Clinicopathological, radiologic, and molecular study of 23 combined hepatocellular-cholangiocarcinomas with stem cell features, cholangiolocellular type.

Cholangiolocellular carcinoma is a type of intrahepatic cholangiocarcinoma (ICC). According to the 2010 World Health Organization classification, this carcinoma is a combined hepatocellular-cholangiocarcinoma with stem cell features, cholangiolocellular type (CHC-SC-CLC). The aim of this study was to compare the clinicopathological characteristics of CHC-SC-CLC and conventional ICC. Based on the gross and histologic characteristics, we divided consecutive ICC tumors into CHC-SC-CLC (n = 23), mass-forming (MF; n = 57), and non-MF (n = 22) groups. Compared with MF and non-MF groups, the CHC-SC-CLC group featured history of hepatolithiasis or bile duct operation in significantly fewer patients (4.3% versus 14.8% and 86.4%, respectively; P < .001) and was more common in the right lobe (70% versus 47% and 27%; P = .033) but lower frequency of invasive growth or peritumoral Glisson sheath invasion (61% and 22% versus 77% and 33% and 100% and 86%, respectively; P = .002 and P < .001) and absence of mucous production (0 versus 77% and 96%; P < .001). In CHC-SC-CLCs, the mutation rate of isocitrate dehydrogenase 1 (IDH1) or IDH2 was significantly higher (35%) than in MF (4%) or non-MF (0) ICCs (P < .001). The 1-, 3-, and 5-year postresection survival rates were also significantly better with CHC-SC-CLCs (93%, 79%, and 52%, respectively) than with MF (72%, 46%, and 40%) or non-MF (61%, 18%, and 0) ICCs (P = .041). Thus, CHC-SC-CLC tumors demonstrated an indolent growth pattern, more frequent IDH1/2 gene mutations, and better prognosis than did MF or non-MF ICC tumors.

Chen J ，He J ，Deng M ，Wu HY ，Shi J ，Mao L ，Sun Q ，Tang M ，Fan XS ，Qiu YD ，Huang Q ... -  《-》

Mutational landscape of combined hepatocellular carcinoma and cholangiocarcinoma, and its clinicopathological significance.

Combined hepatocellular carcinoma and cholangiocarcinoma (cHC-CC), which generally has a poor prognosis, comprises hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and diverse components with intermediate features between HCC and CC. Histological subtypes with stem cell (SC) features (the SC subtype) have different clinicopathological significance in cHC-CC. The mutational status may reflect the clinicopathological subgroup of cHC-CC together with the histological subtype. We examined the mutational statuses of KRAS, IDH1 or IDH2 (IDH1/2), ARID1A, the TERT promoter, and TP53, and their relationships with clinicopathological features in 53 patients with cHC-CC. Background liver diseases were hepatitis B (n = 9), hepatitis C (n = 22), alcoholic liver disease (n = 5), non-alcoholic fatty liver disease (NAFLD) (n = 8), and unknown (n = 9). Mutations in KRAS, IDH1/2, ARID1A, the TERT promoter and TP53 were detected in four (7.5%), six (11.8%) seven (13.2%), 16 (31.3%), and 24 patients (45.3%), respectively. KRAS mutations correlated with higher histological diversity scores and a higher M-factor (P < 0.05). ARID1A mutations correlated with alcoholic liver disease, smaller tumour size, a lower grade of coexistent HCC, and α-fetoprotein (AFP) positivity, and were associated with cholangiolocellular carcinoma subtype predominance (P < 0.05). TERT promoter mutations correlated with hepatitis B, an intermediate subtype-predominant histology, higher clinical stage, and a higher N-factor (P < 0.05), and were associated with gender (female-predominant) and previous therapy. TP53 mutations correlated with AFP positivity (P < 0.05). The results of the mutational analysis revealed that cHC-CC has diverse types of mutations, and also that mutations in the TERT promoter and ARID1A may reflect aetiological impact, different histological subtypes, histogenesis, and tumour aggressiveness. These results suggest the potential efficacy of molecular-based subclassification of cHC-CC.

Sasaki M ，Sato Y ，Nakanuma Y 《-》

Is nestin a diagnostic marker for combined hepatocellular-cholangiocarcinoma?

The type IV intermediate filament, nestin, may be a candidate diagnostic marker for combined hepatocellular-cholangiocarcinoma (cHCC-CCA). Therefore, the significance of nestin as a diagnostic marker for cHCC-CCA categorized by the World Health Organization (WHO) 2019 classification and its relationship with clinicopathological features were examined in the present study. Nestin expression was immunohistochemically assessed in the liver sections from 75 patients with cHCC-CCA, 22 with small duct-type intrahepatic cholangiocarcinoma (iCCA), 20 with large duct-type iCCA and 35 with hepatocellular carcinoma (HCC). Nestin expression and its relationship with clinicopathological features and genetic alterations were investigated in cHCC-CCA. Nestin expression was detected in significantly more patients with cHCC-CCA (66.7%) than in those with large duct-type iCCA (5%) (P < 0.01), HCC (2.9%) (P < 0.01) and small duct-type iCCA (40.9%) (P < 0.05). Nestin expression was partly associated with neural cell adhesion molecule (NCAM) and vimentin expression. Nestin expression was also observed in significantly more patients with small duct-type iCCA than in those with large duct-type iCCA and HCC (P < 0.01). Nestin-positive cHCC-CCA was characterized by a smaller tumour size, the more frequent presence of cholangiolocellular carcinoma (CLC) components, a higher rate of p53 overexpression and a higher rate of multiple genetic alterations (P < 0.05). Furthermore, p53 overexpression was associated with a higher histological grade and multiple genetic alterations (P < 0.05) in nestin-positive cHCC-CCA. Nestin may be a useful diagnostic marker for a specific subgroup of cHCC-CCA and small duct-type iCCA associated with CLC components, p53 mutations and multiple genetic alterations, which are related to stemness and multipotent differentiation.

