Histologic characteristics and prognostic significance in small hepatocellular carcinoma with biliary differentiation: subdivision and comparison with ordinary hepatocellular carcinoma

Dual-phenotype hepatocellular carcinoma: correlation of MRI features with other primary hepatocellular carcinoma and differential diagnosis

Objectives

Dual-phenotype hepatocellular carcinoma (DPHCC) is a rare subtype of hepatocellular carcinoma characterized by high invasiveness and a poor prognosis. The study aimed to compare clinical and magnetic resonance imaging (MRI) features of DPHCC with that of non-DPHCC and intrahepatic cholangiocarcinoma (ICC), exploring the most valuable features for diagnosing DPHCC.

Methods

A total of 208 cases of primary liver cancer, comprising 27 DPHCC, 113 non-DPHCC, and 68 ICC, who undergone gadoxetic acid-enhanced MRI, were enrolled in this study. The clinicopathologic and MRI features of all cases were summarized and analyzed. Univariate and multivariate logistic regression analyses were conducted to identify the predictors. Kaplan-Meier survival analysis was used to evaluate the 1-year and 2-year disease-free survival (DFS) and overall survival (OS) rates in the cohorts.

Results

In the multivariate analysis, the absence of tumor capsule (P = 0.046; OR = 9.777), persistent enhancement (P = 0.006; OR = 46.941), arterial rim enhancement (P = 0.011; OR = 38.211), and target sign on DWI image (P = 0.021; OR = 30.566) were identified as independently significant factors for distinguishing DPHCC from non-DPHCC. Serum alpha-fetoprotein (AFP) >20 μg/L (P = 0.036; OR = 67.097) and hepatitis B virus (HBV) positive (P = 0.020; OR = 153.633) were independent significant factors for predicting DPHCC compared to ICC. The 1-year and 2-year DFS rates for patients in the DPHCC group were 65% and 50%, respectively, whereas those for the non-DPHCC group were 80% and 60% and for the ICC group were 50% and 29%, respectively. The 1-year and 2-year OS rates for patients in the DPHCC group were 74% and 60%, respectively, whereas those for the non-DPHCC group were 87% and 70% and for the ICC group were 55% and 37%, respectively. Kaplan-Meier survival analysis revealed significant differences in the 1-year and 2-year OS rates between the DPHCC and non-DPHCC groups (P = 0.030 and 0.027) as well as between the DPHCC and ICC groups (P = 0.029 and 0.016).

Conclusion

In multi-parameter MRI, combining the assessment of the absence of tumor capsule, persistent enhancement, arterial rim enhancement, and target sign on DWI image with clinical data such as AFP >20 μg/L and HBV status may support in the diagnosis of DPHCC and differentiation from non-DPHCC and ICC. Accurate preoperative diagnosis facilitates the selection of personalized treatment options.

Diagnostic Value of MRI Features in Dual-phenotype Hepatocellular Carcinoma: A Preliminary Study

This study aimed to explore the magnetic resonance imaging (MRI) features of dual-phenotype hepatocellular carcinoma (DPHCC) and their diagnostic value.The data of 208 patients with primary liver cancer were retrospectively analysed between January 2016 and June 2021. Based on the pathological diagnostic criteria, 27 patients were classified into the DPHCC group, 113 patients into the noncholangiocyte-phenotype hepatocellular carcinoma (NCPHCC) group, and 68 patients with intrahepatic cholangiocarcinoma (ICC) were classified into the ICC group. Two abdominal radiologists reviewed the preoperative MRI features by a double-blind method. The MRI features and key laboratory and clinical indicators were compared between the groups. The potentially valuable MRI features and key laboratory and clinical characteristics for predicting DPHCC were identified by univariate and multivariate analyses, and the odds ratios (ORs) were recorded. In multivariate analysis, tumour without capsule (P = 0.046, OR = 9.777), dynamic persistent enhancement (P = 0.006, OR = 46.941), and targetoid appearance on diffusion-weighted imaging (DWI) (P = 0.021, OR = 30.566) were independently significant factors in the detection of DPHCC compared to NCPHCC. Serum alpha-fetoprotein (AFP) > 20 µg/L (P = 0.036, OR = 67.097) and prevalence of hepatitis B virus (HBV) infection (P = 0.020, OR = 153.633) were independent significant factors in predicting DPHCC compared to ICC. The differences in other tumour marker levels and imaging features between the groups were not significant. In MR enhanced and diffusion imaging, tumour without capsule, persistent enhancement and DWI targetoid findings, combined with AFP > 20 µg/L and HBV infection-positive laboratory results, can help to diagnose DPHCC and differentiate it from NCPHCC and ICC. These results suggest that clinical, laboratory and MRI features should be integrated to construct an AI diagnostic model for DPHCC.

The added value of 18F-FDG PET/MRI multimodal imaging in hepatocellular carcinoma for identifying cytokeratin 19 status

PURPOSE

In hepatocellular carcinoma (HCC), cytokeratin 19(CK19) has been proven to be associated with clinical aggressiveness. Therefore, this study aimed to explore the added value of 18F-FDG PET/MRI in predicting CK19 status in HCC.

METHODS

Sixty-six patients who underwent whole-body or abdominal 18F-FDG PET/MRI after conventional PET/CT for HCC were retrospectively enrolled. The maximal standard uptake value (T-SUVmax) and the mean apparent diffusion coefficient (T-ADCmean) of the tumor (T), as well as those of the normal liver tissues (L) were derived, followed by calculations of the T-SUVmax/L-SUVmax (SUVmax-T/L) and the T-ADCmean/L-ADCmean (ADCmean-T/L) ratios. Combined with the postoperative pathological results, the performance in predicting the CK19 status in HCC was evaluated using receiver operating characteristic analysis (ROC).

RESULTS

The areas under the ROC curve (AUCs) for T-SUVmax, SUVmax-T/L, T-ADCmean, and ADCmean-T/L in predicting the CK19-positive HCC were 0.700, 0.717, 0.717, and 0.735, respectively. In the logistic regression analysis, the T-SUVmax was an independent and significant factor to predict CK19-positive HCC, with an odds ratio of 1.27. In addition, no significant differences were found in the pathological grading, microvascular invasion, liver capsular invasion, Hepatitis B virus (HBV) infection, alpha fetoprotein (AFP) level, and tumor diameter between the CK19-positive and CK19-negative groups, except the recurrent rate.

CONCLUSIONS

The radiomic features derived from 18F-FDG PET/MRI can be used to predict the CK19 status of HCC. T-SUVmax and T-ADCmean were significant indicators, whereas T-SUVmax was an independent predictor.

Preoperative prediction of cytokeratin-19 expression for hepatocellular carcinoma using T1 mapping on gadoxetic acid-enhanced MRI combined with diffusion-weighted imaging and clinical indicators

Objectives

To explore the value of T1 mapping on gadoxetic acid-enhanced magnetic resonance imaging (MRI) in preoperative predicting cytokeratin 19 (CK19) expression for hepatocellular carcinoma (HCC).

