Vascularization of colorectal carcinoma liver metastasis: insight into stratification of patients for anti-angiogenic therapies

High CIB1 expression in colorectal cancer liver metastases correlates with worse survival and the replacement histopathological growth pattern

To date, nearly one-quarter of colorectal cancer (CRC) patients develop liver metastases (CRCLM), and its aggressiveness can be correlated to defined histopathological growth patterns (HGP). From the three main HGPs within CRCLM, the replacement HGP emerges as particularly aggressive, characterized by heightened tumor cell motility and vessel co-option. Here, we investigated the correlation between the expression of calcium- and integrin-binding protein 1 (CIB1), a ubiquitously expressed gene involved in various cellular processes including migration and adhesion, and disease-free (DFS) and overall survival (OS) in primary CRC patients. Additionally, we explored the correlation between CIB1 expression and different HGPs of CRCLM. Proteomic analysis was used to evaluate CIB1 expression in a cohort of 697 primary CRC patients. Additionally, single-cell and spatial RNA-sequencing datasets, along with publicly available bulk sequencing data were used to evaluate CIB1 expression in CRCLM. In silico data were further validated by formalin-fixed paraffin-embedded immunohistochemical stainings. We observed that high CIB1 expression is independently associated with worse DFS and OS, regardless of Union Internationale Contre le Cancer stage, gender, or age. Furthermore, the aggressive replacement CRCLM HGP is significantly associated with high CIB1 expression. Our findings show a correlation between CIB1 levels and the clinical aggressiveness of CRC. Moreover, CIB1 may be a novel marker to stratify HGP CRCLM.

Histopathological growth pattern and vessel co-option in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) exhibits different blood imaging features and prognosis depending on histology. To clarity histopathological growth patterns (HGPs) and vascularization processes of iCCA, we collected 145 surgical specimens and histologically classified them into large bile duct (LBD) (20 cases), small bile duct (SBD) (54), cholangiolocarcinoma (CLC) (35), combined SBD-CLC (cSBD-CLC) (26), and ductal plate malformation (DPM) (10) (sub)types. According to the invasive pattern at the interface between tumor and adjacent background liver, HGPs were classified into desmoplastic, pushing, and replacing HGPs. Desmoplastic HGP predominated in LBD type (55.5%), while replacing HGP was common in CLC (82.9%) and cSBD-CLC (84.6%) subtypes. Desmoplastic HGP reflected angiogenesis, while replacing HGP showed vessel co-option in addition to angiogenesis. By evaluating microvessel density (MVD) using vascular markers, ELTD1 identified vessel co-option and angiogenesis, and ELTD1-positive MVD at invasive margin in replacing HGP was significantly higher than those in desmoplastic and pushing HGPs. REDD1, an angiogenesis-related marker, demonstrated preferably higher MVD in the tumor center than in other areas. iCCA (sub)types and HGPs were closely related to vessel co-option and immune-related factors (lymphatic vessels, lymphocytes, and neutrophils). In conclusion, HGPs and vascular mechanisms characterize iCCA (sub)types and vessel co-option linked to the immune microenvironment.

Pre-operative prediction of histopathological growth patterns of colorectal cancer liver metastasis using MRI-based radiomic models

PURPOSE

Histopathological growth patterns (HGPs) of colorectal liver metastases (CRLMs) have prognostic value. However, the differentiation of HGPs relies on postoperative pathology. This study aimed to develop a magnetic resonance imaging (MRI)-based radiomic model to predict HGP pre-operatively, following the latest guidelines.

METHODS

This retrospective study included 93 chemotherapy-naïve patients with CRLMs who underwent contrast-enhanced liver MRI and a partial hepatectomy between 2014 and 2022. Radiomic features were extracted from the tumor zone (RTumor), a 2-mm outer ring (RT+2), a 2-mm inner ring (RT-2), and a combined ring (R2+2) on late arterial phase MRI images. Analysis of variance method (ANOVA) and least absolute shrinkage and selection operator (LASSO) algorithms were used for feature selection. Logistic regression with five-fold cross-validation was used for model construction. Receiver operating characteristic curves, calibrated curves, and decision curve analyses were used to assess model performance. DeLong tests were used to compare different models.

RESULTS

Twenty-nine desmoplastic and sixty-four non-desmoplastic CRLMs were included. The radiomic models achieved area under the curve (AUC) values of 0.736, 0.906, 0.804, and 0.794 for RTumor, RT-2, RT+2, and R2+2, respectively, in the training cohorts. The AUC values were 0.713, 0.876, 0.785, and 0.777 for RTumor, RT-2, RT+2, and R2+2, respectively, in the validation cohort. RT-2 exhibited the best performance.

CONCLUSION

The MRI-based radiomic models could predict HGPs in CRLMs pre-operatively.

Vessel co-option: a unique vascular-immune niche in liver cancer

Tumor vasculature is pivotal in regulating tumor perfusion, immune cell infiltration, metastasis, and invasion. The vascular status of the tumor is intricately linked to its immune landscape and response to immunotherapy. Vessel co-option means that tumor tissue adeptly exploits pre-existing blood vessels in the para-carcinoma region to foster its growth rather than inducing angiogenesis. It emerges as a significant mechanism contributing to anti-angiogenic therapy resistance. Different from angiogenic tumors, vessel co-option presents a distinctive vascular-immune niche characterized by varying states and distribution of immune cells, including T-cells, tumor-associated macrophages, neutrophils, and hepatic stellate cells. This unique composition contributes to an immunosuppressive tumor microenvironment that is crucial in modulating the response to cancer immunotherapy. In this review, we systematically reviewed the evidence and molecular mechanisms of vessel co-option in liver cancer, while also exploring its implications for anti-angiogenic drug resistance and the immune microenvironment, to provide new ideas and clues for screening patients with liver cancer who are effective in immunotherapy.

Prediction of transformation in the histopathological growth pattern of colorectal liver metastases after chemotherapy using CT-based radiomics

Chemotherapy alters the prognostic biomarker histopathological growth pattern (HGP) phenotype in colorectal liver metastases (CRLMs) patients. We aimed to develop a CT-based radiomics model to predict the transformation of the HGP phenotype after chemotherapy. This study included 181 patients with 298 CRLMs who underwent preoperative contrast-enhanced CT followed by partial hepatectomy between January 2007 and July 2022 at two institutions. HGPs were categorized as pure desmoplastic HGP (pdHGP) or non-pdHGP. The samples were allocated to training, internal validation, and external validation cohorts comprising 153, 65, and 29 CRLMs, respectively. Radiomics analysis was performed on pre-enhanced, arterial phase, portal venous phase (PVP), and fused images. The model was used to predict prechemotherapy HGPs in 112 CRLMs, and HGP transformation was analysed by comparing these findings with postchemotherapy HGPs determined pathologically. The prevalence of pdHGP was 19.8% (23/116) and 45.8% (70/153) in chemonaïve and postchemotherapy patients, respectively (P < 0.001). The PVP radiomics signature showed good performance in distinguishing pdHGP from non-pdHGPs (AUCs of 0.906, 0.877, and 0.805 in the training, internal validation, and external validation cohorts, respectively). The prevalence of prechemotherapy pdHGP predicted by the radiomics model was 33.0% (37/112), and the prevalence of postchemotherapy pdHGP according to the pathological analysis was 47.3% (53/112; P = 0.029). The transformation of HGP was bidirectional, with 15.2% (17/112) of CRLMs transforming from prechemotherapy pdHGP to postchemotherapy non-pdHGP and 30.4% (34/112) transforming from prechemotherapy non-pdHGP to postchemotherapy pdHGP (P = 0.005). CT-based radiomics method can be used to effectively predict the HGP transformation in chemotherapy-treated CRLM patients, thereby providing a basis for treatment decisions.

Tumor-liver interface in MRI of liver metastasis enables prediction of EGFR mutation in patients with lung cancer: A proof-of-concept study

BACKGROUND

Preoperative prediction of the epidermal growth factor receptor (EGFR) status in non-small-cell lung cancer (NSCLC) patients with liver metastasis (LM) may have potential clinical values for assisting in treatment decision-making.

PURPOSE

To explore the value of tumor-liver interface (TLI)-based magnetic resonance imaging (MRI) radiomics for detecting the EGFR mutation in NSCLC patients with LM.

