Histopathological growth pattern, proteolysis and angiogenesis in chemonaive patients resected for multiple colorectal liver metastases

Histopathological Growth Patterns Determine the Outcomes of Colorectal Cancer Liver Metastasis Following Liver Resection

INTRODUCTION

Colorectal cancer liver metastasis (CRCLM) remains a lethal diagnosis, with an overall 5-year survival rate of 5-10%. Two distinct histopathological growth patterns (HGPs) of CRCLM are known to have significantly differing rates of patient survival and response to treatment. We set out to review the results of 275 patients who underwent liver resection for CRCLM at the McGill University Health Center (MUHC) and analyze their clinical outcome, mutational burden, and pattern of cancer progression in light of their HGPs, and to consider their potential effect on surgical decision making.

METHODS

We performed a retrospective multivariate analysis on clinical data from patients with CRCLM (n = 275) who underwent liver resection at the McGill University Health Center (MUHC). All tumors were scored using international consensus guidelines by pathologists trained in HGP scoring.

RESULTS

A total of 109 patients (42.2%) were classified as desmoplastic and angiogenic, whereas 149 patients (57.7%) were non-desmoplastic and vessel co-opting. The 5-year survival rates for angiogenic patients compared with vessel co-opting patients were 47.1% and 13%, respectively (p < 0.0001). Multivariate analysis showed patients with vessel co-opting CRCLM had a higher incidence of extrahepatic metastatic disease (p = 0.0215) compared with angiogenic CRCLM. Additionally, KRAS mutation status was a marker of increased likelihood of disease recurrence (p = 0.0434), as was increased number of liver tumors (p = 0.0071) and multiple sites of extrahepatic metastatic disease (p < 0.0001).

CONCLUSIONS

Multivariate analysis identified key clinical prognostic and molecular features correlating with the two HGPs. Determining liver tumor HGPs is essential for patient prognostication and treatment optimization.

Microbiota in colorectal cancer related to liver metastasis

The prevalence of colorectal cancer (CRC) is increasing annually and metastasis is the principal cause of death in patients with CRC, with the liver being the most frequently affected site. Many studies have shown a strong interplay between the gut flora, particularly Fusobacterium nucleatum (F. nucleatum), Escherichia coli, and Bacteroides fragilis, and the development of gut tumors. Some strains can induce gut inflammation and produce toxins that directly harm gut epithelial cells, ultimately accelerating the onset and progression of CRC. However, little clinical evidence exists on the specific interplay between the gut microflora and colorectal cancer liver metastasis (CRLM). Some research showed the existence of viable F. nucleatum in distant metastasis of CRC. Subsequently, gut microbiota products, such as lipopolysaccharides, sodium butyrate, and protein cathepsin K, were also found to affect the development of CRC. This article summarizes the mechanism and research status of the interplay between gut microflora and CRLM, discusses the importance of gut microflora in the treatment of CRLM, and proposes a new approach to understanding the mechanism of CRLM and potential treatments for the microbiome. It is anticipated that the gut microbiota will be a formidable therapeutic and prophylactic tool for treating and preventing CRLM.

The Prognostic Value of Distinct Histological Growth Patterns of Colorectal Peritoneal Metastases: A Pilot Study

BACKGROUND

Different histological growth patterns (HGP) describing the tumor-to-liver interface have been described in colorectal liver metastases and have been associated with a strong prognostic value. However, HGP of peritoneal metastases (PM) of colorectal cancer (CRC) have not yet been described. Our objective was to determine whether distinct HGP can be identified in PMCRC and to evaluate their potential prognostic value in these patients.

METHODS

This retrospective study included 38 patients who underwent curative-intent surgery for PMCRC between July 2012 and March 2019, with PCI≤6, and who had not received preoperative chemotherapy. In each patient, the tumor-to-peritoneum interface was evaluated in the excised peritoneal nodules. The association between HGP and postoperative survival was analyzed by using the Kaplan-Meier method.

RESULTS

Two distinct HGP were identified: a pushing-type (P-HGP), characterized by a fibrous rim separating the PM and peritoneum, and an infiltrating-type (I-HGP), characterized by focal penetration of tumor cells into the surrounding peritoneal lining without a fibrous rim. Fifteen patients had dominant P-HGP, and 23 patients had dominant I-HGP. Patients with dominant P-HGP (>50% tumor-peritoneum interface) had a significantly better DFS (30 months) than those with P-HGP <50% (9 months; p = 0.029). Patients with a P-HGP dominance >60% had better OS (131 months) than those with P-HGP <60% (41 months; p = 0.044).

CONCLUSIONS

This is the first description of two distinct, reproducible HGP in PMCRC. The dominant P-HGP is associated with a favorable prognosis in patients with PMCRC, compared with I-HGP, suggesting that this parameter could ultimately represent a new prognostic biomarker.

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.

Dynamic differentiation of F4/80+ tumor-associated macrophage and its role in tumor vascularization in a syngeneic mouse model of colorectal liver metastasis

Tumor-associated macrophages (TAMs) are highly heterogeneous and play vital roles in tumor progression. Here we adopted a C57BL/6 mouse model imitating the late-stage colorectal liver metastasis (CRLM) by Mc38 colorectal cancer cell injection via the portal vein. With serial sections of CRLM biopsies, we defined 7-9 days post-injection as the critical period for tumor neovascularization, which was initiated from the innate liver vessels via vessel cooption and extended by vascular mimicry and thereof growth of CD34⁺cells. In samples with increasing-sized liver metastases, the infiltrated Ly6C⁺ CD11b⁺ F4/80^- monocytes steadily gained the expression of F4/80, a Kupffer cell marker, before transformed into Ly6C^- CD11b^int F4/80⁺ cells, which, the same phenotype was also adapted by Ly6C^- CD11b^- F4/80⁺ Kupffer cells. F4/80⁺ TAMs showed proximity to neovascularization and tumor vessels, functionally angiogenic in vivo; and greatly promoted the activation of a few key angiogenic markers such as VEGFA, Ki67, etc. in endothelial cells in vitro. Depletion of macrophages or diversion of macrophage polarization during neovascularization impeded tumor growth and vascularization and resulted in greatly reduced F4/80⁺ TAMs, yet increased CD11b⁺ cells due to inhibition of TAM differentiation. In summary, our results showed dynamic and spatial-temporal F4/80⁺ TAM transformation within the tumor microenvironment and strengthened its role as perivascular and angiogenic TAMs in CRLM.