Methods

This retrospective study included 158 patients from two institutions with surgically resected treatment-native solitary HCC who underwent preoperative T1 mapping on gadoxetic acid-enhanced MRI. Patients from institution I (n = 102) and institution II (n = 56) were assigned to training and test sets, respectively. univariable and multivariable logistic regression analyses were performed to investigate the association of clinicoradiological variables with CK19. The receiver operating characteristic (ROC) curve and precision-recall (PR) curve were used to evaluate the performance for CK19 prediction. Then, a prediction nomogram was developed for CK19 expression. The performance of the prediction nomogram was evaluated by its discrimination, calibration, and clinical utility.

Results

Multivariable logistic regression analysis showed that AFP>400ng/ml (OR=4.607, 95%CI: 1.098-19.326; p=0.037), relative apparent diffusion coefficient (rADC)≤0.71 (OR=3.450, 95%CI: 1.126-10.567; p=0.030), T1 relaxation time in the 20-minute hepatobiliary phase (T1rt-HBP)>797msec (OR=4.509, 95%CI: 1.301-15.626; p=0.018) were significant independent predictors of CK19 expression. The clinical-quantitative model (CQ-Model) constructed based on these significant variables had the best predictive performance with an area under the ROC curve of 0.844, an area under the PR curve of 0.785 and an F1 score of 0.778. The nomogram constructed based on CQ-Model demonstrated satisfactory performance with C index of 0.844 (95%CI: 0.759-0.908) and 0.818 (95%CI: 0.693-0.902) in the training and test sets, respectively.

Conclusions

T1 mapping on gadoxetic acid-enhanced MRI has good predictive efficacy for preoperative prediction of CK19 expression in HCC, which can promote the individualized risk stratification and further treatment decision of HCC patients.

Prognostic implications of CT/MRI LI-RADS in hepatocellular carcinoma: State of the art and future directions

Hepatocellular carcinoma (HCC) is the fourth most lethal malignancy with an increasing incidence worldwide. Management of HCC has followed several clinical staging systems that rely on tumour morphologic characteristics and clinical variables. However, these algorithms are unlikely to profile the full landscape of tumour aggressiveness and allow accurate prognosis stratification. Noninvasive imaging biomarkers on computed tomography (CT) or magnetic resonance imaging (MRI) exhibit a promising prospect to refine the prognostication of HCC. The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing the terminology, techniques, interpretation, reporting and data collection of liver imaging. At present, it has been widely accepted as an effective diagnostic system for HCC in at-risk patients. Emerging data have provided new insights into the potential of CT/MRI LI-RADS in HCC prognostication, which may help refine the prognostic paradigm of HCC that promises to direct individualized management and improve patient outcomes. Therefore, this review aims to summarize several prognostic imaging features at CT/MRI for patients with HCC; the available evidence regarding the use of LI-RDAS for evaluation of tumour biology and clinical outcomes, pitfalls of current literature, and future directions for LI-RADS in the management of HCC.

Preoperative Prediction of Cytokeratin 19 Expression for Hepatocellular Carcinoma with Deep Learning Radiomics Based on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging

Purpose

Cytokeratin 19 (CK19) expression is a proven independent prognostic predictor of hepatocellular carcinoma (HCC). This study aimed to develop and validate the performance of a deep learning radiomics (DLR) model for CK19 identification in HCC based on preoperative gadoxetic acid-enhanced magnetic resonance imaging (MRI).

Patients and Methods

A total of 141 surgically confirmed HCCs with preoperative gadoxetic acid-enhanced MRI from two institutions were included. Prediction models were established based on hepatobiliary phase (HBP) images using a training set (n=102) and validated using time-independent (n=19) and external (n=20) test sets. A receiver operating characteristic curve was used to evaluate the performance for CK19 prediction. Recurrence-free survival (RFS) was also analyzed by incorporating the CK19 expression and other factors.

Results

For predicting CK19 expression, the area under the curve (AUC) of the DLR model was 0.820 (95% confidence interval [CI]: 0.732–0.907, P<0.001) with sensitivity, specificity, accuracy of 0.800, 0.766, and 0.775, respectively, and reached 0.781 in the external test set. Combined with alpha fetoprotein, the AUC increased to 0.833 (95% CI: 0.753–0.912, P<0.001) and the sensitivity was 0.960. Intratumoral hemorrhage and peritumoral hypointensity on HBP were independent risk factors for HCC recurrence by multivariate analysis. Based on predicted CK19 expression and the independent risk factors, a nomogram was developed to predict RFS and achieved C-index of 0.707.

Conclusion

This study successfully established and verified an optimal DLR model for preoperative prediction of CK19-positive HCCs based on gadoxetic acid-enhanced MRI. The prediction of CK19 expression in HCC using a non-invasive method can help inform preoperative planning.

Cholangiolocellular Carcinoma With "Ductal Plate Malformation" Pattern May Be Characterized by ARID1A Genetic Alterations

Cholangiolocellular carcinoma (CLC) is a unique subtype of primary liver carcinoma, which sometimes coexists with hepatocellular carcinoma (HCC), cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma (cHCC-CCA). "Ductal plate malformation" (DPM)-pattern of primary liver carcinoma, which resembles biliary lesions in Caroli disease and von Meyenburg complex, is sometimes associated with CLC. We examined genetic alterations of hTERT promoter (hTERT), IDH1 or 2 (IDH1/2), KRAS, ARID1A, PBRM1, ARID2, BAP1, p53 and their association with histologic features such as proportion of CLC and DPM-pattern in 77 patients with primary liver carcinoma diagnosed as cHCC-CCA or CLC. Primary liver carcinomas were histologically subdivided into 29 CLC-predominant (CLC component >80%), 31 with CLC (5% to 80%) and 17 without CLC (<5%). CLC-predominant group was characterized by older age, male-predominant and smaller tumor size. Genetic alterations were detected in hTERT (25%), ARID1A (21%), PBRM1 (20%), ARID2 (3%), BAP1 (1%), p53 (46%), KRAS (5%), and IDH1/2 (8%). ARID1A alteration was more frequent in CLC-predominant group, compared with other groups (P<0.05) and was correlated with the degree of DPM-pattern (P<0.01). Alterations of hTERT and p53 were less frequent in CLC-predominant group compared with "with CLC group" (P<0.05). hTERT mutation was less frequent in carcinomas with DPM-pattern (P<0.01). PBRM1 alteration was more frequent in CLC with focal HCC subgroup and without CLC group compared with other groups (P<0.05). CLC may be a distinct subgroup of primary liver carcinoma, which is different from cHCC-CCA, based on clinicopathologic and genetic alterations. ARID1A alterations may characterize CLC with DPM-pattern and could be a diagnostic immunohistochemical marker for small CLCs with DPM-pattern.

Magnetic resonance texture analysis for the identification of cytokeratin 19-positive hepatocellular carcinoma

PURPOSE

To investigate potential findings associated with cytokeratin 19 (CK19)-positive HCC, with special emphasis on MR texture analysis.