Sasaki M ，Sato Y ，Nakanuma Y 《-》

Diversity in cell differentiation, histology, phenotype and vasculature of mass-forming intrahepatic cholangiocarcinomas.

Mass-forming intrahepatic cholangiocarcinomas (MF-iCCAs), involving small bile ducts, bile ductules or canals of Hering, remain treated as a single entity. We aimed to examine the diversity in histology, phenotype and tumour vasculature of MF-iCCAs. Based on morphology and immunophenotype, we classified MF-iCCAs into small bile duct (SBD), cholangiolocarcinoma (CLC), ductal plate malformation (DPM) and hepatocellular carcinoma (HCC)-like subtypes. Genetic correlations among the histological subtypes were examined by multi-region tumour sequencing. Vasculatures and other clinicopathological features were compared among tumour groups with various proportions of the histological subtypes in 62 MF-iCCAs. Cases of pure SBD, CLC, DPM and HCC-like subtypes numbered 18 (29%), seven (11.3%), none (0%) and two (3%), respectively; the remaining 35 (56.4%) cases comprised several components. Genetic alterations, isocitrate dehydrogenase (IDH)1/2, KRAS, TP53, polybromo-1 (PBRM1) and BRCA1-associated protein 1 (BAP1), were shared among SBD, CLC, DPM and hepatoid components within a tumour. We uncovered distinct vascularisation mechanisms among SBD, CLC and DPM subtypes with a prominent vessel co-option in CLC tumours. iCCA with a DPM pattern had the highest vascular densities (mean microvascular density,140/mm2 ; arterial vessel density, 18.3/mm2 ). Increased CLC component was correlated with longer overall survival time (r = 0.44, P = 0.006). Pure SBD tumours had a lower 5-year overall survival rate compared with MF-iCCA with CLC pattern (30.5 versus 72.4%, P = 0.011). MF-iCCAs comprise four histological subtypes. Given their sharing some driver gene alterations, indicating they can have a common cell origin, SBD, CLC and DPM subtypes, however, differ in cell differentiation, histology, phenotype or tumour vasculature.

Nguyen Canh H ，Takahashi K ，Yamamura M ，Li Z ，Sato Y ，Yoshimura K ，Kozaka K ，Tanaka M ，Nakanuma Y ，Harada K ... -  《-》

Genomic profiling of combined hepatocellular-cholangiocarcinoma reveals similar genetics to hepatocellular carcinoma.

Combined hepatocellular-cholangiocarcinomas (CHC) are mixed tumours with both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) components. CHC prognosis is similar to intrahepatic CC (ICC) and worse than HCC; staging and treatment generally follow ICC algorithms. However, the molecular biology of CHC remains poorly characterised. We performed capture-based next-generation sequencing of 20 CHC and, for comparison, 10 ICC arising in cirrhosis. Intratumour heterogeneity was assessed by separately sequencing the HCC and CC components of nine CHC. CHC demonstrated molecular profiles similar to HCC, even in the CC component. CHC harboured recurrent alterations in TERT (80%), TP53 (80%), cell cycle genes (40%; CCND1, CCNE1, CDKN2A), receptor tyrosine kinase/Ras/PI3-kinase pathway genes (55%; MET, ERBB2, KRAS, PTEN), chromatin regulators (20%; ARID1A, ARID2) and Wnt pathway genes (20%; CTNNB1, AXIN, APC). No CHC had alterations in IDH1, IDH2, FGFR2 or BAP1, genes typically mutated in ICC. TERT promoter mutations were consistently identified in both HCC and CC components, supporting TERT alteration as an early event in CHC evolution. TP53 mutations were present in both components in slightly over half the TP53-altered cases. By contrast, focal amplifications of CCND1, MET and ERRB2, as well as Wnt pathway alterations, were most often exclusive to one component, suggesting that these are late events in CHC evolution. ICC in cirrhosis demonstrated alterations similar to ICC in non-cirrhotic liver, including in IDH1 or IDH2 (30%), CDKN2A (40%), FGFR2 (20%), PBRM1 (20%), ARID1A (10%) and BAP1 (10%). TERT promoter and TP53 mutation were present in only one ICC each. Our data demonstrate that CHC genetics are distinct from ICC (even in cirrhosis) and similar to HCC, which has diagnostic utility and implications for treatment. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Joseph NM ，Tsokos CG ，Umetsu SE ，Shain AH ，Kelley RK ，Onodera C ，Bowman S ，Talevich E ，Ferrell LD ，Kakar S ，Krings G ... -  《-》