and Web of Science databases, with the end of search date being July 1, 2022, regarding FLC diagnosis, imaging, and management.

RESULTS

Surgical resection remains the mainstay of therapy offering a chance for cure; however, given the incidence of metastatic disease at diagnosis and high rates of distant relapse, systemic therapies remain a crucial component of disease control. Unfortunately, few systemic therapies have demonstrated proven benefits. Consequently, recent efforts have galvanized around single-institute or small consortia-based studies specifically focused on enrolling patients with FLC or using agents with a biologic rationale.

CONCLUSIONS

FLC has unique demographic, radiologic, and pathologic features. The rarity of these tumors, coupled with the only recent acknowledgment of the genomic abnormality, has likely led to disease underrecognition and deprioritization of collaborative efforts to establish an evidence-based standard of care. Despite R0 resection, most patients experience recurrence. However, surgical resection is feasible for many recurrences and is associated with good survival. The role of chemotherapy is evolving, and further research is required to define its role in managing this disease.

Rare Inherited Cholestatic Disorders and Molecular Links to Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the most common primary liver cancer affecting adults and the second most common primary liver cancer affecting children. Recent years have seen a significant increase in our understanding of the molecular changes associated with HCC. However, HCC is a complex disease, and its molecular pathogenesis, which likely varies by aetiology, remains to be fully elucidated. Interestingly, some inherited cholestatic disorders that manifest in childhood are associated with early HCC development. This review will thus explore how three genes that are associated with liver disease in childhood (ABCB11, TJP2 and VPS33B) might play a role in the initiation and progression of HCC. Specifically, chronic bile-induced damage (caused by ABCB11 changes), disruption of intercellular junction formation (caused by TJP2 changes) and loss of normal apical–basal cell polarity (caused by VPS33B changes) will be discussed as possible mechanisms for HCC development.

Development and validation of a nomogram for predicting the cancer-specific survival of fibrolamellar hepatocellular carcinoma patients

Fibrolamellar hepatocellular carcinoma (FLC) is a rare subtype of hepatocellular carcinoma. Our study aimed to construct a nomogram to predict the cancer-specific survival (CSS) of FLC. Data of 200 FLC patients enrolled in the Surveillance, Epidemiology, and End Results (SEER) database were divided into the training group and the validation group. Prognostic factors identified in the univariate and multivariate Cox regression analyses were used to construct the nomogram. The concordance index (C-index), calibration curves, time-dependent receiver operating characteristic curve (ROC), and decision curve analysis (DCA) were used to evaluate the performance of the nomogram. As a result, age ≥ 59, N1 stage, M1 stage, tumor size ≤ 2.0 cm, and no surgery were significantly associated with lower CSS in multivariate Cox regression analysis. The calibration plot showed good consistency of the nomogram between predicted and observed outcomes in the training and validation groups. Compared with the TNM staging system, the prognostic evaluation model (PEM) showed a higher C-index (0.823 vs 0.656). The PEM also showed better predictive performance, with areas under the curve of 0.909 and 0.890 for predicting the 1- and 5-year survival. The AUCs of the TNM stage model for predicting 1- and 5-year survival were 0.629 and 0.787, respectively. In addition, the DCA curve showed that the nomogram had better clinical utility. Finally, we concluded that Age, N stage, M stage, tumor size, and surgery are independent prognostic factors for FLC. PEM established based on these five prognostic indicators can help predict the CSS of patients with FLC.

Integrated Phosphoproteomics for Identifying Substrates of Human Protein Kinase A (PRKACA) and Its Oncogenic Mutant DNAJB1-PRKACA

The DNAJB1-PRKACA fusion is the signature genetic event of fibrolamellar hepatocellular carcinoma (FL-HCC), a rare but lethal liver cancer that primarily affects adolescents and young adults. A deletion fuses the first exon of the HSP40 gene (DNAJB1), with exons 2-10 of protein kinase A (PRKACA), producing the chimeric kinase DNAJB1-PKA_ca (J-PKA_ca). The HSP40 portion's scaffolding/chaperone function has been implicated in redirecting substrate recognition to upregulate oncogenic pathways, but the direct substrates of this fusion are not fully known. We integrated cell-based and in vitro phosphoproteomics to identify substrates targeted directly by PKA and J-PKA_ca, comparing phosphoproteome profiles from cells with in vitro rephosphorylation of peptides and proteins from lysates using recombinant enzymes. We identified a subset of phosphorylation sites in both cell-based and in vitro experiments, as well as altered pathways and proteins consistent with observations from related studies. We also treated cells with PKA inhibitors that function by two different mechanisms (rpcAMPs and PKI) and examined phosphoproteome profiles, finding some substrates that persisted in the presence of inhibitors and revealing differences between WT and chimera. Overall, these results provide potential insights into J-PKA_ca's oncogenic activity in a complex cellular system and may provide candidate targets for therapeutic follow-up.