METHODS

This retrospective study included 123 and 44 patients from hospital 1 (between Feb. 2018 and Dec. 2021) and hospital 2 (between Nov. 2015 and Aug. 2022), respectively. The patients received contrast-enhanced T1-weighted (CET1) and T2-weighted (T2W) liver MRI scans before treatment. Radiomics features were extracted from MRI images of TLI and the whole tumor region, separately. The least absolute shrinkage and selection operator (LASSO) regression was used to screen the features and establish radiomics signatures (RSs) based on TLI (RS-TLI) and the whole tumor (RS-W). The RSs were evaluated by the receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 5 and 6 features were identified highly correlated with the EGFR mutation status from TLI and the whole tumor, respectively. The RS-TLI showed better prediction performance than RS-W in the training (AUCs, RS-TLI vs. RS-W, 0.842 vs. 0.797), internal validation (AUCs, RS-TLI vs. RS-W, 0.771 vs. 0.676) and external validation (AUCs, RS-TLI vs. RS-W, 0.733 vs. 0.679) cohort.

CONCLUSION

Our study demonstrated that TLI-based radiomics can improve prediction performance of the EGFR mutation in lung cancer patients with LM. The established multi-parametric MRI radiomics models may be used as new markers that can potentially assist in personalized treatment planning.

The Inhibition of Vessel Co-Option as an Emerging Strategy for Cancer Therapy

Vessel co-option (VCO) is a non-angiogenic mechanism of vascularization that has been associated to anti-angiogenic therapy. In VCO, cancer cells hijack the pre-existing blood vessels and use them to obtain oxygen and nutrients and invade adjacent tissue. Multiple primary tumors and metastases undergo VCO in highly vascularized tissues such as the lungs, liver or brain. VCO has been associated with a worse prognosis. The cellular and molecular mechanisms that undergo VCO are poorly understood. Recent studies have demonstrated that co-opted vessels show a quiescent phenotype in contrast to angiogenic tumor blood vessels. On the other hand, it is believed that during VCO, cancer cells are adhered to basement membrane from pre-existing blood vessels by using integrins, show enhanced motility and a mesenchymal phenotype. Other components of the tumor microenvironment (TME) such as extracellular matrix, immune cells or extracellular vesicles play important roles in vessel co-option maintenance. There are no strategies to inhibit VCO, and thus, to eliminate resistance to anti-angiogenic therapy. This review summarizes all the molecular mechanisms involved in vessel co-option analyzing the possible therapeutic strategies to inhibit this process.

Vascular co-option in resistance to anti-angiogenic therapy

Three different mechanisms of neovascularization have been described in tumor growth, including sprouting angiogenesis, intussusceptive microvascular growth and glomeruloid vascular proliferation. Tumors can also grow by means of alternative mechanisms including vascular co-option, vasculogenic mimicry, angiotropism, and recruitment of endothelial precursor cells. Vascular co-option occurs in tumors independently of sprouting angiogenesis and the non-angiogenic cancer cells are described as exploiting pre-existing vessels. Vascular co-option is more frequently observed in tumors of densely vascularized organs, including the brain, lung and liver, and vascular co-option represents one of the main mechanisms involved in metastasis, as occurs in liver and lung, and resistance to anti-angiogenic therapy. The aim of this review article is to analyze the role of vascular co-option as mechanism through which tumors develop resistance to anti-angiogenic conventional therapeutic approaches and how blocking co-option can suppress tumor growth.

A CT-based radiomics nomogram for predicting histopathologic growth patterns of colorectal liver metastases

PURPOSE

To develop a computed tomography (CT)-based radiomics nomogram for pre-treatment prediction of histopathologic growth patterns (HGPs) in colorectal liver metastases (CRLM) and to validate its accuracy and clinical value.

MATERIALS AND METHODS

This retrospective study included a total of 197 CRLM from 92 patients. Lesions from CRLM were randomly divided into the training study (n = 137) and the validation study (n = 60) with the ratio of 3:1 for model construction and internal validation. The least absolute shrinkage and selection operator (LASSO) was used to screen features. Radiomics score (rad-score) was calculated to generate radiomics features. A predictive radiomics nomogram based on rad-score and clinical features was developed using random forest (RF). The performances of clinical model, radiomic model and radiomics nomogram were thoroughly evaluated by the DeLong test, decision curve analysis (DCA) and clinical impact curve (CIC) allowing for generation of an optimal predictive model.

RESULTS

The radiological nomogram model consists of three independent predictors, including rad-score, T-stage, and enhancement rim on PVP. Training and validation results demonstrated the high-performance level of the model of area under curve (AUC) of 0.86 and 0.84, respectively. The radiomic nomogram model can achieve better diagnostic performance than the clinical model, yielding greater net clinical benefit compared to the clinical model alone.

CONCLUSIONS

A CT-based radiomics nomogram can be used to predict HGPs in CRLM. Preoperative non-invasive identification of HGPs could further facilitate clinical treatment and provide personalized treatment plans for patients with liver metastases from colorectal cancer.

Histopathological growth pattern evolution of tumor in VX2 liver cancer model

The histopathological growth pattern (HGP) is a morphological reflection of interactions between cancer cells and the surrounding tissue, and has been identified with a remarkably predictive value in liver metastases. However, there is still a lack of studies on HGP of primary liver cancer even furtherly on HGP evolution. We employed VX2 tumor-bearing rabbits as the primary liver cancer model of which tumor size and distant metastasis were investigated. HGP assessment and computed tomography scanning was performed in four cohorts of different time points to map the HGP evolution. Additionally, Fibrin deposition and neovascularization were evaluated by Masson staining and immunohistochemical analysis of CD31, hypoxia-inducible factor-1 alpha (HIF1A) and vascular endothelial growth factor (VEGF). Tumors displayed exponential growth in the VX2 liver cancer model, but these tumor-bearing animals did not show any visible metastasis until they reached a specific stage of development. Correspondingly, the components of HGPs changed along with the tumor growth. The proportion of desmoplastic HGP (dHGP) decreased initially and then grew, but in contrast, the level of replacement HGP (rHGP) rose from the 7th day, reached a peak at around the 21st day, and then appeared drop. Importantly, the collagen deposition and expression of HIF1A and VEGF correlated with dHGP, while CD31 did not. HGP evolution presents a two-way switch including dHGP to rHGP and rHGP to dHGP, in which the emergence of rHGP may be linked to metastases. HIF1A-VEGF partially participates in the HGP evolution and presumably plays a key role in the formation of dHGP.

VE-Cadherin modulates β-catenin/TCF-4 to enhance Vasculogenic Mimicry

Vasculogenic Mimicry (VM) refers to the capacity to form a blood network from aggressive cancer cells in an independent way of endothelial cells, to provide nutrients and oxygen leading to enhanced microenvironment complexity and treatment failure. In a previous study, we demonstrated that VE-Cadherin and its phosphorylation at Y658 modulated kaiso-dependent gene expression (CCND1 and Wnt 11) through a pathway involving Focal Adhesion kinase (FAK). In the present research, using a proteomic approach, we have found that β-catenin/TCF-4 is associated with nuclear VE-cadherin and enhances the capacity of malignant melanoma cells to undergo VM in cooperation with VE-Cadherin; in addition, preventing the phosphorylation of Y658 of VE-cadherin upon FAK disabling resulted in VE-Cadherin/β-catenin complex dissociation, increased β-catenin degradation while reducing TCF-4-dependent genes transcription (C-Myc and Twist-1). Uveal melanoma cells knockout for VE-Cadherin loses β-catenin expression while the rescue of VE-Cadherin (but not of the phosphorylation defective VE-Cadherin Y658F mutant) permits stabilization of β-catenin and tumor growth reduction in vivo experiments. In vivo, the concomitant treatment with the FAK inhibitor PF-271 and the anti-angiogenic agent bevacizumab leads to a strong reduction in tumor growth concerning the single treatment. In conclusion, the anomalous expression of VE-Cadherin in metastatic melanoma cells (from both uveal and cutaneous origins), together with its permanent phosphorylation at Y658, favors the induction of the aggressive VM phenotype through the cooperation of β-catenin with VE-Cadherin and by enhancing TCF-4 genes-dependent transcription.

Molecular differences of angiogenic versus vessel co-opting colorectal cancer liver metastases at single-cell resolution

BACKGROUND

Colorectal cancer liver metastases (CRCLM) are associated with a poor prognosis, reflected by a five-year survival rate of 14%. Anti-angiogenic therapy through anti-VEGF antibody administration is one of the limited therapies available. However, only a subgroup of metastases uses sprouting angiogenesis to secure their nutrients and oxygen supply, while others rely on vessel co-option (VCO). The distinct mode of vascularization is reflected by specific histopathological growth patterns (HGPs), which have proven prognostic and predictive significance. Nevertheless, their molecular mechanisms are poorly understood.

METHODS

We evaluated CRCLM from 225 patients regarding their HGP and clinical data. Moreover, we performed spatial (21,804 spots) and single-cell (22,419 cells) RNA sequencing analyses to explore molecular differences in detail, further validated in vitro through immunohistochemical analysis and patient-derived organoid cultures.

