Immune phenotype and histopathological growth pattern in patients with colorectal liver metastases

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.

Microscopic Growth Pattern of Metastatic Colorectal Carcinomas, Morphological Findings of the Non-Neoplastic Liver, and Their Relationship With Prognosis and Survival

Introduction. Various clinicopathological, radiological, and molecular parameters are predictive of prognosis in patients with colorectal carcinoma and distant organ metastases continue to have a significant place among them. Recent studies reveal that not only the presence of metastases but also the histopathological growth pattern of the metastatic tumor significantly affects prognosis. This study aimed to investigate the prognostic significance of the histopathological growth patterns of metastatic tumors, the morphological findings in the peritumoral non-neoplastic liver, and its relationship with survival in patients who have metastatic colorectal carcinoma. Materials and Method. Hematoxylin and eosin-stained slides of the tumors were re-examined in terms of histopathological diagnosis, growth pattern, presence and degree of peritumoral lymphocytic infiltration, steatosis, cholestasis, and peritumoral ductular reaction in the non-neoplastic liver. Results. In terms of histopathological growth patterns, 24 (47%) tumors showed replacement, 19 (37%) showed desmoplastic and 8 (16%) showed pushing growth pattern. In terms of total survival, there was a significant difference (P = .011) between desmoplastic and replacement growth patterns, and the survival period was shorter in patients with replacement growth patterns. Conclusion. Recent studies show that histopathological growth patterns in metastatic liver tumors may be a promising prognostic and predictive parameter. It is important to include this parameter in the pathology reports as it does not require additional equipment for evaluation in routine pathology practice, does not bring additional costs, or takes a long time to evaluate. This feature can be evaluated standardly by every pathologist.

Role of stromal PD-L1 expression in colorectal liver metastasis

BACKGROUND AND AIM

The outcomes of immune checkpoint blockade for colorectal cancer (CRC) treatment are unsatisfactory. Furthermore, the efficacy of immune checkpoint blockade for liver metastasis of various cancer is poor. Here, we investigated the relationship between stromal programmed death-ligand 1 (PD-L1) expression and the prognosis of patients with colorectal cancer liver metastasis (CRLM).

METHODS

The present study enrolled 84 CRLM patients who underwent surgery (R0) for CRC. Immunohistochemistry was performed to analyze stromal PD-L1 expression in CRLM.

RESULTS

Stromal PD-L1 was expressed in 52.3% of CRLM samples, which was associated with fewer not optimally resectable metastases (p = 0.04). Stromal PD-L1 also tended to associate with a lower tumor grade (p = 0.08). Stromal PD-L1-positive patients had longer overall survival (p = 0.003). Multivariate analysis identified stromal PD-L1 expression (p = 0.008) and poorer differentiation (p < 0.001) as independent prognostic indicators. Furthermore, stromal PD-L1 expression was correlated to a high number of tumor-infiltrating lymphocytes (TILs). Stromal PD-L1- and low TIL groups had shorter OS than stromal PD-L1 + and high TIL groups (46.6% vs. 81.8%, p = 0.05) Stromal PD-L1-positive patients had longer disease-free survival (DFS) (p = 0.03) and time to surgical failure (p = 0.001). Interestingly, stromal PD-L1 expression was positively related to the desmoplastic subtype (p = 0.0002) and inversely related to the replacement subtype of the histological growth pattern (p = 0.008).

CONCLUSIONS

Stromal PD-L1 expression may be a significant prognostic marker for CRLM.