MATERIALS AND METHODS

Forty-eight patients with CK19-negative HCC and 38 patients with CK19-positive were retrospectively evaluated by texture analysis based on conventional MRI. Clinicalpathological characteristics, conventional MR imaging findings, and the MR texture analysis contained of 2415 texture features in the seven conventional sequences were compared. Significant features for differentiating were identified by univariate and multivariate analyses. Receiver operating characteristic analyses of the significant findings were performed and compared to evaluate their diagnostic performance.

RESULTS

There was no significant difference between the top1 texture feature (three-dimensional standard deviation separation of intensity on T2-weighted original images, abbreviated as: StdSeparation 3D) and the combined top1-6 feature in identifying CK19-positive HCC(P = 0.660). Univariate and multivariate analyses indicated that serum alpha-fetoprotein (AFP) level ≥400 ng/mL(P = 0.013), arterial rim enhancement(P = 0.005), and StdSeparation 3D texture character(P = 0.002) were independent variables associated with CK19-positive HCCs. The combination of the three indices showed a better performance than AFP level(P = 0.0028), arterial rim enhancement(P < 0.0001), and their combination(P = 0.0098); while no significantly better than the StdSeparation 3D texture character alone(P = 0.0788). An acceptable discrimination(AUC = 0.765) with both sensitivity and specificity greater than 75% was achieved for StdSeparation 3D texture character.

CONCLUSION

Serum AFP level ≥400 ng/mL, arterial rim enhancement, and the StdSeparation 3D texture character were independently associated with CK19-positive HCC. The StdSeparation 3D texture character may be a reliable imaging biomarker which can improve the diagnostic performance.

Connexin 43 plays an important role in the transformation of cholangiocytes with Clonochis sinensis excretory-secretory protein and N-nitrosodimethylamine

Background

Clonorchis sinensis is a group I bio-carcinogen responsible for cholangiocarcinoma (CHCA) in humans. However, the mechanism by which C. sinensis promotes carcinogenesis is unclear.

Methodology

Using the human cholangiocyte line H69, we investigated cell proliferation and gap junction protein expression after stimulation with the hepatotoxin N-nitrosodimethylamine (NDMA) and/or excretory-secretory products (ESP) of C. sinensis, which induce inflammation. NDMA and ESP treatment increased proliferation by 146% and the proportion of cells in the G2/M phase by 37%. Moreover, the expression of the cell proliferation-related proteins E2F1, Ki-67, and cancer related protein cytokeratin 19 and Cox-2 increased in response to combined treatment with NDMA and ESP. The gap-junction proteins connexin (Cx) 43 and Cx26 increased. In contrast, Cx32 expression decreased in cells treated with NDMA and ESP. Silencing of Cx43 reduced cell proliferation and significantly suppressed Cx26 and Cox-2 expression.

Conclusions

These results suggest that Cx43 is an important factor in CHCA induced by C. sinensis ESP and NDMA and further investigations targeting this pathway may allow prevention of this deadly disease.

Clonorchis sinensis, a human fluke, resides in the liver of humans and is commonly found in the common bile duct and gall bladder. This parasite is the main cause of cholangiocarcinoma, also called bile duct cancer, in humans. Of note, the excretory-secretory products (ESP) of C. sinensis are known to cause inflammation in the biliary epithelium, which may ultimately result in neoplasms via production of reactive oxygen species and subsequent DNA damage. Together with N-nitrosodimethylamine (NDMA), a potent hepatotoxin that can cause fibrosis and tumors in the liver, ESP led to an increase in the growth and proliferation of cholangiocytes. Our results showed that examination of changes in the expression of gap junction proteins, which are related to tumorigenesis, showed that connexin 43 was upregulated with ESPs from C. sinensis and NDMA. Together, our results suggest that exposure to C. sinensis, in addition to low levels of carcinogen could promote carcinogenesis in the bile duct epithelium via uncontrolled cell-to-cell communication. Moreover, silencing of Cx43 reduced cancer related protein. Therefore, Cx 43 can serve as a potential target for developing a therapeutic strategy for the treatment of cholangiocarcinoma in humans.

MR features based on LI-RADS identify cytokeratin 19 status of hepatocellular carcinomas

OBJECTIVE

To retrospectively evaluate the value of MR features based on Liver Imaging Reporting and Data System (LI-RADS ver.2017) for identifying the status of cytokeratin (CK) 19 expression of HCC before surgery.

METHODS

A total of 201 patients with 207 HCCs who underwent MR imaging were reviewed retrospectively. MR features based on LI-RADS ver.2017 as well as clinical data were compared between CK19-positive (n = 51) and CK19-negative (n = 156) HCCs groups. Potential predictive parameters were identified by univariate and multivariate logistic regression analysis and diagnostic odds ratios (ORs) were recorded.

RESULTS

MR features including targetoid appearance (p = 0.001) was more frequently observed while non-peripheral "washout" (p < 0.0001) and non-rim arterial phase hyper-enhancement (p < 0.0001) were found less frequently in CK19-positive HCCs compared to CK19-negative HCCs. At multivariate analysis, serum alphafetoprotein (AFP)>20 ng/ml (OR = 5.9) and targetoid appearance (OR = 4.2) and non-peripheral "washout" (OR = 0.2) were significant independent predictors of CK19-positive HCCs.

CONCLUSION

Targetoid appearance and absence non-peripheral "washout" combined with elevated AFP were useful for differentiating CK19-positive HCCs from CK19-negative HCC.

Imaging Features of Gadoxetic Acid-enhanced and Diffusion-weighted MR Imaging for Identifying Cytokeratin 19-positive Hepatocellular Carcinoma: A Retrospective Observational Study

Purpose To determine the preoperative magnetic resonance (MR) imaging findings potentially most useful for predicting cytokeratin 19 (CK19)-positive hepatocellular carcinoma (HCC) and to evaluate the prognosis after curative resection in patients with a single HCC lesion positive for CK19 compared with patients with HCC who are negative for CK19. Materials and Methods The institutional review board approved this study and waived the requirement for informed consent. Two hundred four patients with CK19-negative HCC and 38 with CK19-positive HCC who underwent curative resection after gadoxetic acid-enhanced and diffusion-weighted MR imaging were retrospectively evaluated in a single institution. Two radiologists evaluated preoperative findings at MR imaging. Significant findings for differentiating the two groups were identified at univariate and multivariate analyses. By using receiver operating characteristic analysis, the optimal cut-off values for quantitative variables were determined. Recurrence-free survival rates after surgery were also compared between groups. Results At multivariate analysis, irregular tumor margin (P = .024), arterial rim enhancement (P < .001), lower tumor-to-liver signal intensity (SI) ratio on hepatobiliary phase (HBP) images (≤0.522; P = .01), and lower tumor-to-liver apparent diffusion coefficient (ADC) ratio (≤0.820; P < .001) were independent significant factors to predict CK19-positive HCC. When three of these four criteria were combined, 63.2% (24 of 38; 95% confidence interval: 46.0%, 78.2%) of CK19-positive HCCs were identified with a specificity of 90.7% (185 of 204; 95% confidence interval: 46.0%, 78.2%). When all four criteria were satisfied, specificity was 99.5% (203 of 204; 95% confidence interval: 97.3%, 100%). Recurrence-free survival rates were significantly lower in patients with CK19-positive HCCs compared with those with CK19-negative HCCs after curative resection (63.9% vs 90.0% at 1 year, 63.9% vs 79.9% at 2 years, and 54.8% vs 70.2% at 3 years, P = .001 by log-rank test). Conclusion At gadoxetic acid-enhanced and diffusion-weighted MR imaging, irregular margin, arterial phase rim enhancement, lower tumor-to-liver ADC ratio, and lower tumor-to-liver SI ratio at HBP imaging may be helpful to predict CK19-positive HCC with early recurrence (<2 years) after curative resection. ^© RSNA, 2017 Online supplemental material is available for this article.