RESULTS

We detected specific metabolic alterations and a signature of WNT signalling activation in metastatic cancer cells related to the VCO phenotype. Importantly, in the corresponding healthy liver of CRCLM displaying sprouting angiogenesis, we identified a predominantly expressed capillary subtype of endothelial cells, which could be further explored as a possible predictor for HGP relying on sprouting angiogenesis.

CONCLUSION

These findings may prove to be novel therapeutic targets to the treatment of CRCLM, in special the ones relying on VCO.

Prognostic Significance of the Histopathological Growth Pattern and Tumor-Infiltrating Lymphocytes in Stratifying Survival After Hepatectomy for Colorectal Liver Metastases

BACKGROUND

A histopathological growth pattern (HGP) occurs at the interface between tumor cells and the surrounding liver parenchyma. Desmoplastic HGP (dHGP) is associated with a favorable prognosis and shows denser infiltration of lymphocytes than other HGPs. Tumor-infiltrating lymphocytes (TILs) exert antitumor immunity, nonetheless, their prognostic significance in patients with dHGP is unknown. This study aimed to identify the prognostic significance of HGP and TILs in colorectal liver metastasis (CRLM).

METHODS

The study analyzed 140 patients who underwent hepatectomy for CRLM. Depending on the type of HGP and TIL, the patients were categorized into four groups (dHGP/high TIL, dHGP/low TIL, non-dHGP/high TIL, and non-dHGP/low TIL) for a comparison of their recurrence-free survival (RFS) and overall survival (OS). Uni- and multivariate analyses were performed using a Cox proportional hazards model.

RESULTS

The RFS and OS curves differed significantly between the groups. The multivariate analysis showed that a combination of HGP and TIL could stratify the recurrence and survival outcomes.

CONCLUSION

This study indicated that a combination of HGP and TIL can stratify the risk of survival after hepatectomy in patients with CRLM.

Role of extracellular vesicles in cancer-specific interactions between tumour cells and the vasculature

Cancer progression impacts and exploits the vascular system in several highly consequential ways. Among different types of vascular cells, blood cells and mediators that are engaged in these processes, endothelial cells are at the centre of the underlying circuitry, as crucial constituents of angiogenesis, angiocrine stimulation, non-angiogenic vascular growth, interactions with the coagulation system and other responses. Tumour-vascular interactions involve soluble factors, extracellular matrix molecules, cell-cell contacts, as well as extracellular vesicles (EVs) carrying assemblies of molecular effectors. Oncogenic mutations and transforming changes in the cancer cell genome, epigenome and signalling circuitry exert important and often cancer-specific influences upon pathways of tumour-vascular interactions, including the biogenesis, content, and biological activity of EVs and responses of cancer cells to them. Notably, EVs may carry and transfer bioactive, oncogenic macromolecules (oncoproteins, RNA, DNA) between tumour and vascular cells and thereby elicit unique functional changes and forms of vascular growth and remodeling. Cancer EVs influence the state of the vasculature both locally and systemically, as exemplified by cancer-associated thrombosis. EV-mediated communication pathways represent attractive targets for therapies aiming at modulation of the tumour-vascular interface (beyond angiogenesis) and could also be exploited for diagnostic purposes in cancer.

The molecular mechanisms underlying neutrophil infiltration in vessel co-opting colorectal cancer liver metastases

Colorectal cancer liver metastases (CRCLMs) have two major histopathological growth patterns (HGPs): desmoplastic (DHGP) and replacement (RHGP). The DHGP tumours derive their vasculature by angiogenesis, while the RHGP tumours use vessel co-option. Various studies have associated RHGP tumours with an unfavourable prognosis, as well as high levels of resistance to anti-angiogenic agents and chemotherapy. Recently, we reported higher numbers of neutrophils in the tumour microenvironment (TME) of vessel co-opting tumours compared to their angiogenic counterparts. However, the molecular mechanisms underlying this phenotype are unclear. Herein, we suggested a positive correlation between the expression of angiopoietin-1 (Ang1) in the hepatocytes and the presence of neutrophils in vessel co-opting tumours. Importantly, upregulation of Ang1 in the hepatocytes is associated with the presence of runt-related transcription factor-1 (RUNX1) in the neighboring cancer cells in vitro and in vivo. Altogether, our data suggest the molecular mechanisms by which neutrophils are infiltrated in vessel co-opting CRCLM lesions. This finding may yield novel therapeutic strategies for CRCLM patients in future.

Histopathological growth patterns of liver metastasis: updated consensus guidelines for pattern scoring, perspectives and recent mechanistic insights

The first consensus guidelines for scoring the histopathological growth patterns (HGPs) of liver metastases were established in 2017. Since then, numerous studies have applied these guidelines, have further substantiated the potential clinical value of the HGPs in patients with liver metastases from various tumour types and are starting to shed light on the biology of the distinct HGPs. In the present guidelines, we give an overview of these studies, discuss novel strategies for predicting the HGPs of liver metastases, such as deep-learning algorithms for whole-slide histopathology images and medical imaging, and highlight liver metastasis animal models that exhibit features of the different HGPs. Based on a pooled analysis of large cohorts of patients with liver-metastatic colorectal cancer, we propose a new cut-off to categorise patients according to the HGPs. An up-to-date standard method for HGP assessment within liver metastases is also presented with the aim of incorporating HGPs into the decision-making processes surrounding the treatment of patients with liver-metastatic cancer. Finally, we propose hypotheses on the cellular and molecular mechanisms that drive the biology of the different HGPs, opening some exciting preclinical and clinical research perspectives.

Targeting FAPα-expressing hepatic stellate cells overcomes resistance to antiangiogenics in colorectal cancer liver metastasis models

Vessel co-option has been demonstrated to mediate colorectal cancer liver metastasis (CRCLM) resistance to antiangiogenic therapy. The current mechanisms underlying vessel co-option have mainly focused on "hijacker" tumor cells, whereas the function of the "hijackee" sinusoidal blood vessels has not been explored. Here, we found that the occurrence of vessel co-option in bevacizumab-resistant CRCLM xenografts was associated with increased expression of fibroblast activation protein α (FAPα) in the co-opted hepatic stellate cells (HSCs), which was dramatically attenuated in HSC-specific conditional Fap-knockout mice bearing CRCLM allografts. Mechanistically, bevacizumab treatment induced hypoxia to upregulate the expression of fibroblast growth factor-binding protein 1 (FGFBP1) in tumor cells. Gain- or loss-of-function experiments revealed that the bevacizumab-resistant tumor cell-derived FGFBP1 induced FAPα expression by enhancing the paracrine FGF2/FGFR1/ERK1/-2/EGR1 signaling pathway in HSCs. FAPα promoted CXCL5 secretion in HSCs, which activated CXCR2 to promote the epithelial-mesenchymal transition of tumor cells and the recruitment of myeloid-derived suppressor cells. These findings were further validated in tumor tissues derived from patients with CRCLM. Targeting FAPα+ HSCs effectively disrupted the co-opted sinusoidal blood vessels and overcame bevacizumab resistance. Our study highlights the role of FAPα+ HSCs in vessel co-option and provides an effective strategy to overcome the vessel co-option-mediated bevacizumab resistance.

Clinical implications and mechanism of histopathological growth pattern in colorectal cancer liver metastases

Liver is the most common site of metastases of colorectal cancer, and liver metastases present with distinct histopathological growth patterns (HGPs), including desmoplastic, pushing and replacement HGPs and two rare HGPs. HGP is a miniature of tumor-host reaction and reflects tumor biology and pathological features as well as host immune dynamics. Many studies have revealed the association of HGPs with carcinogenesis, angiogenesis, and clinical outcomes and indicates HGP functions as bond between microscopic characteristics and clinical implications. These findings make HGP a candidate marker in risk stratification and guiding treatment decision-making, and a target of imaging observation for patient screening. Of note, it is crucial to determine the underlying mechanism shaping HGP, for instance, immune infiltration and extracellular matrix remodeling in desmoplastic HGP, and aggressive characteristics and special vascularization in replacement HGP (rHGP). We highlight the importance of aggressive features, vascularization, host immune and organ structure in formation of HGP, hence propose a novel "advance under camouflage" hypothesis to explain the formation of rHGP.

