Prognostic value of desmoplastic stroma in intrahepatic cholangiocarcinoma

Tumor Apparent Diffusion Coefficient is Associated with Early Recurrence of Intrahepatic Cholangiocarcinoma

RATIONALE AND OBJECTIVES

Identifying intrahepatic cholangiocarcinoma (iCCA) patients who are at high risk for early recurrence (ER) can guide personalized treatment strategy and improve survival. This study aimed to investigate the value of preoperative MRI, especially diffusion-weighted imaging, in predicting ER, including in patients receiving neoadjuvant therapy.

MATERIALS AND METHODS

This study included 175 pathologically-confirmed iCCA patients who underwent curative resection (114 men, 61 women; mean age 59.0 ± 9.56 years). MRI features, particularly apparent diffusion coefficient (ADC), were analyzed and compared between ER and non-ER cases. Survival analyses of ER were evaluated using Cox regression and Kaplan-Meier analysis.

RESULTS

ER occurred in 54.3% (95/175) of patients. Multivariate logistic regression analysis identified tumor ADC as the only independent predictor of ER (odds ratio = 0.034, P < 0.001), with AUCs of 0.758 (95%CI 0.664, 0.836) in the testing cohort and 0.779 (95%CI 0.622, 0.893) in the validation cohort. The optimal ADC threshold was 1.273 × 10-3 mm2/s. Tumor ADC was comparable to the AJCC 8th staging system in predicting ER (AUC 0.758 vs 0.650 in testing cohort and 0.779 vs 0.661 in validation cohort). Multivariate Cox analysis identified high tumor burden score (HR = 1.109, P = 0.009), non-smooth margin (HR = 2.265, P = 0.008) and tumor ADC (HR = 0.111, P < 0.001) as independent risk factors for ER. Lower ADC values were linked to shorter RFS in both testing and validation cohorts (P < 0.001 and 0.0219), as well as in patients receiving neoadjuvant therapy (P = 0.003).

CONCLUSION

Preoperative MRI, particularly ADC, can help predict ER in iCCA, regardless of the application of neoadjuvant therapy, comparable to the AJCC 8th staging system.

Prognostic impact of the tumour microenvironment in intrahepatic cholangiocarcinoma: identification of a peritumoural fibro-immune interface

The tumour microenvironment (TME) of intrahepatic cholangiocarcinoma (iCCA) is complex and plays a role in prognosis and resistance to treatments. We aimed to decipher the iCCA TME phenotype using multiplex sequential immunohistochemistry (MS-IHC) to investigate which cell types and their spatial location may affect its prognosis. This was a retrospective study of 109 iCCA resected samples. For all cases, we used an open-source software to analyse a panel of markers (αSMA, FAP, CD8, CD163) by MS-IHC for characterize the different TME cells and their location. RNA sequencing was performed to determine the main iCCA transcriptomic classes. The association of the TME composition with overall survival (OS) was assessed by univariate and multivariate analyses. A high proportion of activated fibroblasts (FAP +) was significantly associated with poor OS (HR = 2.33, 95%CI = 1.43-3.81, p = 0.001). CD8 T lymphocytes excluded from the epithelial compartment were significantly associated with worse OS (HR = 1.86, 95% CI = 1.07-3.22, p = 0.014). The combination of a high proportion of FAP + fibroblasts and CD8 T lymphocytes excluded from the epithelial compartment, observed in 21 cases (19%), was significantly associated with poor OS on univariate (HR = 2.49, 95% CI = 1.44-4.28, p = 0.001) and multivariate analyses (HR = 2.77, 95% CI = 1.56-4.92, p < 0.001). In these cases, CD8 T lymphocytes were predominantly located at the tumour/non-tumour interface (19/21, 90%), and an association with the transcriptomic inflammatory stroma class was observed (10/21, 48%). Our results confirm the TME prognostic role in iCCA, highlighting the impact in the process of spatial heterogeneity, especially cell colocalization of immune and fibroblastic cells creating a peritumoural fibro-immune interface.