Serum Wisteria Floribunda Agglutinin-Positive Sialylated Mucin 1 as a Marker of Progenitor/Biliary Features in Hepatocellular Carcinoma

Histological molecular classification of hepatocellular carcinoma (HCC) is clinically important for predicting the prognosis. However, a reliable serum marker has not been established. The aim of this study was to evaluate the diagnostic value of serum Wisteria Floribunda agglutinin-positive sialylated mucin 1 (WFA-sialylated MUC1), which is a novel biliary marker, as a marker of HCC with hepatic progenitor cell (HPC)/biliary features and of prognosis. A total of 144 consecutive patients who underwent complete radiofrequency ablation of primary HCC were enrolled. A serum WFA-sialylated MUC1 level of 900 μL/mL was determined as the optimal cutoff value for prediction of immunohistochemical staining for HPC/biliary features [sialylated MUC1 and cytokeratin 19 (CK19)]. Positive staining rate of sialylated MUC1 and CK19 was significantly higher in patients with WFA-sialylated MUC1 ≥900 than those with WFA-sialylated MUC1 <900. Furthermore, cumulative incidence of HCC recurrence was significantly higher in patients with WFA-sialylated MUC1 ≥900 and on multivariate analysis, serum WFA-sialylated MUC1 levels was an independent predictor of HCC recurrence. These results revealed that serum WFA-sialylated MUC1 was associated with histological feature of HCC and recurrence after curative therapy and it could be a novel marker of HPC/biliary features in HCC and of prognosis.

Variant differentiation patterns in primary liver carcinoma

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are two distinct forms of primary liver carcinoma recognizable at the microscope by their architectural and cytological characteristics, as well as specific immunohistochemical profiles. This straightforward concept however, is increasing imperiled by the recognition of primary liver carcinomas that do not subscribe to a dichotomous paradigm of differentiation, and instead demonstrate biphenotypic differentiation, stem/progenitor cell like features or other variant patterns of differentiation. Appropriate nomenclature, diagnostic criteria, prognostic significance and optimal therapeutic approach for these variant tumors are not completely defined, not leasyt because they are not always identified correctly and when they are, lack of uniform terminology hinders collection of adequate number of cases to facilitate their study. Similar to hepatocellular carcinoma and in contrast with intrahepatic cholangiocarcinoma, primary liver tumors showing biphenotypic differentiation, stem/progenitor cell features or variant differentiation occur mainly, but not always, on a background of chronic liver disease. They are particularly frequent after neo-adjuvant therapy. Whether they represent trans-differentiation of malignant cells, or whether they derive from a stem/progenitor cell that gives rise to divergent differentiation remains yet another area of uncertainty.

Keratin 19 as a key molecule in progression of human hepatocellular carcinomas through invasion and angiogenesis

BACKGROUND

Keratin (K) 19-positive hepatocellular carcinoma (HCC) is well known to have a higher malignant potential than K19-negative HCC: However, the molecular mechanisms involved in K19-mediated progression of HCC remain unclear. We attempted to clarify whether K19 directly affects cell survival and invasiveness in association with cellular senescence or epithelial-mesenchymal transition (EMT) in K19-positive HCC.

METHODS

K19 expression was analysed in 136 HCC surgical specimens. The relationship of K19 with clinicopathological factors and survival was analysed. Further, the effect of K19 on cell proliferation, invasion, and angiogenesis was examined by silencing K19 in the human HCC cell lines, HepG2, HuH-7, and PLC/PRF/5. Finally, we investigated HCC invasion, proliferation, and angiogenesis using K19-positive HCC specimens.

RESULTS

Analysis of HCC surgical specimens revealed that K19-positive HCC exhibited higher invasiveness, metastatic potential, and poorer prognosis. In vitro experiments using the human HCC cell lines revealed that K19 silencing suppressed cell growth by inducting apoptosis or upregulating p16 and p27, resulting in cellular senescence. In addition, transfection with K19 siRNA upregulated E-cadherin gene expression, significantly inhibited the invasive capacity of the cells, downregulated angiogenesis-related molecules such as vasohibin-1 (VASH1) and fibroblast growth factor 1 (FGFR1), and upregulated vasohibin-2 (VASH2). K19-positive HCC specimens exhibited a high MIB-1 labelling index, decreased E-cadherin expression, and high microvessel density around cancer foci.

CONCLUSION

K19 directly promotes cancer cell survival, invasion, and angiogenesis, resulting in HCC progression and poor clinical outcome. K19 may therefore be a novel drug target for the treatment of K19-positive HCC.

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

AIMS

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.

METHODS AND RESULTS

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).

CONCLUSIONS

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.

Immunohistochemical study of hepatocyte, cholangiocyte and stem cell markers of hepatocellular carcinoma: the second report: relationship with tumor size and cell differentiation

Background

The purpose of this study is to investigate whether ordinary hepatocellular carcinomas (HCCs) show positivity of stem/progenitor cell markers and cholangiocyte markers during the process of tumor progression.

Methods

Ninety‐four HCC lesions no larger than 8 cm from 94 patients were immuno‐histochemically studied using two hepatocyte markers (Hep par 1 and α‐fetoprotein), five cholangiocyte markers (cytokeratin CK7, CK19, Muc1, epithelial membrane antigen and carcinoembryonic antigen) and three hepatic stem/progenitor cell markers (CD56, c‐Kit and EpCAM). The tumors were classified into three groups by tumor size: S1, < 2.0 cm; S2, 2.0–5.0 cm; S3, 5.0–8.0 cm. The tumors were also classified according to tumor differentiation: well, moderately and poorly differentiated. The relationship between the positive ratios of these markers, tumor size and tumor differentiation was examined.

Results

The positive ratios of cholangiocyte markers tended to be higher in larger sized and more poorly differentiated tumors (except for CK7). The positive ratios of stem/progenitor cell markers tended to be higher in larger sized and more poorly differentiated tumors (except for c‐Kit).

Conclusion

Ordinary HCC can acquire the characteristic of positivity of cholangiocyte and stem/progenitor cell markers during the process of tumor progression.

Keratin 19 protein expression is an independent predictor of survival in human hepatocellular carcinoma

AIM

We aimed to assess the clinicopathological relevance and prognostic significance of expression of the hepatic progenitor cell markers keratin 19 (K19), epithelial cell adhesion molecule (EpCAM) and CD117 (c-KIT) in a White series of hepatocellular carcinoma (HCC).