Histopathological growth patterns of neuroendocrine tumor liver metastases

Histopathological growth patterns (HGPs) of liver metastases represent a potential biomarker for prognosis after resection. They have never been studied in neuroendocrine tumor liver metastases (NETLM). This study evaluated if distinct HGPs can be observed in resected NETLM and if they have prognostic value. Sixty-three patients who underwent resection of NETLM between 01-01-2001 and 31-12-2021 were retrospectively included. HGPs were scored on Haematoxylin&Eosin slides using light microscopy, distinguishing desmoplastic- (dHGP), pushing- (pHGP) and replacement HGP (rHGP). Average HGP scores were calculated per patient. Each patient was classified according to predominant HGP. Overall and Disease-Free Survival (OS and DFS) were evaluated through Kaplan-Meier analysis and Cox regression. Eighteen patients had predominant dHGP (29%), 33 had predominant pHGP (52%) and 11 had predominant rHGP (17%). One patient had mixed HGP (2%). Five-year OS was 76% (95%CI: 66-87%) for the overall cohort. Five-year OS was 92% (95%CI: 77-100%) for dHGP, was 73% (95%CI: 59-91%) for pHGP, 50% (95%CI: 25-100%) for rHGP. Five-year DFS was 39% (95%CI: 19-83%) for dHGP, 44% (95%CI: 27-71%) for rHGP and 50% (95%CI: 23-100%) for pHGP. There was no significant association between HGP and OS or DFS in multivariable analysis. Distinct HGPs could be identified in NETLM. In patients who underwent resection of NETLM, no association was found between HGPs and postoperative survival. Half of the patients with NETLM have a predominant pushing growth pattern, which is a rare growth pattern in liver metastases from breast and 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.

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.

Histopathological Growth Pattern in Colorectal Liver Metastasis and The Tumor Immune Microenvironment

Almost half of all patients with colorectal cancer present with or eventually develop metastasis, most frequently in the liver. Understanding the histopathological growth patterns and tumor immune microenvironment of colorectal liver metastases may help determine treatment strategies and assess prognosis. A literature search was conducted to gather information on cancer biology, histopathological growth patterns, and the tumor immune microenvironment in colorectal liver metastases, including their mechanisms and their impact on clinical outcomes. A first consensus on histopathological growth patterns emerged in 2017, identifying five growth patterns. Later studies found benefits from a two-tier system, desmoplastic and non-desmoplastic, incorporated into the updated 2022 consensus. Furthermore, the tumor immune microenvironment shows additional characteristic features with relevance to cancer biology. This includes density of T-cells (CD8+), expression of claudin-2, presence of vessel co-option versus angiogenesis, as well as several other factors. The relation between histopathological growth patterns and the tumor immune microenvironment delineates distinct subtypes of cancer biology. The distinct subtypes are found to correlate with risk of metastasis or relapse, and hence to clinical outcome and long-term survival in each patient. In order to optimize personalized and precision therapy for patients with colorectal liver metastases, further investigation into the mechanisms of cancer biology and their translational aspects to novel treatment targets is warranted.

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.

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.

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.

Prognostic implications of adaptive immune features in MMR-proficient colorectal liver metastases classified by histopathological growth patterns

BACKGROUND

After resection, colorectal cancer liver metastases (CRLM) surrounded by a desmoplastic rim carry a better prognosis than the metastases replacing the adjacent liver. However, these histopathological growth patterns (HGPs) are insufficient to guide clinical decision-making. We explored whether the adaptive immune features of HGPs could refine prognostication.

METHODS

From 276 metastases resected in 176 patients classified by HGPs, tissue microarrays were used to assess intratumoral T cells (CD3), antigen presentation capacity (MHC class I) and CD73 expression producing immunosuppressive adenosine. We tested correlations between these variables and patient outcomes.

RESULTS

The 101 (57.4%) patients with dominant desmoplastic HGP had a median recurrence-free survival (RFS) of 17.1 months compared to 13.3 months in the 75 patients (42.6%) with dominant replacement HGP (p = 0.037). In desmoplastic CRLM, high vs. low CD73 was the only prognostically informative immune parameter and was associated with a median RFS of 12.3 months compared to 26.3, respectively (p = 0.010). Only in dominant replacement CRLM, we found a subgroup (n = 23) with high intratumoral MHC-I expression but poor CD3⁺ T cell infiltration, a phenotype associated with a short median RFS of 7.9 months.

CONCLUSIONS

Combining the assessments of HGP and adaptive immune features in resected CRLM could help identify patients at risk of early recurrence.

Histopathological growth patterns modify the prognostic impact of microvascular invasion in non-cirrhotic hepatocellular carcinoma

BACKGROUND

Microvascular invasion (MVI) is an established prognosticator in hepatocellular carcinoma (HCC). Histopathological growth patterns (HGPs) classify the invasive margin of hepatic tumors, with superior survival observed for the desmoplastic HGP. Our aim was to investigate non-cirrhotic HCC in light of MVI and the HGP.