Cancer-Associated Fibroblasts in Intrahepatic Cholangiocarcinoma: Insights into Origins, Heterogeneity, Lymphangiogenesis, and Peritoneal Metastasis

Intrahepatic cholangiocarcinoma (iCCA) denotes a rare, highly malignant, and heterogeneous class of primary liver adenocarcinomas exhibiting phenotypic characteristics of cholangiocyte differentiation. Among the distinctive pathological features of iCCA, one that differentiates the most common macroscopic subtype (eg, mass-forming type) of this hepatic tumor from conventional hepatocellular carcinoma, is a prominent desmoplastic reaction manifested as a dense fibro-collagenous-enriched tumor stroma. Cancer-associated fibroblasts (CAFs) represent the most abundant mesenchymal cell type in the desmoplastic reaction. Although the protumor effects of CAFs in iCCA have been increasingly recognized, more recent cell lineage tracing studies, advanced single-cell RNA sequencing, and expanded biomarker analyses have provided new awareness into their ontogeny, as well as underscored their biological complexity as reflected by the presence of multiple subtypes. In addition, evidence has been described to support CAFs' potential to display cancer-restrictive roles, including immunosuppression. However, CAFs also play important roles in facilitating metastasis, as exemplified by lymph node metastasis and peritoneal carcinomatosis, which are common in iCCA. Herein, the authors provide a timely appraisal of the origins and phenotypic and functional complexity of CAFs in iCCA, together with providing mechanistic insights into lymphangiogenesis and peritoneal metastasis relevant to this lethal human cancer.

Friend or foe? The elusive role of hepatic stellate cells in liver cancer

Liver fibrosis is a substantial risk factor for the development and progression of liver cancer, which includes hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). Studies utilizing cell fate mapping and single-cell transcriptomics techniques have identified quiescent perisinusoidal hepatic stellate cells (HSCs) as the primary source of activated collagen-producing HSCs and liver cancer-associated fibroblasts (CAFs) in HCC and liver metastasis, complemented in iCCA by contributions from portal fibroblasts. At the same time, integrative computational analysis of single-cell, single-nucleus and spatial RNA sequencing data have revealed marked heterogeneity among HSCs and CAFs, with distinct subpopulations displaying unique gene expression signatures and functions. Some of these subpopulations have divergent roles in promoting or inhibiting liver fibrogenesis and carcinogenesis. In this Review, we discuss the dual roles of HSC subpopulations in liver fibrogenesis and their contribution to liver cancer promotion, progression and metastasis. We review the transcriptomic and functional similarities between HSC and CAF subpopulations, highlighting the pathways that either promote or prevent fibrosis and cancer, and the immunological landscape from which these pathways emerge. Insights from ongoing studies will yield novel strategies for developing biomarkers, assessing prognosis and generating new therapies for both HCC and iCCA prevention and treatment.

Apparent diffusion coefficient correlates with different histopathological features in several intrahepatic tumors

OBJECTIVES

To investigate associations between apparent diffusion coefficient (ADC) and cell count, Ki 67, tumor-stroma ratio (TSR), and tumoral lymphocytes in different hepatic malignancies.

METHODS

We identified 149 cases with performed liver biopsies: hepatocellular cancer (HCC, n = 53), intrahepatic cholangiocarcinoma (iCC, n = 29), metastases of colorectal cancer (CRC, n = 24), metastases of breast cancer (BC, n = 28), and metastases of pancreatic cancer (PC, n = 15). MRI was performed on a 1.5-T scanner with an axial echo-planar sequence. MRI was done before biopsy. Biopsy images of target lesions were selected. The cylindrical region of interest was placed on the ADC map of target lesions in accordance with the needle position on the biopsy images. Mean ADC values were estimated. TSR, cell counts, proliferation index Ki 67, and number of tumor-infiltrating lymphocytes were estimated. Spearman's rank correlation coefficients and intraclass correlation coefficients were calculated.