METHODS

We evaluated the immunohistochemical expression of K19, EpCAM and CD117 in 89 surgical specimens of HCC from Greek patients (mean age 66.7±11.3 years, male 75.2%) followed up for 39.6±25.3 months.

RESULTS

K19, EpCAM and CD117 expression was detected in tumour cells of 10.11, 15.38 and 3.7% HCCs, respectively. Female sex was correlated with EpCAM immunohistochemical expression (P=0.035), whereas no other significant relationship with clinicopathological parameters was observed. K19 positivity tended to be correlated with microvascular invasion (P=0.054). In univariate analysis, K19 positivity and microvascular invasion were found to be associated with decreased recurrence-free survival (P<0.001 and P=0.004, respectively) and overall survival (P=0.002 and P=0.029, respectively). EpCAM and CD117 positivity was not correlated with patient survival. In multivariate analysis, K19 positivity emerged as an independent predictor of recurrence-free survival (odds ratio=7.84, 95% confidence interval=2.658-22.912, P<0.001) and overall survival (odds ratio=3.845, 95% confidence interval=1.401-10.549, P=0.009).

CONCLUSION

Our study confirms the prognostic significance of K19 expression in Caucasian patients with HCCs, providing further evidence that it may be used to stratify HCC according to tumour aggressiveness.

Biphenotypic (hepatobiliary) primary liver carcinomas: the work in progress

Recent WHO classification for combined hepatocellular-cholangiocarcinoma and recognized stem cell subtypes has increased attention to such tumors; however, the resulting burst of reporting and research indicates that this classification, while provocative, is incomplete for description of the full array of primary liver carcinomas with biphenotypic (hepatobiliary) differentiation. We review the history of such lesions and consider the wider array of such tumors previously described. Mixed hepatobiliary phenotypes and immunophenotypes are found in individual tumors at the tissue level - with architectural and cytologic features supportive of both differentiation states - and at the cellular level, with individual cells that display cytology of one cell type, but immunophenotypically showing mixed expression. Pathobiologic and clinical questions to be answered by future research are suggested.

Pathogenesis and prognosis of hepatocellular carcinoma at the cellular and molecular levels

Different approaches predict the outcome for patients with hepatocellular carcinoma (HCC). The expression of biliary-hepatic progenitor cell markers generally correlates with poor prognosis. This article focuses on the pathogenesis of HCC, how differentiation or dedifferentiation leads to a phenotype switch, and heterogeneity in the same tumor. A tumor cell decides its fate based on a complex interplay of signaling pathways. Interaction with the microenvironment decides whether it will invade, proliferate, or enter survival mode. Several signaling pathways contribute to stemness features, reflecting a small chemoresistant subpopulation of the tumor that expresses biliary-hepatic progenitor cell markers.

Clinicopathological significance of 'subtypes with stem-cell feature' in combined hepatocellular-cholangiocarcinoma

BACKGROUNDS & AIMS

Combined hepatocellular-cholangiocarcinoma (cHC-CC), a malignant liver tumour with poor prognosis, is composed of hepatocellular carcinoma (HCC), cholangiocarcinoma (CC) and diverse components with intermediate features between HCC and CC, which correspond to hepatic progenitor cells. According to the WHO classification 2010, we surveyed the prevalence and clinicopathological significance of each subtype with stem-cell features [SC subtype; typical subtype (TS), intermediate cell subtype (INT) and cholangiolocellular type (CLC)] in cHC-CC and HCC.

METHODS

Sixty-two patients with cHC-CC (19 women and 43 men) and 26 patients with HCC (all men) were examined. The prevalence of each component was histologically assessed with assistance of mucin and immunohistochemical stainings.

RESULTS

SC subtypes were observed in all cHC-CCs in various amount and combination. The prevalence of each SC subtype in cHC-CC was as follows: TS, 10 (16.1%); INT, 53 (83.9%) and CLC, 44 (71.0%). The proportion of INT was significantly correlated with gender (female-dominant) (P < 0.05), tumour size (P < 0.05), histological grading of HCC (P < 0.01) and inversely correlated with the degree of stromal fibrosis (P < 0.05). The proportion of CLC was significantly correlated with the degree of fibrosis (P < 0.01) and inflammation (P < 0.01), and inversely correlated with tumour size (P < 0.01) and histological grading of HCC (P < 0.05). The proportion of TS was significantly inversely correlated with the degree of inflammation (P < 0.01). Histological diversity score was significantly correlated with vascular invasion and the positivity for α-foetoprotein.

CONCLUSION

The proportion of each SC subtype was significantly associated with certain clinicopathological factors, suggesting different properties of each SC subtypes.

Prognosis of hepatocellular carcinoma expressing cytokeratin 19: Comparison with other liver cancers

AIM: To investigate whether expressing biliary phenotype predicted poor outcome after the surgical treatment in primary liver cancers.

METHODS: Out of 204 patients that underwent liver resection due to hepatocellular carcinoma (HCC), liver specimens of 70 patients with HCC were evaluated for biliary components by cytokeratin (CK) 19 immunostain (CK19^- HCC and CK19⁺ HCC). CK19 positivity was defined as membranous and/or cytoplasmic expression in ≥ 5% of tumor cells with moderate or strong intensity. Patients with other primary liver cancers, such as combined HCC and cholangiocarcinoma (cHCC-CC), intrahepatic cholangiocarcinoma (ICC) who received curative liver resection, were also included in the study. Clinical characteristics of CK19^- HCC and CK19⁺ HCC patients, including survival outcome after curative liver resection, were compared with that of cHCC-CC and ICC patients.

RESULTS: The overall survival (OS) rate of CK19^- HCC (n = 49) after the curative surgical treatment was 90.7%, and 80.4% at 1 and 5 years after the resection. OS rate of CK19⁺ HCC (n = 21) was 74.3%, 28.9% and OS rate of cHCC-CC (n = 22) was 66.7%, 32.2% at 1 and 5 years after the surgery. For ICC (n = 19), 1 and 5-year-OS rate was 50.2% and 14.3% after the curative resection. The OS rates of CK19⁺ HCC and cHCC-CC were significantly lower than that of CK19^- HCC, but higher than the OS rate of ICC (P = 0.000). There was no statistically significant difference in OS rate between CK19⁺ HCC and cHCC-CC. The disease free survival (DFS) rate of CK19^- HCC was 72.0% and 54.5% at 1 and 3 years after the surgical treatment. DFS rate of CK19⁺ HCC was 53.3%, 34.3% and DFS rate of cHCC-CC was 51.5%, 39.2% at 1 and 3 years after the resection. For ICC, 1 and 3-year-DFS rate was 28.0% and 14.0% after the curative resection. DFS rate of CK19^- HCC was significantly higher than that of ICC (P = 0.017), but marginally higher than DFS rate of either CK19⁺ HCC or cHCC-CC (P = 0.097, P = 0.089, respectively). Predictors of outcome after the surgery of primary liver cancer were pathology of the resected mass, existence of microvascular invasion and accompanying satellite nodule.

