Prognostic significance for recurrence of fibroblast growth factor receptor 2 in intrahepatic cholangiocarcinoma patients undergoing curative hepatic resection

Tubulocystic Carcinoma of Bile Ducts: A Distinct Type of Cholangiocarcinoma Associated With Adenofibroma-type Lesions

A type of cholangiocarcinoma (CCA) characterized by peculiar histologic patterns and underlying adenofibromatous lesions has been reported in the literature mostly as individual case reports. This study aims to further clarify the defining characteristics of this spectrum of lesions. Clinicopathologic analysis of 8 biliary tumors with tubulocystic architecture arising in the background of adenofibroma-type lesions was performed. Three of these were also investigated with next-generation sequencing with a 174 genes panel. The patients were 5 males and 3 females, with a mean age of 64.6. All tumors were intrahepatic except for one perihilar that protruded into soft tissues. The mean size was 4.4 cm. At histology, all cases showed a peculiar and cytologically bland tubulocystic pattern that closely resembled tubulocystic-type kidney cancers, including back-to-back microcystic units that formed relatively demarcated nodules, and occurring in the background of adenofibromatous lesions. One case showed perineural invasion by otherwise deceptively benign-appearing microcystic structures, one had areas transitioning to intraductal tubulopapillary neoplasm, and 3 cases harbored more conventional small-duct CCA foci. In those 3 cases, both the tubulocystic and conventional CCA components were investigated by next-generation sequencing separately, and they shared the molecular alterations, including recurrent mutations in chromatin remodeling genes, such as ARID1A , BAP1 , and PBRM1 , and the actionable FGFR2-MCU fusion gene. In the limited follow-up, all but one were alive and free of disease after surgical resection. In conclusion, we described a distinct entity of CCA with specific histo-molecular features, for which we propose the designation of tubulocystic carcinoma of bile ducts.

Molecular biological role of epithelial splicing regulatory protein 1 in intrahepatic cholangiocarcinoma

AIM

Epithelial splicing regulatory protein 1 (ESRP1) regulates tumor progression and metastasis through the epithelial‒mesenchymal transition by interacting with zinc finger E-box binding 1 (ZEB1) and CD44 in cancers. However, the role of ESRP1 in intrahepatic cholangiocarcinoma (iCCA) remains unclear.

METHODS

Three iCCA cell lines (HuCCT-1, SSP-25, and KKU-100) were analyzed using small interfering RNA to investigate the molecular biological functions of ESRP1 and ZEB1. The association between clinicopathological features and the expression of ESRP1 and ZEB1 in iCCA tissues was analyzed immunohistochemically. Proteomic analysis was performed to identify molecules related to ESRP1 expression.

RESULTS

ESRP1 expression was upregulated in HuCCT-1 and SSP-25 cells. Cell migration and invasion were enhanced, and the expression of ZEB1 and CD44s (CD44 standard) isoforms were upregulated in the ESRP1 silencing cells. Moreover, ESRP1 silencing increased the expression of N-cadherin and vimentin, indicating the presence of mesenchymal properties. Conversely, ZEB1 silencing increased the expression of ESRP1 and CD44v (CD44 variant) isoforms. Immunohistochemical analysis revealed that a lower ESRP1-to-ZEB1 expression ratio was associated with poor recurrence-free survival in patients with iCCA. Flotillin 2, a lipid raft marker related to epithelial‒mesenchymal transition, was identified as a protein related to the interactive feedback loop in proteomic analysis.

CONCLUSIONS

ESRP1 suppresses tumor progression in iCCA by interacting with ZEB1 and CD44 to regulate epithelial‒mesenchymal transition.

Expression of fibroblast growth factor receptor 2 (FGFR2) in combined hepatocellular-cholangiocarcinoma and intrahepatic cholangiocarcinoma: clinicopathological study