RESULTS

Inter-reader agreement was excellent regarding the ADC measurements. In HCC, ADC correlated with cell count (r =  - 0.68, p < 0.001) and with TSR (r = 0.31, p = 0.024). In iCC, ADC correlated with TSR (r = 0.60, p < 0.001) and with cell count (r =  - 0.54, p = 0.002). In CRC metastases, ADC correlated with cell count (r =  - 0.54 p = 0.006) and with Ki 67 (r =  - 0.46, p = 0.024). In BC liver metastases, ADC correlated with TSR (r = 0.55, p < 0.002) and with Ki 67 (r =  - 0.51, p = 0.006). In PC metastases, no significant correlations were found.

CONCLUSIONS

ADC correlated with tumor cellularity in HCC, iCC, and CRC liver metastases. ADC reflects TSR in BC liver metastases, HCC, and iCC. ADC cannot reflect intratumoral lymphocytes.

CLINICAL RELEVANCE STATEMENT

The present study shows that the apparent diffusion coefficient can be used as a surrogate imaging marker for different histopathological features in several malignant hepatic lesions.

KEY POINTS

• ADC reflects different histopathological features in several hepatic tumors. • ADC correlates with tumor cellularity in HCC, iCC, and CRC metastases. • ADC strongly correlates with tumor-stroma ratio in BC metastases and iCC.

Tumor-Infiltrating Lymphocytes and Tumor-Stroma Ratio on Early-Stage Cervix Carcinoma: Prognostic Value of Two Distinct Morphological Patterns of Microenvironment

Background Tumor progression is influenced by the complex network of different cellular elements that make up its microenvironment. Tumor-infiltrating lymphocytes (TILs) and stroma characteristics reflect two faces of the intricate mechanisms involved in the tumor-host interaction and can be easily evaluated by routine histological examination. Their prognostic value could be demonstrated in different tumor tumor types, but they are poorly explored in cervical cancer. Methodology In this retrospective study, we analyzed the association of TILs, tumor-stroma ratio (TSR), and pattern of stromal fibroblasts with prognosis and classical clinicopathological variables. We studied 61 patients with early-stage cervical cancer. We reviewed histological type, tumor grade, Silva pattern of invasion for adenocarcinomas, tumor thickness, depth of stromal invasion, lymph vascular space invasion, and lymph node status. The median follow-up was 37.77 months (range 4.77 to 112.37 months). Results The TSR did not correlate with any clinicopathological features or disease-free and overall survival. On the other hand, the reactive pattern of stroma composed of larger fibroblasts and less collagenization was associated with the FIGO IB2 stage (p=0.04), larger tumor (p=0.03), and deeper infiltration (p=0.005). There were more recurrences in the group of reactive stroma (33.13% vs. 11.5%), although the difference did not reach statistical significance. Reactive stroma was associated with lower survival free of recurrence (p=0.05) and overall survival (p=0.009). High TILs were associated with squamous cell type (p=0.003), higher tumor grade (p=0.02), and more LVSI (p=0.02). Tumors with higher TILs presented higher free recurrence interval (p=0.06) and overall survival (p=0.03). No association was observed between stroma characteristics and TILs. Conclusions Our study suggested that although immune activation and stromal changes are important features of microenvironment remodeling during tumoral progression, they are independent, following distinct carcinogenetic pathways. Pathological assessment of stroma characteristics and TILs adds significant prognostic information and demonstrates how a simple routine laboratory assessment can generate a better understanding of biological phenomena.

Whole slide image features predict pathologic complete response and poor clinical outcomes in triple-negative breast cancer

INTRODUCTION

Breast cancers are complex ecosystem like networks of malignant cells and their associated microenvironment. Applications for machine intelligence and the tumoral microenvironment are expanding frontiers in pathology. Previously, computational approaches have been developed to quantify and spatially analyze immune cells, proportionate stroma, and detect tumor budding. Little work has been done to analyze different types of tumor-associated stromata both quantitatively and computationally in relation to clinical endpoints.

METHODS

We aimed to quantify stromal features from whole slide images (WSI) including stromata (myxoid, collagenous, immune) and tumoral components and combined them with traditional clinical and pathologic parameters in 120 triple-negative breast cancer (TNBC) patients treated with neoadjuvant chemotherapy (NAC) to predict pathologic complete response (pCR) and poor clinical outcomes.