Prognostic implications of histologic growth patterns and tumor-infiltrating macrophages in colorectal liver metastases

PURPOSE

Histopathologic patterns at the invasion fronts of tumors predict metastatic potential and prognosis in several cancers. We examined whether such patterns at the interface between colorectal liver metastases and hepatic parenchyma have similar prognostic value.

METHODS

Microscopic growth patterns at edges of metastases including desmoplasia, pushing borders, and replacement of hepatocytes were retrospectively analyzed with respect to surgical outcomes in 142 patients who underwent hepatectomy for colorectal metastases.

RESULTS

Patterns included desmoplasia in 58 patients (41%), hepatocyte replacement in 41 (29%), and pushing borders in 43 (30%). Maximum metastasis diameter and serum carcinoembryonic antigen concentration in patients showing desmoplastic tumor growth were lower than those in others (P < 0.05 and P < 0.01). Disease-free survival and overall survival were better in patients showing desmoplastic growth, while a non-desmoplastic tumor growth pattern showed a negative influence. More cluster of differentiation (CD) 68-positive M1 macrophages and fewer CD206-positive M2 macrophages were demonstrated at interfaces of tumors with hepatic parenchyma when desmoplasia was present, although markers for proliferative activity (MIB1 index) and metastatic potential (E-cadherin expression) appeared uninfluenced by desmoplasia.

CONCLUSION

Better long-term results were associated with metastatic tumors showing desmoplastic growth patterns at invasion fronts, which may reflect local immune state in a prognostically useful manner.

Type I and II interferon signaling in colorectal cancer liver metastasis

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

The Histopathological Growth Pattern of Colorectal Liver Metastases Impacts Local Recurrence Risk and the Adequate Width of the Surgical Margin

BACKGROUND

The histopathological growth pattern (HGP) of colorectal liver metastases (CLM) has been associated with prognosis. This study was designed to elucidate if the HGP is associated with local recurrence risk and impacts the adequate width of surgical margin.

METHODS

All consecutive patients resected for CLM in 2018-2019 were considered. HGP was prospectively classified as follows: desmoplastic, pushing, and replacement. Surgical margin was classified as follows: R0 (margin ≥ 1 mm), R1vasc (0-mm margin, tumor detachment from intrahepatic vessels), and R1par (tumor exposure along transection plane). R0 resections were further distinguished in R0min (1-mm margin) and R0wide (> 1-mm margin).

RESULTS

A total of 340 resection areas in 136 patients were analyzed (70 R0min, 143 R0wide, 31 R1vasc, 96 R1par). HGP was desmoplastic in 26 cases, pushing in 221, and replacement in 93. Thirty-six local recurrences occurred (11%, median follow-up 21 months): 1 after R0wide, 4 after R0min, 3 after R1vasc, and 28 after R1par resection. In R1par group, local recurrence rate was high independently of HGP (29%). In R1vasc and R0min groups, local recurrence risk was higher in the replacement group (R1vasc: 29% vs. 4% if pushing/desmoplastic; R0min: 11% vs. 4%). In R0wide group, local recurrence risk was low for all HGP ( < 1%). Independent predictors of local recurrence were replacement HGP (odds ratio = 1.654, P = 0.036), and R1par resection (odds ratio = 57.209, P < 0.001 vs. R0).

CONCLUSIONS

Replacement HGP is associated with an increased risk of local recurrence. In these patients, a wide surgical margin should be pursued, because R1vasc and R0min resections could be insufficient. R1par resection is inadequate, independently of the HGP.

Randomized Phase 2 Study Comparing Pathological Responses of Resected Colorectal Cancer Metastases after Bevacizumab with mFOLFOX6 or FOLFIRI (BEV-ONCO Trial)

Retrospective studies reported that preoperative oxaliplatin-based chemotherapy increased pathological response (PR) in patients resected for colorectal liver metastases (CRLM). This multicenter prospective randomized (1/1) phase II trial evaluated PR on resected CRLM after preoperative mFOLFOX6 (arm A) or FOLFIRI (arm B) + bevacizumab. The primary endpoint was the major pathological response rate (MPRR), defined as the percentage of patients presenting CRLMs with mean tumor regression grade (TRG) < 3. Secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). Out of 65 patients, 57 patients (28 and 29 in arm A/B) were resected for CRLM (one patient with lung metastases). Clinical and treatment characteristics were similar in both arms. One-month postoperative complications were 39.3%/31.0% in arm A/B (p = 0.585). MPRR and complete PR were 32.1%/20.7% (p = 0.379) and 14.3%/0.0% (p = 0.052) in arm A/B, respectively. PFS and OS were not different. Patients with PR among all CRLMs (max TRG ≤ 3; 43.8% of patients) had a lower risk of relapse (PFS: HR = 0.41, 95%CI = 0.204−0.840, p = 0.015) and a tendency towards better survival (OS: HR = 0.34, 95%CI = 0.104−1.114, p = 0.075). The homogeneity of PR was associated with improved PFS/OS. This trial fails to demonstrate a significant increase in MPRR in patients treated with mFOLFOX6-bevacizumab but confirms PR as an important prognostic factor.

Is precision medicine for colorectal liver metastases still a utopia? New perspectives by modern biomarkers, radiomics, and artificial intelligence

The management of patients with liver metastases from colorectal cancer is still debated. Several therapeutic options and treatment strategies are available for an extremely heterogeneous clinical scenario. Adequate prediction of patients’ outcomes and of the effectiveness of chemotherapy and loco-regional treatments are crucial to reach a precision medicine approach. This has been an unmet need for a long time, but recent studies have opened new perspectives. New morphological biomarkers have been identified. The dynamic evaluation of the metastases across a time interval, with or without chemotherapy, provided a reliable assessment of the tumor biology. Genetics have been explored and, thanks to their strong association with prognosis, have the potential to drive treatment planning. The liver-tumor interface has been identified as one of the main determinants of tumor progression, and its components, in particular the immune infiltrate, are the focus of major research. Image mining and analyses provided new insights on tumor biology and are expected to have a relevant impact on clinical practice. Artificial intelligence is a further step forward. The present paper depicts the evolution of clinical decision-making for patients affected by colorectal liver metastases, facing modern biomarkers and innovative opportunities that will characterize the evolution of clinical research and practice in the next few years.

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.

