SMAD4 gene mutation predicts poor prognosis in patients undergoing resection for colorectal liver metastases. Eur J Surg Oncol. 2018;44:684-692. [PMID: 29551247 DOI: 10.1016/j.ejso.2018.02.247]

Tumoral and circulating genomic landscape inform survival differences in colorectal carcinomatosis

Colorectal peritoneal metastases (CPM) are the third most common site of metastatic spread of colorectal cancer and are associated with worse survival than other sites of metastatic disease. In recent years tumoral circulating tumoral DNA (ctDNA) mutational status has been increasingly utilized in clinical decision making for metastatic colorectal cancer patients despite its utility in CPM being poorly understood. Here we describe standard of care performed mutational profiles and associated outcomes for unresectable CPM patients, with a contextual comparison to 160 unresected colorectal liver metastases (CLM) patients. Of 508 patients, 288 (57 %) had CPM alone and 220 (43 %) had CPM with extraperitoneal metastases. Patients with synchronous CPM and CLM had worse overall survival (HR 1.67 [95 %CI 1.26-2.22]). Mutations in ctDNA were noted in 110/145 (75.9 %) of CPM patients, with mutations in KRAS or PIK3CA ctDNA being associated with worse survival. Importantly, the association between tumoral mutational profile and survival differed by site of metastatic disease. The prognostic significance of specific mutations, particularly BRAF and KRAS, differs between patients with CPM and CLM, and supports the distinct biology of these metastatic sites and the importance of tissue and circulating genomic profiling to risk-stratify these patients according to site of metastasis.

Assessment and treatment considerations for patients with colorectal liver metastases: AHPBA consensus guideline and update for surgeons

BACKGROUND

Colorectal cancer most commonly metastasizes to the liver. While various treatment strategies have been developed, surgical management of these patients has vital implications on the prognosis and survival of this group of patients. There remains a need for a consensus guideline regarding the surgical evaluation and management of patients with colorectal liver metastases (CRLM).

METHODS

This review article is a consensus guideline established by the members of the AHPBA Professional Standards Committee, as an amalgamation of existent literature and a guide to surgeons managing this complex disease.

RESULTS

These guidelines reports the benefits and shortcomings of various diagnostic modalities including imaging and next-generation sequencing in the management of patients with CRLM. While surgery has established survival benefits in patients with resectable disease, this report notes the importance of treatment sequencing with non-surgical modalities as well as between colon and liver resection. Finally, the guidelines address the various treatment modalities for patients with unresectable disease, that may have significant impact on survival.

CONCLUSION

CRLM is a complex diagnosis which warrants multidisciplinary approach with early surgical involvement in both assessment and management of the disease, to optimize patient outcomes and survival.

Debate: Improvements in Systemic Therapies for Liver Metastases Will Increase the Role of Locoregional Treatments

The benefit of resection of liver metastases depends on primary diseases. Neuroendocrine tumors are associated with favorable prognosis after resection of liver metastases. Gastric cancer has worse tumor biology, and resection of gastric liver metastases should be performed in selected patients. A multidisciplinary approach is well established for colorectal liver metastases (CLMs). Resection remains the only curative treatment of CLM. Chemotherapy and molecular-targeted therapy have improved survival in unresectable metastatic colorectal cancer. Understanding of the following two strategies, conversion therapy and two-stage hepatectomy, are important to make this patient group to be candidates for curative-intent surgery.

Proteogenomic Characterization of Early Intrahepatic Recurrence after Curative-Intent Treatment of Colorectal Liver Metastases

Clinical and pathological factors are insufficient to accurately identify patients at risk of early recurrence after curative-intent treatment of colorectal liver metastases (CRLM). This study aimed to identify candidate prognostic proteogenomic biomarkers for early intrahepatic recurrence after curative-intent resection of CRLM. Patients diagnosed with intrahepatic recurrence within 6 months of liver resection were categorized as the "early recurrence" group, while those who achieved a recurrence-free status for 10 years were designated as "durable remission". Comprehensive genomic and proteomic profiling of fresh frozen samples from these prognostically distinct groups was performed using the TruSight Oncology 500 assay and label-free data-dependent acquisition liquid chromatography-mass spectrometry. Genetic alterations were identified in 117 of the 523 profiled genes in patients with early recurrence. The most common somatic mutations linked to early recurrence were TP53 (88%), APC (71%), KRAS (38%), and SMAD4 (21%). SMAD4 alterations were absent in samples from patients with a durable remission. Calponin-2, versican core protein, glutathione peroxidase 3, fibulin-5, and amyloid-β precursor protein were upregulated more than 2-fold in early recurrence. Exploratory analysis of these proteogenomic biomarkers suggests that SMAD4, calponin-2, and glutathione peroxidase 3 may have the potential to predict early recurrence, enabling improved prognostication and precision oncology in CRLM.

Determination of the frequency and distribution of APC, PIK3CA, and SMAD4 gene mutations in Ugandan patients with colorectal cancer

Uganda is a developing low-income country with a low incidence of colorectal cancer, which is steadily increasing. Ugandan colorectal cancer (CRC) patients are young and present with advanced-stage disease. In our population, there is a scarcity of genetic oncological studies, therefore, we investigated the mutational status of CRC tissues, focusing in particular on the adenomatous polyposis coli (APC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and SMAD4 genes. Our objective was to determine whether there were any differences between other populations and Ugandan patients. We performed next-generation sequencing on the extracted DNA from formalin-fixed paraffin-embedded adenocarcinoma samples from 127 patients (mean (SD) age: 54.9 (16.0) years; male:female sex ratio: 1.2:1). Most tumours were located in the rectum 56 (44.1%), 14 (11%) tumours were high grade, and 96 (75.6%) were moderate grade CRC. Stage III + IV CRC tumours were found in 109 (85.8%) patients. We identified 48 variants of APC, including 9 novel APC mutations that were all pathogenic or deleterious. For PIK3CA, we found 19 variants, of which 9 were deleterious or pathogenic. Four PIK3CA novel pathogenic or deleterious variants were included (c.1397C > G, c.2399_2400insA, c.2621G > C, c.2632C > G). Three SMAD4 variants were reported, including two pathogenic or deleterious variants (c.1268G > T, c.556dupC) and one tolerant (c.563A > C) variant. One novel SMAD4 deleterious mutation (c.1268G > T) was reported. In conclusion, we provide clinicopathological information and new genetic variation data pertinent to CRC in Uganda.

A new TGF-β risk score predicts clinical and immune landscape in colorectal cancer patients

Background

Aberrant TGF-β signaling pathway can lead to invasive phenotype of colorectal cancer (CRC), resulting in poor prognosis. It is pivotal to develop an effective prognostic factor on the basis of TGF-β-related genes to accurately identify risk of CRC patients.

Methods

We performed differential analysis of TGF-β-related genes in CRC patients from databases and previous literature to obtain TGF-β-related differentially expressed genes (TRDEGs). LASSO-Cox regression was utilized to build a CRC prognostic feature model based on TRDEGs. The model was validated using two GEO validation sets. Wilcoxon rank-sum test was utilized to test correlation of model with clinical factors. ESTIMATE algorithm and ssGSEA and tumor mutation burden (TMB) analysis were used to analyze immune landscape and mutation burden of high-risk (HR) and low-risk (LR) groups. CellMiner database was utilized to identify therapeutic drugs with high sensitivity to the feature genes.

Results

We established a six-gene risk prognostic model with good predictive accuracy, which independently predicted CRC patients' prognoses. The HR group was more likely to experience immunotherapy benefits due to higher immune infiltration and TMB. The feature gene TGFB2 could inhibit the efficacy of drugs such as XAV-939, Staurosporine, and Dasatinib, but promote the efficacy of drugs such as CUDC-305 and by-product of CUDC-305. Similarly, RBL1 could inhibit the drug action of Fluphenazine and Imiquimod but promote that of Irofulven.

Conclusion

A CRC risk prognostic signature was developed on basis of TGF-β-related genes, which provides a reference for risk and further therapeutic selection of CRC patients.