RESULTS

High collagenous stroma on WSI was best associated with lower rates of pCR, while combined high proportionated stroma (myxoid, collagenous, and immune) most optimally predicted worse clinical survival outcomes. When combining clinical, pathologic, and WSI features, Receiver Operator Characteristics (ROC) curves for LASSO features was up to 0.67 for pCR and 0.77 for poor outcomes.

CONCLUSION

The techniques demonstrated in the present study can be performed with appropriate quality assurance. Future trials are needed to demonstrate whether coupling applications for machine intelligence, inclusive of the tumor mesenchyme, can improve outcomes prediction for patients with breast cancer.

Cancer-Associated Fibroblasts and Extracellular Matrix: Therapeutical Strategies for Modulating the Cholangiocarcinoma Microenvironment

During the last decade, immunotherapy has radically changed perspectives on anti-tumor treatments. However, solid tumor treatment by immunotherapy has not met expectations. Indeed, poor clinical response to treatment has highlighted the need to understand and avoid immunotherapy resistance. Cholangiocarcinoma (CCA) is the second cause of hepatic cancer-related deaths because of drug inefficacy and chemo-resistance in a majority of patients. Thus, intense research is ongoing to better understand the mechanisms involved in the chemo-resistance processes. The tumor microenvironment (TME) may be involved in tumor therapy resistance by limiting drug access. Indeed, cells such as cancer-associated fibroblasts (CAFs) alter TME by producing in excess an aberrant extracellular matrix (ECM). Interestingly, CAFs are the dominant stromal component in CCA that secrete large amounts of stiff ECM. Stiff ECM could contribute to immune exclusion by limiting anti-tumor T-cells drop-in. Herein, we summarize features, functions, and interactions among CAFs, tumor-associated ECM, and immune cells in TME. Moreover, we discuss the strategies targeting CAFs and the remodeling of the ECM to improve immunotherapy and drug therapies.

Extracellular matrix drives tumor organoids toward desmoplastic matrix deposition and mesenchymal transition

Patient-derived tumor organoids have been established as promising tools for in vitro modelling of multiple tumors, including cholangiocarcinoma (CCA). However, organoids are commonly cultured in basement membrane extract (BME) which does not recapitulate the intricacies of the extracellular matrix (ECM). We combined CCA organoids (CCAOs) with native tumor and liver scaffolds, obtained by decellularization, to effectuate a model to study the interaction between epithelial tumor cells and their surrounding ECM. Decellularization resulted in removal of cells while preserving ECM structure and retaining important characteristics of the tissue origin, including stiffness and presence of desmoplasia. The transcriptome of CCAOs in a tumor scaffold much more resembled that of patient-paired CCA tissue in vivo compared to CCAOs cultured in BME or liver scaffolds. This was accompanied by an increase in chemoresistance to clinically-relevant chemotherapeutics. CCAOs in decellularized scaffolds revealed environment-dependent proliferation dynamics, driven by the occurrence of epithelial-mesenchymal transition. Furthermore, CCAOs initiated an environment-specific desmoplastic reaction by increasing production of multiple collagen types. In conclusion, convergence of organoid-based models with native ECM scaffolds will lead to better understanding of the in vivo tumor environment. STATEMENT OF SIGNIFICANCE: The extracellular matrix (ECM) influences various facets of tumor behavior. Understanding the exact role of the ECM in controlling tumor cell fate is pertinent to understand tumor progression and develop novel therapeutics. This is particularly the case for cholangiocarcinoma (CCA), whereby the ECM displays a distinct tumor environment, characterized by desmoplasia. However, current models to study the interaction between epithelial tumor cells and the environment are lacking. We have developed a fully patient-derived model encompassing CCA organoids (CCAOs) and human decellularized tumor and tumor-free liver ECM. The tumor ECM induced recapitulation of various aspects of CCA, including migration dynamics, transcriptome and proteome profiles, and chemoresistance. Lastly, we uncover that epithelial tumor cells contribute to matrix deposition, and that this phenomenon is dependent on the level of desmoplasia already present.