The Colorectal Cancer Tumor Microenvironment and Its Impact on Liver and Lung Metastasis

Simple Summary

Colorectal cancer (CRC) is the third most common cancer worldwide. Metastasis to secondary organs, such as the liver and lungs, is a key driver of CRC-related mortality. The tumor microenvironment, which consists of the primary cancer cells, as well as associated support and immune cells, significantly affects the behavior of CRC cells at the primary tumor site, as well as in metastatic lesions. In this paper, we review the role of the individual components of the tumor microenvironment on tumor progression, immune evasion, and metastasis, and we discuss the implications of these components on antitumor therapies.

Abstract

Colorectal cancer (CRC) is the third most common malignancy and the second most common cause of cancer-related mortality worldwide. A total of 20% of CRC patients present with distant metastases, most frequently to the liver and lung. In the primary tumor, as well as at each metastatic site, the cellular components of the tumor microenvironment (TME) contribute to tumor engraftment and metastasis. These include immune cells (macrophages, neutrophils, T lymphocytes, and dendritic cells) and stromal cells (cancer-associated fibroblasts and endothelial cells). In this review, we highlight how the TME influences tumor progression and invasion at the primary site and its function in fostering metastatic niches in the liver and lungs. We also discuss emerging clinical strategies to target the CRC TME.

Infiltrative tumour growth pattern correlates with poor outcome in oesophageal cancer

Objective

Oesophageal cancer (OEC) is an aggressive disease with a poor survival rate. Prognostic markers are thus urgently needed. Due to the demonstrated prognostic value of histopathological growth pattern (HGP) in other cancers, we performed a retrospective assessment of HGP in patients suffering from invasive OEC.

Design

A first cohort composed of 89 treatment-naïve operated patients with OEC from The Cancer Genome Atlas (TCGA) public database was constituted, from which H&E images and RNA-sequencing data were retrieved. Next, a second cohort composed of 99 patients with OEC treated and operated in a Belgian hospital was established. H&E-stained sections and extracted tumorous RNA were obtained from the samples. HGP were assessed on H&E slides as infiltrative (IGP) or expansive (EGP). TCGA RNA-sequencing data were analysed through the gene set enrichment analysis and Cytoscape softwares. Real-time quantitative PCR (qPCR) experiments were performed to assess gene expression in the Belgian cohort.

Results

IGP patients displayed a grim prognosis compared with EGP patients, while IGP was found as associated with numerous lymphovascular emboli and perinervous infiltrations. Analyses of the TCGA expression data showed that angiogenesis, epithelial-to-mesenchymal transition (EMT) and inflammation were significantly upregulated in IGP compared with EGP samples. qPCR experiments of three genes appearing as highly upregulated in each pathway showed no difference in expression according to the HGP.

Conclusion

The current study demonstrates the poor prognostic value carried by IGP in OC and suggests angiogenesis, EMT and inflammation as key carcinogenetic pathways upregulated in this pattern.

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.

Clinico-metabolic characterization improves the prognostic value of histological growth patterns in patients undergoing surgery for colorectal liver metastases

BACKGROUND AND OBJECTIVES

The histological growth pattern (HGP) represents a strong prognostic factor in patients undergoing surgery for colorectal liver metastases (CRLM). We evaluated whether the combination of HGP with clinico-metabolic parameters could improve its prognostic value.

METHODS

In a series of 108 patients undergoing resection of CRLM, the HGP of CRLM was scored according to international guidelines. Baseline clinico-metabolic clinical status was evaluated using a metabolic-Clinical Risk Score (mCRS), combining traditional Memorial Sloan Kettering-CRS parameters with the tumor-to-liver glucose uptake ratio as measured with 18 Fluorodeoxyglucose/positron emission tomography.

RESULTS

In patients with desmoplastic HGP (DHGP) CRLM (20% of all patients), 5- and 10-years overall survival (OS) and disease free survival (DFS) were 66% and 43% and 37% and 24.5%, as compared with 35% and 21% and 11% and 11% in the non-DHGP group (p = 0.07 and 0.054). Among DHGP patients, those with a low-risk mCRS had improved postoperative outcomes, 5- and 10-years OS and DFS reaching 83.3% and 62.5% and 50% and 33%, as compared with 18% and 0% and 0% and 0% in high-risk mCRS patients (p = 0.007 and 0.003). In contrast, mCRS did not influence postoperative survivals in non-DHGP patients.

CONCLUSIONS

Combining the clinico-metabolic characteristics with the HGP may improve prognostication in patients undergoing surgery for CRLM.

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.

Histopathological Growth Patterns and Survival After Resection of Colorectal Liver Metastasis: An External Validation Study

Background

After resection of colorectal cancer liver metastases (CRLM), 2 main histopathological growth patterns can be observed: a desmoplastic and a nondesmoplastic subtype. The desmoplastic subtype has been associated with superior survival. These findings require external validation.

Methods

An international multicenter retrospective cohort study was conducted in patients treated surgically for CRLM at 3 tertiary hospitals in the United States and the Netherlands. Determination of histopathological growth patterns was performed on hematoxylin and eosin-stained sections of resected CRLM according to international guidelines. Patients displaying a desmoplastic histopathological phenotype (only desmoplastic growth observed) were compared with patients with a nondesmoplastic phenotype (any nondesmoplastic growth observed). Cutoff analyses on the extent of nondesmoplastic growth were performed. Overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier and multivariable Cox analysis. All statistical tests were 2-sided.

Results

In total 780 patients were eligible. A desmoplastic phenotype was observed in 19.1% and was associated with microsatellite instability (14.6% vs 3.6%, P = .01). Desmoplastic patients had superior 5-year OS (73.4%, 95% confidence interval [CI] = 64.1% to 84.0% vs 44.2%, 95% CI = 38.9% to 50.2%, P < .001) and DFS (32.0%, 95% CI = 22.9% to 44.7% vs 14.7%, 95% CI = 11.7% to 18.6%, P < .001) compared with their nondesmoplastic counterparts. A desmoplastic phenotype was associated with an adjusted hazard ratio for death of 0.36 (95% CI = 0.23 to 0.58) and 0.50 (95% CI = 0.37 to 0.66) for cancer recurrence. Prognosis was independent of KRAS and BRAF status. The cutoff analyses found no prognostic relationship between either OS or DFS and the extent of nondesmoplastic growth observed (all P > .1).

Conclusions

This external validation study confirms the remarkably good prognosis after surgery for CRLM in patients with a desmoplastic phenotype. The extent of nondesmoplastic growth does not affect prognosis.