Imaging Features of Fibrolamellar Hepatocellular Carcinoma with Contrast-Enhanced Ultrasound

PURPOSE

 Fibrolamellar hepatocellular carcinoma (f-HCC) is a rare primary liver tumor. Imaging plays an important role in diagnosis. The aim of this retrospective study was to analyze contrast-enhanced ultrasound (CEUS) features of histologically proven f-HCC in comparison to benign focal nodular hyperplasia (FNH).

MATERIALS & METHODS

 16 patients with histologically proven f-HCC lesions and 30 patients with FNH lesions were retrospectively reviewed regarding CEUS features to determine the malignant or benign nature of the focal liver lesions (FLL). Five radiologists assessed the CEUS enhancement pattern and came to a consensus using the EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) guideline criteria.

RESULTS

 Fibrolamellar hepatocellular carcinoma manifested as a single and huge FLL. On CEUS, f-HCC showed heterogeneous hyperenhancement in the arterial phase and hypoenhancement (16/16, 100 %) in the portal venous and late phases (PVLP) as a sign of malignancy. In contrast to the hypoenhancement of f-HCC in the PVLP, all patients with FNH showed hyperenhancement as the most distinctive feature (P < 0.01). 8 f-HCC lesions showed a central scar as an unenhanced area (8/16, 50.0 %), which could also be detected in 53.3 % (16/30) of FNH lesions (P > 0.05).

CONCLUSION

 By analyzing the hypoenhancement in the PVLP, CEUS imaging reliably diagnosed f-HCC as a malignant FLL. CEUS also showed differentiation between f-HCC and FNH lesions, showing similar non-enhanced central scars, whereas f-HCC lesions showed peripheral hyperenhancement in the arterial phase and early washout in the PVLP.

A nomogram integrating hepatic reserve and tumor characteristics for hepatocellular carcinoma following curative liver resection

BACKGROUND

Because of the mutual influence of liver dysfunction and malignancy, overall survival (OS) is a composite clinical endpoint in hepatocellular carcinoma (HCC). We developed a nomogram integrating albumin-bilirubin (ALBI) grade, a new index of hepatic reserve, and tumor characteristics of HCC for predicting OS following curative liver resection.

METHODS

The nomogram was built to estimate the probabilities of 1, 3, and 5-y OS based on training cohort of 709 HCC, which was validated in an international independent dataset. The prognostic value of the nomogram was determined by concordance index (C-index), time-dependent receiver operating characteristics (tdROC), and decision curves, comparing with ALBI grade alone, the Cancer of the Liver Italian Program (CLIP), the Barcelona Clinic Liver Cancer (BCLC), and Okuda staging systems.

RESULTS

Independent factors derived from multivariable Cox analysis of the training cohort to predict OS were tumor grade, microvascular invasion, tumor size and ALBI grade which were assembled into nomogram. The calibration curves for probability of OS showed optimal agreement between nomogram-prediction and actual observation, which was tested in validation cohort. The C-index, tdROC and decision curves showed the nomogram was superior to CLIP, ALBI grade, BCLC and Okuda. The patients could also be stratified into low, intermediate risk, and high risk of the mortality by the normogram in both development and validation cohorts.

CONCLUSIONS

The nomogram integrating hepatic reserve and tumor characteristics provided a highly accurate estimation of OS in patients with HCC after curative liver resection, contributing to assess patient prognosis.

The biology of Hepatocellular carcinoma: implications for genomic and immune therapies

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is a leading cause of cancer-related death worldwide. It is highly refractory to most systemic therapies. Recently, significant progress has been made in uncovering genomic alterations in HCC, including potentially targetable aberrations. The most common molecular anomalies in this malignancy are mutations in the TERT promoter, TP53, CTNNB1, AXIN1, ARID1A, CDKN2A and CCND1 genes. PTEN loss at the protein level is also frequent. Genomic portfolios stratify by risk factors as follows: (i) CTNNB1 with alcoholic cirrhosis; and (ii) TP53 with hepatitis B virus-induced cirrhosis. Activating mutations in CTNNB1 and inactivating mutations in AXIN1 both activate WNT signaling. Alterations in this pathway, as well as in TP53 and the cell cycle machinery, and in the PI3K/Akt/mTor axis (the latter activated in the presence of PTEN loss), as well as aberrant angiogenesis and epigenetic anomalies, appear to be major events in HCC. Many of these abnormalities may be pharmacologically tractable. Immunotherapy with checkpoint inhibitors is also emerging as an important treatment option. Indeed, 82% of patients express PD-L1 (immunohistochemistry) and response rates to anti-PD-1 treatment are about 19%, and include about 5% complete remissions as well as durable benefit in some patients. Biomarker-matched trials are still limited in this disease, and many of the genomic alterations in HCC remain challenging to target. Future studies may require combination regimens that include both immunotherapies and molecularly matched targeted treatments.