Probiotic Supplementation Suppresses Tumor Growth in an Experimental Colorectal Cancer Liver Metastasis Model

Colorectal cancer (CRC) ranks third in incidence and second in mortality of all cancers worldwide. At the time of primary diagnosis, around 20% of patients already have metastatic CRC and only around 20% are candidates for radical resection. Thus, most of the patients have to undergo chemotherapy (CTx). Due to chemoresistance and side effects, novel treatment additives are crucial for controlling the disease and prolonging patient survival. The aim of this study was to evaluate probiotic supplementation and its antitumorigenic effects in an experimental CRC liver metastasis model. Six-week-old male Wistar rats received either a multispecies probiotic (1.2 × 10⁹ CFU/daily) or placebo mixture. On day 14 of the experiment, rat CRC cells (CC531) were implanted under the liver capsule later treated by FOLFOX CTx. Change in tumor volume was measured by performing micro computed tomography (micro-CT) scanning on experimental days 28 and 34. Additionally, immunohistochemical staining with anti-MPO, anti-Ki67, and anti-CD31 were performed. Tumor apoptosis was evaluated using TUNEL staining. Micro-CT image analysis indicates that probiotic supplementation significantly inhibits tumor growth. No synergistic effects between probiotic supplementation and FOLFOX CTx was observed. Reduced tumor volume was achieved by inhibiting angiogenesis, as tumor microvascular density was significantly lower in rats receiving probiotic supplementation. This study shows that a multispecies probiotic mixture significantly reduces angiogenesis and inhibits CRC liver metastasis growth in an experimental rat model.

Angiopoietin-1 Upregulates Cancer Cell Motility in Colorectal Cancer Liver Metastases through Actin-Related Protein 2/3

Resistance to anti-angiogenic therapy is a major challenge in the treatment of colorectal cancer liver metastases (CRCLMs). Vessel co-option has been identified as a key contributor to anti-angiogenic therapy resistance in CRCLMs. Recently, we identified a positive correlation between the expression of Angiopoietin1 (Ang1) in the liver and the development of vessel co-opting CRCLM lesions in vivo. However, the mechanisms underlying its stimulation of vessel co-option are unclear. Herein, we demonstrated Ang1 as a positive regulator of actin-related protein 2/3 (ARP2/3) expression in cancer cells, in vitro and in vivo, which is known to be essential for the formation of vessel co-option in CRCLM. Significantly, Ang1-dependent ARP2/3 expression was impaired in the cancer cells upon Tie2 or PI3K/AKT inhibition in vitro. Taken together, our results suggest novel mechanisms by which Ang1 confers the development of vessel co-option in CRCLM, which, targeting this pathway, may serve as promising therapeutic targets to overcome the development of vessel co-option in CRCLM.

Cancer Cells Promote Phenotypic Alterations in Hepatocytes at the Edge of Cancer Cell Nests to Facilitate Vessel Co-Option Establishment in Colorectal Cancer Liver Metastases

Vessel co-option is correlated with resistance against anti-angiogenic therapy in colorectal cancer liver metastases (CRCLM). Vessel co-opting lesions are characterized by highly motile cancer cells that move toward and along the pre-existing vessels in the surrounding nonmalignant tissue and co-opt them to gain access to nutrients. To access the sinusoidal vessels, the cancer cells in vessel co-opting lesions must displace the hepatocytes and occupy their space. However, the mechanisms underlying this displacement are unknown. Herein, we examined the involvement of apoptosis, autophagy, motility, and epithelial-mesenchymal transition (EMT) pathways in hepatocyte displacement by cancer cells. We demonstrate that cancer cells induce the expression of the proteins that are associated with the upregulation of apoptosis, motility, and EMT in adjacent hepatocytes in vitro and in vivo. Accordingly, we observe the upregulation of cleaved caspase-3, cleaved poly (ADP-ribose) polymerase-1 (PARP-1) and actin-related protein 2/3 (ARP2/3) in adjacent hepatocytes to cancer cell nests, while we notice a downregulation of E-cadherin. Importantly, the knockdown of runt-related transcription factor 1 (RUNX1) in cancer cells attenuates the function of cancer cells in hepatocytes alterations in vitro and in vivo. Altogether, our data suggest that cancer cells exploit various mechanisms to displace hepatocytes and access the sinusoidal vessels to establish vessel co-option.

Histological growth patterns of colorectal cancer liver metastases: a strong prognostic marker associated with invasive patterns of the primary tumor and p53 alteration

The histological growth pattern of liver metastases (desmoplastic, pushing, and replacement patterns) at the tumor-liver parenchymal interface is a prognostic factor in patients with colorectal cancer. However, data regarding its association with the primary tumor characteristics and molecular alterations are limited. This study evaluated the histological growth pattern in 136 cases of colorectal cancer liver metastases without preoperative treatment, comparing it with the clinicopathological features of the primary tumor. Liver metastasis exhibiting predominantly non-desmoplastic pattern (<50%), observed in 74 cases (54%), was associated with hepatic vein invasion (P = 0.025), worse recurrence-free survival (P < 0.001) and overall survival (P = 0.008). In multivariate analyses, multiple tumors (P < 0.001) and non-desmoplastic patterns (P = 0.009) were associated with worse recurrence-free survival, and tumor size (P = 0.025) and non-desmoplastic pattern (P = 0.025) were associated with worse overall survival. In 88 patients with available primary tumor tissue slides, non-desmoplastic pattern in the liver metastasis was associated with high-grade tumor budding (P = 0.002), high-grade poorly differentiated cluster (P = 0.021), absence of mucinous histology (P = 0.016), and aberrant p53 expression (complete loss or overexpression; P < 0.001) of the primary colorectal cancer. In conclusion, the histological growth pattern in liver metastasis was a strong and independent prognostic factor for colorectal cancer. Our observations highlight the significant associations between histological growth patterns in liver metastases and histopathological features of the primary tumor, especially invasive front morphology and p53 aberration.

Angiogenic and molecular diversity determine hepatic melanoma metastasis and response to anti-angiogenic treatment

BACKGROUND

Cutaneous melanoma exhibits heterogeneous metastatic patterns and prognosis. In this regard, liver metastasis, which is detected in ~ 10-20% of stage 4 patients, came to the fore of melanoma research, as it recently evolved as decisive indicator of treatment resistance to immune checkpoint inhibition.

METHODS

Hepatic metastases were induced by intrasplenic injection of five different murine melanoma cell lines. The efficiencies of hepatic colonization, morphologic patterns, gene expression profiles and degree of vascularization were analyzed and Sorafenib was applied as anti-angiogenic treatment.

RESULTS

WT31 melanoma showed the highest efficiency of hepatic colonization, while intermediate efficiencies were observed for B16F10 and RET, and low efficiencies for D4M and HCmel12. RNAseq-based gene expression profiles of high and intermediate metastatic melanomas in comparison to low metastatic melanomas indicated that this efficiency predominantly associates with gene clusters involved in cell migration and angiogenesis. Indeed, heterogeneous vascularization patterns were found in the five models. Although the degree of vascularization of WT31 and B16F10 metastases differed, both showed a strong response to Sorafenib with a successful abrogation of the vascularization.

CONCLUSION

Our data indicate that molecular heterogeneity of melanomas can be associated with phenotypic and prognostic features of hepatic metastasis paving the way for organ-specific anti-angiogenic therapeutic approaches.

Differentiation of histopathological growth patterns of colorectal liver metastases by MRI features

Background

It is necessary to develop an accurate non-invasive method to determine the histopathological growth pattern (HGP) of colorectal liver metastasis (CRLM) before surgery. The present study aimed to identify various HGPs of CRLM by magnetic resonance imaging (MRI) features.

Methods

This retrospective study included 53 chemo-naïve patients with CRLM between December 2013 and September 2019. The HGPs of CRLM were assessed according to the international consensus guidelines, and were classified as either replacement HGP (rHGP) or non-rHGP. The MRI features of CRLM were retrospectively reviewed in consensus by two radiologists. The differences of MRI features between rHGP and non-rHGP tumors were compared by using Chi-square test and Student's t-test. The Spearman or Pearson correlation analysis was performed to determine the correlation between different MRI features. A receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic ability.

Results

Of the 53 chemo-naïve patients (mean age, 60.11±9.85 years; age range, 38-86 years), 12 were diagnosed as rHGP, while 41 were diagnosed as non-rHGP. Rim enhancement were more common in rHGP than in non-rHGP (P<0.001). Besides, the diameter difference (ΔD) between the precontrast and postcontrast images of rHGP was significantly larger than that of the non-rHGP (P=0.001). The rim width was correlated with ΔD, but not correlated with tumor size. The non-rHGP colorectal liver metastases were prone to be washed out in the delayed phases (P=0.043). The area under the curve (AUC) for the differentiation of rHGP and non-rHGP by using rim enhancement and ΔD was 0.828 (95% CI: 0.708-0.949).