Mechanisms of metastatic colorectal cancer

Despite extensive research and improvements in understanding colorectal cancer (CRC), its metastatic form continues to pose a substantial challenge, primarily owing to limited therapeutic options and a poor prognosis. This Review addresses the emerging focus on metastatic CRC (mCRC), which has historically been under-studied compared with primary CRC despite its lethality. We delve into two crucial aspects: the molecular and cellular determinants facilitating CRC metastasis and the principles guiding the evolution of metastatic disease. Initially, we examine the genetic alterations integral to CRC metastasis, connecting them to clinically marked characteristics of advanced CRC. Subsequently, we scrutinize the role of cellular heterogeneity and plasticity in metastatic spread and therapy resistance. Finally, we explore how the tumour microenvironment influences metastatic disease, emphasizing the effect of stromal gene programmes and the immune context. The ongoing research in these fields holds immense importance, as its future implications are projected to revolutionize the treatment of patients with mCRC, hopefully offering a promising outlook for their survival.

Challenges and Opportunities for Precision Surgery for Colorectal Liver Metastases

The incidence of colorectal cancer and colorectal liver metastases (CRLM) is increasing globally due to an interaction of environmental and genetic factors. A minority of patients with CRLM have surgically resectable disease, but for those who have resection as part of multimodal therapy for their disease, long-term survival has been shown. Precision surgery-the idea of careful patient selection and targeting of surgical intervention, such that treatments shown to be proven to benefit on a population level are the optimal treatment for each individual patient-is the new paradigm of care. Key to this is the understanding of tumour molecular biology and clinically relevant mutations, such as KRAS, BRAF, and microsatellite instability (MSI), which can predict poorer overall outcomes and a poorer response to systemic therapy. The emergence of immunotherapy and hepatic artery infusion (HAI) pumps show potential to convert previously unresectable disease to resectable disease, in addition to established systemic and locoregional therapies, but the surgeon must be wary of poor-quality livers and the spectre of post-hepatectomy liver failure (PHLF). Volume modulation, a cornerstone of hepatic surgery for a generation, has been given a shot in the arm with the advent of liver venous depletion (LVD) ensuring significantly more hypertrophy of the future liver remnant (FLR). The optimal timing of liver resection for those patients with synchronous disease is yet to be truly established, but evidence would suggest that those patients requiring complex colorectal surgery and major liver resection are best served with a staged approach. In the operating room, parenchyma-preserving minimally invasive surgery (MIS) can dramatically reduce the surgical insult to the patient and lead to better perioperative outcomes, with quicker return to function.

Somatic Mutations in Surgically Treated Colorectal Liver Metastases: An Overview

Colorectal cancer is the second most common cause of cancer death in the United States, and up to half of patients develop colorectal liver metastases (CRLMs). Notably, somatic genetic mutations, such as mutations in RAS, BRAF, mismatch repair (MMR) genes, TP53, and SMAD4, have been shown to play a prognostic role in patients with CRLM. This review summarizes and appraises the current literature regarding the most relevant somatic mutations in surgically treated CRLM by not only reviewing representative studies, but also providing recommendations for areas of future research. In addition, advancements in genetic testing and an increasing emphasis on precision medicine have led to a more nuanced understanding of these mutations; thus, more granular data for each mutation are reviewed when available. Importantly, such knowledge can pave the way for precision medicine with the ultimate goal of improving patient outcomes.

Local Therapy Improves Survival for Early Recurrence After Resection of Colorectal Liver Metastases

BACKGROUND

Early recurrence following hepatectomy for colorectal liver metastases (CLM) is associated with worse survival; yet, impact of further local therapy is unclear. We sought to evaluate whether local therapy benefits patients with early recurrence following hepatectomy for CLM.

METHODS

Clinicopathologic and survival outcomes of patients managed with hepatectomy for CLM (1/2001-12/2020) were queried from a prospectively maintained database. Timing of recurrence was stratified as early (recurrence-free survival [RFS] < 6 months), intermediate (RFS 6-12 months), and later (RFS > 12 months). Local therapy was defined as ablation, resection, or radiation.

RESULTS

Of 671 patients, 541 (81%) recurred with 189 (28%) early, 180 (27%) intermediate, and 172 (26%) later recurrences. Local therapy for recurrence resulted in improved survival, regardless of recurrence timing (early 78 vs. 32 months, intermediate 72 vs. 39 months, later 132 vs. 65 months, all p < 0.001). Following recurrence, treatment with local therapy (hazard ratio [HR] = 0.24), liver and extrahepatic recurrence (HR = 1.81), RAS + TP53 co-mutation (HR = 1.52), and SMAD4 mutation (HR = 1.92) were independently associated with overall survival (all p ≤ 0.002). Among patients with recurrence treated by local therapy, patients older than 65 years (HR 1.79), liver and extrahepatic recurrence (HR 2.05), primary site or other recurrence (HR 1.90), RAS-TP53 co-mutation (HR 1.63), and SMAD4 mutation (HR 2.06) had shorter post-local therapy survival (all p ≤ 0.04).

CONCLUSIONS

While most patients recur after hepatectomy for CLM, local therapy may result in long-term survival despite early recurrence. Somatic mutational profiling may help to guide the multidisciplinary consideration of local therapy after recurrence.

Multimodal Management of Colorectal Liver Metastases: State of the Art

Liver is the most common site of colorectal cancer (CRC) metastases. Treatment of CRC liver metastases (CRLM) includes different strategies, prevalently based on the clinical and oncological intent. Valid approaches in liver-limited or liver-prevalent disease include surgery, percutaneous ablative procedures (radiofrequency ablation, microwave ablation), intra-arterial perfusional techniques (chemo-embolization, radio-embolization) as well as stereotactic radiotherapy. Systemic treatments, including chemotherapy, immunotherapy and other biological agents, are the only options for patients with no chance of locoregional approaches. The use of chemotherapy in other settings, such as neoadjuvant, adjuvant or conversion therapy of CRLM, is commonly accepted in the clinical practice, although data from several clinical trials have been mostly inconclusive. The optimal integration of all these strategies, when applicable and clinically indicated, should be ever considered in patients affected by CRLM based on clinical evidence and multidisciplinary experience. Here we revised in detail all the possible therapeutic approaches of CRLM focusing on the current evidences, the studies still in progress and the often contradictory data.

In Vitro Organoid-Based Assays Reveal SMAD4 Tumor-Suppressive Mechanisms for Serrated Colorectal Cancer Invasion

Colon cancer is the third most prominent cancer and second leading cause of cancer-related deaths in the United States. Up to 20% of colon cancers follow the serrated tumor pathway driven by mutations in the MAPK pathway. Loss of SMAD4 function occurs in the majority of late-stage colon cancers and is associated with aggressive cancer progression. Therefore, it is important to develop technology to accurately model and better understand the genetic mechanisms behind cancer invasion. Organoids derived from tumors found in the Smad4KO BRAFV600E/+ mouse model present multiple phenotypes characteristic of invasion both in ex vivo and in vivo systems. Smad4KO BRAFV600E/+ tumor organoids can migrate through 3D culture and infiltrate through transwell membranes. This invasive behavior can be suppressed when SMAD4 is re-expressed in the tumor organoids. RNA-Seq analysis reveals that SMAD4 expression in organoids rapidly regulates transcripts associated with extracellular matrix and secreted proteins, suggesting that the mechanisms employed by SMAD4 to inhibit invasion are associated with regulation of extracellular matrix and secretory pathways. These findings indicate new models to study SMAD4 regulation of tumor invasion and an additional layer of complexity in the tumor-suppressive function of the SMAD4/Tgfβ pathway.

Unraveling Resistance to Immunotherapy in MSI-High Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related deaths. Incidences of early CRC cases are increasing annually in high-income countries, necessitating effective treatment strategies. Immune checkpoint inhibitors (ICIs) have shown significant clinical efficacy in various cancers, including CRC. However, their effectiveness in CRC is limited to patients with mismatch-repair-deficient (dMMR)/microsatellite instability high (MSI-H) disease, which accounts for about 15% of all localized CRC cases and only 3% to 5% of metastatic CRC cases. However, the varied response among patients, with some showing resistance or primary tumor progression, highlights the need for a deeper understanding of the underlying mechanisms. Elements involved in shaping the response to ICIs, such as tumor microenvironment, immune cells, genetic changes, and the influence of gut microbiota, are not fully understood thus far. This review aims to explore potential resistance or immune-evasion mechanisms to ICIs in dMMR/MSI-H CRC and the cell types involved, as well as possible pitfalls in the diagnosis of this particular subtype.

Postoperative infectious complications are associated with diminished overall survival of patients undergoing resection for colorectal liver metastases

INTRODUCTION

Postoperative infectious complications (PIC) remain one of the most common complications after surgery. The influence of PIC on long-term survival for patients after liver surgery for colorectal liver metastases (CRLM) needs further investigation.