Spatiotemporal regulation of cholangiocarcinoma growth and dissemination by peritumoral myofibroblasts in a Vcam1-dependent manner

Intrahepatic cholangiocarcinoma (iCCA) is characterized by its highly desmoplastic stroma. Myofibroblasts (MFs) are present both within the tumor mass (intratumoral MFs, iMFs) and at the tumor border (peritumoral MFs, pMFs). Using a spheroid-based coculture system, we show that the initial iCCA-pMF contact is growth suppressive to the tumor cells. However, prolonged iCCA-pMF interaction elicits significant tumor cell invasion and dissemination. We find that vascular cell adhesion molecule-1 (Vcam1) level is elevated in tumor cells in contact with pMFs but low in disseminated tumor cells both in vitro and in vivo. A gene regulatory network analysis of mouse and patient iCCA tumors and Vcam1 knockout (Vcam1^KO) demonstrate a heavy involvement of Vcam1 in epithelial-to-mesenchymal transition. While Vcam1^KO has only a limited impact on tumor cell growth in their monoculture, Vcam1^KO spheroids exhibit instant dissemination and a severe growth defect when cocultured with pMFs. When transplanted into the liver, Vcam1^KO iCCA cells show a similar increase in dissemination but a significant defect in establishing primary and metastatic tumors. Incomplete blocking of Vcam1 in vivo reduces the size but increase the number of metastatic lesions. Overall, our study shows a spatiotemporal regulation of iCCA growth and dissemination by pMFs in a Vcam1-dependent manner.

Pathology of Cholangiocarcinomas

Cholangiocarcinomas (CCA) are heterogeneous tumors that arise from epithelial cells of the biliary tract. They represent the second primary liver malignancy, after hepatocellular carcinoma. Recent epidemiological data show an increased incidence of intrahepatic CCA without any identified causes. According to their location on the biliary tract, intrahepatic, perihilar (p) and distal (d) CCA can be individualized. Intrahepatic CCA (iCCA) are subdivided into small duct type iCCA and large duct type iCCA, according to the level or size of the biliary duct affected. These two subgroups are characterized by distinct risk factors, gross aspect, histopathological and molecular features, and therapeutic management. The role of biopsy in iCCA is to confirm the diagnosis and to eliminate various differential diagnostics, in particular, metastases. In p/d CCA, biopsy requires more invasive approaches, and tissue samples are difficult to obtain, leading to a high rate of false negatives. In this review, we will discuss the different classifications of CCA (anatomical and macroscopic). We will describe the various microscopic and phenotypic subtypes of CCA. Finally, we will deal with their mode of extension, the role of biopsy and pre-neoplastic lesions.

Unraveling the actin cytoskeleton in the malignant transformation of cholangiocyte biology

Correct actin cytoskeleton organization is vital in the liver organ homeostasis and disease control. Rearrangements of the actin cytoskeleton may play a vital role in the bile duct cells cholangiocytes. An abnormal actin network leads to aberrant cell morphology, deregulated signaling networks and ultimately triggering the development of cholangiocarcinoma (CCA) and paving the route for cancer cell dissemination (metastasis). In this review, we will outline alterations of the actin cytoskeleton and the potential role of this dynamic network in initiating CCA, as well as regulating the course of this malignancy. Actin rearrangements not only occur because of signaling pathways, but also regulate and modify cellular signaling. This emphasizes the importance of the actin cytoskeleton itself as cause for aberrant signaling and in promoting tumorigenic phenotypes. We will highlight the impact of aberrant signaling networks on the actin cytoskeleton and its rearrangement as potential cause for CCA. Often, these exact mechanisms in CCA are limited understood and still must be elucidated. Indeed, focusing future research on how actin affects and regulates other signaling pathways may provide more insights into the mechanisms of CCA development, progression, and metastasis. Moreover, manipulation of the actin cytoskeleton organization highlights the potential for a novel therapeutic area.