METHODS

A retrospective cohort study was performed in resected non-cirrhotic HCC. MVI was assessed prospectively. The HGP was determined retrospectively, blinded, and according to guidelines. Overall and disease-free survival (OS, DFS) were evaluated by Kaplan-Meier and multivariable Cox regression.

RESULTS

The HGP was determined in 155 eligible patients, 55 (35%) featured a desmoplastic HGP. MVI was observed in 92 (59%) and was uncorrelated with HGP (64% vs 57%, p = 0.42). On multivariable analysis, non-desmoplastic and MVI-positive were associated with an adjusted HR [95%CI] of 1.61 [0.98-2.65] and 3.22 [1.89-5.51] for OS, and 1.59 [1.05-2.41] and 2.30 [1.52-3.50] for DFS. Effect modification for OS existed between HGP and MVI (p < 0.01). Non-desmoplastic MVI-positive patients had a 5-year OS of 36% (HR: 5.21 [2.68-10.12]), compared to 60% for desmoplastic regardless of MVI (HR: 2.12 [1.08-4.18]), and 86% in non-desmoplastic MVI-negative.

CONCLUSION

HCCs in non-cirrhotic livers display HGPs which may be of prognostic importance, especially when combined with MVI.

The management of colorectal liver metastases amenable of surgical resection: How to shape treatment strategies according to clinical, radiological, pathological and molecular features

Metastatic colorectal cancer (mCRC) patients have poor chances of long term survival, being < 15% of them still alive after 5 years from diagnosis. Nonetheless, patients with colorectal liver metastases (CRLM) may be eligible for metastases resection thus being able to achieve long-term disease remission and survival. The likelihood for patients with CRLM of being or becoming eligible for liver metastasectomy is increasing, thanks to the evolution of surgical techniques, the availability of active systemic treatments and the widespread diffusion of experienced multidisciplinary boards to manage these patients. However, disease relapse after liver surgery is common and occurs in two-thirds of resected patients. Therefore, adequate radiological staging and risk stratification is crucial for the optimal selection of patients candidate to surgery in order to maximize the benefit-risk ratio of liver metastasectomy and to individualize the treatment strategy. Based on the multidimensional assessment, three possible approaches are available: upfront liver surgery followed by adjuvant chemotherapy, perioperative chemotherapy preceding and following liver surgery, and an upfront systemic treatment including chemotherapy plus a targeted agent, both chosen according to patients' and tumours' characteristics, then followed by liver surgery if indicated. In this review, we describe the most important factors impacting the therapeutic choices in patients with resectable and potentially resectable CRLM, and we discuss the most promising factors that may reshape the future decision-making process of these patients.

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.

Artificial intelligence in the diagnosis and management of colorectal cancer liver metastases

Colorectal cancer (CRC) is the third most common malignancy worldwide, with approximately 50% of patients developing colorectal cancer liver metastasis (CRLM) during the follow-up period. Management of CRLM is best achieved via a multidisciplinary approach and the diagnostic and therapeutic decision-making process is complex. In order to optimize patients' survival and quality of life, there are several unsolved challenges which must be overcome. These primarily include a timely diagnosis and the identification of reliable prognostic factors. Furthermore, to allow optimal treatment options, a precision-medicine, personalized approach is required. The widespread digitalization of healthcare generates a vast amount of data and together with accessible high-performance computing, artificial intelligence (AI) technologies can be applied. By increasing diagnostic accuracy, reducing timings and costs, the application of AI could help mitigate the current shortcomings in CRLM management. In this review we explore the available evidence of the possible role of AI in all phases of the CRLM natural history. Radiomics analysis and convolutional neural networks (CNN) which combine computed tomography (CT) images with clinical data have been developed to predict CRLM development in CRC patients. AI models have also proven themselves to perform similarly or better than expert radiologists in detecting CRLM on CT and magnetic resonance scans or identifying them from the noninvasive analysis of patients' exhaled air. The application of AI and machine learning (ML) in diagnosing CRLM has also been extended to histopathological examination in order to rapidly and accurately identify CRLM tissue and its different histopathological growth patterns. ML and CNN have shown good accuracy in predicting response to chemotherapy, early local tumor progression after ablation treatment, and patient survival after surgical treatment or chemotherapy. Despite the initial enthusiasm and the accumulating evidence, AI technologies' role in healthcare and CRLM management is not yet fully established. Its limitations mainly concern safety and the lack of regulation and ethical considerations. AI is unlikely to fully replace any human role but could be actively integrated to facilitate physicians in their everyday practice. Moving towards a personalized and evidence-based patient approach and management, further larger, prospective and rigorous studies evaluating AI technologies in patients at risk or affected by CRLM are needed.

