ATF4 links ER stress with reticulophagy in glioblastoma cells

Selective degradation of the endoplasmic reticulum (ER; reticulophagy) is a type of autophagy involved in the removal of ER fragments. So far, amino acid starvation as well as ER stress have been described as inducers of reticulophagy, which in turn restores cellular energy levels and ER homeostasis. Here, we explored the autophagy-inducing mechanisms that underlie the autophagic cell death (ACD)-triggering compound loperamide (LOP) in glioblastoma cells. Interestingly, LOP triggers upregulation of the transcription factor ATF4, which is accompanied by the induction of additional ER stress markers. Notably, knockout of ATF4 significantly attenuated LOP-induced autophagy and ACD. Functionally, LOP also specifically induces the engulfment of large ER fragments within autophagosomes and lysosomes as determined by electron and fluorescence microscopy. LOP-induced reticulophagy and cell death are predominantly mediated through the reticulophagy receptor RETREG1/FAM134B and, to a lesser extent, TEX264, confirming that reticulophagy receptors can promote ACD. Strikingly, apart from triggering LOP-induced autophagy and ACD, ATF4 is also required for LOP-induced reticulophagy. These observations highlight a key role for ATF4, RETREG1 and TEX264 in response to LOP-induced ER stress, reticulophagy and ACD, and establish a novel mechanistic link between ER stress and reticulophagy, with possible implications for additional models of drug-induced ER stress.Abbreviations: ACD: autophagic cell death; ATF6: activating transcription factor 6; ATL3: atlastin 3; BafA₁: bafilomycin A₁; CCPG1: cell cycle progression gene 1; co-IP: co-immunoprecipitation; DDIT3/CHOP: DNA damage inducible transcript 3; ER: endoplasmic reticulum; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; GABARAP: GABA type A receptor-associated protein; GBM: glioblastoma multiforme; HSPA5/BiP: heat shock protein family (Hsp70) member 5; LOP: loperamide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; RETREG1/FAM134B: reticulophagy regulator 1; RTN3L: reticulon 3 long; SEC62: SEC62 homolog, protein translocation factor; TEX264: testis-expressed 264, reticulophagy receptor; UPR: unfolded protein response.

CT-radiomics and clinical risk scores for response and overall survival prognostication in TACE HCC patients

We aimed to identify hepatocellular carcinoma (HCC) patients who will respond to repetitive transarterial chemoembolization (TACE) to improve the treatment algorithm. Retrospectively, 61 patients (mean age, 65.3 years ± 10.0 [SD]; 49 men) with 94 HCC mRECIST target-lesions who had three consecutive TACE between 01/2012 and 01/2020 were included. Robust and non-redundant radiomics features were extracted from the 24 h post-embolization CT. Five different clinical TACE-scores were assessed. Seven different feature selection methods and machine learning models were used. Radiomics, clinical and combined models were built to predict response to TACE on a lesion-wise and patient-wise level as well as its impact on overall-survival prognostication. 29 target-lesions of 19 patients were evaluated in the test set. Response rates were 37.9% (11/29) on the lesion-level and 42.1% (8/19) on the patient-level. Radiomics top lesion-wise response prognostications was AUC 0.55-0.67. Clinical scores revealed top AUCs of 0.65-0.69. The best working model combined the radiomic feature LargeDependenceHighGrayLevelEmphasis and the clinical score mHAP_II_score_group with AUC = 0.70, accuracy = 0.72. We transferred this model on a patient-level to achieve AUC = 0.62, CI = 0.41-0.83. The two radiomics-clinical features revealed overall-survival prognostication of C-index = 0.67. In conclusion, a random forest model using the radiomic feature LargeDependenceHighGrayLevelEmphasis and the clinical mHAP-II-score-group seems promising for TACE response prognostication.

Dual-energy CT based material decomposition to differentiate intrahepatic cholangiocarcinoma from hepatocellular carcinoma

PURPOSE

To assess the potential of material decomposition in dual-energy CT (DECT) to differentiate intrahepatic cholangiocarcinoma (iCCA) from hepatocellular carcinoma (HCC).

METHOD

In this retrospective study, we included 94 patients (26 female (27.7 %), median age 64.5 (interquartile range 55.5-74.5) years) with either iCCA or HCC who underwent abdominal contrast-enhanced DECT in arterial phase. To test for differences between iCCA (n = 47) and HCC (n = 47), we evaluated mean attenuation and DECT material density values including iodine density (ID), normalized iodine uptake (NIU), fat fraction, and lesion-to-liver parenchyma ratio. Histopathology served as reference standard for all lesions. We used univariate logistic regression models for the outcome iCCA versus HCC. ROC curve analysis was applied to assess discriminative ability of the model. Model accuracy was evaluated by calculating the Brier score. Youden index was applied to establish thresholds to differentiate between iCCA and HCC.