Understanding the Immunoenvironment of Primary Liver Cancer: A Histopathology Perspective

One of the most common cancers worldwide, primary liver cancer remains a major cause of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma represent the majority of primary liver cancer cases. Despite advances in the development of novel anti-cancer therapies that exploit targets within the immune system, survival rates from liver cancer remain poor. Furthermore, responses to immunotherapies, such as immune checkpoint inhibitors, have revealed limited and variable responses amongst patients with hepatocellular carcinoma, although combination immunotherapies have shown recent breakthroughs in clinical trials. This has shifted the focus towards improving our understanding of the underlying immune and molecular characteristics of liver tumours that may influence their response to immune-modulating treatments. In this review, we outline the complex interactions that occur in the tumour microenvironment of hepatocellular carcinoma and cholangiocarcinoma, respectively, from a histopathological perspective. We explore the potential role of a classification system based on immune-specific characteristics within each cancer type, the importance of understanding inter- and intra-tumoural heterogeneity and consider the future role of histopathology and novel technologies within this field.

Immunophenotypic and molecular characterization of pancreatic neuroendocrine tumors producing serotonin

Serotonin producing pancreatic neuroendocrine tumors (SP-PanNET) account for 0.58-1.4% of all pancreatic neuroendocrine tumors (PanNET). They may present with atypical symptoms, such as acute pancreatitis and are often radiologically characterized by main pancreatic duct dilatation. SP-PanNET are well differentiated neuroendocrine tumors (NET) distinct from classical PanNET by atypical serotonin secretion and abundant dense stroma deposition, like serotonin producing ileal NET leading in some cases to difficulties to reliably distinguish SP-PanNET from ileal NET metastases. The biology and molecular profile of SP-PanNET remain poorly characterized and the cell of origin within the pancreas is unclear. To address these questions, we analyzed a large cohort of SP-PanNET by immunohistochemistry (n = 29; ATRX, DAXX, MENIN, Islet1, PAX6, PDX1, ARX, CDX2), whole genome copy number array (Oncoscan™) and a large NGS panel (NovoPM™) (n = 10), FISH (n = 13) and RNA sequencing (n = 24) together with 21 ileal NET and 29 nonfunctioning PanNET (NF-PanNET). These analyses revealed a unique genomic profile with frequent isolated loss of chromosome 1 (14 cases-61%) and few pathogenic mutations (KMT2C in 2 cases, ARID1A in 1 case). Unsupervised RNAseq-based clustering showed that SP-PanNET were closer to NF-PanNET than ileal NET with an exclusive beta cell-like signature. SP-PanNET showed TGF-β pathway activation signatures associated with extracellular matrix remodeling and similar signature were reproduced in vitro when pancreatic stellate cells were exposed to serotonin. SP-PanNET immunohistochemical profile resemble that of ileal NET except for PDX1 and PAX6 expression to a lesser extend suggesting that these two markers may be useful to diagnose SP-PanNET. Taken together, this suggests that SP-PanNET are a very specific PanNET entity with a peculiar biology leading to the characteristic fibrotic aspect.

Advances of cancer-associated fibroblasts in liver cancer

Liver cancer is one of the most common malignant tumors worldwide, it is ranked sixth in incidence and fourth in mortality. According to the distinct origin of malignant tumor cells, liver cancer is mainly divided into hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Since most cases are diagnosed at an advanced stage, the prognosis of liver cancer is poor. Tumor growth depends on the dynamic interaction of various cellular components in the tumor microenvironment (TME). As the most abundant components of tumor stroma, cancer-associated fibroblasts (CAFs) have been involved in the progression of liver cancer. The interplay between CAFs and tumor cells, immune cells, or vascular endothelial cells in the TME through direct cell-to-cell contact or indirect paracrine interaction, affects the initiation and development of tumors. Additionally, CAFs are not a homogeneous cell population in liver cancer. Recently, single-cell sequencing technology has been used to help better understand the diversity of CAFs in liver cancer. In this review, we mainly update the knowledge of CAFs both in HCC and CCA, including their cell origins, chemoresistance, tumor stemness induction, tumor immune microenvironment formation, and the role of tumor cells on CAFs. Understanding the context-dependent role of different CAFs subsets provides new strategies for precise liver cancer treatment.

Targeting tumor microenvironment for cholangiocarcinoma: Opportunities for precision medicine

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CCA has a dismal prognosis, and it is usually diagnosed in advanced stage for which available treatments have limited efficacy.