Prognostic assessment of resected colorectal liver metastases integrating pathological features, RAS mutation and Immunoscore

Surgical resection of colorectal liver metastases combined with systemic treatment aims to maximize patient survival. However, recurrence rates are very high postsurgery. In order to assess patient prognosis after metastasis resection, we evaluated the main patho-molecular and immune parameters of all surgical specimens. Two hundred twenty-one patients who underwent, after different preoperative treatment, curative resection of 582 metastases were analyzed. Clinicopathological parameters, RAS tumor mutation, and the consensus Immunoscore (I) were assessed for all patients. Overall survival (OS) and time to relapse (TTR) were estimated using the Kaplan-Meier method and compared by log-rank tests. Cox proportional hazard models were used for uni- and multivariate analysis. Immunoscore and clinicopathological parameters (number of metastases, surgical margin, histopathological growth pattern, and steatohepatitis) were associated with relapse in multivariate analysis. Overall, pathological score (PS) that combines relevant clinicopathological factors for relapse, and I, were prognostic for TTR (2-year TTR rate PS 0-1: 49.8.% (95% CI: 42.2-58.8) versus PS 2-4: 20.9% (95% CI: 13.4-32.8), hazard ratio (HR) = 2.54 (95% CI: 1.82-3.53), p < 0.0000; and 2-year TTR rate I 0: 25.7% (95% CI: 16.3-40.5) versus I 3-4: 60% (95% CI: 47.2-76.3), HR = 2.87 (95% CI: 1.73-4.75), p = 0.0000). Immunoscore was also prognostic for OS (HR [I 3-4 versus I 0] = 4.25, 95% CI: 1.95-9.23; p = 0.0001). Immunoscore (HR [I 3-4 versus I 0] = 0.27, 95% CI: 0.12-0.58; p = 0.0009) and RAS mutation (HR [mutated versus WT] = 1.66, 95% CI: 1.06-2.58; p = 0.0265) were significant for OS. In conclusion, PS including relevant clinicopathological parameters and Immunoscore permit stratification of stage IV colorectal cancer patient prognosis in terms of TTR and identify patients with higher risk of recurrence. Immunoscore remains the major prognostic factor for OS.

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 radiomicstumor and radiomicsTLI models showed better performance than any single sequence and clinical model. In addition, the radiomicsTLI model exhibited better performance than radiomicstumor 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.

Morphological Characteristics and Clinical Significance of Different Types of Tumor Vessels in Patients with Stages I-IIA of Squamous Cervical Cancer

The determination of factors associated with progression of cervical cancer is important, both for a recurrence risk assessment and for determining optimal treatment tactics. Previously, we showed the prognostic value of different types of tumor microvessels (MVs) in gastric and breast cancer. The object of this research was to study the morphology and clinical significance of different tumor microvessels in early cervical cancer. A total of 65 archived paraffin blocks of patients with I-IIA stages of squamous cervical cancer were investigated. Samples were stained with Mayer hematoxylin and immunohistochemically using antibodies to CD34, podoplanin, HIF-1a, and Snail. The eight types of tumor MVs differed in morphology were identified. It was established that only the dilated capillaries (DСs) with weak expression of CD34, the contact type DCs, the capillaries in tumor solid component, and the lymphatic vessels in the lymphoid and polymorphic cell infiltrates of tumor stroma are associated with clinical and pathological characteristics of early cervical cancer. Preliminary results also suggest that a combination of fragmentation in tumor solid component and the contact type DCs may predict a recurrence of early cervical cancer. Given the small number of cervical cancer recurrences, the predictive significance of the described markers requires a more thorough examination.

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.

Enrichment of the tumour immune microenvironment in patients with desmoplastic colorectal liver metastasis

BACKGROUND

Patients with resected colorectal liver metastasis (CRLM) who display only the desmoplastic histopathological growth pattern (dHGP) exhibit superior survival compared to patients with any non-desmoplastic growth (non-dHGP). The aim of this study was to compare the tumour microenvironment between dHGP and non-dHGP.

METHODS

The tumour microenvironment was investigated in three cohorts of chemo-naive patients surgically treated for CRLM. In cohort A semi-quantitative immunohistochemistry was performed, in cohort B intratumoural and peritumoural T cells were counted using immunohistochemistry and digital image analysis, and in cohort C the relative proportions of individual T cell subsets were determined by flow cytometry.

RESULTS

One hundred and seventeen, 34, and 79 patients were included in cohorts A, B, and C, with dHGP being observed in 27%, 29%, and 15% of patients, respectively. Cohorts A and B independently demonstrated peritumoural and intratumoural enrichment of cytotoxic CD8+ T cells in dHGP, as well as a higher CD8+/CD4+ ratio (cohort A). Flow cytometric analysis of fresh tumour tissues in cohort C confirmed these results; dHGP was associated with higher CD8+ and lower CD4+ T cell subsets, resulting in a higher CD8+/CD4+ ratio.

CONCLUSION

The tumour microenvironment of patients with dHGP is characterised by an increased and distinctly cytotoxic immune infiltrate, providing a potential explanation for their superior survival.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

The "histological replacement growth pattern" represents aggressive invasive behavior in liver metastasis from pancreatic cancer

Background

In the case of liver metastasis (LM), tumors showing the replacement growth pattern (RGP), in which metastatic cells infiltrate and replace hepatocytes with minimal desmoplastic reaction and inflammatory cell infiltration, associate with a poor prognosis. The heterogeneity, frequency, and prognostic value of the RGP in LM from pancreatic cancer (PCa) are not well known.

Methods

In the circumference of treatment‐naïve resected LMs from patients with PCa, the heterogeneity of the GP was assessed. Next, the clinicopathological features of LMs showing the RGP in needle biopsy specimens were investigated in patients with treatment‐naïve advanced PCa.

Results

Thirteen of the 14 (93%) in all resected LMs and 7 of the 9 (78%) in RGP component GP in resected LMs showed homogeneous GP. A RGP was found in 50% of the needle biopsy specimens of LMs obtained from 107 patients. The median overall survival times in the RGP group and non‐RGP group were 3.6 and 10.4 months. Multivariate analysis identified RGP as an independent poor prognostic factor. Median value of CD8 positive percentage in RGP was lower than that in non‐RGP (0.75 vs 1.46, P = .04). Median overall survival times in low CD8 groups tend to be shorter than those in high CD8 group (8.2 vs 4.2 months).

Conclusion

Most LMs from PCa show a homogeneous GP. The RGP was observed in about a half of the LMs from PCa patients, and was identified as a poor prognostic factor.