Conclusions

The MRI features of CRLM are characteristic and could help to differentiate rHGP and non-rHGP.

Comprehensive Imaging Characterization of Colorectal Liver Metastases

Colorectal liver metastases (CRLM) have heterogenous histopathological and immunohistochemical phenotypes, which are associated with variable responses to treatment and outcomes. However, this information is usually only available after resection, and therefore of limited value in treatment planning. Improved techniques for in vivo disease assessment, which can characterise the variable tumour biology, would support further personalization of management strategies. Advanced imaging of CRLM including multiparametric MRI and functional imaging techniques have the potential to provide clinically-actionable phenotypic characterisation. This includes assessment of the tumour-liver interface, internal tumour components and treatment response. Advanced analysis techniques, including radiomics and machine learning now have a growing role in assessment of imaging, providing high-dimensional imaging feature extraction which can be linked to clinical relevant tumour phenotypes, such as a the Consensus Molecular Subtypes (CMS). In this review, we outline how imaging techniques could reproducibly characterize the histopathological features of CRLM, with several matched imaging and histology examples to illustrate these features, and discuss the oncological relevance of these features. Finally, we discuss the future challenges and opportunities of CRLM imaging, with a focus on the potential value of advanced analytics including radiomics and artificial intelligence, to help inform future research in this rapidly moving field.

The emerging roles of circular RNAs in vessel co-option and vasculogenic mimicry: clinical insights for anti-angiogenic therapy in cancers

Unexpected resistance to anti-angiogenic treatment prompted the investigation of non-angiogenic tumor processes. Vessel co-option (VC) and vasculogenic mimicry (VM) are recognized as primary non-angiogenic mechanisms. In VC, cancer cells utilize pre-existing blood vessels for support, whereas in VM, cancer cells channel and provide blood flow to rapidly growing tumors. Both processes have been implicated in the development of tumor and resistance to anti-angiogenic drugs in many tumor types. The morphology, but rare molecular alterations have been investigated in VC and VM. There is a pressing need to better understand the underlying cellular and molecular mechanisms. Here, we review the emerging circular RNA (circRNA)-mediated regulation of non-angiogenic processes, VC and VM.

Runt related transcription factor-1 plays a central role in vessel co-option of colorectal cancer liver metastases

Colorectal cancer liver metastasis (CRCLM) has two major histopathological growth patterns: angiogenic desmoplastic and non-angiogenic replacement. The replacement lesions obtain their blood supply through vessel co-option, wherein the cancer cells hijack pre-existing blood vessels of the surrounding liver tissue. Consequentially, anti-angiogenic therapies are less efficacious in CRCLM patients with replacement lesions. However, the mechanisms which drive vessel co-option in the replacement lesions are unknown. Here, we show that Runt Related Transcription Factor-1 (RUNX1) overexpression in the cancer cells of the replacement lesions drives cancer cell motility via ARP2/3 to achieve vessel co-option. Furthermore, overexpression of RUNX1 in the cancer cells is mediated by Transforming Growth Factor Beta-1 (TGFβ1) and thrombospondin 1 (TSP1). Importantly, RUNX1 knockdown impaired the metastatic capability of colorectal cancer cells in vivo and induced the development of angiogenic lesions in liver. Our results confirm that RUNX1 may be a potential target to overcome vessel co-option in CRCLM.

Radiomics diagnosed histopathological growth pattern in prediction of response and 1-year progression free survival for colorectal liver metastases patients treated with bevacizumab containing chemotherapy

OBJECTIVE

To investigate the capability of a radiomics model, which was designed to identify histopathologic growth pattern (HGP) of colorectal liver metastases (CRLMs) based on contrast-enhanced multidetector computed tomography (ceMDCT), to predict early response and 1-year progression free survival (PFS) in patients treated with bevacizumab-containing chemotherapy.

METHODS

Patients with unresectable CRLMs who were treated with bevacizumab-containing chemotherapy were included in this multicenter retrospective study. For each target lesion, the radiomics-diagnosed HGP (RAD_HGP) of desmoplastic (D) pattern or replacement (R) pattern was determined. Logistic regression and receiver operating characteristic (ROC) curves were used to assess lesion- and patient-based responses according to morphologic response criteria. One-year PFS was calculated using Kaplan-Meier curves. Hazard ratios for 1-year PFS were obtained through Cox proportional hazard regression analysis.

RESULTS

Among 119 study patients, 206 D pattern and 140 R pattern lesions were identified. In patients with multiple lesions, 52 had D pattern, 31 had R pattern, and 36 had mixed (D + R) pattern. The area under the curve value for RAD_HGP in predicting early response was 0.707 for lesion-based analysis and 0.720 for patient-based analysis. Patients with D pattern had a significantly longer PFS than patients with R pattern or mixed pattern (P < 0.001). RAD_HGP was the only independent predictor of 1-year PFS.

CONCLUSIONS

HGP diagnosed using a radiomics model could be used as an effective predictor of PFS for patients with CRLMs treated with bevacizumab-containing chemotherapy.

Tumor vessel co-option probed by single-cell analysis

Tumor vessel co-option is poorly understood, yet it is a resistance mechanism against anti-angiogenic therapy (AAT). The heterogeneity of co-opted endothelial cells (ECs) and pericytes, co-opting cancer and myeloid cells in tumors growing via vessel co-option, has not been investigated at the single-cell level. Here, we use a murine AAT-resistant lung tumor model, in which VEGF-targeting induces vessel co-option for continued growth. Single-cell RNA sequencing (scRNA-seq) of 31,964 cells reveals, unexpectedly, a largely similar transcriptome of co-opted tumor ECs (TECs) and pericytes as their healthy counterparts. Notably, we identify cell types that might contribute to vessel co-option, i.e., an invasive cancer-cell subtype, possibly assisted by a matrix-remodeling macrophage population, and another M1-like macrophage subtype, possibly involved in keeping or rendering vascular cells quiescent.

Claudin-2 promotes colorectal cancer liver metastasis and is a biomarker of the replacement type growth pattern

Claudin-2 promotes breast cancer liver metastasis by enabling seeding and early cancer cell survival. We now demonstrate that Claudin-2 is functionally required for colorectal cancer liver metastasis and that Claudin-2 expression in primary colorectal cancers is associated with poor overall and liver metastasis-free survival. We have examined the role of Claudin-2, and other claudin family members, as potential prognostic biomarkers of the desmoplastic and replacement histopathological growth pattern associated with colorectal cancer liver metastases. Immunohistochemical analysis revealed higher Claudin-2 levels in replacement type metastases when compared to those with desmoplastic features. In contrast, Claudin-8 was highly expressed in desmoplastic colorectal cancer liver metastases. Similar observations were made following immunohistochemical staining of patient-derived xenografts (PDXs) that we have established, which faithfully retain the histopathology of desmoplastic or replacement type colorectal cancer liver metastases. We provide evidence that Claudin-2 status in patient-derived extracellular vesicles may serve as a relevant prognostic biomarker to predict whether colorectal cancer patients have developed replacement type liver metastases. Such a biomarker will be a valuable tool in designing optimal treatment strategies to better manage patients with colorectal cancer liver metastases.

Tabariès et al. describe that claudin 2 is a promoter of colorectal cancer liver metastasis. Furthermore, high Claudin-2 expression is associated with shorter time to liver-specific recurrence and is a biomarker of replacement type CRC liver metastases.

Alternative Vascularization Mechanisms in Tumor Resistance to Therapy

Simple Summary

Tumors rely on blood vessels to grow and metastasize. Malignant tumors can employ different strategies to create a functional vascular network. Tumor cells can use normal processes of vessel formation but can also employ cancer-specific mechanisms, by co-opting normal vessels present in tissues or by turning themselves into vascular cells. These different types of tumor vessels have specific molecular and functional characteristics that profoundly affect tumor behavior and response to therapies, including drugs targeting the tumor vasculature (antiangiogenic therapies). In this review, we discuss how vessels formed by different mechanisms affect the intrinsic sensitivity of tumors to therapy and, on the other hand, how therapies can affect tumor vessel formation, leading to resistance to drugs, cancer recurrence, and treatment failure. Potential strategies to avoid vessel-mediated resistance to antineoplastic therapies will be discussed.

Abstract

Blood vessels in tumors are formed through a variety of different mechanisms, each generating vessels with peculiar structural, molecular, and functional properties. This heterogeneity has a major impact on tumor response or resistance to antineoplastic therapies and is now emerging as a promising target for strategies to prevent drug resistance and improve the distribution and efficacy of antineoplastic treatments. This review presents evidence of how different mechanisms of tumor vessel formation (vasculogenesis, glomeruloid proliferation, intussusceptive angiogenesis, vasculogenic mimicry, and vessel co-option) affect tumor responses to antiangiogenic and antineoplastic therapies, but also how therapies can promote alternative mechanisms of vessel formation, contributing to tumor recurrence, malignant progression, and acquired drug resistance. We discuss the possibility of tailoring treatment strategies to overcome vasculature-mediated drug resistance or to improve drug distribution and efficacy.