RESULTS

Comparison of quantitative image parameters revealed significant differences between iCCA and HCC for ID (1.6 ± 0.5 mg/ml vs 2.8 ± 0.8 mg/ml, p < 0.001), NIU (14.5 ± 4.8 vs 24.8 ± 10.3, p < 0.001), attenuation (41.9 ± 10.1 HU vs 47.9 ± 8.9 HU, p = 0.003), and fat fraction (12.0 ± 7.8 % vs 9.0 ± 6.4 %, p = 0.045). ROC curve analysis revealed highest ability to differentiate iCCA from HCC for ID (AUC = 0.93, 95 % CI 0.89-0.98). For ID, an optimal threshold of 2.33 mg/dl was determined to discriminate between iCCA and HCC (sensitivity 89.4 %, specificity 76.6 %).

CONCLUSIONS

DECT-based iodine quantification can serve as a tool for the differentiation of iCCA and HCC in contrast-enhanced CT. ID yielded the highest diagnostic performance and may assist in clinical routine CT diagnostics.

Impact of small duct- and large duct type on survival in patients with intrahepatic cholangiocarcinoma: Results from a German tertiary center

BACKGROUND & AIMS

In recent years, histopathological characterization of intrahepatic cholangiocarcinoma revealed small duct type (SD-iCCA) and large duct type (LD-iCCA). Data on the prevalence of the subtypes are limited and highly varying. The aim of this study was to assess the prevalence of SD-iCCA and LD-iCCA and their impact on survival for the first time in a European cohort.

MATERIALS AND METHODS

All patients with surgically resected iCCA diagnosed between December 2005 and December 2021 at the University Hospital Frankfurt were analyzed by an expert hepatobiliary pathologist. For overall survival (OS) and progression-free survival (PFS), Kaplan-Meier curves and Cox-regression analyses were performed.

RESULTS

In total, 116 patients with surgically resected iCCA treated in our tertiary hospital were classified as SD-iCCA (73.3%, n = 85) and LD-iCCA (26.7%, n = 31). Subgroup analyses revealed median OS of 54.4 months (95% CI = 38.3 - 70.4 months) and 25.4 months (95% CI = 15.1 - 35.7 months) for SD-iCCA and LD-iCCA, respectively (p = 0.027). The median PFS for patients receiving gemcitabine-based chemotherapy with SD- and LD-iCCA was 8.4 months (95% CI = 4.7 - 12 months) and 3.3 months (95% CI = 1.8 - 4.7 months), respectively (p = 0.011). While LD-iCCA was as a significant risk factor of OS (HR = 1.7, 95% CI = 1 - 2.8, p = 0.031) in univariate analysis, it was not significant in multivariate analysis.

CONCLUSION

In contrast to data from Asia, SD-iCCA is more prevalent than LD-iCCA in our cohort. LD-iCCA is associated with impaired OS after surgical resection and decreased PFS for patients receiving chemotherapy. These findings may suggest including the histological subtype in clinical routine diagnostics.

STF-62247 and pimozide induce autophagy and autophagic cell death in mouse embryonic fibroblasts

Induction of autophagy can have beneficial effects in several human diseases, e.g. cancer and neurodegenerative diseases (ND). Here, we therefore evaluated the potential of two novel autophagy-inducing compounds, i.e. STF-62247 and pimozide, to stimulate autophagy as well as autophagic cell death (ACD) using mouse embryonic fibroblasts (MEFs) as a cellular model. Importantly, both STF-62247 and pimozide triggered several hallmarks of autophagy in MEFs, i.e. enhanced levels of LC3B-II protein, its accumulation at distinct cytosolic sites and increase of the autophagic flux. Intriguingly, autophagy induction by STF-62247 and pimozide resulted in cell death that was significantly reduced in ATG5- or ATG7-deficient MEFs. Consistent with ACD induction, pharmacological inhibitors of apoptosis, necroptosis or ferroptosis failed to protect MEFs from STF-62247- or pimozide-triggered cell death. Interestingly, at subtoxic concentrations, pimozide stimulated fragmentation of the mitochondrial network, degradation of mitochondrial proteins (i.e. mitofusin-2 and cytochrome c oxidase IV (COXIV)) as well as a decrease of the mitochondrial mass, indicative of autophagic degradation of mitochondria by pimozide. In conclusion, this study provides novel insights into the induction of selective autophagy as well as ACD by STF-62247 and pimozide in MEFs.

Computed Tomography Radiomics to Differentiate Intrahepatic Cholangiocarcinoma and Hepatocellular Carcinoma

AIMS

Intrahepatic cholangiocarcinoma (iCCA) and hepatocellular carcinoma (HCC) differ in prognosis and treatment. We aimed to non-invasively differentiate iCCA and HCC by means of radiomics extracted from contrast-enhanced standard-of-care computed tomography (CT).