Immunoscore and its introduction in clinical practice

Current cancer classification is based on intrinsic tumor parameters such as characteristic of tumor cells, tumor progression, tumor invasion and the presence of distant metastases, as summarized by the AJCC/UICC-TNM stratification system. There is currently no immune-based classification of cancer. We provided evidence that the immune contexture, as defined by the type, density, functional immune orientation and the location of immune cells within tumor, strongly influences the outcome of colorectal cancer (CRC) patients. To translate this information to the clinic, we developed an immunohistochemistry and digital pathology-based assay named Immunoscore that allows the quantification of two T cell subsets (CD3 and CD8) in two tumor regions (core and invasive margin of tumors). We have demonstrated that the standardized consensus Immunoscore has a prognostic value superior and independent to the one of the traditional TNM system in an international study in stage I-III colon cancer patients, therefore validating the Immunoscore as the first immune-based scoring system. In additional analyses, we showed the prognostic value of Immunoscore for stage II-IV CRC patients, as well as the predictive value of Immunoscore in stage III colon cancer patients. The Immunoscore may help predict and stratify patients who will benefit from adjuvant chemotherapy. Moreover, the Immunoscore allows the classification of tumors from hot to cold categories, and could consequently guide clinical decision for the choice of treatment.

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.

Histologic features and genomic alterations of primary colorectal adenocarcinoma predict growth patterns of liver metastasis

BACKGROUND

Different histological growth patterns (HGPs) of colorectal carcinoma (CRC) liver metastasis are associated with patients' prognosis and response to antiangiogenic therapy. However, the relationship between HGPs of liver metastasis and clinicopathological and genomic characteristics of primary cancer has not been well established.

AIM

To assess whether certain clinicopathological and genomic features of primary CRC could predict the HGPs of liver metastasis.

METHODS

A total of 29 patients with paired resections of both primary CRC and liver metastasis were divided into two groups: A (15 cases with desmoplastic liver metastasis) and B (14 cases with replacement liver metastasis). Clinical information was obtained from patients' charts. Mismatch repair proteins, BRAFV600E, and PD-L1 were evaluated by immunohistochemistry. Five cases were selected randomly from each group for whole exome sequencing (WES) analysis.

RESULTS

In the primary tumor, expanding growth pattern, low tumor budding score (TBS), and Crohn's disease-like response (CDR) were associated with desmoplastic liver metastasis and better overall survival, whereas infiltrating growth pattern alone of primary carcinoma could predict the replacement liver metastasis and worse overall survival (P < 0.05). On WES analysis, primary carcinoma with desmoplastic liver metastasis showed mutations in APC (4/5); TP53 (3/5); KRAS, PIK3CA, and FAT4 (2/5); BRCA-1, BRCA2, BRAF, and DNAH5 (1/5), whereas primary carcinoma with replacement liver metastasis showed mutations in APC and TP53 (3/5); KRAS, FAT4, DNH5, SMAD, ERBB2, ERBB3, LRP1, and SDK1 (1/5).

CONCLUSION

The HGPs, TBS, and CDR of primary CRC as well as the presence of specific genetic mutations such as those in PIK3CA could be used to predict the HGPs of liver metastasis, response to therapy, and patients' prognosis.

Histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy

Colorectal liver metastases (CRLM) exhibit distinct histopathological growth patterns (HGPs) that are indicative of prognosis following surgical treatment. This study aims to assess the reliability and replicability of this histological biomarker. Within and between metastasis HGP concordance was analysed in patients who underwent surgery for CRLM. An independent cohort was used for external validation. Within metastasis concordance was assessed in CRLM with ≥ 2 tissue blocks. Similarly, concordance amongst multiple metastases was determined in patients with ≥ 2 resected CRLM. Diagnostic accuracy [expressed in area under the curve (AUC)] was compared by number of blocks and number of metastases scored. Interobserver agreement (Cohen’s k) compared to the gold standard was determined for a pathologist and a PhD candidate without experience in HGP assessment after one and two training sessions. Both the within (95%, n = 825) and the between metastasis (90%, n = 363) HGP concordance was high. These results could be replicated in the external validation cohort with a within and between metastasis concordance of 97% and 94%, respectively. Diagnostic accuracy improved when scoring 2 versus 1 blocks(s) or CRLM (AUC = 95.9 vs. 97.7 [p = 0.039] and AUC = 96.5 vs. 93.3 [p = 0.026], respectively), but not when scoring 3 versus 2 blocks or CRLM (both p > 0.2). After two training sessions the interobserver agreement for both the pathologist and the PhD candidate were excellent (k = 0.953 and k = 0.951, respectively). The histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy, making them a reliable and replicable histological biomarker.

Liver Metastases and Histological Growth Patterns: Biological Behavior and Potential Clinical Implications-Another Path to Individualized Medicine?

Colorectal cancer is a major health burden and despite the recent advances in healthcare and screening programs, a great percentage of patients already present metastases once their disease is found. In those cases, liver surgery has an essential role, but even with neoadjuvant chemotherapy there is a high rate of intrahepatic recurrence. New prognostic factors are needed in order to decide the best surgical approach considering the biological behavior of the tumors in order to tailor the used therapies, moving towards individualized medicine/treatment. However, the majority of the factors described in literature are expensive, time consuming, and difficult to apply on a daily basis. Histological growth patterns have emerged over the past few years as a reproducible characteristic, an easy to apply one, and with very low costs since it only needs the standard Haematoxylin and Eosin stained slides of observation. In this article, we provide a review of the histological growth patterns of liver metastases and their prognostic significance, biological meaning, and therapeutic importance.

Growth patterns of colorectal cancer liver metastases and their impact on prognosis: a systematic review

Background

Colorectal cancer liver metastases (CRLM) grow in distinct histological patterns that have been associated with outcome after surgical resection. We conducted a systematic review to evaluate the frequency of different CRLM growth patterns and their impact on prognosis.

Methods

We searched Embase and MEDLINE databases from inception to 1 December 2017 to identify studies that reported CRLM growth pattern histopathology, their frequencies, and/or data related to outcome.

Results

We included a total of 23 studies (2432 patients with CRLM) published between 1991 and 2017. There were variations in the terminology used to describe the growth patterns as well as in their histopathological definitions. A 'desmoplastic' pattern was most frequently considered, followed by 'pushing' and 'replacement' patterns. Data supported the presence of both intralesional and interlesional heterogeneity. There were no differences in growth pattern distribution stratified by chemotherapy. While heterogeneity of histopathology assessment precluded formal meta-analysis, the majority of articles found favourable outcomes for desmoplastic and unfavourable outcomes for replacement CRLM, independently of when the study was conducted.