Different Forms of Tumor Vascularization and Their Clinical Implications Focusing on Vessel Co-option in Colorectal Cancer Liver Metastases

In modern anti-cancer therapy of metastatic colorectal cancer (mCRC) the anti-angiogenic treatment targeting sprouting angiogenesis is firmly established for more than a decade. However, its clinical benefits still remain limited. As liver metastases (LM) represent the most common metastatic site of colorectal cancer and affect approximately one-quarter of the patients diagnosed with this malignancy, its treatment is an essential aspect for patients' prognosis. Especially in the perioperative setting, the application of anti-angiogenic drugs represents a therapeutic option that may be used in case of high-risk or borderline resectable colorectal cancer liver metastases (CRCLM) in order to achieve secondary resectability. Regarding CRCLM, one reason for the limitations of anti-angiogenic treatment may be represented by vessel co-option (VCO), which is an alternative mechanism of blood supply that differs fundamentally from the well-known sprouting angiogenesis and occurs in a significant fraction of CRCLM. In this scenario, tumor cells hijack pre-existing mature vessels of the host organ independently from stimulating new vessels formation. This represents an escape mechanism from common anti-angiogenic anti-cancer treatments, as they primarily target the main trigger of sprouting angiogenesis, the vascular endothelial growth factor A. Moreover, the mechanism of blood supply in CRCLM can be deduced from their phenotypic histopathological growth pattern (HGP). For that, a specific guideline has already been implemented. These HGP vary not only regarding their blood supply, but also concerning their tumor microenvironment (TME), as notable differences in immune cell infiltration and desmoplastic reaction surrounding the CRCLM can be observed. The latter actually serves as one of the central criteria for the classification of the HGP. Regarding the clinically relevant effects of the HGP, it is still a topic of research whether the VCO-subgroup of CRCLM results in an impaired treatment response to anti-angiogenic treatment when compared to an angiogenic subgroup. However, it is well-proved, that VCO in CRCLM generally relates to an inferior survival compared to the angiogenic subgroup. Altogether the different types of blood supply result in a relevant influence on the patients' prognosis. This reinforces the need of an extended understanding of the underlying mechanisms of VCO in CRCLM with the aim to generate more comprehensive approaches which can target tumor vessels alternatively or even other components of the TME. This review aims to augment the current state of knowledge on VCO in CRCLM and other tumor entities and its impact on anti-angiogenic anti-cancer therapy.

Vascular co-option and vasculogenic mimicry mediate resistance to antiangiogenic strategies

BACKGROUND

The concept that all the tumors need the formation of new vessels to grow inspired the hypothesis that inhibition of angiogenesis would have led to "cure" cancer. The expectancy that this type of therapy would have avoided the insurgence of resistance was based on the concept that targeting normal vessels, instead of the cancer cells which easily develop new mutations, would have allowed evasion of drug caused selection is, however, more complex as it was made apparent by the discovery of nonangiogenic tumors. At the same time an increasing number of trials with antiangiogenic drugs were coming out as not as successful as expected, mostly because of the appearance of unexpected resistance.

RECENT FINDINGS

Among the several different mechanisms of resistance to antiangiogenic treatment by now described, we review the evidences that vascular co-option and vasculogenic mimicry by nonangiogenic tumors are effectively two of such mechanisms. We focused on reviewing exclusively the study, both clinical and preclinical, that offer a demonstration that vascular co-option and vasculogenic mimicry are effectively two mechanisms of both intrinsic and acquired resistance.

CONCLUSION

The discovery that vascular co-opting and vasculogenic mimicry are two ways of escaping antiangiogenic treatment, prompts the need for a better understanding of this phenomenon in order to improve cancer treatment.

Prognostic Factors After Hepatectomy for Gastric Adenocarcinoma Liver Metastases: Desmoplastic Growth Pattern as the Key to Improved Overall Survival

Purpose

Hepatectomy (Hp) is an alternative approach for the treatment of gastric carcinoma liver metastases (GCLM). However, prognostic factors that may assist patient selection are still controversial. Several pathologic features, such as the growth pattern (GP), associated with prognosis in colorectal cancer liver metastases, were never investigated in GCLM. Our principal aim was to assess if the GP has prognostic impact on GCLM.

Patients and Methods

Review of the clinical and pathological characteristics of 19 consecutive patients submitted to surgical resection of GCLM with curative intent at our department. Major potential prognostic factors considered were patients’ gender, age, timing and extent of Hp, postoperative course, as well as histopathological characteristics of primary and secondary tumors.

Results

Major morbidity occurred in four patients, mortality in one. Median and 5-year overall survival were 17 months and 26.7%, respectively. Ten patients developed recurrent disease and two patients survived more than 10 years. Factors independently associated with overall survival were the absence of major morbidity, distal location of the primary tumor, and desmoplastic GP (p<0.05).

Conclusion

The selection of patients is crucial for the improvement of survival rates of GCLM. Consequently, we demonstrate for the first time that the desmoplastic GP of GCLM is associated with improved outcomes, prompting further research on tumor–host interactions.

Enhanced Rim on MDCT of Colorectal Liver Metastases: Assessment of Ability to Predict Progression-Free Survival and Response to Bevacizumab-Based Chemotherapy

OBJECTIVE. The purpose of this article is to evaluate the enhanced rim on the portal venous phase (PVP) on MDCT as a predictor of 1-year progression-free survival (PFS) and response to bevacizumab-based chemotherapy in patients with colorectal liver metastases (CRLM). MATERIALS AND METHODS. We retrospectively identified 111 patients with primary unresectable CRLM treated with bevacizumab-based chemotherapy at two institutions between 2012 and 2018. Pretreatment contrast-enhanced MDCT images were reviewed and data on clinical characteristics were collected from the electronic medical records. Univariable and multivariable analyses were conducted to assess several imaging features and clinical characteristics as potential predictors of 1-year PFS and objective response rate (ORR). RESULTS. After 1 year of follow-up, liver metastatic tumor progression was detected in 52 patients (46.8%) after bevacizumab-based chemotherapy. A log-rank test showed that enhanced rim on PVP (chi-square test, 5.862; p = 0.015) and the occurrence of liver resection surgery (chi-square test, 7.836; p = 0.005) were significant predictors of 1-year PFS. Multivariable analysis showed that enhanced rim on PVP images was an independent predictor of 1-year PFS (hazard ratio, 0.510; 95% CI, 0.282-0.926; p = 0.027) and ORR (odds ratio, 4.694; p < 0.001). CONCLUSION. The presence of an enhanced rim on PVP MDCT is an independent predictor of survival and response to bevacizumab-based chemotherapy among patients with CRLM.

Identification of Predominant Histopathological Growth Patterns of Colorectal Liver Metastasis by Multi-Habitat and Multi-Sequence Based Radiomics Analysis

Purpose: Developing an MRI-based radiomics model to effectively and accurately predict the predominant histopathologic growth patterns (HGPs) of colorectal liver metastases (CRLMs). Materials and Methods: In this study, 182 resected and histopathological proven CRLMs of chemotherapy-naive patients from two institutions, including 123 replacement CRLMs and 59 desmoplastic CRLMs, were retrospectively analyzed. Radiomics analysis was performed on two regions of interest (ROI), the tumor zone and the tumor-liver interface (TLI) zone. Decision tree (DT) algorithm was used for radiomics modeling on each MR sequence, and fused radiomics model was constructed by combining the radiomics signature of each sequence. The clinical and combination models were developed through multivariate logistic regression method. The performance of the developed models was assessed by receiver operating characteristic (ROC) curves with indicators of area under curve (AUC), accuracy, sensitivity, and specificity. A nomogram was constructed to evaluate the discrimination, calibration, and usefulness. Results: The fused radiomics^tumor and radiomics^TLI models showed better performance than any single sequence and clinical model. In addition, the radiomics^TLI model exhibited better performance than radiomics^tumor model (AUC of 0.912 vs. 0.879) in internal validation cohort. The combination model showed good discrimination, and the AUC of nomogram was 0.971, 0.909, and 0.905 in the training, internal validation, and external validation cohorts, respectively. Conclusion: MRI-based radiomics method has high potential in predicting the predominant HGPs of CRLM. Preoperative non-invasive identification of predominant HGPs could further explore the ability of HGPs as a potential biomarker for clinical treatment strategy, reflecting different biological pathways.