METHODS

Data of patients who underwent liver resection for CRLM between 2012 and 2017 at the Department of Surgery, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin were evaluated. Overall survival (OS) was stratified according to the development of PIC. Independent predictors of PIC and diminished survival were identified using regression models.

RESULTS

Of 270 patients, eighty-four (31%) patients developed PIC including intraabdominal infections (n = 51, 61%), cholangitis (n = 5, 6%), pneumonia (n = 12, 14%), wound infections (n = 28, 33%), urinary tract infections (n = 5, 6%), or central line-associated bloodstream infections (n = 4, 5%). PIC were associated with a significantly diminished five-year OS (30% vs. 43%, p = 0.008). Age >65 years (p = 0.016, hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.2-4.0), comorbidity (p = 0.019, HR [95% CI] = 2.4 [1.2-4.9]), simultaneous resection of primary tumor (p = 0.005, HR [95% CI] = 4.3 [1.6-11.9]), biliary drainage (p < 0.001, HR [95% CI] = 4.1 [2.0-8.5]), and length of procedure ≥272 min (p = 0.012, HR [95% CI] = 2.2 [1.2-4.1]) were independent predictors for the development of PIC. Body-mass index (BMI) > 30 kg/m2 (p = 0.002, HR [95% CI] = 2.4 [1.4-4.0]), postoperative major complications (p = 0.003, HR [95% CI] = 2.2 [1.3-3.8]), and 3- or 4-MRGN bacteria (p = 0.001, HR [95% CI] = 7.7 [2.2-27.3]) were independently associated with diminished OS.

CONCLUSIONS

PIC are associated with diminished OS after resection for CRLM. Age >65 years, comorbidities, simultaneous resection of the primary tumor, and biliary drainages were identified as independent risk factors for the development of PIC. High BMI, postoperative major morbidity and 3-/4-MRGN bacteria were independently predictive of worse OS. These factors need to be considered in perioperative management for patients with CRLM.

Locoregional treatment for colorectal liver metastases aiming for precision medicine

In patients with colorectal liver metastases (CLM), surgery is potentially curative. The use of novel surgical techniques and complementary percutaneous ablation allows for curative-intent treatment even in marginally resectable cases. Resection is used as part of a multidisciplinary approach, which for nearly all patients will include perioperative chemotherapy. Small CLM can be treated with parenchymal-sparing hepatectomy (PSH) and/or ablation. For small CLM, PSH results in better survival and higher rates of resectability of recurrent CLM than non-PSH. For patients with extensive bilateral distribution of CLM, two-stage hepatectomy or fast-track two-stage hepatectomy is effective. Our increasing knowledge of genetic alterations allows us to use them as prognostic factors alongside traditional risk factors (e.g. tumor diameter and tumor number) to select patients with CLM for resection and guide surveillance after resection. Alteration in RAS family genes (hereafter referred to as "RAS alteration") is an important negative prognostic factor, as are alterations in the TP53, SMAD4, FBXW7, and BRAF genes. However, APC alteration appears to improve prognosis. RAS alteration, increased number and diameter of CLM, and primary lymph node metastasis are well-known risk factors for recurrence after CLM resection. In patients free of recurrence 2 y after CLM resection, only RAS alteration is associated with recurrence. Thus, surveillance intensity can be stratified by RAS alteration status after 2 y. Novel diagnostic instruments and tools, such as circulating tumor DNA, may lead to further evolution of patient selection, prognostication, and treatment algorithms for CLM.

Relationship between Epithelial-to-Mesenchymal Transition and Tumor-Associated Macrophages in Colorectal Liver Metastases

The liver is the most common metastatic site in colorectal cancer (CRC) patients. Indeed, 25-30% of the cases develop colorectal liver metastasis (CLM), showing an extremely poor 5-year survival rate and resistance to conventional anticancer therapies. Tumor-associated macrophages (TAMs) provide a nurturing microenvironment for CRC metastasis, promoting epithelial-to-mesenchymal transition (EMT) through the TGF-β signaling pathway, thus driving tumor cells to acquire mesenchymal properties that allow them to migrate from the primary tumor and invade the new metastatic site. EMT is known to contribute to the disruption of blood vessel integrity and the generation of circulating tumor cells (CTCs), thus being closely related to high metastatic potential in numerous solid cancers. Despite the fact that it is well-recognized that the crosstalk between tumor cells and the inflammatory microenvironment is crucial in the EMT process, the association between the EMT and the role of TAMs is still poorly understood. In this review, we elaborated on the role that TAMs exert in the induction of EMT during CLM development. Since TAMs are the major source of TGF-β in the liver, we also focused on novel insights into their role in TGF-β-induced EMT.

Mutational Status of SMAD4 and FBXW7 Affects Clinical Outcome in TP53-Mutated Metastatic Colorectal Cancer

Next-generation sequencing (NGS) provides a molecular rationale to inform prognostic stratification and to guide personalized treatment in cancer patients. Here, we determined the prognostic and predictive value of actionable mutated genes in metastatic colorectal cancer (mCRC). Among a total of 294 mCRC tumors examined by targeted NGS, 200 of them derived from patients treated with first-line chemotherapy plus/minus monoclonal antibodies were included in prognostic analyses. Discriminative performance was assessed by time-dependent estimates of the area under the curve (AUC). The most recurrently mutated genes were TP53 (64%), KRAS or NRAS (49%), PIK3CA (15%), SMAD4 (14%), BRAF (13%), and FBXW7 (9.5%). Mutations in FBXW7 correlated with worse OS rates (p = 0.036; HR, 2.24) independently of clinical factors. Concurrent mutations in TP53 and FBXW7 were associated with increased risk of death (p = 0.02; HR, 3.31) as well as double-mutated TP53 and SMAD4 (p = 0.03; HR, 2.91). Analysis of the MSK-IMPACT mCRC cohort (N = 1095 patients) confirmed the same prognostic trend for the previously identified mutated genes. Addition of the mutational status of these genes upon clinical factors resulted in a time-dependent AUC of 87%. Gene set enrichment analysis revealed specific molecular pathways associated with SMAD4 and FBXW7 mutations in TP53-defficient tumors. Conclusively, SMAD4 and FBXW7 mutations in TP53-altered tumors were predictive of a negative prognostic outcome in mCRC patients treated with first-line regimens.

TGF-β Signaling in Metastatic Colorectal Cancer (mCRC): From Underlying Mechanism to Potential Applications in Clinical Development

Colorectal cancer (CRC) is a serious public health issue, and it has the leading incidence and mortality among malignant tumors worldwide. CRC patients with metastasis in the liver, lung or other distant sites always have poor prognosis. Thus, there is an urgent need to discover the underlying mechanisms of metastatic colorectal cancer (mCRC) and to develop optimal therapy for mCRC. Transforming growth factor-β (TGF-β) signaling plays a significant role in various physiologic and pathologic processes, and aberrant TGF-β signal transduction contributes to mCRC progression. In this review, we summarize the alterations of the TGF-β signaling pathway in mCRC patients, the functional mechanisms of TGF-β signaling, its promotion of epithelial-mesenchymal transition, its facilitation of angiogenesis, its suppression of anti-tumor activity of immune cells in the microenvironment and its contribution to stemness of CRC cells. We also discuss the possible applications of TGF-β signaling in mCRC diagnosis, prognosis and targeted therapies in clinical trials. Hopefully, these research advances in TGF-β signaling in mCRC will improve the development of new strategies that can be combined with molecular targeted therapy, immunotherapy and traditional therapies to achieve better efficacy and benefit mCRC patients in the near future.

Genomic Predictors of Recurrence Patterns After Complete Resection of Colorectal Liver Metastases and Adjuvant Hepatic Artery Infusion Chemotherapy

BACKGROUND

Despite curative hepatectomy, most colorectal liver metastasis (CRLM) patients relapse locally within 2 years. Genomic predictors for hepatic recurrence are poorly understood. This study was designed to identify genomic signatures for recurrence in resected CRLM patients treated with adjuvant hepatic artery infusion (HAI) and/or systemic (SYS) chemotherapy.

METHODS

Patients undergoing curative hepatectomy and adjuvant HAI+SYS or SYS between January 2000 and October 2017 with next-generation sequencing data were catalogued. Gene and signaling-level alterations were checked for association with time to any (AR), liver (LR), and extrahepatic recurrence (ER) by using Kaplan-Meier analysis.