Conclusions

The results suggest that CRLM growth patterns may have prognostic potential and that they may be considered for standardised routine histopathological reporting. Further understanding of the different growth patterns may provide important insights into the biological mechanisms that underlie metastatic growth in the liver.

Non-angiogenic tumours and their influence on cancer biology

Solid tumours need a blood supply, and a large body of evidence has previously suggested that they can grow only if they induce the development of new blood vessels, a process known as tumour angiogenesis. On the basis of this hypothesis, it was proposed that anti-angiogenic drugs should be able to suppress the growth of all solid tumours. However, clinical experience with anti-angiogenic agents has shown that this is not always the case. Reports of tumours growing without the formation of new vessels can be found in the literature dating back to the 1800s, yet no formal recognition, description and demonstration of their special biological status was made until recently. In 1996, we formally recognized and described non-angiogenic tumours in lungs where the only blood vessels present were those originating from normal lung tissue. This is far from an isolated scenario, as non-angiogenic tumour growth has now been observed in tumours of many different organs in both humans and preclinical animal models. In this Opinion article, we summarize how these tumours were discovered and discuss what we know so far about their biology and the potential implications of this knowledge for cancer treatment.

Collagen IV-conveyed signals can regulate chemokine production and promote liver metastasis

Liver metastases remain a major cause of death from gastrointestinal tract cancers as well as from other malignancies such as breast and lung carcinomas and melanoma. Understanding the underlying biology is essential for the design of effective targeted therapies. We previously reported that collagen IV α1/α2 overexpression in non-metastatic lung carcinoma (M27^colIV) cells increased their metastatic ability, specifically to the liver and documented high collagen IV levels in surgical resections of liver metastases from diverse tumor types. Here, we aimed to elucidate the functional relevance of collagen IV to metastatic outgrowth in the liver. Gene expression profiling revealed in M27^colIVcells significant increases in the expression of chemokines CCL5 (5.7-fold) and CCL7 (2.6-fold) relative to wild-type cells, and this was validated by qPCR and western blotting. Similarly, in human colon carcinoma KM12C and KM12SM cells with divergent liver-colonizing potentials, CCL7 and CCL5 production correlated with type IV collagen expression and the metastatic phenotype. CCL7 silencing by short hairpin RNA (shRNA) reduced experimental liver metastasis in both cell types, whereas CCL5 silencing reduced metastasis of M27^colIV cells, implicating these cytokines in metastatic expansion in the liver. Subsequent functional analyses implicated both MEK/ERK and PI3K signaling upstream of CCL7 upregulation and identified CCL7 (but not CCL5) as a critical migration/invasion factor, acting via the chemokine receptor CCR3. Chemokine CCL5 was identified as a regulator of the T-cell immune response in the liver. Loss of CCL7 in KM12SM cells was also associated with altered E-cadherin and reduced vimentin and Snail expression, implicating it in epithelial-to-mesenchymal transition in these cells. Moreover, in clinical specimens of colon cancer liver metastases analyzed by immunohistochemistry, CCL5 and CCL7 levels paralleled those of collagen IV. The results identify the chemokines CCL5 and CCL7 as type IV collagen-regulated genes that promote liver metastasis by distinct and complementary mechanisms.

Prognostic Utility of Histological Growth Patterns of Colorectal Lung Oligometastasis

Background

Patients with resectable colorectal lung oligometastasis (CLOM) demonstrate a heterogeneous oncological outcome. However, the parameters for predicting tumor aggressiveness have not yet been fully investigated in CLOM. This study was performed to determine the prognostic value of histological growth patterns in patients who underwent surgery for CLOM.

Methods

The study included 92 patients who were diagnosed with CLOM among the first resection cases. CLOMs grow according to three histological patterns: aerogenous, pushing, and desmoplastic patterns. The growth patterns were evaluated on archival hematoxylin and eosin–stained tissue sections.

Results

The aerogenous pattern was found in 29.4% (n=27) of patients, the pushing pattern in 34.7% (n=32), the desmoplastic pattern in 6.5% (n=6), and a mix of two growth patterns in 29.4% (n=27). The size of the aerogenous pattern was significantly smaller than that of metastases with other patterns (p=.033). Kaplan-Meier analysis demonstrated that patients showing an aerogenous pattern appeared to have a poorer prognosis, which was calculated from the time of diagnosis of the CLOM (p=.044). The 5-year survival rate from the diagnosis of colorectal cancer tended to be lower in patients with an aerogenous pattern than in those who had a non-aerogenous pattern; however, the difference was marginally significant (p=.051). In the multivariate Cox analysis, the aerogenous pattern appeared as an independent predictor of poor overall survival (hazard ratio, 3.122; 95% confidence interval, 1.196 to 8.145; p=.020).

Conclusions

These results suggest that the growth patterns may play a part as a histology-based prognostic parameter for patients with CLOM.

International consensus guidelines for scoring the histopathological growth patterns of liver metastasis

BACKGROUND

Liver metastases present with distinct histopathological growth patterns (HGPs), including the desmoplastic, pushing and replacement HGPs and two rarer HGPs. The HGPs are defined owing to the distinct interface between the cancer cells and the adjacent normal liver parenchyma that is present in each pattern and can be scored from standard haematoxylin-and-eosin-stained (H&E) tissue sections. The current study provides consensus guidelines for scoring these HGPs.

METHODS

Guidelines for defining the HGPs were established by a large international team. To assess the validity of these guidelines, 12 independent observers scored a set of 159 liver metastases and interobserver variability was measured. In an independent cohort of 374 patients with colorectal liver metastases (CRCLM), the impact of HGPs on overall survival after hepatectomy was determined.

RESULTS

Good-to-excellent correlations (intraclass correlation coefficient >0.5) with the gold standard were obtained for the assessment of the replacement HGP and desmoplastic HGP. Overall survival was significantly superior in the desmoplastic HGP subgroup compared with the replacement or pushing HGP subgroup (P=0.006).

CONCLUSIONS

The current guidelines allow for reproducible determination of liver metastasis HGPs. As HGPs impact overall survival after surgery for CRCLM, they may serve as a novel biomarker for individualised therapies.