MATERIALS AND METHODS

In total, 94 patients (male, n = 68, mean age 63.3 ± 12.4 years) with histologically confirmed iCCA (n = 47) or HCC (n = 47) who underwent contrast-enhanced abdominal CT between August 2014 and November 2021 were retrospectively included. The enhancing tumour border was manually segmented in a clinically feasible way by defining three three-dimensional volumes of interest per tumour. Radiomics features were extracted. Intraclass correlation analysis and Pearson metrics were used to stratify robust and non-redundant features with further feature reduction by LASSO (least absolute shrinkage and selection operator). Independent training and testing datasets were used to build four different machine learning models. Performance metrics and feature importance values were computed to increase the models' interpretability.

RESULTS

The patient population was split into 65 patients for training (iCCA, n = 32) and 29 patients for testing (iCCA, n = 15). A final combined feature set of three radiomics features and the clinical features age and sex revealed a top test model performance of receiver operating characteristic (ROC) area under the curve (AUC) = 0.82 (95% confidence interval =0.66-0.98; train ROC AUC = 0.82) using a logistic regression classifier. The model was well calibrated, and the Youden J Index suggested an optimal cut-off of 0.501 to discriminate between iCCA and HCC with a sensitivity of 0.733 and a specificity of 0.857.

CONCLUSIONS

Radiomics-based imaging biomarkers can potentially help to non-invasively discriminate between iCCA and HCC.

Fluorescence confocal microscopy on liver specimens for full digitization of transplant pathology

Fluorescence confocal microscopy (FCM) is a rapidly evolving tool that provides real-time virtual HE images of native tissue. Data about the potential of FCM as an alternative to frozen sections for the evaluation of donor liver specimens are lacking so far. The aim of the current study was to determine the value of FCM in liver specimens according to the criteria of the German Society for Organ Procurement. In this prospective study, conventional histology and FCM scans of 50 liver specimens (60% liver biopsies, 26% surgical specimens, and 14% donor samples) were evaluated according to the German Society for Organ Procurement. A comparison of FCM scans and conventional frozen sections revealed almost perfect levels of agreement for cholangitis (κ = 0.877), fibrosis (κ = 0.843), and malignancy (κ = 0.815). Substantial levels of agreement could be obtained for macrovesicular steatosis (κ = 0.775), inflammation (κ = 0.763), necrosis (κ = 0.643), and steatohepatitis (κ = 0.643). Levels of agreement were moderate for microvesicular steatosis (κ = 0.563). The strength of agreement between frozen sections and FCM was superior to the comparison of conventional HE and FCM imaging. We introduce FCM as a potential alternative to the frozen section that may represent a novel approach to liver transplant pathology where timely feedback is crucial and the deployment of human resources is becoming increasingly difficult.

The NeuroSAFE frozen section technique during radical prostatectomy - Implementation and optimization of technical aspects in a routine pathology workflow

BACKGROUND AND AIMS

In prostate cancer patients, application of the NeuroSAFE frozen section technique during radical prostatectomy has been shown to increase the rate of nerve sparing surgery and to improve functional outcome for the patients. The aim of this study is to report on technical and organizational optimization opportunities of the procedure.

MATERIAL AND METHODS

All patients submitted to bilateral intraoperative frozen section from January 2018 until December 2020 (n = 452) were retrospectively analyzed and parameters such as turnaround time, staff situation in the laboratory and histologic properties of the tumors were assessed.

RESULTS

The median turnaround time per case was 40.3 ( ± 10.5) min. In 2020 the average time needed from accessioning to diagnosis was 38.1 min. Multivariate linear regression suggested that the number of technical assistants/cryotomes (46.1 min vs. 39.13 min; p < 0.001), the place of microscopic examination (43.0 min vs. 38.7 min; p < 0.001) and the presence of a positive margin (38.0 vs. 44.0 min; p < 0.001) were significant influential factors. The turnaround time was independent of the uropathological expertize of the consultant (39.84 min vs. 40.7 min; p = 0.09), the tumor grade (42.3 vs 39.8 min; p = 0.493) and the presence of extraprostatic extension (44.0 vs 39.8 min; p = 0.099).

CONCLUSION

The implementation of simple optimization measures in the workflow as well as structured training of all pathology staff involved in the examination leads to a significant increase in the efficiency of the examination while maintaining the same level of resources. The results could thus be a contribution to the broader application of the procedure.

Evaluation of an IDH1/2 Mutation FastTrack Assay for Patients with Cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma, a malignancy originating from the bile ducts, poses significant treatment challenges due to its typically late diagnosis and limited therapeutic options. However, recent advances in molecular genetics enable more personalized treatment approaches. A notable breakthrough in this context is the identification of isocitrate dehydrogenase (IDH) mutations, particularly IDH1 and IDH2, which occur in a subset of cholangiocarcinoma patients. Those with IDH1/2 mutations may benefit from targeted therapies. For instance, Ivosidenib, an IDH1 inhibitor, has shown efficacy in clinical trials, offering a new therapeutic option for patients with IDH1-mutant cholangiocarcinoma. Developing and implementing standardized protocols for testing and reporting mutation status are crucial for consistency and accuracy in clinical practice. Both the Idylla™ IDH1-2 Mutation Assay Kit as a FastTrack method and Next-Generation Sequencing (NGS) panels play critical roles in molecular characterization of cholangiocarcinoma.