Predicting liver metastases growth patterns: Current status and future possibilities

Colorectal cancer is highly incident worldwide and presents a health burden with elevated mortality rate despite prevention, detection, and treatment, mainly due to metastatic liver disease. Histological growth patterns of colorectal cancer liver metastases have emerged as a reproducible prognostic factor, with biological implications and therapeutic windows. Nonetheless, the histological growth patterns of colorectal cancer liver metastases are only known after pathological examination of a liver resection specimen, thus limiting the possibilities of pre-surgical decision. Predicting the histological growth pattern of colorectal cancer liver metastases would provide valuable information for patient-tailored medicine. In this article, we perform a review of the histological growth patterns and their implications, with a focus on the possibilities for their prediction.

Tumour budding and its clinical implications in gastrointestinal cancers

Tumour budding in colorectal cancer has become an important prognostic factor. Represented by single cells or small tumour cell clusters at the invasion front of the tumour mass, these tumour buds seem to reflect cells in a ‘hybrid’ state of epithelial–mesenchymal transition, and evidence indicates that the presence of these entities is associated with lymph node metastasis, local recurrence and distant metastatic disease. The International Tumour Budding Consensus Conference (ITBCC) has highlighted a scoring system for the reporting of tumour budding in colorectal cancer, as well as different clinical scenarios that could affect patient management. Other organs are not spared: tumour budding has been described in numerous gastrointestinal and non-gastrointestinal cancers. Here, we give an update on ITBCC validation studies in the context of colorectal cancer and the clinical implications of tumour budding throughout the upper gastrointestinal and pancreatico-biliary tract.

Histopathological growth patterns correlate with the immunoscore in colorectal cancer liver metastasis patients after hepatectomy

Various scoring systems have been proposed to predict the postoperative prognosis of colorectal liver metastasis (CRLM), including the clinical risk score (CRS), the immunoscore and so on. Recently, histopathological growth patterns (HGPs) have been recognized. However, the correlation between HGPs and the immunoscore, and their prognostic values in patients with CRLM after liver resection remain undetermined. In this study, HGPs were retrospectively evaluated in H&E-stained slides from 166 CRLM patients. The immunoscore was calculated according to the densities of immunostained CD3 + and CD8 + cells. A risk score combining HGPs, the immunoscore and the CRS was defined and divided patients into the low-, medium- and high-risk group. Our results showed that the densities of CD3 + and CD8 + cells were higher in the desmoplastic HGP (dHGP) group than in the non-dHGP group, and the proportion of high immunoscores was also higher in the dHGP group (51.9% vs. 33.0%, respectively, P = 0.020). Patients with the dHGP had significantly longer relapse-free survival (RFS) and overall survival (OS) than those with the non-HGP. The low-risk group showed significantly higher 2-year RFS and 5-year OS rates than the other two groups (RFS: 76.2%, 43.7% and 33.1%, respectively; P < 0.001; OS: 89.7%, 54.4% and 33.3%, respectively; P < 0.001). In conclusion, the dHGP correlates with relatively high immunoscores, predicting a favorable prognosis independent of the immunoscore and CRS. A novel risk score combining HGPs, the immunoscore and the CRS may be used for the stratification of CRLM patients' survival.

Neutrophils expressing lysyl oxidase-like 4 protein are present in colorectal cancer liver metastases resistant to anti-angiogenic therapy

Colorectal cancer liver metastases (CRCLM) that present with a replacement histopathological growth pattern (HGP) are resistant to neoadjuvant anti-angiogenic therapy. Surrogate biomarkers are not available to preoperatively identify patients with these tumors. Here we identify differentially expressed genes between CRCLM with a replacement HGP and those with a desmoplastic HGP using RNA sequencing. We demonstrate that LOXL4 is transcriptionally upregulated in replacement HGP CRCLM compared with desmoplastic HGP CRCLM and the adjacent normal liver. Interestingly, lysyl oxidase-like 4 (LOXL4) protein was expressed by neutrophils present in the tumor microenvironment in replacement HGP CRCLM. We further demonstrate that LOXL4 expression is higher in circulating neutrophils of cancer patients compared with healthy control patients and its expression can be induced by stimulation with lipopolysaccharide and TNF-α. Our study is the first to show the expression of LOXL4 in neutrophils and reveals the potential for LOXL4-expressing neutrophils to support the replacement HGP phenotype and to serve as a surrogate biomarker for this subtype of CRCLM. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Critical considerations for targeting colorectal liver metastases with nanotechnology

Colorectal cancer remains a significant cause of morbidity and mortality worldwide. Half of all patients develop liver metastases, presenting unique challenges for their treatment. The shortcomings of conventional chemotherapy has encouraged the use of nanomedicines; the application of nanotechnology in the diagnosis and treatment of disease. In spite of technological improvements in nanotechnology, the complexity of biological systems hinders the prospect of nanomedicines being applied in cancer therapy at the present time. This review highlights current biological barriers and discusses aspects of tumor biology together with the physicochemical features of the nanocarrier, that need to be considered in order to develop effective nanotherapeutics for colorectal cancer patients with liver metastases. It becomes clear that incorporating an interdisciplinary approach when developing nanomedicines should assure appropriate disease-driven design and that this will form a critical step in improving their clinical translation. This article is characterized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Vessel co-option and resistance to anti-angiogenic therapy

Vessel co-option is a non-angiogenic mechanism of tumour vascularisation in which cancer cells utilise pre-existing blood vessels instead of inducing new blood vessel formation. Vessel co-option has been observed across a range of different tumour types, in both primary cancers and metastatic disease. Importantly, vessel co-option is now implicated as a major mechanism that mediates resistance to conventional anti-angiogenic drugs and this may help to explain the limited efficacy of this therapeutic approach in certain clinical settings. This includes the use of anti-angiogenic drugs to treat advanced-stage/metastatic disease, treatment in the adjuvant setting and the treatment of primary disease. In this article, we review the available evidence linking vessel co-option with resistance to anti-angiogenic therapy in numerous tumour types, including breast, colorectal, lung and pancreatic cancer, glioblastoma, melanoma, hepatocellular carcinoma, and renal cell carcinoma. The finding that vessel co-option is a significant mechanism of resistance to anti-angiogenic therapy may have important implications for the future of anti-cancer therapy, including (a) predicting response to anti-angiogenic drugs, (b) the need to develop therapies that target both angiogenesis and vessel co-option in tumours, and (c) predicting the response to other therapeutic modalities, including immunotherapy.

Angiopoietin1 Deficiency in Hepatocytes Affects the Growth of Colorectal Cancer Liver Metastases (CRCLM)

Colorectal cancer liver metastases (CRCLM) that receive their blood supply via vessel co-option are associated with a poor response to anti-angiogenic therapy. Angiopoietins (Ang1 and Ang2) with their Tyrosine-protein kinase receptor (Tie2) have been shown to support vessel co-option. We demonstrate significantly higher expression of Ang1 in hepatocytes adjacent to the tumor region of human chemonaïve and treated co-opting (replacement histopathological growth patterns: RHGP) tumors. To investigate the role of the host Ang1 expression, Ang1 knockout (KO) mice were injected intra-splenically with metastatic MC-38 colon cancer cells that develop co-opting liver metastases. We observed a reduction in the number of liver metastases and interestingly, for the first time, the development of angiogenic driven desmoplastic (DHGP) liver metastases. In addition, in-vitro, knockout of Ang1 in primary hepatocytes inhibited viability, migration and invasion ability of MC-38 cells. We also demonstrate that Ang 1 alone promotes the migration and growth of both human and mouse colon cancer cell lines These results provide evidence that high expression of Ang1 in the host liver is important to support vessel co-option (RHGP lesions) and when inhibited, favours the formation of angiogenic driven liver metastases (DHGP lesions).

Vessel co-option in cancer

All solid tumours require a vascular supply in order to progress. Although the ability to induce angiogenesis (new blood vessel growth) has long been regarded as essential to this purpose, thus far, anti-angiogenic therapies have shown only modest efficacy in patients. Importantly, overshadowed by the literature on tumour angiogenesis is a long-standing, but continually emerging, body of research indicating that tumours can grow instead by hijacking pre-existing blood vessels of the surrounding nonmalignant tissue. This process, termed vessel co-option, is a frequently overlooked mechanism of tumour vascularization that can influence disease progression, metastasis and response to treatment. In this Review, we describe the evidence that tumours located at numerous anatomical sites can exploit vessel co-option. We also discuss the proposed molecular mechanisms involved and the multifaceted implications of vessel co-option for patient outcomes.