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CCA TME presents an abundant desmoplastic stroma and exhibits a high heterogeneity.

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TME plays a central role in cancer development and in the resistance to treatments.

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Treatments targeting the TME in association with cytotoxic agents could represent a promising therapeutic strategy.

Systemic treatments (e.g., chemotherapy and targeted therapies) have limited efficacy for patients with locally advanced – unresectable – and metastatic cholangiocarcinoma (CCA), with an overall survival of less than a year. Tumor microenvironment (TME) represents the ecosystem surrounding the tumor which comprises immune cells, fibroblasts, endothelial cells, and a wide range of soluble factors. CCA TME is characterized by an abundant desmoplastic stroma, exhibits a high heterogeneity and it plays a central role in cancer onset and progression. There is growing evidence suggesting that it is possible to target TME in association with other treatment modalities, such as cytotoxic chemotherapy or targeted therapies, paving the way to possible combination strategies with a synergistic effect. Herein, we describe the components of CCA TME – such as cancer-associated fibroblasts and other cells of pivotal importance - with their most relevant interactions, focusing on the preclinical rationale for the development of effective anticancer treatments.

Clinical relevance of biomarkers in cholangiocarcinoma: critical revision and future directions

Cholangiocarcinoma (CCA) is a malignant tumour arising from the biliary system. In Europe, this tumour frequently presents as a sporadic cancer in patients without defined risk factors and is usually diagnosed at advanced stages with a consequent poor prognosis. Therefore, the identification of biomarkers represents an utmost need for patients with CCA. Numerous studies proposed a wide spectrum of biomarkers at tissue and molecular levels. With the present paper, a multidisciplinary group of experts within the European Network for the Study of Cholangiocarcinoma discusses the clinical role of tissue biomarkers and provides a selection based on their current relevance and potential applications in the framework of CCA. Recent advances are proposed by dividing biomarkers based on their potential role in diagnosis, prognosis and therapy response. Limitations of current biomarkers are also identified, together with specific promising areas (ie, artificial intelligence, patient-derived organoids, targeted therapy) where research should be focused to develop future biomarkers.

Computational portraits of the tumoral microenvironment in human breast cancer

Breast cancer is the most diagnosed cancer in humans. In recent years, myxoid and proportionated stroma have been described as clinically significant in many cancer subtypes. Here computational portraits of tumor-associated stromata were created from a machine learning (ML) classifier using QuPath to evaluate proportionated stromal area (PSA), myxoid stromal ratio (MSR), and immune stroma proportion (ISP) from whole slide images (WSI). The ML classifier was validated in independent training (n = 40) and validation (n = 109) cohorts finding MSR, PSA, and ISP to be associated with tumor stage, lymph node status, Nottingham grade, stromal differentiation (SD), tumor size, estrogen receptor (ER), progesterone receptor (PR), and receptor tyrosine-protein kinase erbB-2 (HER-2). Overall, MSR correlated better with the clinicopathologic profile than PSA and ISP. High MSR was found to be associated with high tumor stage, low ISP, and high Nottingham histologic score. As a computational biomarker, high MSR was more likely to be associated with luminal B like, Her-2 enriched, and triple-negative biomarker status when compared to luminal A like. The supervised ML superpixel approach demonstrated here can be performed by a trained pathologist to provide a faster and more uniformed approach to the analysis to the tumoral microenvironment (TME). The TME may be relevant for clinical decision-making, determining chemotherapeutic efficacy, and guiding a more overall precision-based breast cancer care.

CT-based clinico-radiological nomograms for prognosis prediction in patients with intrahepatic mass-forming cholangiocarcinoma: a multi-institutional study

OBJECTIVES

To establish prognostic nomograms based on CT imaging features for predicting the prognosis in patients with intrahepatic mass-forming cholangiocarcinoma (IMCC) before and after surgery.