METHODS

Under this aspect, a set of cholangiocarcinomas was tested using the Idylla™ platform regarding the respective recommended guidelines and standards of DIN EN ISO:17020 and DIN EN ISO:15198.

RESULTS

Overall, 25 clinically diagnosed intrahepatic cholangiocarcinomas or Adeno-CUPs were analyzed. IDH1/2 mutations were identified in 68% (17/25) of cases using both methods, with high concordance between NGS and Idylla™ results. Discrepancies were observed in two samples, where Idylla™ detected no mutations, but NGS reported IDH1 and IDH2 mutations, respectively.

CONCLUSIONS

IdyllaTM offers a rapid, user-friendly, and specific method for detecting IDH1/2 mutations, ideal for immediate clinical needs. NGS, while more time-consuming and costly, provides comprehensive genetic profiles valuable for personalized medicine and research. The choice between these methods should be guided by the clinical context, resource availability, and individual patient needs. For routine diagnostics, we recommend an algorithmic approach starting with the FastTrack method followed by NGS for wildtype cases.

Heterogeneity of small duct- and large duct-type intrahepatic cholangiocarcinoma

AIMS

The histological subtype of intrahepatic cholangiocarcinoma (iCCA) is associated with different mutational characteristics that impact clinical management. So far, data are lacking on the presence of small duct iCCA (SD-iCCA) and large duct iCCA (LD-iCCA) in a single patient. The aim of the current study was to determine the presence and degree of intratumoural heterogeneity of SD- and LD-iCCA features in different tumour regions.

METHODS AND RESULTS

All patients treated with surgically resected iCCA at Frankfurt University Hospital between December 2005 and March 2023 were retrospectively analysed. Histomorphological features of SD- and LD-iCCA were evaluated by an expert hepatobiliary pathologist. Tissue samples suspicious for subtype heterogeneity were further investigated. Immunohistochemistry for N-cadherin, S100P, MUC5AC, MUC6, TFF1 and AGR2 and mutational profiling with the Illumina TruSight Oncology 500 (TSO500) assay were performed separately for the SD- and LD-iCCA regions. Of 129 patients with surgically resected iCCA, features of either SD- or LD-iCCA were present in 67.4% (n = 87) and 24.8% of the patients (n = 32), respectively; 7.8% (n = 10) had histomorphological features of both SD- and LD-iCCA, seven patients (5.4%) of which had sufficient formalin-fixed, paraffin-embedded tissue for further analysis. Heterogeneity of both subtypes could be confirmed with immunohistochemistry. In five of seven (71.4%) patients, molecular profiling revealed intratumoural differences in genetic alterations between the SD- and LD-iCCA region. In one patient, a BRAF mutation (p.V600E) was found in the SD-iCCA but not in the LD-iCCA region of the tumour.

CONCLUSIONS

A marked portion of patients with iCCA exhibits both SD- and LD-iCCA in different tumour regions. In case of the presence of histopathological heterogeneity, mutational profiling should be considered to avoid missing therapeutically relevant genetic alterations.

CXCL1 and CXCL6 Are Potential Predictors for HCC Response to TACE

Distinct immune patterns of hepatocellular carcinoma (HCC) may have prognostic implications in the response to transarterial chemoembolization (TACE). Thus, we aimed to exploratively analyze tumor tissue of HCC patients who do or do not respond to TACE, and to identify novel prognostic biomarkers predictive of response to TACE. We retrospectively included 15 HCC patients who had three consecutive TACE between January 2019 and November 2019. Eight patients had a response while seven patients had no response to TACE. All patients had measurable disease according to mRECIST. Corresponding tumor tissue samples were processed for differential expression profiling using NanoString nCounter^® PanCancer immune profiling panel. Immune-related pathways were broadly upregulated in TACE responders. The top differentially regulated genes were the upregulated CXCL1 (log2fc 4.98, Benjamini-Hochberg (BH)-p < 0.001), CXCL6 (log2fc 4.43, BH-p = 0.016) and the downregulated MME (log2fc -4.33, BH-p 0.001). CD8/T-regs was highly increased in responders, whereas the relative number of T-regs to tumor-infiltrating lymphocytes (TIL) was highly decreased. We preliminary identified CXCL1 and CXCL6 as candidate genes that might have the potential to serve as therapeutically relevant biomarkers in HCC patients. This might pave the way to improve patient selection for TACE in HCC patients beyond expert consensus.