CONCLUSION: Primary liver cancers with biliary components tended to show poorer surgical outcome. This suggested that immuno-phenotype of liver cancers was as important as their morphological classification.

Hepatoid carcinoma of the pancreas penetrating into the gastric cavity: a case report and literature review

A 79-year-old Japanese woman was admitted to our hospital for treatment of a pancreatic tumor measuring approximately 7 × 5 cm. The tumor had invaded the left adrenal gland and gastric wall and had penetrated into the gastric cavity. Surgical resection was performed. The tumor was composed of a brown to whitish solid area and a zone of hemorrhage, necrosis, and cystic degeneration resembling the gross features of solid pseudopapillary tumor (SPT). Histologically, the tumor showed a heterogeneous growth pattern with a combination of seat-like, trabecular, papillary and hemorrhagic-necrotic areas in various proportions. The differential diagnoses first considered were acinar cell carcinoma, neuroendocrine carcinoma and SPT with malignant transformation. Immunohistochemistry showed tumor cells were negative for pancreatic exocrine enzymes and endocrine markers. Tumor cells diffusely expressed cytokeratin 19, alpha-fetoprotein, carcinoembryonic antigen and glypican-3, but lacked vimentin or β-catenin expression. Small proportions of tumor cells expressed hepatocyte paraffin-1. Although typical morphological features of well-differentiated hepatocellular carcinoma (HCC) were not distinctly apparent, the tumor morphology partly resembled poorly differentiated HCC. Given these findings and considerations, the tumor was finally diagnosed as poorly differentiated hepatoid carcinoma of the pancreas.

Expression of K19 and K7 in dysplastic nodules and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumors characterized by a multistep process of tumor development. Nodular lesions that differ from the surrounding liver parenchyma and are characterized by cytological or structural atypia are termed dysplastic nodules (DNs). DNs are well-known precancerous HCC lesions. Expression of keratin (K) 19 and K7, molecular markers of hepatic progenitor cells and cholangiocytes, has been reported in certain HCCs. However, it remains unclear whether K19-positive HCC cells are derived from true hepatic progenitor cells or mature cells that have undergone a dedifferentiation or a transdifferentiation process. In total, 107 tissue sections (13 low-grade DNs, 15 high-grade DNs, 27 small HCCs and 52 large HCCs) from resected liver samples and 132 HCC tissue microarray (TMA) cores were subjected to immunohistochemical analysis for K19 and K7. Clinicopathological data of the HCC patients were evaluated. K19 expression was found in 0% of DNs, 19% of small HCCs (≤2 cm), 8% of large HCCs (>2 cm) and 8% of TMA samples. K7 expression was found in 14% of DNs, 41% of small HCCs, 15% of large HCCs and 6% of TMA samples. Among the five K19-positive small HCCs, four were distinctly nodular and one tumor was an infiltrative type. No vaguely nodular HCC was positive for K19. K19 expression was significantly associated with histological grade (P=0.023), serum α-fetoprotein level (P=0.001) and K7 expression (P=0.001) in HCC. K19 expression was an independent prognostic factor for overall survival in non-viral HCC patients (P=0.003). K19 expression is extremely rare in DNs and occurs in progressed small HCCs. Our results suggest that K19 expression may be an acquired feature of carcinoma cells during HCC progression in certain HCCs.

MRI features of hepatocellular carcinoma expressing progenitor cell markers

BACKGROUND & AIMS

To determine whether magnetic resonance (MR) imaging features differ between hepatocellular carcinomas (HCCs) with and without expression of progenitor cell markers, such as cytokeratin (CK) 19 and epithelial cell adhesion molecule (EpCAM).

METHODS

Sixty-three patients with 71 HCCs who underwent surgery after preoperative gadoxetic acid-enhanced MR imaging were evaluated. HCCs expressing progenitor cell markers were defined as showing CK19 or EpCAM expression. MR imaging features, including the fat component, arterial enhancement (global vs. peripheral), dynamic enhancement (washout vs. progressive or persistent), nodule-in-nodule appearance and MR gross morphology (expanding vs. non-expanding), were compared between HCCs with and without progenitor cell markers expression. Lesion-to-liver signal intensity ratio (SIR) and apparent diffusion coefficient values were compared using an independent samples t-test. Early recurrence rates were also compared.

RESULTS

HCCs expressing progenitor cell markers were more commonly of the non-expanding type (P = 0.016), more frequently had a progressive or persistent dynamic enhancement pattern (P = 0.008) and less frequently demonstrated a nodule-in-nodule appearance (P = 0.009). HCCs expressing progenitor cell markers had significantly higher SIRs on diffusion-weighted images (DWIs) (b = 50 and 800, P < 0.001; b = 400, P = 0.001) and a significantly lower SIR on hepatobiliary phase images (P = 0.024). The early recurrence rate was significantly higher in patients with prior HCCs that expressed progenitor cell markers (P = 0.045).

CONCLUSIONS

HCCs expressing progenitor cell markers can be characterized according to their non-expanding MR gross morphology, persistent or progressive dynamic enhancement patterns, higher SIRs on DWIs, lower SIRs on hepatobiliary phase images and less frequent nodule-in-nodule appearance.

Anatomic pathology of hepatocellular carcinoma: impact on prognosis and response to therapy

A better understanding of signaling pathways in HCC pathogenesis has led to targeted therapies against HCC. Identification of liver cancer stem cell markers and their related pathways is one of the most important goals of liver cancer research. New therapies should ideally target cancer stem cells and not normal stem/progenitor cells, because the latter are very important in regeneration and repair. Individualized HCC therapy will require better definition of patient subgroups that benefit most or should be protected from therapy failure and unwanted side effects. Tumor tissue acquisition should be mandatory, reversing the practice that was established years ago when targeted HCC therapy was but a pipe dream.

Pathobiological features of small hepatocellular carcinoma: correlation between tumor size and biological behavior

PURPOSE

Increasing evidence has suggested that tumor size is one of the independent prognostic factors of patients with hepatocellular carcinoma (HCC). However, the criteria used to determine when HCC should be classified as small remain controversial. Our objective was to evaluate the relationship between the size of HCC and its clinicopathological features.

METHODS

A retrospective study on 618 patients who underwent partial hepatectomy for solitary HCC was performed. These patients were divided into Groups 1-5 according to the tumor diameter: ≤ 1, 1.1-2, 2.1-3, 3.1-5 and >5 cm, respectively. The clinicopathological variables of the patients in each group were compared statistically.

RESULTS

Except for the microHCC (≤ 1 cm) which differed significantly from the other four groups in the clinicopathological variables, almost no differences existed among HCC ranging from 1 to 3 cm, or HCCs > 3 cm. If ≤ 3 cm was used as the cut-off point for small HCC (SHCC), and >3 cm for large HCC (LHCC), significant differences (P < 0.05-0.01) were observed between SHCC and LHCC in: histological grades I-II (48.0 vs. 19.4 %), capsular invasion (15.4 vs. 36.3%), tumor thrombi (6.9 vs. 23.5%), satellite nodules (12.3 vs. 35.5%), noninvasive growth patterns (69.6 vs. 25.4%), the overall survival (OS, 119.6 ± 34.7 vs. 68.5 ± 6.6 months), and the recurrence-free survival (RFS, 67.0 ± 16.7 vs. 29.5 ± 3.2 months). Multivariate Cox regression analyses show that tumor size >3 cm was one of the independent prognostic factors for both OS and RFS.