Immune checkpoints and liver resection after neoadjuvant chemotherapy including bevacizumab in patients with microsatellite-stable colorectal liver metastases

BACKGROUND

The clinical value of immune checkpoint expression as prognostic biomarker in bevacizumab-pretreated patients with resected microsatellite-stable (MMS) colorectal liver metastases is unclear and was retrospectively investigated in this study.

METHODS

Expression analyses of IDO-1, PD-L1, and CTLA-4 were performed by immunohistochemistry in resected bevacizumab-pretreated colorectal liver metastases. Association of immune checkpoint expression in tumor cells and immune cells with response and clinical outcome was investigated. Expression profiles were compared with those of patients with anti-EGFR-targeted therapy and lung metastases, respectively.

RESULTS

One hundred thirty-six patients with MMS disease were investigated (79 (58.1%) male/57 (41.9%) female, median age 62.9 years (range 31.0-80.4)). High expression of IDO-1 in immune cells was associated with longer OS (not reached versus 44.8 months, HR 0.23 (95% CI 0.09, 0.55), P = 0.001). Low expression of CTLA-4 in tumor cells was associated with better histological response (26 major, 19 partial, 18 none versus 14 major, 23 partial, 30 none, P = 0.032). Expression profiles differed compared to patients with anti-EGFR-targeted therapy and patients with lung metastases.

CONCLUSION

Immune checkpoint expression was associated with response and survival. IDO-1 may serve as a novel prognostic and/or predictive biomarker in patients with MMS colorectal liver metastases.

Relationship between Fusobacterium nucleatum and antitumor immunity in colorectal cancer liver metastasis

Fusobacterium nucleatum has been detected in 8%-13% of human colorectal cancer, and shown to inhibit immune responses against primary colorectal tumors in animal models. Thus, we hypothesized that the presence of F. nucleatum might be associated with reduced T cell density in colorectal cancer liver metastases (CRLM). We quantified F. nucleatum DNA in 181 CRLM specimens using quantitative PCR assay. The densities of CD8+ T cells, CD33+ cells (marker for myeloid-derived suppressor cells [MDSCs]), and CD163+ cells (marker for tumor-associated macrophages [TAMs]) in CRLM tissue were determined by immunohistochemical staining. Fusobacterium nucleatum was detected in eight (4.4%) of 181 CRLM specimens. Compared with F. nucleatum-negative CRLM, F. nucleatum-positive CRLM showed significantly lower density of CD8+ T cells (P = .033) and higher density of MDSCs (P = .001). The association of F. nucleatum with the density of TAMs was not statistically significant (P = .70). The presence of F. nucleatum is associated with a lower density of CD8+ T cells and a higher density of MDSCs in CRLM tissue. Upon validation, our findings could provide insights to develop strategies that involve targeting microbiota and immune cells for the prevention and treatment of CRLM.

Liver Metastatic Colorectal Tumor Cells Change Their Phenotype During Consecutive Passages on Chick Embryo Chorioallantoic Membrane: Lessons from the Lab to the Clinic

BACKGROUND/AIM

Colon cancer liver metastases with desmoplastic growth pattern (dGP) have a highly heterogeneous therapy response. The aim of the study was to evaluate the dGP liver metastasis molecular profile from a chemo-naive patient by mimicking metastatic process on an experimental chick embryo chorioallantoic membrane (CAM) model.

MATERIALS AND METHODS

Three successive CAM passages of dGP human colorectal liver metastases were immunophenotyped for keratin (K) 8, and 20, CLIC1, VEGF, EGFR, CD34, podoplanin, Ki67, E-cadherin and vimentin.

RESULTS

Metastatic cells gradually lost K20 while K8, E-cadherin and vimentin heterogeneously increased during passages. VEGF, CLIC 1, EGFR expression increased in metastatic cells especially at the tumor graft periphery. Scattered proliferating and non-proliferating podoplanin-positive tumor cells, lymphatic and blood vessels were heterogeneously detected in tumor xenografts depending on passage stage.