Colonization with multidrug-resistant organisms is associated with impaired survival of patients with surgically resected cholangiocarcinoma

BACKGROUND & AIMS

Colonization with multidrug-resistant organisms (MDRO) has been shown to impair survival in patients with various malignancies. Despite the increasing spread of MDRO, its impact on patients with cholangiocarcinoma (CCA) is unclear. Aim of this study was to analyse the impact of MDRO-colonization on overall prognosis in CCA patients.

METHODS

All patients with surgically resected CCA diagnosed between August 2005 and November 2021 at the University Hospital Frankfurt were screened for MDRO. CCA patients with a positive MDRO screening before or within the first 90 days after diagnosis of CCA were defined as colonized. Patients with a negative MDRO screening were defined as non-colonized.

RESULTS

Hundred and sixty nine patients were included. 32% (n = 54) were screened MDRO positive, while 68% (115) were non-colonized. Median overall survival (OS) for colonized patients was 17.1 months (95% CI = 9-25.2 months) compared to 50 months (95% CI = 37.1-62.8) for MDRO-negative patients (p ≤ .001). Non-cancer-related mortality (p ≤ .001) and infectious-related death (p ≤ .001) was significantly higher in the MDRO-colonized group. In multivariate analysis, MDRO colonization (HR = 2.1, 95% CI = 1.4-3.3, p = .001), ECOG 1 (HR = 2.5, 95% CI = 1.6-4, p ≤ .001) and N1 status (HR = 1.7, 95% CI = 1.1-2.6, p = .017) were independent risk factors for OS.

CONCLUSION

MDRO-colonization contributes to poor survival in patients with surgically resected CCA. MDRO surveillance is necessary to optimize clinical management of infections and to potentially reduce mortality in this critical population.

Active Autophagy Is Associated with Favorable Outcome in Patients with Surgically Resected Cholangiocarcinoma

Data on the impact of autophagy in primary cholangiocarcinoma (CCA) remain scarce. Here, we therefore investigated the role of active autophagy and its impact on survival in CCA patients. All CCA patients who underwent surgical resection with curative intent between 08/2005 and 12/2021 at University Hospital Frankfurt were evaluated. Autophagic key proteins were studied by immunohistochemistry. iCCA processed for gene expression profiling of immune-exhaustion gene sets was used for an autophagy approach in silico. Active autophagy was present in 23.3% of the 172 CCA patients. Kaplan-Meier curves revealed median OS of 68.4 months (95% CI = 46.9-89.9 months) and 32.7 months (95% CI = 23.6-41.8 months) for active and non-active autophagy, respectively (p ≤ 0.001). In multivariate analysis, absence of active autophagy (HR = 2, 95% CI = 1.1-3.5, p = 0.015) was an independent risk factor for OS. Differential-expression profiling revealed significantly upregulated histone deacetylases (HDAC) mRNA in patients showing non-active autophagy. In line with this, pan-acetylated lysine was significantly more prominent in CCA patients with ongoing autophagy (p = 0.005). Our findings strengthen the role of active autophagy as a prognostically relevant marker and a potential therapeutic target.

Expression of MUC16/CA125 Is Associated with Impaired Survival in Patients with Surgically Resected Cholangiocarcinoma

MUC16/CA125 is associated with cancer proliferation in several tumor entities. The data on MUC16 expression in cholangiocarcinoma (CCA) tissue are very limited. The aim of this study was to assess the MUC16 status and its impact on survival in CCA patients. All the patients with surgically resected CCA that were diagnosed between August 2005 and December 2021 at the University Hospital Frankfurt were retrospectively analyzed. A 7-Mucin biomarker panel was assessed by immunohistochemistry. For overall survival (OS), Kaplan−Meier curves and Cox-regression analyses were performed. Randomly selected intrahepatic cholangiocarcinoma (iCCA) were further processed for differential expression profiling. A total of 168 patients with CCA were classified as MUC16 (−) (66%, n = 111) and MUC16 (+) (34%, n = 57). Subgroup analyses revealed a median OS of 56.1 months (95% CI = 42.4−69.9 months) and 27.4 months (95% CI = 15.8−39.1 months) for MUC16 (−) and MUC16 (+), respectively (p < 0.001). In multivariate analysis, MUC16 (+) (HR = 1.6, 95% CI = 1−2.6, p = 0.032) was an independent risk factor for poor prognosis. Prominently deregulated pathways have been identified following MUC16 expression, overrepresented in cell cycle and immune system exhaustion processes. These findings suggest including MUC16 in clinical routine diagnostics as well as studying its molecular pathways to identify further mechanistic key players.

Multiparametric Evaluation of Radiomics Features and Dual-Energy CT Iodine Maps for Discrimination and Outcome Prediction of Thymic Masses

RATIONALE AND OBJECTIVES

To investigate the diagnostic value of radiomics features and dual-source dual-energy CT (DECT) based material decomposition in differentiating low-risk thymomas, high-risk thymomas, and thymic carcinomas.