Genetic alterations including fusions in fibroblast growth factor receptor 2 (FGFR2) are detected in 10-20% of intrahepatic cholangiocarcinoma (iCCA), and FGFR2 inhibitors are effective for the treatment of iCCA. We examined a prevalence of FGFR2 genetic alterations and their clinicopathological significance in combined hepatocellular-cholangiocarcinoma (cHCC-CCA). FGFR2 expression, which is a surrogate marker for FGFR2 genetic alterations, was immunohistochemically assessed in the liver sections from 75 patients with cHCC-CCA, 35 with small duct-type iCCA, 30 with large duct-type iCCA, and 35 with hepatocellular carcinoma (HCC). FGFR2 genetic alterations were detected by reverse transcription-PCR and direct sequence. An association of FGFR2 expression with clinicopathological features was investigated in cHCC-CCAs. FGFR2 expression was detected in significantly more patients with cHCC-CCA (21.3%) and small duct-type iCCA (25.7%), compared to those with large duct-type iCCA (3.3%) and HCC (0%) (p < 0.05). FGFR2-positive cHCC-CCAs were significantly smaller size (p < 0.05), with more predominant cholangiolocarcinoma component (p < 0.01) and less nestin expression (p < 0.05). Genetic alterations of ARID1A and BAP1 and multiple genes were significantly more frequent in FGFR2-positive cHCC-CCAs (p < 0.05). 5'/3' imbalance in FGFR2 genes indicating exon18-truncated FGFR2 was significantly more frequently detected in FGFR2-positive cHCC-CCAs and small duct iCCAs, compared to FGFR2-negative ones (p < 0.05). FGFR2::BICC fusion was detected in a case of cHCC-CCAs. FGFR2 genetic alterations may be prevalent in cHCC-CCAs as well as small duct-type iCCAs, which suggest cHCC-CCAs may also be a possible therapeutic target of FGFR2 inhibitors.

Impact of ACSL4 on the prognosis of hepatocellular carcinoma: Association with cancer-associated fibroblasts and the tumour immune microenvironment

BACKGROUND & AIMS

Recently, the association between hepatocellular carcinoma (HCC) and ferroptosis has been the focus of much attention. The expression of long chain fatty acyl-CoA ligase 4 (ACSL4), a marker of ferroptosis, in tumour tissue is related to better prognosis in various cancers. In HCC, ACSL4 expression indicates poor prognosis and is related to high malignancy. However, the mechanism remains to be fully understood.

METHODS

We retrospectively enrolled 358 patients with HCC who had undergone hepatic resection. Immunohistochemistry (IHC) for ACSL4 was performed. Factors associated with ASCL4 expression were investigated by spatial transcriptome analysis, and the relationships were investigated by IHC. The association between ACSL4 and the tumour immune microenvironment was examined in a public dataset and investigated by IHC.

RESULTS

Patients were divided into ACSL4-positive (n = 72, 20.1%) and ACSL4-negative (n = 286, 79.9%) groups. ACSL4 positivity was significantly correlated with higher α-fetoprotein (p = .0180) and more histological liver fibrosis (p = .0014). In multivariate analysis, ACSL4 positivity was an independent prognostic factor (p < .0001). Spatial transcriptome analysis showed a positive correlation between ACSL4 and cancer-associated fibroblasts; this relationship was confirmed by IHC. Evaluation of a public dataset showed the correlation between ACSL4 and exhausted tumour immune microenvironment; this relationship was also confirmed by IHC.

CONCLUSION

ACSL4 is a prognostic factor in HCC patients and its expression was associated with cancer-associated fibroblasts and anti-tumour immunity.

Impact of TP53-induced glycolysis and apoptosis regulator on malignant activity and resistance to ferroptosis in intrahepatic cholangiocarcinoma

TP53-induced glycolysis and apoptosis regulator (TIGAR) is an important gene that encodes a regulatory enzyme of glycolysis and reactive oxygen species (ROS) detoxification and is associated with worse prognosis in various cancers. Ferroptosis is a recently identified type of programmed cell death that is triggered by iron-dependent lipid peroxidation. There are no reports on the prognostic impact of TIGAR on intrahepatic cholangiocarcinoma (ICC), and its role in ferroptosis is unclear. Ninety ICC patients who had undergone hepatic resection were enrolled. Immunohistochemical staining for TIGAR was performed. The regulation of malignant activity by TIGAR and the association between ferroptosis and TIGAR were investigated in vitro. Twenty-two (24.4%) patients were categorized into TIGAR-high and -low groups by immunohistochemical staining. There were no noticeable differences in background factors between the two groups, but TIGAR positivity was an independent prognostic factor in disease-free survival (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.04-3.85, p = 0.0378) and overall survival (HR, 2.10; 95% CI, 1.03-4.30, p = 0.00422) in a multivariate analysis. In vitro, TIGAR knockdown (KD) decreased cell motility (cell proliferation/migration/invasion/colony-forming capabilities) and elevated ROS and lipid peroxidation. This indicated that TIGAR KD induced ferroptosis. TIGAR KD-induced ferroptosis was suppressed using liproxstatin. TIGAR KD decreased the expression of glutathione peroxidase 4, known as factor-suppressing ferroptosis. The combination of TIGAR KD with cisplatin significantly induced more ferroptosis. In conclusion, TIGAR is associated with poor outcomes in ICC patients and resistance to ferroptosis.