CONCLUSION

By mimicking repetitive metastatic processes we proved that metastatic cells change their phenotype. This may explain why not all metastases have a similar response to therapy.

The circulating soluble form of the CD40 costimulatory immune checkpoint receptor and liver metastasis risk in rectal cancer

BACKGROUND

In colorectal cancer, the inflamed tumour microenvironment with its angiogenic activities is immune- tolerant and incites progression to liver metastasis. We hypothesised that angiogenic and inflammatory factors in serum samples from patients with non-metastatic rectal cancer could inform on liver metastasis risk.

METHODS

We measured 84 angiogenic and inflammatory markers in serum sampled at the time of diagnosis within the population-based cohort of 122 stage I-III patients. In a stepwise manner, the statistically strongest proteins associated with time to development of liver metastasis were analysed in the corresponding serum samples from 273 stage II-III rectal cancer patients in three independent cohorts.

RESULTS

We identified the soluble form of the costimulatory immune checkpoint receptor cluster of differentiation molecule 40 (sCD40) as a marker of liver metastasis risk across all patient cohorts-the higher the sCD40 level, the shorter time to liver metastasis. In patients receiving neoadjuvant treatment, the sCD40 value remained an independent variable associated with progression to liver metastasis along with the local treatment response. Of note, serum sCD40 was not associated with progression to lung metastasis.

CONCLUSIONS

Circulating sCD40 is a marker of liver metastasis risk in rectal cancer and may be developed for use in clinical practice.

Liver Immune Microenvironment and Metastasis from Colorectal Cancer-Pathogenesis and Therapeutic Perspectives

A drastic difference exists between the 5-year survival rates of colorectal cancer patients with localized cancer and distal organ metastasis. The liver is the most favorable organ for cancer metastases from the colorectum. Beyond the liver-colon anatomic relationship, emerging evidence highlights the impact of liver immune microenvironment on colorectal liver metastasis. Prior to cancer cell dissemination, hepatocytes secrete multiple factors to recruit or activate immune cells and stromal cells in the liver to form a favorable premetastatic niche. The liver-resident cells including Kupffer cells, hepatic stellate cells, and liver-sinusoidal endothelial cells are co-opted by the recruited cells, such as myeloid-derived suppressor cells and tumor-associated macrophages, to establish an immunosuppressive liver microenvironment suitable for tumor cell colonization and outgrowth. Current treatments including radical surgery, systemic therapy, and localized therapy have only achieved good clinical outcomes in a minority of colorectal cancer patients with liver metastasis, which is further hampered by high recurrence rate. Better understanding of the mechanisms governing the metastasis-prone liver immune microenvironment should open new immuno-oncology avenues for liver metastasis intervention.

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.

The Tumor Microenvironment in Liver Metastases from Colorectal Carcinoma in the Context of the Histologic Growth Patterns

Colorectal carcinoma (CRC) is the third most common cancer. Likewise, it is a disease that has a long survival if it is prematurely detected. However, more than 50% of patients will develop metastases, mainly in the liver (LM-CRC), throughout the evolution of their disease, which accounts for most CRC-related deaths. Treatment it is certainly a controversial issue, since it has not been shown to increase overall survival in the adjuvant setting, although it does improve disease free survival (DFS). Moreover, current chemotherapy combinations are administered based on data extrapolated from primary tumors (PT), not considering that LM-CRC present a very particular tumor microenvironment that can radically condition the effectiveness of treatments designed for a PT. The liver has a particular histology and microenvironment that can determine tumor growth and response to treatments: double blood supply, vascularization through fenestrated sinusoids and the presence of different mesenchymal cell types, among other particularities. Likewise, the liver presents a peculiar immune response against tumor cells, a fact that correlates with the poor response to immunotherapy. All these aspects will be addressed in this review, putting them in the context of the histological growth patterns of LM-CRC, a particular pathologic feature with both prognostic and predictive repercussions.

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.

Association between the histopathological growth patterns of liver metastases and survival after hepatic surgery in breast cancer patients

Currently, there are no markers to identify patients with liver-only or liver-dominant metastases that would benefit from hepatic surgery. Here we characterized histopathological growth patterns (HGPs) of liver metastases in a consecutive series of 36 breast cancer patients who underwent hepatic surgery. Survival analyses showed that the presence of a desmoplastic HGP in the liver metastases (a rim of fibrous tissue separating cancer cells from the liver parenchyma, present in 20 (56%) patients) is independently associated with favorable progression-free and overall survival when compared with the replacement HGP (cancer cells growing into the liver parenchyma, present in 16 (44%) patients).