MATERIALS AND METHODS

This retrospective study included 32 patients (16 males, mean age 66 ± 14 years) with pathologically confirmed thymic masses who underwent contrast-enhanced DECT between 10/2014 and 01/2023. Two experienced readers evaluated all patients regarding conventional radiomics features, as well as DECT-based features, including attenuation (HU), iodine density (mg/mL), and fat fraction (%). Data comparisons were performed using analysis of variance and chi-square statistic tests. Receiver operating characteristic curve analysis and Cox-regression tests were used to discriminate between low-risk/high-risk thymomas and thymic carcinomas.

RESULTS

Of the 32 thymic tumors, 12 (38%) were low-risk thymomas, 11 (34%) were high-risk thymomas, and 9 (28%) were thymic carcinomas. Values differed significantly between low-risk thymoma, high-risk thymoma, and thymic carcinoma regarding DECT-based features (p ≤ 0.023) and 30 radiomics features (p ≤ 0.037). The area under the curve to differentiate between low-risk/high-risk thymomas and thymic cancer was 0.998 (95% CI, 0.915-1.000; p < 0.001) for the combination of DECT imaging parameters and radiomics features, yielding a sensitivity of 100% and specificity of 96%. During a follow-up of 60 months (IQR, 35-60 months), the multiparametric approach including radiomics features, DECT parameters, and clinical parameters showed an excellent prognostic power to predict all-cause mortality (c-index = 0.978 [95% CI, 0.958-0.998], p = 0.003).

CONCLUSION

A multiparametric approach including conventional radiomics features and DECT-based features facilitates accurate, non-invasive discrimination between low-risk/high-risk thymomas and thymic carcinomas.

Small duct and large duct type intrahepatic cholangiocarcinoma reveal distinct patterns of immune signatures

PURPOSE

Dedicated gene signatures in small (SD-iCCA) and large (LD-iCCA) duct type intrahepatic cholangiocarcinoma remain unknown. We performed immune profiling in SD- and LD-iCCA to identify novel biomarker candidates for personalized medicine.

METHODS

Retrospectively, 19 iCCA patients with either SD-iCCA (n = 10, median age, 63.1 years (45-86); men, 4) or LD-iCCA (n = 9, median age, 69.7 years (62-85); men, 5)) were included. All patients were diagnosed and histologically confirmed between 04/2009 and 01/2021. Tumor tissue samples were processed for differential expression profiling using NanoString nCounter® PanCancer Immune Profiling Panel.

RESULTS

With the exception of complement signatures, immune-related pathways were broadly downregulated in SD-iCCA vs. LD-iCCA. A total of 20 immune-related genes were strongly downregulated in SD-iCCA with DMBT1 (log2fc = -5.39, p = 0.01) and CEACAM6 (log2fc = -6.38, p = 0.01) showing the strongest downregulation. Among 7 strongly (log2fc > 2, p ≤ 0.02) upregulated genes, CRP (log2fc = 5.06, p = 0.02) ranked first, and four others were associated with complement (C5, C4BPA, C8A, C8B). Total tumor-infiltrating lymphocytes (TIL) signature was decreased in SD-iCCA with elevated ratios of exhausted-CD8/TILs, NK/TILs, and cytotoxic cells/TILs while having decreased ratios of B-cells/TILs, mast cells/TILs and dendritic cells/TILs. The immune profiling signatures in SD-iCCA revealed downregulation in chemokine signaling pathways inclulding JAK2/3 and ERK1/2 as well as nearly all cytokine-cytokine receptor interaction pathways with the exception of the CXCL1/CXCR1-axis.

CONCLUSION

Immune patterns differed in SD-iCCA versus LD-iCCA. We identified potential biomarker candidate genes, including CRP, CEACAM6, DMBT1, and various complement factors that could be explored for augmented diagnostics and treatment decision-making.

Biomechanical Assessment of Liver Integrity: Prospective Evaluation of Mechanical Versus Acoustic MR Elastography

BACKGROUND

Magnetic resonance elastography (MRE) can quantify tissue biomechanics noninvasively, including pathological hepatic states like metabolic dysfunction-associated steatohepatitis.

PURPOSE

To compare the performance of 2D/3D-MRE using the gravitational (GT) transducer concept with the current commercial acoustic (AC) solution utilizing a 2D-MRE approach. Additionally, quality index markers (QIs) were proposed to identify image pixels with sufficient quality for reliably estimating tissue biomechanics.

STUDY TYPE

Prospective.

POPULATION

One hundred seventy participants with suspected or confirmed liver disease (median age, 57 years [interquartile range (IQR), 46-65]; 66 females), and 11 healthy volunteers (median age, 31 years [IQR, 27-34]; 5 females).