Evaluation of Tumor Budding in Primary Colorectal Cancer and Corresponding Liver Metastases Based on H&E and Pancytokeratin Staining

In colorectal cancer, tumor budding is associated with tumor progression and represents an additional prognostic factor in the TNM classification. Tumor buds can be found at the invasive front (peritumoral budding; PTB) and in the tumor center (intratumoral budding; ITB) of primary tumors. Previous studies have shown that tumor buds are also present in colorectal liver metastases (CRLM). Data on the prognostic and predictive role in this clinical context are still sparse and no standardized approach to evaluate budding in CRLM has been published so far. This study aimed to analyze and correlate perimetastatic (PMB) and intrametastatic budding (IMB) on H&E and pancytokeratin staining, compare it to budding results in corresponding primary tumors and to propose a standardized scoring system in CRLM as the basis for future studies. Tumor tissue of 81 primary tumors and 139 corresponding CRLM was used for ngTMA construction. For each primary tumor and metastasis, two punches from the center and two punches from the periphery from areas with highest tumor budding density were included. TMA slides were stained for H&E and pancytokeratin (Pan-CK). PTB, ITB, PMB, and IMB were analyzed and classified as bd1, bd2, and bd3 according to ITBCC guidelines. ITB and PTB as well as IMB and PMB showed significant correlation on H&E and Pan-CK staining. No correlation was found for tumor bud counts in primary tumors and corresponding metastases. The agreement for categorized tumor bud counts showed fair to good agreement for metastases and poor agreement for primary tumors between different classes on H&E and Pan-CK staining. Based on our results, tumor budding in primary tumors and CRLM seems to be different processes which might be the results of differing surrounding microenvironments. The evaluation of tumor budding in CRLM is challenging in cases without desmoplastic stroma reaction or intense perimetastatic ductular reaction. We therefore propose to evaluate tumor budding only in metastases with desmoplastic stroma reaction based on H&E staining since important morphological features are obscured on Pan-CK staining.

Prediction of Histopathologic Growth Patterns of Colorectal Liver Metastases with a Noninvasive Imaging Method

OBJECTIVES

To predict histopathologic growth patterns (HGPs) in colorectal liver metastases (CRLMs) with a noninvasive radiomics model.

METHODS

Patients with chemotherapy-naive CRLMs who underwent abdominal contrast-enhanced multidetector CT (MDCT) followed by partial hepatectomy between January 2007 and January 2019 from two institutions were included in this retrospective study. Hematoxylin- and eosin-stained histopathologic sections of CRLMs were reviewed, with HGPs defined according to international consensus. Lesions were divided into training and validation datasets based on patients' sources. Radiomic features were extracted from pre- and post-contrast (arterial and portal venous) phase MDCT images, with review focusing on the segmented tumor-liver interface zones of CRLMs. Minimum redundancy maximum relevance and decision tree methods were used for radiomics modeling. Multivariable logistic regression analyses and ROC curves were used to assess the predictive performance of these models in predicting HGP types.

RESULTS

A total of 126 CRLMs with histopathologic-demonstrated desmoplastic (n = 68) or replacement (n = 58) HGPs were assessed. The radiomics signature consisted of 20 features of each phase selected. The 3 phases fused radiomics signature demonstrated the best predictive performance in distinguishing between replacement and desmoplastic HGPs (AUCs of 0.926 and 0.939 in the training and external validation cohorts, respectively). The clinical-radiomics combined model showed good discrimination (C-indices of 0.941 and 0.833 in the training and external validation cohorts, respectively).

CONCLUSIONS

A radiomics model derived from MDCT images may effectively predict the HGP of CRLMs, thus providing a basis for prognostic stratification and therapeutic decision-making.

Total circulating cell-free DNA as a prognostic biomarker in metastatic colorectal cancer before first-line oxaliplatin-based chemotherapy

BACKGROUND

Metastatic colorectal cancer (mCRC) is a heterogeneous disease where prognosis is dependent both on tumor biology and host factors. Total circulating cell-free DNA (cfDNA) has shown to harbor prognostic information in mCRC, although less is known about the biological correlates of cfDNA levels in this patient group. The primary objective was to evaluate the prognostic value of pretreatment cfDNA in patients receiving the first-line oxaliplatin-based chemotherapy for mCRC, by using a predefined upper limit of normal (ULN) from a cohort of presumed healthy individuals. The secondary objective was to model cfDNA levels as a function of predefined tumor and host factors.

PATIENTS AND METHODS

This was a retrospective post hoc study based on a prospective multicenter phase III trial, the NORDIC-VII study. DNA was purified from 547 plasma samples and cfDNA quantified by a droplet digital PCR assay (B2M, PPIA) with controls for lymphocyte contamination. Main clinical end point was overall survival (OS).

RESULTS

cfDNA was quantified in 493 patients, 54 were excluded mainly due to lymphocyte contamination. Median cfDNA level was 7673 alleles/ml (1050-1 645 000) for B2M and 5959 alleles/ml (555-854 167) for PPIA. High cfDNA levels were associated with impaired outcome; median OS of 16.6 months for levels above ULN and 25.9 months for levels below ULN (hazard ratio = 1.83, 95% confidence interval 1.51-2.21, P < 0.001). The result was confirmed in multivariate OS analysis adjusting for established clinicopathological characteristics. A linear regression model predicted cfDNA levels from sum of longest tumor diameters by RECIST, the presence of liver metastases and systemic inflammatory response as measured by interleukin 6 (F(6, 357) = 62.7, P < 0.001).

CONCLUSION

cfDNA holds promise as a minimally invasive and clinically relevant prognostic biomarker in mCRC before initiating first-line oxaliplatin-based chemotherapy and may be a complex entity associated with tumor burden, liver metastases and systemic inflammatory response.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00145314.

Dietary glycine decreases both tumor volume and vascularization in a combined colorectal liver metastasis and chemotherapy model

Rationale: Chemotherapy (CTx) with FOLFOX is indicated prior to resection of liver metastases; however, its effect is limited due to chemoresistance and its toxicity prevents from aggressive surgery needed in some cases. Hepatoprotective glycine has been shown to have anti-tumorigenic properties in various cancers. Thus, this study was designed to evaluate the effects of glycine combined with FOLFOX on colorectal liver metastases (CRLM).

Methods: The effect of glycine combined with 5-fluorouracil and oxaliplatin was investigated in vitro on colorectal cancer (CC531). Further, Wag/Rij rats with CRLM were treated with 5% dietary glycine ± FOLFOX. µCT liver scan, anti-Ki67, and anti-CD31 were compared.

Results: Glycine alone and combined with CTx has no effect on both CC531 viability in vitro and tumor proliferation in vivo; however, glycine significantly decreased tumor volume to about 42-35% of controls in vivo (p<0.05) with a 60% decreased tumor microvascular density (MVD) (p=0.004). Further glycine doesn't counteract anti-tumor properties of CTx.

Conclusions: This study nicely demonstrates that glycine inhibits the growth of CRLM and does not decrease CTx effectiveness. Underlying mechanisms most likely include a decreased tumor MVD. Clinical trials are warranted to implement non-toxic hepatoprotective glycine in novel anti-cancer strategies in humans.

Dysfunctional Mechanism of Liver Cancer Mediated by Transcription Factor and Non-coding RNA

Background:

There have been numerous experiments and studies on liver cancer by biomedical scientists, while no comprehensive and systematic exploration has yet been conducted. Therefore, this study aimed to systematically dissect the transcriptional and non-coding RNAmediated mechanisms of liver cancer dysfunction.

Method:

At first, we collected 974 liver cancer associated genes from the Online Mendelian Inheritance in Man (OMIM). Afterwards, their interactors were recruited from STRING database so as to identify 18 co-expression modules in liver cancer patient expression profile. Crosstalk analysis showed the interactive relationship between these modules. In addition, core drivers for modules were identified, including 111 transcription factors (STAT3, JUN and NFKB1, etc.) and 1492 ncRNAs (FENDRR and miR-340-5p, etc.).

Results:

In view of the results of enrichment, we found that these core drivers were significantly involved in Notch signaling, Wnt / β-catenin pathways, cell proliferation, apoptosis-related functions and pathways, suggesting they can affect the development of liver cancer. Furthermore, a global effect on bio-network associated with liver cancer has been integrated from the ncRNA and TF pivot network, module crosstalk network, module-function/pathways network. It involves various development and progression of cancer.

Conclusion:

Overall, our analysis further suggests that comprehensive network analysis will help us to not only understand in depth the molecular mechanisms, but also reveal the influence of related gene dysfunctional modules on the occurrence and progression of liver cancer. It provides a valuable reference for the design of liver cancer diagnosis and treatment.