Defining best practices for tissue procurement in immuno-oncology clinical trials: consensus statement from the Society for Immunotherapy of Cancer Surgery Committee

Immunotherapy is now a cornerstone for cancer treatment, and much attention has been placed on the identification of prognostic and predictive biomarkers. The success of biomarker development is dependent on accurate and timely collection of biospecimens and high-quality processing, storage and shipping. Tumors are also increasingly used as source material for the generation of therapeutic T cells. There have been few guidelines or consensus statements on how to optimally collect and manage biospecimens and source material being used for immunotherapy and related research. The Society for Immunotherapy of Cancer Surgery Committee has brought together surgical experts from multiple subspecialty disciplines to identify best practices and to provide consensus on how best to access and manage specific tissues for immuno-oncology treatments and clinical investigation. In addition, the committee recommends early integration of surgeons and other interventional physicians with expertise in biospecimen collection, especially in clinical trials, to optimize the quality of tissue and the validity of correlative clinical studies in cancer immunotherapy.

Tumor microenvironment conditions that favor vessel co-option in colorectal cancer liver metastases: A theoretical model

Vessel co-option is an alternative strategy by which tumour cells vascularize and gain access to nutrients to support tumour growth, survival and metastasis. In vessel co-option, the cancer cells move towards the pre-existing vasculature and hijack them. Vessel co-option is adopted by a wide range of human tumours including colorectal cancer liver metastases (CRCLM) and is responsible for the effectiveness of treatment in CRCLM. Furthermore, vessel co-option is an intrinsic feature and an acquired mechanism of resistance to anti-angiogenic treatment. In this review, we describe the microenvironment, the molecular players, discovered thus far of co-opting CRCLM lesions and propose a theoretical model. We also highlight key unanswered questions that are critical to improving our understanding of CRCLM vessel co-option and for the development of effective approaches for the treatment of co-opting tumours.

Prognostic impact of immune-microenvironment in colorectal liver metastases resected after triplets plus a biologic agent: A pooled analysis of five prospective trials

BACKGROUND

Immune-contexture of tumour microenvironment (TME) influences prognosis of colorectal cancer (CRC) patients and can be altered by cytotoxic and targeted agents. Limited data are available regarding the immune-TME of CRC after treatment.

METHODS

An extensive immunohistochemistry evaluation of immunological parameters on tumour cells and TME of colorectal liver metastases from 106 patients who underwent secondary resection, after receiving triplets FOLFOXIRI (5-fluorouracil, oxaliplatin and irinotecan) or COI (capecitabine, oxaliplatin and irinotecan) plus bevacizumab (N = 59) or cetuximab (N = 47) in five first-line no-profit clinical trials was performed.

RESULTS

No substantial differences were reported in immunological parameters according to administered targeted agent, RAS/BRAF mutational status and histopathological or Response Evaluation Criteria in Solid Tumours response. Stromal expression of Cyclooxygenase-2 (COX-2) (p = 0.002), Human leukocyte antigen (HLA) (p = 0.003) and Programmed cell death protein 1 (PD1) (p = 0.002) were independent prognostic factors for longer relapse-free survival (RFS) at multivariate analysis with a positive trend for post-resection overall survival (OS). Patients whose metastases expressed stromal COX-2, HLA and PD1 (inflamed-score positive) reported longer RFS (25.5 versus 9.8 months; p < 0.001) and post-resection OS (64.3 versus 37.7 months; p = 0.003) as compared with others. In addition, patients with higher expression of CD4 and CD8 T-cells in tumour core and invasive margin (CD4/CD8-score) showed a better post-resection OS (not-reached versus 41.6 months; p = 0.032). A combined score of inflamed-score and CD4/CD8-score (combo-score) showed a clear prognostic role.

CONCLUSIONS

The present study emphasises the role of immune-TME as independent predictor of survival in patients resected after triplets plus biologic. Inflamed-, CD4/C8- and combo-scores should be confirmed as prognostic factors in further studies.