Molecular Pathways: Targeting the Microenvironment of Liver Metastases

Curative treatment for metastatic solid cancers remains elusive. The liver, which is nourished by a rich blood supply from both the arterial and portal venous systems, is the most common site of visceral metastases, particularly from cancers arising in the gastrointestinal tract, with colorectal cancer being the predominant primary site in Western countries. A mounting body of evidence suggests that the liver microenvironment (LME) provides autocrine and paracrine signals originating from both parenchymal and nonparenchymal cells that collectively create both pre- and prometastatic niches for the development of hepatic metastases. These resident cells and their molecular mediators represent potential therapeutic targets for the prevention and/or treatment of liver metastases (LM). This review summarizes: (i) the current therapeutic options for treating LM, with a particular focus on colorectal cancer LM; (ii) the role of the LME in LM at each of its phases; (iii) potential targets in the LME identified through preclinical and clinical investigations; and (iv) potential therapeutic approaches for targeting elements of the LME before and/or after the onset of LM as the basis for future clinical trials. Clin Cancer Res; 23(21); 6390-9. ©2017 AACR.

Metastatic ocular melanoma to the liver exhibits infiltrative and nodular growth patterns

We examined liver specimens from 15 patients with uveal melanoma (UM) who had died of their disseminated disease. We found 2 distinct growth patterns of UM metastasis: infiltrative (n = 12) and nodular (n = 3). In the infiltrative pattern, individual UM cells with a CD133+ cancer stem cell-like phenotype were present and formed aggregates of stage I <50-μm-diameter micrometastases in the sinusoidal spaces. These micrometastases appeared to expand, destroy adjacent hepatocytes, and form stage II 51- to 500-μm-diameter and then stage III >500μm-diameter metastases, which were encapsulated by collagenized fibrous septae. In the nodular growth pattern, CD133+ melanoma cells aggregated adjacent to portal venules and subsequently appeared to grow and efface the adjacent hepatocytes to form stage II 51- to 500-μm-diameter nodules that surrounded the portal venule. These avascular nodules appeared to further expand to form stage III >500-μm-diameter nodules that exhibited vascularization with minimal fibrosis. The tumor stem cell-like phenotype seen in individual UM cells was lost as the tumors progressed. There were CD56+ natural killer cells in sinusoidal spaces and CD3+ lymphocytes in periportal areas. The nodular growth pattern showed UM cells expressing MMP9 and VEGF. UM cells in both above-described growth patterns exhibited variable BAP1 expression. We propose that changes in the liver microenvironment are related to metastatic UM growth. We hypothesize that these changes include immune regulation within the sinusoidal space for the infiltrative pattern and changes in the VEGF/PEDF ratio for the nodular pattern.

Reduction of Nodular Growth Pattern of Metastatic Uveal Melanoma after Radioembolization of Hepatic Metastases

AIM

The aim of this study was to report a case of metastatic uveal melanoma in which radioembolized nodular liver metastases decreased in size while infiltrative sinusoidal metastases progressed, leading to jaundice without obstruction of the biliary ducts.

METHODS

The relevant clinical features, imaging, and histopathologic findings of this case are reviewed.

RESULTS

A 61-year-old Caucasian male with a history of uveal melanoma of the left eye status post plaque brachytherapy developed numerous liver metastases. After progression on systemic therapies, he underwent palliative radioembolization. Despite some radiographic improvement in the liver metastases, he developed hyperbilirubinemia without biliary tract obstruction or signs of liver failure. A biopsy of radiographically normal liver demonstrated extensive sinusoidal infiltration with melanoma.

CONCLUSIONS

Distinct angiographic and histopathologic growth patterns of metastatic uveal melanoma differ in their amenability to radioembolization. Sinusoidal infiltration may lead to hyperbilirubinemia in the absence of overt obstruction or liver failure.

Microvessel density and endothelial cell proliferation levels in colorectal liver metastases from patients given neo-adjuvant cytotoxic chemotherapy and bevacizumab

The treatment of patients with colorectal liver metastasis has improved significantly and first line therapy is often combined chemotherapy and bevacizumab, although it is unknown who responds to this regimen. Colorectal liver metastases grow in different histological growth patterns showing differences in angiogenesis. To identify possible response markers, histological markers of angiogenesis were assessed. Patients who underwent resection of colorectal liver metastasis at Rigshospitalet, Copenhagen, Denmark from 2007 to 2011 were included (n = 254) including untreated and patients treated with chemotherapy or chemotherapy plus bevacizumab. The resected liver metastases were characterised with respect to growth pattern, endothelial and tumour cell proliferation as well as microvessel density and tumour regression. Tumour regression grade of liver metastases differed significantly between untreated/chemotherapy treated patients in comparison to chemotherapy plus bevacizumab treated patients (both p < 0.0001). Microvessel density was decreased in liver metastases from patients treated with bevacizumab in comparison to those from untreated/chemotherapy-treated patients (p = 0.006/p = 0.002). Tumour cell proliferation assessed by Ki67 expression correlated to a shorter recurrence free survival in the total patient cohort. In conclusion, liver metastases from patients treated with neo-adjuvant chemotherapy and bevacizumab had significantly lower microvessel densities and tumour regression grades when compared to liver metastases from untreated or chemotherapy treated patients. This may indicate that bevacizumab treatment results in altered vascular biology and tumour viability, with possible tumour reducing effect.

Inflammation and uPAR-Expression in Colorectal Liver Metastases in Relation to Growth Pattern and Neo-adjuvant Therapy

Proteolytic activity and inflammation in the tumour microenvironment affects cancer progression. In colorectal cancer (CRC) liver metastases it has been observed that three different immune profiles are present, as well as proteolytic activity, determined by the expression of urokinase-type plasminogen activator (uPAR).The main objectives of this study were to investigate uPAR expression and the density of macrophages (CD68) and T cells (CD3) as markers of inflammation in resected CRC liver metastases, where patients were neo-adjuvantly treated with chemotherapy with or without the angiogenesis inhibitor bevacizumab. Chemonaive patients served as a control group. The markers were correlated to growth patterns (GP) of liver metastases, i.e. desmoplastic, pushing and replacement GP. It was hypothesised that differences in proteolysis and inflammation could reflect tumour specific growth and therapy related changes in the tumour microenvironment. In chemonaive patients, a significantly higher level of uPAR was observed in desmoplastic liver metastases in comparison to pushing GP (p = 0.01) or replacement GP (p = 0.03). A significantly higher density of CD68 was observed in liver metastases with replacement GP in comparison to those with pushing GP (p = 0.01). In liver metastases from chemo treated patients, CD68 density was significantly higher in desmoplastic GP in comparison to pushing GP (p = 0.03). In chemo and bevacizumab treated patients only a significant lower CD3 expression was observed in liver metastases with a mixed GP than in those with desmoplastic (p = 0.01) or pushing GP (p = 0.05). Expression of uPAR and the density of macrophages at the tumour margin of liver metastasis differ between GP in the untreated patients. A higher density of T cells was observed in the bevacizumab treated patients, when desmoplastic and pushing metastases were compared to liver metastases with a mix of the GP respectively, however no specific correlations between the immune markers of macrophages and T cells or GP of liver metastases could be demonstrated.