RESULTS

Of 172 receiving HAI+SYS, 100 patients recurred, with 69 LR and 83 ER. Five- and ten-year LR-free rates were 57% (95% confidence interval [CI] 48-65%) and 51% (95% CI 41-60%), respectively. Five- and 10-year ER-free, rates were 51% (95% CI 43-58%) and 45% (95% CI 36-54%), respectively. More ER was observed with tumors harboring altered KRAS (38% [95% CI 25-50%] vs. 63% [95% CI 53-71%], p-adj = 0.003) and RAS/RAF (36% [95% CI 25-48%] vs. 66% [95% CI 56-74%], p-adj < 0.001) than wild-type. Co-altered RAS/RAF-TP53 was associated with worse AR (26% [95% CI 14-40%] vs. 48% [95% CI 39-57%], p-unadj < 0.001), ER (30% [95% CI 17-45%] vs. 62% [95% CI 53-70%], p-unadj < 0.001), and LR rate (40% [95% CI 24-57%] vs. 70% [95% CI 60-77%], p-unadj = 0.002). On multivariable analysis, controlling for clinical risk score, ablation, margin status, and primary T-stage, co-altered RAS/RAF-TP53 was associated with increased risk for AR (HR = 2.14, 95% CI 1.38-3.31, p-unadj < 0.001), LR (HR = 1.79, 95% CI 1.06-3.02, p-unadj = 0.029), and ER (HR = 2.81, 95% CI 1.78-4.44, p-unadj < 0.001).

CONCLUSIONS

Altered KRAS, RAS/RAF, and RAS/RAF-TP53 associated with earlier local and distant recurrence in resected CRLM patients receiving adjuvant HAI+SYS. Co-altered RAS/RAF-TP53 was a novel predictor of LR warranting investigation of whether genomic cooperativity is associated with this relapsing phenotype. Systemic therapies tailored to high-risk tumor biology are needed to reduce distant relapse after hepatectomy.

Precision surgery for colorectal liver metastases: Current knowledge and future perspectives

Precision surgery for colorectal liver metastases (CRLM) includes optimal selection of both the patient and surgery. Initial attempts of using clinical risk scores to identify patients for whom technically feasible surgery is oncologically futile failed. Since then, patient selection for single-stage hepatectomy followed three distinct approaches, all of which incorporated biomarkers. The BRAF V600E mutation, the G12V KRAS variant, and the triple mutation of RAS, TP53, and SMAD4 appear to be the most promising, but none can be used in isolation to deny surgery in otherwise resectable cases. Combining biomarkers with clinicopathologic factors that predict poor prognosis may be used to select patients for surgery, but external validation and matched analyses with medically treated counterparts are needed. Patient selection for special surgical procedures (two-stage hepatectomy [TSH], Associating Liver Partition and Portal vein Ligation for staged hepatectomy [ALPPS], and liver transplant [LT]) has been recently refined. Specifically, BRAF mutations and right-sided laterality have been proposed as separate contraindications to LT. A similar association of right-sided laterality, particularly when combined with RAS mutations, with very poor outcomes has been observed for ALPPS and has been suggested as a biologic contraindication. Data are scarce for TSH but RAS mutations may portend very poor survival following TSH completion. The selection of the best single-stage hepatectomy (optimal margin and type of resection) based on biomarkers remains debated, although there is some evidence that RAS may play a significant role. Lastly, although there are currently no criteria to select among the three special techniques based on their efficacy or appropriateness in different settings, RAS mutational status may be used to select patients for TSH, while right-sided tumor in conjunction with a RAS mutation may be a contraindication to LT and ALPPS.

Impact of Preoperative CEA Uptrend on Survival Outcomes in Patients with Colorectal Liver Metastasis After Hepatectomy

BACKGROUND

Preoperative carcinoembryonic antigen (CEA) has been reported as a prognostic factor in patients with colorectal liver metastasis (CRLM) after hepatectomy. However, the impact of a preoperative "CEA uptrend" on prognosis after hepatectomy in these patients remains unknown. This study assessed the impact of CEA uptrend on prognosis in patients undergoing hepatectomy for CRLM.

METHODS

Consecutive patients with CRLM who underwent hepatectomy between 2009 and 2018 were retrospectively analyzed. Patients with CRLM for whom CEA was measured both around 1 month before (CEA-1m) and within 3 days (CEA-3d) before hepatectomy were enrolled. A CEA-3d higher than both the upper limit of normal (5 ng/ml) and CEA-1m was defined as a CEA uptrend.

RESULTS

Study participants comprised 212 patients with CRLM. Of these, 88 patients (41.5%) showed a CEA uptrend. CEA uptrend indicated better discriminatory ability (corrected Akaike information criteria, 733.72) and homogeneity (likelihood ratio chi-square value, 18.80) than CEA-3d or CEA-1m. Patients with CEA uptrend showed poorer overall survival than those without CEA uptrend (p < 0.001). After adjusting for known prognostic factors, the prognostic significance of CEA uptrend retained (hazard ratio 2.63, 95% confidence interval 1.63-4.26, p < 0.001). In subgroup analyses, the prognostic significance of CEA uptrend was retained irrespective of the status of RAS mutation or response to preoperative chemotherapy.

CONCLUSIONS

CEA uptrend offers better prediction of survival outcomes than conventional CEA measurements in patients undergoing hepatectomy for CRLM.

Improved Survival over Time After Resection of Colorectal Liver Metastases and Clinical Impact of Multigene Alteration Testing in Patients with Metastatic Colorectal Cancer

BACKGROUND

The past 20 years have seen advances in colorectal cancer management. We sought to determine whether survival in patients undergoing resection of colorectal liver metastases (CLM) has improved in association with three landmark advances: introduction of irinotecan- and/or oxaliplatin-containing regimens, molecular targeted therapy, and multigene alteration testing.

METHODS

Patients undergoing CLM resection during 1998-2014 were identified and grouped by resection year. The influence of alterations in RAS, TP53, and SMAD4 was evaluated and validated in an external cohort including patients with unresectable metastatic colorectal cancer.

RESULTS

Of 1961 patients, 1599 met the inclusion criteria. Irinotecan- and/or oxaliplatin-containing regimens and molecular targeted therapy were used for more than 50% of patients starting in 2001 and starting in 2006, respectively, so patients were grouped as undergoing resection during 1998-2000, 2001-2005, or 2006-2014. Liver resectability indications expanded over time. The 5-year overall survival (OS) rate was significantly better in 2006-2014, vs. 2001-2005 (56.5% vs. 44.1%, P < 0.001). RAS alteration was associated with worse 5-year OS than RAS wild-type (44.8% vs. 63.3%, P < 0.001). However, OS did not differ significantly between patients with RAS alteration and wild-type TP53 and SMAD4 and patients with RAS wild-type in our cohort (P = 0.899) or the external cohort (P = 0.932). Of 312 patients with genetic sequencing data, 178 (57.1%) had clinically actionable alterations.

CONCLUSION

OS after CLM resection has improved with advances in medical therapy and surgical technique. Multigene alteration testing is useful for prognostication and identification of potential therapeutic targets.

Genomic Stratification of Resectable Colorectal Liver Metastasis Patients and Implications for Adjuvant Therapy and Survival

OBJECTIVE

To determine whether genomic risk groups identified by somatic mutation testing of colorectal liver metastasis (CRLM) can be used for "molecularly-guided" selection for adjuvant systemic chemotherapy and hepatic artery infusion of FUDR (SYS+HAI-FUDR).

BACKGROUND

Several genomic biomarkers have been associated with clinical phenotype and survival for patients with resectable CRLM. It is unknown whether prognostication afforded by genomic stratification translates into enhanced patient selection for adjuvant hepatic artery infusion therapy.

METHODS

Consecutive patients with resected CRLM and available mutational characterization via Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets were reviewed from a prospective institutional database. Patients were stratified into three genomic risk groups based on previously defined alterations in SMAD4, EGFR and the RAS/RAF pathway. The association between SYS+HAI-FUDR and overall survival, relative to adjuvant chemotherapy alone (SYS), was evaluated in each genomic risk group by Cox proportional hazard regression and propensity score matched analyses.