FIELD STRENGTH/SEQUENCE

Participants were scanned twice at 1.5 T and 60 Hz vibration frequency: first, using AC-MRE (2D-MRE, spin-echo EPI sequence, 11 seconds breath-hold), and second, using GT-MRE (2D- and 3D-MRE, gradient-echo sequence, 14 seconds breath-hold).

ASSESSMENT

Image analysis was performed by four independent radiologists and one biomedical engineer. Additionally, superimposed analytic plane shear waves of known wavelength and attenuation at fixed shear modulus were used to propose pertinent QIs.

STATISTICAL TESTS

Spearman's correlation coefficient (r) was applied to assess the correlation between modalities. Interreader reproducibility was evaluated using Bland-Altman bias and reproducibility coefficients. P-values <0.05 were considered statistically significant.

RESULTS

Liver stiffness quantified via GT-2D/3D correlated well with AC-2D (r ≥ 0.89 [95% CI: 0.85-0.92]) and histopathological grading (r ≥ 0.84 [95% CI: 0.72-0.91]), demonstrating excellent agreement in Bland-Altman plots and between readers (κ ≥ 0.86 [95% CI: 0.81-0.91]). However, GT-2D showed a bias in overestimating stiffness compared to GT-3D. Proposed QIs enabled the identification of pixels deviating beyond 10% from true stiffness based on a combination of total wave amplitude, temporal sinusoidal nonlinearity, and wave signal-to-noise ratio for GT-3D.

CONCLUSION

GT-MRE represents an alternative to AC-MRE for noninvasive liver tissue characterization. Both GT-2D and 3D approaches correlated strongly with the established commercial approach, offering advanced capabilities in abdominal imaging compared to AC-MRE.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

[Fluorescence confocal microscopy-complete digitization of pathology]

BACKGROUND

Fluorescence-based confocal microscopy (FCM) can be used to create virtual H&E sections in real time. So far, FCM has been used in dermato-, uro-, and gynecopathology. FCM allows the creation of a completely digitized frozen section, which could potentially replace conventional frozen sections in the future.

OBJECTIVE

The aim of the current work is to implement FCM technology as a component of fully digitized processes in the pathological workflow. For this purpose, the current use of FCM in liver transplant pathology will be extended to other disciplines such as urology and otorhinolaryngology.

MATERIALS AND METHODS

The FCM technique continues to be used prospectively on native tissue samples from potential donor livers. Conventional frozen sections are used comparatively to virtual FCM scans.

RESULTS

The data show a nearly perfect agreement for the detection of cholangitis, fibrosis, and malignancy, and a high level of agreement for, e.g., macrovesicular steatosis, inflammation, steatohepatitis, and necrosis between virtual FCM scans and conventional routine diagnostic frozen sections.

CONCLUSION

Since the availability of time- and cost-intensive frozen section diagnostics in the context of transplant pathology in continuous operation (24/7) is now only established at very few university centers in Germany due to an increasing shortage of specialists, the use of FCM could be an important building block in the current process leading towards a fully digitized pathology workflow and should thus be extended to various disciplines.

Expression of claudin-18.2 in cholangiocarcinoma: a comprehensive immunohistochemical analysis from a German tertiary centre

AIMS

Anti-claudin-18.2 (CLDN18.2) therapy was recently approved for the treatment of gastric or gastro-oesophageal junction adenocarcinoma. The aim of the present study was to investigate the expression of CLDN18.2 in cholangiocarcinoma (CCA) to determine whether there is a subgroup of patients who might also benefit from anti-CLDN18.2 therapy.

METHODS AND RESULTS

A tissue microarray (TMA) cohort of all CCA patients who underwent surgical resection with curative intent between August 2005 and December 2021 at University Hospital Frankfurt were immunohistochemically evaluated using the VENTANA® CLDN18 (43-14A) antibody. Tumour positivity for CLDN18.2 was determined as follows: ≥ 75% of tumour cells with moderate-to-strong CLDN18 membranous staining. In total, 160 patients with surgically resected CCA were suitable for immunohistochemistry (IHC) analysis. Of the patients, 13.1% (n = 21) showed moderate to strong membranous staining of VENTANA® CLDN18 antibody, while 86.9% (n = 139) were negative. Subtype analysis revealed strong differences in CLDN18 expression. Positive staining of CLDN18 could be observed in 26.5% (n = nine of 34) and 7.4% (n = seven of 95) of the perihilar (pCCA) and intrahepatic (iCCA) subgroup, respectively. CCA patients with CLDN18 expression had a more frequently intraoperative finding of distant metastasis (P = 0.002), lymph node metastasis (P = 0.008) and positive perineural invasion (Pn1) status (P = 0.022).

CONCLUSIONS

The present study suggests that a subset of patients with CCA exhibited a marked expression of CLDN18.2. These findings underline the need to perform a clinical study evaluating the efficacy of anti-CLDN18.2 therapy in patients suffering from CCA.