CONCLUSIONS

The 3 cm cutoff seems to best determine the biological behavior and clinical prognosis of patients undergoing partial hepatectomy for early stage HCC. Overall, HCC smaller than 3 cm in diameter was closely related with a better prognosis which reflected the relatively benign pathobiological features at an early developmental stage. As HCC > 3 cm exhibited a tendency towards more aggressive behavior, we suggest that HCC ≤ 3 cm in diameter should be used as a critical size of SHCC at which curative treatment achieves better long-term survivals.

Hepatocellular carcinoma expressing cholangiocyte phenotype is a novel subtype with highly aggressive behavior

BACKGROUND

The pathobiological features and surgical outcomes of patients with classical hepatocellular carcinoma (HCC)-expressing cholangiocyte markers that we named dual-phenotype HCC (DPHCC) remain unclear. The purpose of this study was to assess the association between the phenotype and surgicopathologic features of DPHCC.

METHODS

A retrospective single-center study was performed on the surgicopathologic features of DPHCC from 1530 consecutive surgical specimens. Immunohistochemical staining was performed with antibodies to hepatocytes (Hep Par 1/pCEA) and cholangiocytes (cytokeratin 19 [CK19]/mucin core protein-1 [MUC-1]).

RESULTS

DPHCC accounted for 10.1% (n = 155) of total HCCs. The serum alfa-fetoprotein and CA19-9 were elevated in 87.7% (n = 136) and 20.7% (n = 32) of patients, respectively; the former had close correlation with the immunostaining of CK19 (P < 0.01). The combination of immunostaining intensities of CK19 and MUC-1 was significantly associated with tumor size, microvascular invasion, and satellite nodule formation (P < 0.05-0.01). Compared to patients with pure HCC, those with DPHCC had significantly lower overall survival (30.4 ± 3.7 vs. 43.6 ± 3.9 months, P < 0.05) and recurrence-free survival (13.2 ± 2.0 vs. 23.4 ± 2.5 months, P < 0.01), respectively. Multivariate Cox regression analyses identified CK19-positive expression to be an independent prognostic factor for both overall survival and recurrence-free survival.

CONCLUSIONS

DPHCC is a novel surgicopathologic entity that has a highly aggressive behavior and worse postoperative prognosis than pure HCC. Because the morphological features between DPHCC and conventional HCC overlap, we recommend that CK19 be routinely used in the pathological diagnosis of HCC for screening DPHCC.

Epidermal growth factor induces cytokeratin 19 expression accompanied by increased growth abilities in human hepatocellular carcinoma

Cytokeratin (CK) 19-positive hepatocellular carcinoma (HCC) has been reported to have a poor prognosis. The mechanism of the development of CK19-positive HCC remains to be studied. To clarify this, in vitro experiments were performed using human HCC cell lines (PLC-5, HepG2), and the phenotypic changes after stimulation with several growth factors were examined using quantitative reverse transcriptase PCR, western blotting, and immunofluorescence staining. In vivo experiments using human HCC specimens obtained from a total of 78 patients and clinicopathological analysis were also performed. Among the growth factors tested, epidermal growth factor (EGF) had prominent effects on inducing CK19 expression in PLC-5 and HepG2, which was accompanied by the reduced expression of α-fetoprotein in PLC-5. The induction of CK19 expression after EGF stimulation was accompanied by the phosphorylation of c-Jun-N-terminal kinase (JNK)/stress-activated protein kinase, which was blocked by the addition of JNK inhibitors. EGF also increased proliferative abilities and invasive properties of the HCC cell lines. In vivo, 9 (12%) of 78 HCC cases showed positive immunohistochemical staining of CK19. The extent of positive immunohistochemical signals of EGF, EGF receptor (EGFR), and JNK expression was significantly intense in CK-19-positive HCC than those of CK19-negative HCC. Clinicopathological analysis showed that CK19-positive HCC had a high incidence of portal vein invasion, extrahepatic metastasis and an early relapse, which was associated with the worsened 2-year disease free survival. These results indicate that the activation of the EGF-EGFR signaling pathway is associated with the development of CK19-positive HCC, and the EGF-induced increase in growth abilities of HCC may account for the poor prognosis of the patients.

Hepatic progenitor cells: an update

Liver progenitor cells are activated in most human liver diseases. The dynamics, and therefore subpopulations, of progenitor cells are, however, different in acute versus chronic hepatocytic diseases and in biliary diseases. The role of Wnt and Notch signaling pathways in activation and differentiation of human hepatic progenitor cells holds great promise because they can be manipulated by drugs. Hepatocytic differentiation requires inhibition of Notch (numb switched on), whereas cholangiocytic differentiation requires Notch activation. In this way, the patients' own regenerative response could be supported, which could eventually even avoid the need for transplantation in several patients.

The use of Cytokeratin 19 (CK19) immunohistochemistry in lesions of the pancreas, gastrointestinal tract, and liver

Cytokeratin immunostaining forms the bedrock of the immunohistochemical evaluation of tumors. Cytokeratin 19 (CK19) belongs to a family of keratins, which are normally expressed in the lining of the gastroenteropancreatic and hepatobiliary tracts. CK19 immunohistochemistry has been used successfully in thyroid tumors to recognize papillary carcinomas for some time. However, its use in the pancreas, liver, and gastrointestinal tract (GIT) has only recently come to the fore. The purpose of this review is to look at the use of CK19 immunohistochemistry in tumors occurring at these sites. CK19 has been shown to be an independent prognostic factor for pancreatic neuroendocrine tumors, especially the insulin-negative tumors. CK19 positive tumors are associated with poor outcome irrespective of the established pathologic parameters such as size, mitoses, lymphovascular invasion, and necrosis. It is recommended that CK19 be part of the immunohistochemical panel in the work-up of pancreatic endocrine tumors. CK19 is positive in the most of neuroendocrine tumors occurring in the rest of the GIT, except rectal tumors, which are negative. In the liver, CK19 is of prognostic value in hepatocellular carcinomas and is of use in distinguishing cholangiocarcinoma from hepatocellular carcinomas. It can also be used to highlight native ductules in the liver and helps separate conditions such as focal nodular hyperplasia from hepatic adenoma. The vast majority of adenocarcinomas in the GIT and pancreas are CK19 positive.

Biliary phenotype of hepatocellular carcinoma after preoperative transcatheter arterial chemoembolization

BACKGROUND AND AIM

Transcatheter arterial chemoembolization (TACE) is now the mainstay of treatment for non-curative hepatocellular carcinoma (HCC), and hoped to have chemotherapeutic and ischemic effects; however, the histopathological changes of HCC caused by TACE have not been sufficiently discussed so far. We aimed to assess the morphological and immunohistochemical features of HCC treated with TACE by immunostaining cytokeratin (CK) 7, CK14, CK19 and vimentin, and to correlate these data with observed clinicopathological characteristics.