RESULTS

A total of 334 patients (SYS+HAI-FUDR 204; SYS 130) were identified; the rates of RAS/RAF alterations and SMAD4 inactivation were 47.4% and 11.7%, respectively. After a median follow-up of 58 months, adjuvant SYS+HAI-FUDR was independently associated with a reduced risk of death (HR 0.50, 95%CI 0.26-0.98, P = 0.045) in the low-risk genomic group, but not in the moderate-risk (HR 1.07, 95%CI 0.5-2.07, P = 0.749) or high-risk (HR 1.62, 95%CI 0.29-9.12, P = 0.537) cohorts. Following propensity score matching, adjuvant SYS+HAI-FUDR remained associated with significant improvements in long-term survival selectively in the low-risk genomic cohort (5-year actuarial survival: 89% vs. 68%, P = 0.019).

CONCLUSIONS

Genomic alterations in RAS/RAF, SMAD4, and EGFR may be useful to guide treatment selection in resectable CRLM patients and warrant external validation and integration in future clinical trial design.

Association of genomic profiles and survival in early onset and screening‐age colorectal cancer patients with liver metastases resected over 15 years

BACKGROUND

This study explores whether genomic profiles of colorectal liver metastasis (CRLM) patients with early onset (EO, < 50 years old) and screening age (SA) primary diagnosis are associated with overall survival (OS).

METHODS

All patients undergoing hepatectomy between 2002 and 2017 were identified and tumor specimens with next-generation sequencing data were cataloged. Gene and signaling-level alterations were checked for association with OS from primary diagnosis accommodating for left-truncated survival.

RESULTS

Of 1822 patients, 333 were sequenced-127 (38%) EO-CRLM and 206 (62%) SA-CRLM patients. More aggressive features presented in EO-CRLM patients-synchronous metastatic presentation (83% vs. 75%, p < 0.001) and primary node-positive disease (71% vs. 61%, p < 0.001). The median OS from primary diagnosis was 11.8 years (95% confidence interval = 7.94-NA). Five-year OS did not differ by age (p = 0.702). On multivariable analysis, altered APC (EO-CRLM: [hazard ratio [HR] = 0.37, p = 0.018] vs. SA-CRLM:[HR = 0.61, p = 0.260]), BRAF (EO-CRLM:[HR = 4.38, p = 0.007] vs. SA-CRLM:[HR = 4.78, p = 0.032]), and RAS-TP53 (EO-CRLM:[HR = 2.82, p = 0.011] vs. SA-CRLM:[HR = 2.35, p = 0.003]) associated with OS.

CONCLUSIONS

Despite bearing more aggressive features, EO-CRLM patients had similar genomic profiles and survival as SA-CRLM patients. Better performance status in younger patients leading to increased treatment tolerance may partly explain this. As screening and treatment strategies from older patients are applied to younger patients, genomic predictors of biology identified historically in older cohorts could apply to EO patients.

SMAD4 is critical in suppression of BRAF-V600E serrated tumorigenesis

BRAF-driven colorectal cancer is among the poorest prognosis subtypes of colon cancer. Previous studies suggest that BRAF-mutant serrated cancers frequently exhibit Microsatellite Instability (MSI) and elevated levels of WNT signaling. The loss of tumor-suppressor Smad4 in oncogenic BRAF-V600E mouse models promotes rapid serrated tumor development and progression, and SMAD4 mutations co-occur in human patient tumors with BRAF-V600E mutations. This study assesses the role of SMAD4 in early-stage serrated tumorigenesis. SMAD4 loss promotes microsatellite stable (MSS) serrated tumors in an oncogenic BRAF-V600E context, providing a model for MSS serrated cancers. Inactivation of Msh2 in these mice accelerated tumor formation, and whole-exome sequencing of both MSS and MSI serrated tumors derived from these mouse models revealed that all serrated tumors developed oncogenic WNT mutations, predominantly in the WNT-effector gene Ctnnb1 (β-catenin). Mouse models mimicking the oncogenic β-catenin mutation show that the combination of three oncogenic mutations (Ctnnb1, Braf, and Smad4) are critical to drive rapid serrated dysplasia formation. Re-analysis of human tumor data reveals BRAF-V600E mutations co-occur with oncogenic mutations in both WNT and SMAD4/TGFβ pathways. These findings identify SMAD4 as a critical factor in early-stage serrated cancers and helps broaden the knowledge of this rare but aggressive subset of colorectal cancer.

Computational quantification of global effects induced by mutations and drugs in signaling networks of colorectal cancer cells

Colorectal cancer (CRC) is one of the most deadly and commonly diagnosed tumors worldwide. Several genes are involved in its development and progression. The most frequent mutations concern APC, KRAS, SMAD4, and TP53 genes, suggesting that CRC relies on the concomitant alteration of the related pathways. However, with classic molecular approaches, it is not easy to simultaneously analyze the interconnections between these pathways. To overcome this limitation, recently these pathways have been included in a huge chemical reaction network (CRN) describing how information sensed from the environment by growth factors is processed by healthy colorectal cells. Starting from this CRN, we propose a computational model which simulates the effects induced by single or multiple concurrent mutations on the global signaling network. The model has been tested in three scenarios. First, we have quantified the changes induced on the concentration of the proteins of the network by a mutation in APC, KRAS, SMAD4, or TP53. Second, we have computed the changes in the concentration of p53 induced by up to two concurrent mutations affecting proteins upstreams in the network. Third, we have considered a mutated cell affected by a gain of function of KRAS, and we have simulated the action of Dabrafenib, showing that the proposed model can be used to determine the most effective amount of drug to be delivered to the cell. In general, the proposed approach displays several advantages, in that it allows to quantify the alteration in the concentration of the proteins resulting from a single or multiple given mutations. Moreover, simulations of the global signaling network of CRC may be used to identify new therapeutic targets, or to disclose unexpected interactions between the involved pathways.

Optimal patient selection for successful two-stage hepatectomy of bilateral colorectal liver metastases

Two-stage hepatectomy (TSH) is one of the specific surgical techniques that can expand the pool of resectable patients with initially unresectable colorectal liver metastases (CRLM). The indication of TSH for CRLM is only bilateral, multinodular disease, which cannot be resected by a single hepatectomy. TSH is nowadays considered an effective treatment for selected patients, with acceptable morbidity/mortality rates and promising long-term outcomes. However, not all eligible patients can benefit from the TSH strategy. One of the most important issues is dropout from the strategy (failure to complete both of the two sequential procedures), because the survival of such patients is drastically worse compared with patients who can complete both stages. Another important issue is the early recurrence rate and subsequent poor survival even after completion of TSH. Thus, the selection of appropriate patients who can really benefit from the TSH strategy is crucial. This review discusses the optimal patient selection for TSH, which should be helpful for the development of treatment strategies for patients with extensive CRLM.

Genetic mutations associated with sensitivity to neoadjuvant chemotherapy in metastatic colon cancer: A case report and review of literature

BACKGROUND

Colorectal liver metastases (CLM) occur in 15%-30% of patients with colorectal cancer (CRC). Advancements in next generation sequencing (NGS) can provide more precise prognoses for cancer patients and help guide clinical treatment. However, the genetic variants that predict high sensitivity to neoadjuvant chemotherapy remain unclear, especially in patients with CLM. The aim of this study was to identify the relevant genetic variants in a single CLM patient and to summarize the current evidence on mutations and single nucleotide polymorphisms (SNPs) that objectively predict sensitivity to neoadjuvant chemotherapy.

CASE SUMMARY

A 76-year-old male patient, who was diagnosed as stage IV colon cancer with liver metastases, was found to have APC/TP53/KRAS mutations. He showed a good therapeutic response to 12 courses of oxaliplatin regimens combined with Bevacizumab. Genetic analysis of the patient identified 5 genes with 7 detected SNPs that may be related to a better response to chemotherapy drugs. In addition, a critical literature review was performed based on a standardized appraisal form after selecting the articles. Ultimately, 21 eligible studies were appraised to assess the association between gene mutations and good prognosis. Mutations in KRAS, TP53, SMAD4, and APC were identified as being associated with a poor response to chemotherapy drugs, whereas mutations of CREBBP and POLD1 were associated with longer overall survival.

CONCLUSION

NGS can identify precise predictors of response to neoadjuvant chemotherapy, leading to improved outcomes for CRC patients.

Prognostic role and clinicopathological features of SMAD4 gene mutation in colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Approximately 5.0-24.2% of colorectal cancers (CRCs) have inactivating mutations in SMAD4, making it one of the frequently mutated genes in CRC. We thus carried out a comprehensive system review and meta-analysis investigating the prognostic significance and clinicopathological features of SMAD4 gene mutation in CRC patients.