Growth pattern of colorectal liver metastasis as a marker of recurrence risk

Despite improved therapy of advanced colorectal cancer, the median overall survival (OS) is still low. A surgical removal has significantly improved survival, if lesions are entirely removed. The purpose of this retrospective explorative study was to evaluate the prognostic value of histological growth patterns (GP) in chemonaive and patients receiving neo-adjuvant therapy. Two-hundred-fifty-four patients who underwent liver resection of colorectal liver metastases between 2007 and 2011 were included in the study. Clinicopathological data and information on neo-adjuvant treatment were retrieved from patient and pathology records. Histological GP were evaluated and related to recurrence free and OS. Kaplan-Meier curves, log-rank test and Cox regression analysis were used. The 5-year OS was 41.8% (95% CI 33.8-49.8%). Growth pattern evaluation of the largest liver metastasis was possible in 224 cases, with the following distribution: desmoplastic 63 patients (28.1%); pushing 77 patients (34.4%); replacement 28 patients (12.5%); mixed 56 patients (25.0%). The Kaplan-Meier analyses demonstrated that patients resected for liver metastases with desmoplastic growth pattern had a longer recurrence free survival (RFS) than patients resected for non-desmoplastic liver metastases (p=0.05). When patients were stratified according to neo-adjuvant treatment in the multivariate Cox regression model, hazard ratios for RFS compared to desmoplastic were: pushing (HR=1.37, 95% CI 0.93-2.02, p=0.116), replacement (HR=2.16, 95% CI 1.29-3.62, p=0.003) and mixed (HR=1.70, 95% CI 1.12-2.59, p=0.013). This was true for chemonaive patients as well as for patients who received neo-adjuvant treatment.

Tissue inhibitor of matrix metalloproteinase-1 expression in colorectal cancer liver metastases is associated with vascular structures

Metastatic growth by colorectal cancer cells in the liver requires the ability of the cancer cells to interact with the new microenvironment. This interaction results in three histological growth patterns of liver metastases: desmoplastic, pushing, and replacement. In primary colorectal cancer several proteases, involved in the degradation of extracellular matrix components, are up‐regulated. In liver metastases, their expression is growth pattern dependent. Tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) is a strong prognostic marker in plasma from colorectal cancer patients, with significant higher levels in patients with metastatic disease. We therefore wanted to determine the expression pattern of TIMP‐1 in primary colorectal cancers and their matching liver metastases. TIMP‐1 mRNA was primarily seen in α‐smooth‐muscle actin (α‐SMA)‐positive cells. In all primary tumors and liver metastases with desmoplastic growth pattern, TIMP‐1 mRNA was primarily found in α‐SMA‐positive myofibroblasts located at the invasive front. Some α‐SMA‐positive cells with TIMP‐1 mRNA were located adjacent to CD34‐positive endothelial cells, identifying them as pericytes. This indicates that TIMP‐1 in primary tumors and liver metastases with desmoplastic growth pattern has dual functions; being an MMP‐inhibitor at the cancer periphery and involved in tumor‐induced angiogenesis in the pericytes. In the liver metastases with pushing or replacement growth patterns, TIMP‐1 was primarily expressed by activated hepatic stellate cells at the metastasis/liver parenchyma interface. These cells were located adjacent to CD34‐positive endothelial cells, suggesting a function in tumor‐induced angiogenesis. We therefore conclude that TIMP‐1 expression is growth pattern dependent in colorectal cancer liver metastases. © 2015 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.

The morphological growth patterns of colorectal liver metastases are prognostic for overall survival

Colorectal metastases in the liver grow according to three histological patterns: a pushing pattern, a replacement pattern, and a desmoplastic pattern. The objective of the current study was to explore the prognostic significance of these three growth patterns for survival. The study included 217 consecutive patients, liver resected between 2007 and 2011 due to hepatic metastases from colorectal adenocarcinoma. The growth patterns were assessed on archival hematoxylin and eosin-stained tissue sections. In 150 metastases, the density of the immune cell infiltrate at the tumor periphery was judged by a semi-quantitative method. The prevalence of the pushing-type, the desmoplastic-type, and the replacement-type was 33%, 32%, and 11%, respectively; 24% of the metastases displayed a mixed pattern. Kaplan-Meier analysis and Cox regression demonstrated a prognostic significance of the growth patterns (P=0.0006, log-rank test), as the replacement pattern appeared as an independent predictor of poor overall survival. For patients with replacement growth, the hazard of death was 2-2.5 times higher than for patients with pushing growth (P=0.004, cox regression) or mixed growth (P=0.01), and nearly four times higher than for patients with desmoplastic growth (P<0.0001). The negative prognostic effect of the replacement growth pattern was even more pronounced after adjusting for tumor size. Desmoplastic growth corresponded with small tumor size, dense lymphocytic infiltration and a more favorable prognosis. Eventually, the growth patterns may contribute to a histology-based prognostic biomarker for patients with colorectal liver metastases.

The multifaceted role of the microenvironment in liver metastasis: biology and clinical implications

The liver is host to many metastatic cancers, particularly colorectal cancer, for which the last 2 decades have seen major advances in diagnosis and treatment. The liver is a vital organ, and the extent of its involvement with metastatic disease is a major determinant of survival. Metastatic cells arriving in the liver via the bloodstream encounter the microenvironment of the hepatic sinusoid. The interactions of the tumor cells with hepatic sinusoidal and extrasinusoidal cells (endothelial, Kupffer, stellate, and inflammatory cells) determine their fate. The sinusoidal cells can have a dual role, sometimes fatal to the tumor cells but also facilitatory to their survival and growth. Adhesion molecules participate in these interactions and may affect their outcome. Bone marrow-derived cells and chemokines also play a part in the early battle for survival of the metastases. Once the tumor cells have arrested and survived the initial onslaught, tumors can grow within the liver in 3 distinct patterns, reflecting differing host responses, mechanisms of vascularization, and proteolytic activity. This review aims to present current knowledge of the interactions between the host liver cells and the invading metastases that has implications for the clinical course of the disease and the response to treatment.