METHODS

Two models were established for overall survival (OS) prediction in a training set (179 IMCC patients underwent surgery at institution 1 from 2009 to 2019): imaging-based nomogram included imaging features and clinical characteristics acquired before surgery; postoperative nomogram included imaging-based score, equal to the linear predictor of the imaging-based nomogram, and pathological parameters. Both prognostic nomograms were validated in an independent external dataset (103 IMCC patients received surgical treatment at two independent institutions from 2009 to 2019). Predictive performance and discrimination were evaluated and compared with the common prognostic models.

RESULTS

The imaging-based nomogram was developed according to preoperative serum carbohydrate antigen 19-9 and four imaging features including multiple nodules, arterial enhancement pattern, CT-reported lymph node (LN) metastasis, and capsular retraction; the postoperative nomogram was built based on the imaging-based score and three pathological parameters including tumor differentiation grade, capsular invasion, and LN status. Both nomograms presented improved prognostic performance and discrimination (concordance index, 0.770-0.812; integrated Brier score, 0.120-0.138) compared with the common prognostic models in the training and external validation datasets. Besides, the nomograms stratified IMCC patients into two risk strata for OS.

CONCLUSIONS

Nomograms based on CT imaging features can provide accurate individual survival prediction for IMCC patients before and after surgery, which may help to improve personalized treatment.

KEY POINTS

• Imaging features including multiple nodules, arterial enhancement pattern, CT-reported LN metastasis, and capsular retraction were poor independent prognostic factors for IMCC patients. • The imaging-based nomograms presented improved prognostic performance and discrimination compared with the common prognostic models. • The nomograms can provide accurate individual survival prediction for IMCC patients before and after surgery.

A Novel Superpixel Approach to the Tumoral Microenvironment in Colorectal Cancer

Colorectal cancer (CRC) is the most common malignancy of the gastrointestinal tract. The stroma and the tumoral microenvironment (TME) represent ecosystem-like biological networks and are new frontiers in CRC. The present study demonstrates the use of a novel machine learning-based superpixel approach for whole slide images to unravel this biology. Findings of significance include the association of low proportionated stromal area, high immature stromal percentage, and high myxoid stromal ratio (MSR) with worse prognostic outcomes in CRC. Overall, stromal computational markers outperformed all others at predicting clinical outcomes. MSR may be able to prognosticate patients independent of pathological stage, representing an optimal way to effectively prognosticate CRC patients which circumvents the need for more extensive molecular and/or computational profiling. The superpixel approaches to the TME demonstrated here can be performed by a trained pathologist and recorded during synoptic cancer reporting with appropriate quality assurance. Future clinical trials will have the ultimate say in determining whether we can better tailor the need for adjuvant therapy in patients with CRC.

The cancer-inhibitory effects of proliferating tumor-residing fibroblasts

Initiation, local progression, and metastasis of cancer are associated with specific morphological, molecular, and functional changes in the extracellular matrix and the fibroblasts within the tumor microenvironment (TME). In the early stages of tumor development, fibroblasts are an obstacle that cancer cells must surpass or nullify to progress. Thus, in early tumor progression, specific signaling from cancer cells activates bio-pathways, which abolish the innate anticancer properties of fibroblasts and convert a high proportion of them to tumor-promoting cancer-associated fibroblasts (CAFs). Following this initial event, a wide spectrum of gene expression changes gradually leads to the development of a stromal fibroblast population with complex heterogeneity, creating fibroblast subtypes with characteristic profiles, which may alternate between being tumor-promotive and tumor-suppressive, topologically and chronologically in the TME. These fibroblast subtypes form the tumor's histological landscape including areas of cancer growth, inflammation, angiogenesis, invasion fronts, proliferating and non-proliferating fibroblasts, cancer-cell apoptosis, fibroblast apoptosis, and necrosis. These features reflect general deregulation of tissue homeostasis within the TME. This review discusses fundamental and current knowledge that has established the existence of anticancer fibroblasts within the various interacting elements of the TME. It is proposed that the maintenance of fibroblast proliferation is an essential parameter for the activation of their anticancer capacity, similar to that by which normal fibroblasts would be activated in wound repair, thus maintaining tissue homeostasis. Encouragement of research in this direction may render new means of cancer therapy and a greater understanding of tumor progression.