METHODS

A detailed literature search was conducted in PubMed, Web of Science and Embase databases to study the relationship between SMAD4 mutations and the demographic and clinicopathological characteristics in CRC patients. The hazard ratios (HRs) with 95% confidence intervals (CI) were used to evaluate the effect of SMAD4 mutations on overall survival (OS) and progression-free survival (PFS)/recurrence-free survival (RFS).

RESULTS

Ten studies enrolling 4394 patients were eligible for inclusion. Data on OS were available from 5 studies and data on PFS/RFS were available from 3 studies. Comparing SMAD4-mutated CRC patients with SMAD4 wild-type CRC patients, the summary HR for OS was 1.46 (95% CI 1.28-1.67, P = 0.001), the summary HR for PFS/RFS was 1.59 (95% CI 1.14-2.22, P = 0.006). In terms of clinicopathology parameters, 9 studies have data that can be extracted, SMAD4 mutations were associated with tumor location (odds ratio [OR] = 1.15, colon/rectum, 95% CI 1.01-1.31, P = 0.042), TNM stage (OR = 1.28, stage IV/I-III, 95% CI 1.03-1.58, P = 0.025), lymph node metastasis (OR = 1.42, N1 + N2/N0, 95% CI 1.20-1.67, P < 0.001), mucinous differentiation (OR = 2.23, 95% CI 1.85-2.70, P < 0.001) and rat sarcoma viral oncogene homolog (RAS) mutation status (OR = 2.13, 95% CI 1.37-3.34, P = 0.001). No connection was found with age, gender, tumor grade, microsatellite instability status and b-viral oncogene homolog B1 mutation status. Besides, publication bias was not observed in any study.

CONCLUSIONS

This meta-analysis suggests that SMAD4 mutation was associated with OS, PFS/RFS, and clinicopathological parameters, including tumor site, disease stage, RAS status, lymph node metastasis and mucinous differentiation. Our meta-analysis indicated that SMAD4 mutations could predict the poor prognosis and aggressive clinicopathological characteristics of CRC. More large-sample cohort studies are needed to confirm this conclusion. Since SMAD4 mutations are closely related to RAS mutations, their relationship warrants further investigation.

Systems-level biomarkers identification and drug repositioning in colorectal cancer

Colorectal cancer (CRC) is the most commonly diagnosed fatal cancer in both women and men worldwide. CRC ranked second in mortality and third in incidence in 2020. It is difficult to diagnose CRC at an early stage as there are no clinical symptoms. Despite advances in molecular biology, only a limited number of biomarkers have been translated into routine clinical practice to predict risk, prognosis and response to treatment. In the last decades, systems biology approaches at the omics level have gained importance. Over the years, several biomarkers for CRC have been discovered in terms of disease diagnosis and prognosis. On the other hand, a few drugs are being developed and used in clinics for the treatment of CRC. However, the development of new drugs is very costly and time-consuming as the research and development takes about 10 years and more than $1 billion. Therefore, drug repositioning (DR) could save time and money by establishing new indications for existing drugs. In this review, we aim to provide an overview of biomarkers for the diagnosis and prognosis of CRC from the systems biology perspective and insights into DR approaches for the prevention or treatment of CRC.

Failure to Cure Patients with Colorectal Liver Metastases: The Impact of the Liver Surgeon

BACKGROUND

Lack of a liver surgeon (LS) may lead to failure to cure in patients with possibly resectable colorectal liver metastases (CRLM). This study aims to quantify the failure-to-cure rate due to noninclusion of an LS.

PATIENTS AND METHODS

All patients who underwent chemotherapy with palliative intent for CRLM at a community oncology network between 2010 and 2018 were identified from a prospectively maintained cancer registry. Two LS blinded to patient management and outcome reviewed pretreatment imaging and assigned each scan a newly developed resectability score. Nominal group technique and independent scores were combined to determine probability of curative-intent resection. Interobserver agreement was calculated using κ testing.

RESULTS

This study included 72 palliative CRLM patients. Demographic factors were: 44 (59%) male, median age 68 years (range 36-94 years), 23 (32%) rectal primary, 24 (33%) receiving oxaliplatin-based chemotherapy. Of the 72 patients with CRLM, 6 had left-sided metastases only. The median number of CRLM was 6 (1-8). Agreement on resectability was achieved in 32 (44%) patients for the entire cohort and 17 (54%) in patients without extrahepatic disease. A lower median number of CRLM was found in the group considered to be resectable by the two LS (2 versus 8; p = 0.001). Substantial agreement was found between liver surgeons in the group of patients without extrahepatic disease (κ = 0.9043).

CONCLUSIONS

Over 44% of patients who were assigned palliative chemotherapy at tumor boards without an LS were considered potentially resectable upon independent LS review.

Prognostic and Predictive Biomarkers in Oligometastatic Disease

Metastatic lesions are largely responsible for cancer-related deaths and are synonymous with a poor prognosis. However, this is not always true for patients with oligometastases whose disease may be amenable to curative-intent local therapies. It has been proposed that an "intermediate state" (oligometastasis) exists in between locoregional and advanced disease states; however, the clinical definition of oligometastasis varies, and there is limited understanding of how tumor biology differs between oligometastases and polymetastases. There is evidence that local therapies can extend survival in patients with oligometastases, yet patient selection for local intervention and/or systemic therapy remains a challenge. Prognostic and predictive biomarkers of oligometastatic disease are strongly needed to identify patient candidates most likely to gain survival benefit from local therapies and to aid in the incorporation of ablative treatments in the context of existing systemic therapies.

Debate: Improvements in Systemic Therapies for Liver Metastases Will Increase the Role of Locoregional Treatments

The benefit of resection of liver metastases depends on primary diseases. Neuroendocrine tumors are associated with favorable prognosis after resection of liver metastases. Gastric cancer has worse tumor biology, and resection of gastric liver metastases should be performed in selected patients. A multidisciplinary approach is well established for colorectal liver metastases (CLMs). Resection remains the only curative treatment of CLM. Chemotherapy and molecular-targeted therapy have improved survival in unresectable metastatic colorectal cancer. Understanding of the following two strategies, conversion therapy and two-stage hepatectomy, are important to make this patient group to be candidates for curative-intent surgery.

Alteration of FBXW7 is Associated with Worse Survival in Patients Undergoing Resection of Colorectal Liver Metastases

BACKGROUND

For patients undergoing resection of colorectal liver metastases (CLMs), the prognostic role of somatic gene alterations is increasingly recognized. F-box/WD repeat-containing protein 7 (FBXW7) is a tumor suppressor gene found in approximately 10% of patients with colorectal cancer. The aim of this study is to assess the association of FBXW7 with overall survival after CLM resection.

METHODS

Patients who underwent initial CLM resection during 2001-2016 and had genetic sequencing data were studied. Risk factors for overall survival (OS) were evaluated with Cox proportional hazards models using backward elimination.

RESULTS

Of 2045 patients who underwent CLM resection during the study period, 476 were included. The majority (90.5%) underwent prehepatectomy chemotherapy. A total of 27 patients (5.7%) had FBXW7 alteration, along with 240 (50.4%) RAS, 337 (70.8%) TP53, 51 (10.7%) SMAD4, and 27 (5.7%) BRAF. Cox proportional hazards model analyses including 5 somatic gene alteration status and 12 clinicopathologic factors revealed FBXW7(hazard ratio [HR] 1.99, P = 0.015), BRAF (HR 2.47, P = 0.023), RAS (HR 2.42, P < 0.001), TP53 (HR 2.00, P < 0.001), and SMAD4 alterations (HR 1.90, P = 0.004) as significantly associated with OS, together with three clinicopathologic factors, prehepatectomy chemotherapy > 6 cycles (HR 1.51, P = 0.021), number of CLM (HR 1.05, P = 0.007), and largest liver metastasis diameter (HR 1.07, P = 0.023). The covariate-adjusted 5-year OS was significantly lower in patients with FBXW7 alteration than in patients with FBXW7 wild-type (40.4% vs.59.4%, P = 0.015).

CONCLUSIONS

FBXW7 alterations are associated with worse survival after CLM resection. The information on multiple somatic gene alterations is imperative for risk stratification and patient selection for CLM resection.