Fluorescence confocal microscopy for evaluation of fresh surgical specimens and consecutive tumor cell isolation in rare pediatric tumors

Fluorescence confocal microscopy (FCM) is an optical technique that uses laser light sources of different wavelengths to generate real-time images of fresh, unfixed tissue specimens. FCM allows histological evaluation of fresh tissue samples without the associated cryo artifacts after frozen sectioning. The aim of this study was to prospectively evaluate pediatric tumor specimens and assess their suitability for fresh tumor sampling. In addition, we aimed to determine whether tumor cell isolation for stable cell culture is still feasible after FCM imaging. Pediatric tumor specimens were imaged using FCM. Tumor viability and suitability for tissue sampling were evaluated and compared with H&E staining after paraffin embedding. In addition, FCM-processed and non-FCM-processed tissue samples were sent for tumor cell isolation to evaluate possible effects after FCM processing. When comparing estimated tumor cell viability using FCM and H&E, we found good to excellent correlating estimates (intraclass correlation coefficient = 0.891, p < 0.001), as well as substantial agreement in whether the tissue appeared adequate for fresh tissue collection (κ = 0.762, p < 0.001). After FCM, seven out of eight samples yielded passable cell cultures, compared to eight out of eight for non-FCM processed samples. Our study suggests that the use of FCM in tumor sampling can increase the yield of suitable fresh tumor samples by identifying viable tumor areas and ensuring that sufficient tissue remains for diagnosis. Our study also provides first evidence that the isolation and growth of tumor cells in culture are not compromised by the FCM technique.

Impact of IDH1 mutation on clinical course of patients with intrahepatic cholangiocarcinoma: a retrospective analysis from a German tertiary center

PURPOSE

IDH1 mutation is a known biomarker for targeted therapy of intrahepatic cholangiocarcinoma (iCCA), while its prognostic relevance for current palliative chemotherapy is still unclear. Aim of this study was to analyze clinicopathological characteristics of patients with IDH1 mutations and to outline a potential impact on the outcome after state-of-the-art palliative chemotherapy regimens.

METHODS

All patients with iCCA receiving large panel molecular profiling and follow-up treatment at Frankfurt University Hospital until 04/2022 were retrospectively analyzed. Clinicopathological characteristics were assessed for IDH1 mutated (mut) and IDH1 wild type (wt) patients, and progression-free survival (PFS) and overall survival (OS) were determined.

RESULTS

In total, 75 patients with iCCA received molecular profiling. Of the patients with available DNA data, pathogenic mutations in IDH1 were found in 14.5% (n = 10). IDH1 mut status was associated with lower serum CA-19/9 (p = 0.023), lower serum lactate dehydrogenase (p = 0.006), and a higher proportion of primary resectability (p = 0.028) as well as response to chemotherapy after recurrence (p = 0.009). Median PFS was 5.9 months (95% CI 4.4-7.3 months) for IDH1 wt in comparison to 9.8 months (95% CI 7.7-12 months) for patients with IDH1 mut (p = 0.031). IDH1 wt was a significant risk factor for shortened PFS in univariate (p = 0.043), but not in multivariate analysis (p = 0.061). There was no difference in OS between both groups.

CONCLUSION

Patients with IDH1 mutated iCCA seem to have a favorable tumor biology including a longer PFS for palliative chemotherapy regimens compared to IDH1 wild type.

[The model transferability of AI in digital pathology : Potential and reality]

OBJECTIVE

Artificial intelligence (AI) holds the potential to make significant advancements in pathology. However, its actual implementation and certification for practical use are currently limited, often due to challenges related to model transferability. In this context, we investigate the factors influencing transferability and present methods aimed at enhancing the utilization of AI algorithms in pathology.

MATERIALS AND METHODS

Various convolutional neural networks (CNNs) and vision transformers (ViTs) were trained using datasets from two institutions, along with the publicly available TCGA-MIBC dataset. These networks conducted predictions in urothelial tissue and intrahepatic cholangiocarcinoma (iCCA). The objective was to illustrate the impact of stain normalization, the influence of various artifacts during both training and testing, as well as the effects of the NoisyEnsemble method.

RESULTS

We were able to demonstrate that stain normalization of slides from different institutions has a significant positive effect on the inter-institutional transferability of CNNs and ViTs (respectively +13% and +10%). In addition, ViTs usually achieve a higher accuracy in the external test (here +1.5%). Similarly, we showcased how artifacts in test data can negatively affect CNN predictions and how incorporating these artifacts during training leads to improvements. Lastly, NoisyEnsembles of CNNs (better than ViTs) were shown to enhance transferability across different tissues and research questions (+7% Bladder, +15% iCCA).

DISCUSSION

It is crucial to be aware of the transferability challenge: achieving good performance during development does not necessarily translate to good performance in real-world applications. The inclusion of existing methods to enhance transferability, such as stain normalization and NoisyEnsemble, and their ongoing refinement, is of importance.