METHODS

Eighty cases of surgically resected HCC with preoperative TACE and 146 cases of HCC resected without TACE as a control were analyzed.

RESULTS

The incidences of intrahepatic metastasis, poorly differentiated histology, multinucleated giant cells, mitotic figures and cytoplasmic inclusion bodies in the TACE group were significantly higher than those in the non-TACE group. The TACE group showed reactivity for CK7 in 56.3% (45/80) of patients, CK14 in 12.5% (10/80), CK19 in 23.8% (19/80) and vimentin in 6.3% (5/80) of patients. CK19 expression in the TACE group was significantly higher than in the non-TACE group (P = 0.0423). There was no correlation between immunoreactivity and the number of times TACE was carried out, but the expression of CK19 and vimentin in the massive necrotic group was higher than that in the mild necrotic group (P = 0.0197, P = 0.0229, respectively). Only TACE was an independent determinant of CK19 expression in all cases by multivariate analysis.

CONCLUSIONS

These results suggest that preoperative TACE may have an impact on the biliary phenotype of HCC. Some post-therapeutic HCC patients might develop HCC with a biliary phenotype indicating more aggressive malignancies.

Expression of multidrug resistance-associated protein 1 in hepatocellular carcinoma is associated with a more aggressive tumour phenotype and may reflect a progenitor cell origin

BACKGROUND

Hepatocellular carcinoma (HCC) responds poorly to chemotherapy owing to multidrug resistance (MDR). Recent studies showed that part of HCC could be of progenitor cell origin. Because some MDR-conferring transporters [multidrug resistance-associated protein 1 (MRP1), MDR1, MRP3 and breast cancer resistance protein (BCRP)] are expressed in hepatic progenitor cells (HPCs), expression in HCC might reflect a progenitor cell origin and provide the tumour cells with a MDR phenotype.

METHODS

The transcriptional profile of transporter genes was assessed in 139 HCCs earlier subjected to global gene expression analysis. In addition, we performed real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry for MRP1, MRP3, MDR1, BCRP and biliary/HPC markers keratin 7 and/or keratin 19 (K7/K19) on an independent set of 23 HCCs and surrounding liver.

RESULTS

Micro-array analysis showed that MRP1 was the only transporter with increased mRNA levels in HCC compared with the surrounding tissue. MRP1 mRNA levels were significantly higher in HCCs with poor survival and the 'hepatoblast subtype' of HCC, thought to be derived from HPCs. In 11 of 23 HCCs of the independent set, we found a diffuse protein expression of MRP1 compared with negative hepatocytic expression observed in normal (surrounding) hepatocytes. MRP1 was expressed in K19(+) non-neoplastic HPCs and K19(+) tumour cells. In addition, MRP3 and BCRP were expressed in K7/K19(+) tumour cells. MRP1 expression was high in poorly differentiated HCCs, large tumours (>7 cm) and microvascular invasive tumours.

CONCLUSIONS

MRP1 correlated with K19 mRNA and protein expression in two independent series of HCC. In addition, MRP1 was, together with MRP3 and BCRP, colocalized with K7/K19 in the tumour. Therefore, MRP1 expression could be a reflection of the HPC origin of this subgroup of HCCs and may result in an aggressive tumour phenotype.

The overexpression of polycomb group proteins Bmi1 and EZH2 is associated with the progression and aggressive biological behavior of hepatocellular carcinoma

Polycomb-group proteins Bmi1 and EZH2 are involved in the malignant transformation and biological aggressiveness of several human carcinomas. We herein examined the significance of the Bmi1 and EZH2 expression in hepatocellular carcinoma (HCC) and its preneoplastic lesions, dysplastic nodules. The expression of Bmi1 and EZH2 were examined immunohistochemically in HCC (n=27) and dysplastic nodules (n=14), and combined hepatocellular and cholangiocarcinoma (HC-CC) (n=14). The effect of Bmi1 and EZH2 knockdown was examined in cultured HCC cells (HuH7 and HepG2) using siRNA. It was determined that Bmi1 was constantly expressed in cholangiocytes, but not in hepatocytes, and EZH2 was detected in neither cholangiocytes nor hepatocytes. Bmi1 and EZH2 were overexpressed in HCC and more extensively in HC-CC (P<0.01). Interestingly, Bmi1 and EZH2 were not overexpressed in the dysplastic nodules. The expression of Bmi1 and EZH2 was heterogeneous and associated with vascular infiltration, the histological grades, and the cell proliferation activity in HCC and HC-CC. In cultured carcinoma cells overexpressing Bmi1 and EZH2, knockdown of Bmi1 and EZH2 resulted in decreased cell proliferation activities. Therefore, the overexpression of polycomb-group proteins Bmi1 and EZH2 is associated with the malignant progression of HCC, thereby reflecting the aggressive biological behavior in HCC and HC-CC.

Ezrin expression is associated with hepatocellular carcinoma possibly derived from progenitor cells and early recurrence after surgical resection

Heterogeneous biological characteristics of hepatocellular carcinoma may be attributed to the cellular origin of the tumor. Patients with hepatocellular carcinoma probably derived from hepatic progenitor cells had early tumor recurrence after surgical resection or liver transplantation, suggesting that these tumors have aggressive characteristics. Ezrin, a member of the ERM (ezrin-radixin-moesin) cytoskeleton-associated protein family, is highly expressed in several types of human cancers and correlations between its immunoreactivity and patient outcome have been shown. In this study, ezrin expression, as well as cytokeratin19 and cytokeratin 7 expression, which are regarded as progenitor cell/ductular markers were immunohistochemically assessed in cases of hepatocellular carcinoma. In normal livers, ezrin expression was not found in any cell types, whereas cytokeratin 7 and cytokeratin 19 were exclusively stained in bile duct cells. In contrast, in livers with chronic hepatitis or cirrhosis, positive ezrin expression was observed in ductular reactions with strong intensity and intermediate hepatobiliary cells with various intensity. Of 77 cases of hepatocellular carcinoma, 28 (36%) had positive ezrin expression, 32 (42%) had cytokeratin 7 expression, and 11 (14%) had cytokeratin 19 expression. Ezrin expression in hepatocellular carcinoma was significantly associated with cytokeratin 19 expression, but not with cytokeratin 7 expression. Patients with ezrin-positive hepatocellular carcinoma had a significantly higher prevalence of elevated serum alpha-fetoprotein. Patients with immunohistochemical ezrin-positive hepatocellular carcinoma demonstrated significantly shorter recurrence-free and overall survival compared to patients with ezrin-negative hepatocellular carcinoma. Multivariate analysis revealed positive ezrin expression and multiple tumors to be independently associated with early recurrence in patients with hepatocellular carcinoma after curative surgical resection. These results suggested that hepatocellular carcinoma with ezrin expression might be at least partly derived from hepatic progenitor cells. Measurement of ezrin expression might be used to identify patients with an increased risk of early recurrence.