NANOG regulates the proliferation of PCSCs via the TGF-β1/SMAD pathway

Purpose

In prostate cancer, castration resistance is a factor that frequently leads to death in individuals with this disease. Recent studies have suggested that prostate cancer stem cells (PCSCs) are pivotal regulators in the establishment of castration resistance. The nanog homeobox (NANOG) and the transforming growth factor (TGF)-β1/drosophila mothers against decapentaplegic protein (SMAD) signaling pathways are involved in several cancer stem cells but are not involved in PCSCs. The purpose of this study is to investigate the effect of NANOG on the proliferation of PCSCs regulated by the TGF-β1/SMAD signaling pathway.

Methods

In this study, we used flow cytometry to isolate CD44+/CD133+/NANOG+ PCSCs from DU145 prostate cancer cells. Then we used short hairpin RNA to silence NANOG and observed the biological behavior and the TGF-β1/SMAD signal of PCSCs.

Results

NANOG decreased PCSC proliferation, increased apoptosis, and blocked cell cycling at G0/G1. Furthermore, reduction in the TGF-β1, p15, and p-SMAD2 expression was observed.

Conclusion

These findings suggest that NANOG positively regulates the growth of PCSCs through the TGF-β1/SMAD signaling pathway.

Nomogram model characterized by mutant genes and clinical indexes to identify high-risk patients with stage III/IV colorectal cancer

Background

The aim of the present study was to construct a nomogram model of high-risk stage III/IV colorectal cancer (CRC).

Methods

Gene mutation and clinical information of 251 CRC patients were downloaded from The Cancer Genome Atlas (TCGA). Targeted next-generation sequencing was performed on 44 patients to screen shared mutation genes with frequency >5% between TCGA and clinical cohorts. Univariable and multivariable logistic regression analyses were used to analyze the mutant genes and clinical indexes, and a high-risk stage III/IV nomogram model was constructed. The nomogram model was further validated in the clinical cohort.

Results

SMAD family member 4 (SMAD4), zinc finger homeobox 3 (ZFHX3), and phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 2 (PREX2) mutations; pathological location; and preoperative carcinoembryonic antigen (CEA) value were screened out to compose a high-risk III/IV nomogram model. The nomogram had good calibration and discriminative ability, with an area under the curve of 0.76 [95% confidence interval (CI): 0.69-0.84]. Hosmer-Leme show test indicated that the model had good goodness of fit (P=0.83). The decision curve revealed this a nomogram model was feasible in clinical practice. In our clinical cohort, the calibration curve did not show good calibration and discrimination.

Conclusions

We established a nomogram model, including the mutation status of SMAD4, ZFHX3, and PREX2; pathological location; and preoperative CEA value, which showed accuracy in the risk prediction of stage III/IV CRC patients.

Impact and clinical usefulness of genetic data in the surgical management of colorectal cancer liver metastasis: a narrative review

Importance

In patients who undergo surgery for colorectal cancer liver metastases (CRLM), a number of somatic mutations have been associated with worse overall (OS) and recurrence-free survival (RFS). Although useful, an association with prognosis does not necessarily equate to an impact on surgical management.

Objective

The aim of this review was to investigate whether the best-studied somatic mutations impact surgical management of CRLM by informing: (I) post-hepatectomy surveillance; (II) selection of surgical technique; (III) selection of optimal margin width; and (IV) selection of patients for surgery. Lastly, we discuss the refinement of genetic data from overall mutation status to specific variants, as well as lesser studied somatic mutations.

Evidence Review

We conducted a computerized search using PubMed and Google Scholar for reports published so far, using mesh headings and keywords related to genetic data and CRLM.

Findings

Genetic data may impact surgical management of CRLM in three ways. Firstly, KRAS mutations can predict lung recurrences. Secondly, KRAS mutations may help tailor margin width. Thirdly, KRAS mutations may help tailor surgical technique.

Conclusions

Although genetic data may impact post-hepatectomy surveillance, selection of surgical technique and optimal margin width, their use to guide surgical selection remains elusive, as the data cannot support denying surgery to patients according to their somatic mutation profile.

Signal transduction pathway mutations in gastrointestinal (GI) cancers: a systematic review and meta-analysis

The present study was conducted to evaluate the prevalence of the signaling pathways mutation rate in the Gastrointestinal (GI) tract cancers in a systematic review and meta-analysis study. The study was performed based on the PRISMA criteria. Random models by confidence interval (CI: 95%) were used to calculate the pooled estimate of prevalence via Metaprop command. The pooled prevalence indices of signal transduction pathway mutations in gastric cancer, liver cancer, colorectal cancer, and pancreatic cancer were 5% (95% CI: 3-8%), 12% (95% CI: 8-18%), 17% (95% CI: 14-20%), and 20% (95% CI: 5-41%), respectively. Also, the mutation rates for Wnt pathway and MAPK pathway were calculated to be 23% (95% CI, 14-33%) and 20% (95% CI, 17-24%), respectively. Moreover, the most popular genes were APC (in Wnt pathway), KRAS (in MAPK pathway) and PIK3CA (in PI3K pathway) in the colorectal cancer, pancreatic cancer, and gastric cancer while they were beta-catenin and CTNNB1 in liver cancer. The most altered pathway was Wnt pathway followed by the MAPK pathway. In addition, pancreatic cancer was found to be higher under the pressure of mutation compared with others based on pooled prevalence analysis. Finally, APC mutations in colorectal cancer, KRAS in gastric cancer, and pancreatic cancer were mostly associated gene alterations.

The Landmark Series: Randomized Control Trials Examining Perioperative Chemotherapy and Postoperative Adjuvant Chemotherapy for Resectable Colorectal Liver Metastasis

Surgical resection remains the only curative treatment option for patients with colorectal liver metastases (CLM). However, the high recurrence rate after resection has led physicians to investigate multidisciplinary treatments combining surgery and medical therapy. Currently, the evidence to support medical therapy in patients with resectable CLM is limited. For patients with resectable CLM, the National Comprehensive Cancer Network Guidelines (version 2.2020) for colon and rectal cancer recommends either upfront surgery and postoperative adjuvant chemotherapy or preoperative chemotherapy followed by surgery and postoperative adjuvant chemotherapy. This article reviews randomized control trials regarding medical therapy before and after curative resection of CLM, and summarizes the updated long-term report of the New EPOC trial which investigated the addition of cetuximab to perioperative chemotherapy for patients with resectable CLM.

Extended Molecular Profiling Improves Stratification and Prediction of Survival After Resection of Colorectal Liver Metastases

OBJECTIVE

The aim of this study was to assess the effect of cancer-related genes and their mutations analyzed by next-generation sequencing (NGS) on the oncological outcome after resection of colorectal liver metastases (CRLM).

BACKGROUND

Traditional prognostic scores include clinical and pathological parameters of primary tumor and metastases. The modified clinical risk score (m-CS), based on size of metastases, primary tumor nodal status, and RAS mutation status outperformed traditional scores. We hypothesized to further improve the scoring system based on the results of NGS.

METHODS

Cancer tissues of 139 patients with CRLM were used for NGS. The work-up included the analysis of recurrent somatic mutations and copy number changes of 720 genes. Clinical data were extracted from a prospectively collected institutional liver database.

RESULTS

Depending on significance, the following cancer-related genes and their alterations (%) were further investigated: APC (86%), TP53 (78%), KRAS (29%), SMAD4 (15%), PIK3CA (14%), BRAF (8%), ERBB2 (6%), SMAD3 (5%), SMAD2 (4%), and NRAS (4%). The most predictive parameters for poor oncological outcome were alterations in the SMAD family (P = 0.0186) and RAS-RAF pathway (P = 0.032). Refining the m-CS by replacing RAS with RAS-RAF pathway and adding SMAD family resulted in an extended clinical risk score which is highly predictive for oncological outcome (P < 0.0001).

CONCLUSION

In conclusion, mutations of the SMAD family revealed a strong prognostic effect after surgery for CRLM. Integration of alterations of the SMAD family as well as the RAS/RAF pathway resulted in a new, still simple but highly prognostic score.

Novel Alternatively Spliced Variants of Smad4 Expressed in TGF-β-Induced EMT Regulating Proliferation and Migration of A549 Cells

INTRODUCTION

Non-small cell lung cancer (NSCLC) is a worldwide malignance threatening human life. TGF-β/Smad signaling is known to regulate cell proliferation, differentiation, migration and growth. As the only co-Smad playing crucial roles in TGF-β signaling, Smad4 is reported to be frequently mutated or to occur as alternatively spliced in tumor cells. Smad4 was reported to be involved in the TGF-β-induced EMT process. However, whether the alternative splicing occurs in the TGF-β-induced EMT process in NSCLC was not clear.

METHODS

In our current study, we explored the alternative splicing of Smad4 during the process of TGF-β-induced EMT in A549 cells. 10 ng/mL TGF-β was used to induce EMT. Then, nest-PCR and agarose electrophoresis were performed to detect the expression of Smad4 variants and sequencing to get the variant DNA sequences. For recombinant expression of variants of Smad4 in A549 cells, we used lentiviral variants to infect cells. In order to explore the effects of variants on the proliferation and migration of A549 cells, the MTT assay, colony formation assay and wound-healing assay were done. The effects of variants on E-cad and VIM protein expression were explored through Western blot.

RESULTS

There were several novel gene fragments expressed in TGF-β-induced A549 cells, and the sequencing results showed that they were indeed the Smad4 variants that were not reported. For recombinant expression of Smad4 variants in A549 cells, we found that they have significant effects on the proliferation and migration of cells, and also regulated the E-cad and VIM protein expression.

CONCLUSION

Our results indicated that novel Smad4 variants were expressed in TGF-β-induced EMT process. The functional study showed that these novel variants regulate cell proliferation and migration and affect E-cad and VIM protein expression, showing the potential as targets for cancer therapy.

Innovation and Future Perspectives in the Treatment of Colorectal Liver Metastases

Technological advances and investigation into tumor biology have enhanced treatments of patients with colorectal liver metastases (CLM). This article briefly summarizes paradigm shifts in treatments of this disease in the following 4 sections. (1) Small metastases: The treatment of multiple and small CLM has evolved from anatomic resection to parenchyma-sparing hepatectomy. Survival after parenchyma-sparing hepatectomy was similar to or better than anatomic resection. The use of preoperative chemotherapy may cause tumor disappearance. However, the use of fiducial markers may aid in intraoperative localization. Post-resection completion ablation is a new useful treatment concept. It was defined as percutaneous ablation under cross-sectional imaging guidance to eradicate CLM which were intentionally unresected during latest surgery. (2) Bilateral (bilobar) metastases: Two-stage hepatectomy (TSH) is a well-established approach for treating multiple bilateral CLM. The use of hybrid operating room accelerates this sequence because it allows first-stage hepatectomy, portal vein embolization, and computed tomography in one hospitalization. This accelerated TSH sequence enables the second-stage hepatectomy within 4 weeks compared to 8 weeks using conventional TSH sequence. (3) Synchronous lung metastases: For patients with synchronous liver and lung metastases, simultaneous surgical approach is feasible. Specifically, a transdiaphragmatic approach enables simultaneous resection of liver and lung metastases via one abdominal incision. (4) Multiple mutation: Somatic gene mutation testing is increasingly used to evaluate tumor biology. Mutations in TP53, RAS, and SMAD4 affect prognosis through three different signaling pathways of colorectal carcinogenesis. This information can be used to change clinical decision-making regarding surveillance intensity and treatments for liver recurrence.

Targeting RICTOR Sensitizes SMAD4-Negative Colon Cancer to Irinotecan

Deciphering molecular targets to enhance sensitivity to chemotherapy is becoming a priority for effectively treating cancers. Loss of function mutations of SMAD4 in colon cancer are associated with metastatic progression and resistance to 5-fluorouracil (5-FU), the most extensively used drug of almost all chemotherapy combinations used in the treatment of metastatic colon cancer. Here, we report that SMAD4 deficiency also confers resistance to irinotecan, another common chemotherapeutic frequently used alone or in combination with 5-FU against colon cancer. Mechanistically, we find that SMAD4 interacts with and inhibits RICTOR, a component of the mTORC2 complex, resulting in suppression of downstream effector phosphorylation of AKT at Serine 473. In silico meta-analysis of publicly available gene expression datasets derived from tumors indicates that lower levels of SMAD4 or higher levels of RICTOR/AKT, irrespective of the SMAD4 status, correlate with poor survival, suggesting them as strong prognostic biomarkers and targets for therapeutic intervention. Moreover, we find that overexpression of SMAD4 or depletion of RICTOR suppresses AKT signaling and increases sensitivity to irinotecan in SMAD4-deficient colon cancer cells. Consistent with these observations, pharmacologic inhibition of AKT sensitizes SMAD4-negative colon cancer cells to irinotecan in vitro and in vivo. Overall, our study suggests that hyperactivation of the mTORC2 pathway is a therapeutic vulnerability that could be exploited to sensitize SMAD4-negative colon cancer to irinotecan. IMPLICATIONS: Hyperactivation of the mTORC2 pathway in SMAD4-negative colon cancer provides a mechanistic rationale for targeted inhibition of mTORC2 or AKT as a distinctive combinatorial therapeutic opportunity with chemotherapy for colon cancer.

The Role of TGF-β Signaling Regulatory MicroRNAs in the Pathogenesis of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers globally and is associated with a high mortality rate. The transforming growth factor beta (TGF-β) signaling pathway plays an important role in normal intestinal tissue function, but has also been implicated in the development of CRC. MicroRNAs (miRNAs) have also recently emerged as important regulators of cancer development and progression. They act by targeting multiple signaling pathways including the TGF-β signaling pathway. There is growing evidence demonstrating that miRNAs target various components of the TGF-β signaling pathway, including TGF-β1, TGF-β2, regulatory SMADs (SMAD1, 2, 3, 5 and 9), co-mediator SMAD4, inhibitory SMADs (SMAD6 and 7) and the TGF-β receptors, and thereby alter the proliferation and migration of CRC cells. In this review, we summarize the data concerning the interaction between TGF-β signaling pathway and miRNAs with the aim to better understanding the CRC molecular mechanisms and hence better management of this disease.

Transforming Growth Factor-β Signaling Pathway in Colorectal Cancer and Its Tumor Microenvironment

Transforming growth factor-beta (TGF-β) signaling is one of the important cellular pathways that play key roles for tissue maintenance. In particular, it is important in the context of inflammation and tumorigenesis by modulating cell growth, differentiation, apoptosis, and homeostasis. TGF-β receptor type 2 (TGFBR2) mutations affected by a mismatch repair deficiency causes colorectal cancers (CRCs) with microsatellite instability, which is, however, associated with relatively better survival rates. On the other hand, loss of SMAD4, a transcription factor in the TGF-β superfamily signaling, promotes tumor progression. Loss of heterozygosity on chromosome 18 can case SMAD4-deficient CRC, which results in poorer patients' survival. Such bidirectional phenomenon driven by TGF-β signaling insufficiency reflects the complexity of this signaling pathway in CRC. Moreover, recent understanding of CRC at the molecular level (consensus molecular subtype classification) provides deep insight into the important roles of TGF-β signaling in the tumor microenvironment. Here we focus on the TGF-β signaling in CRC and its interaction with the tumor microenvironment. We summarize the molecular mechanisms of CRC tumorigenesis and progression caused by disruption of TGF-β signaling by cancer epithelial cells and host stromal cells.

Transforming Growth Factor-β Signaling Pathway in Colorectal Cancer and Its Tumor Microenvironment

Transforming growth factor-beta (TGF-β) signaling is one of the important cellular pathways that play key roles for tissue maintenance. In particular, it is important in the context of inflammation and tumorigenesis by modulating cell growth, differentiation, apoptosis, and homeostasis. TGF-β receptor type 2 (TGFBR2) mutations affected by a mismatch repair deficiency causes colorectal cancers (CRCs) with microsatellite instability, which is, however, associated with relatively better survival rates. On the other hand, loss of SMAD4, a transcription factor in the TGF-β superfamily signaling, promotes tumor progression. Loss of heterozygosity on chromosome 18 can case SMAD4-deficient CRC, which results in poorer patients’ survival. Such bidirectional phenomenon driven by TGF-β signaling insufficiency reflects the complexity of this signaling pathway in CRC. Moreover, recent understanding of CRC at the molecular level (consensus molecular subtype classification) provides deep insight into the important roles of TGF-β signaling in the tumor microenvironment. Here we focus on the TGF-β signaling in CRC and its interaction with the tumor microenvironment. We summarize the molecular mechanisms of CRC tumorigenesis and progression caused by disruption of TGF-β signaling by cancer epithelial cells and host stromal cells.