Clinical impact of c-MET expression and genetic mutational status in colorectal cancer patients after liver resection

Implications of RAS Mutations on Oncological Outcomes of Surgical Resection and Thermal Ablation Techniques in the Treatment of Colorectal Liver Metastases

Simple Summary

Modern management of colorectal liver metastases (CRLM) requires a thorough knowledge of tumor biology and oncogenes mutations. RAS mutations are of paramount interest for the indication of targeted therapies and is increasingly considered as a negative prognostic factor for patients undergoing surgical resection or ablation for CRLM. Several studies discussed the results of specific technical considerations according to RAS mutational status on the oncological outcomes after surgical resection/ablation for CRLM. We reviewed the available data on the real impact of RAS mutations on the prognosis with special regard to the need of a tailored surgical (ablation) approach according to tumoral biology.

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide and the second leading cause of cancer-related death. More than 50% of patients with CRC will develop liver metastases (CRLM) during their disease. In the era of precision surgery for CRLM, several advances have been made in the multimodal management of this disease. Surgical treatment, combined with a modern chemotherapy regimen and targeted therapies, is the only potential curative treatment. Unfortunately, 70% of patients treated for CRLM experience recurrence. RAS mutations are associated with worse overall and recurrence-free survival. Other mutations such as BRAF, associated RAS /TP53 and APC/PIK3CA mutations are important genetic markers to evaluate tumor biology. Somatic mutations are of paramount interest for tailoring preoperative treatment, defining a surgical resection strategy and the indication for ablation techniques. Herein, the most relevant studies dealing with RAS mutations and the management of CRLM were reviewed. Controversies about the implication of this mutation in surgical and ablative treatments were also discussed.

Reevaluating the prognostic value of RAS mutation status in patients with resected liver metastases from colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Although the value of Rat Sarcoma Oncogene (RAS) mutation status in predicting long-term outcomes in patients with colorectal liver metastases (CRLM) is widely accepted, the magnitude of its impact has recently been challenged by three large cohort studies. The aim of this meta-analysis is to reevaluate the impact of RAS mutations on overall survival (OS) and disease-free survival (DFS) in patients who underwent curative-intent resection of CRLM.

METHODS

A comprehensive literature search was performed for studies reporting outcomes of patients undergoing curative-intent surgery stratified by RAS mutation status. Exclusion criteria were defined a priori. Subgroup analysis was performed to evaluate the effect of publication date, sample size, and KRAS vs any RAS mutation on overall outcomes.

RESULTS

Ten studies incorporating 3115 patients with known RAS status were identified. Pooled results revealed significantly worse OS (Hazard Ratio 1.5, 95% CI 1.31-1.71) and DFS (Hazard Ratio 1.36, 95% CI 1.22-1.52) in RAS-mutated patients. Subgroup analyses revealed that studies including more than 300 patients or published after 2015 reported lower HR than their counterparts.

CONCLUSION

The results of this meta-analysis suggest that the prognostic value of RAS mutation status in patients with CRLM has been previously overestimated.

Impact of BRAF mutations on clinical outcomes following liver surgery for colorectal liver metastases: An updated meta-analysis

BACKGROUND

Data regarding clinical outcomes of patients undergoing hepatic resection for BRAF-mutated colorectal liver metastases (CRLM) are scarce. Most of the studies report an impaired median overall survival (OS) in BRAF-mutated patients, but controversial Results regarding both recurrence-free survival (RFS) and recurrence patterns. The purpose of this updated meta-analysis was to better precise the impact of BRAF mutations on clinical outcomes following liver surgery for CRLM study, especially on recurrence.

METHODS

A systematic literature review was performed to identify articles reporting clinical outcomes including both OS and RFS, recurrence patterns, and clinicopathological details of patients who underwent complete liver resection for CRLM, stratified according to BRAF mutational status.

RESULTS

Thirteen retrospective studies, including 5192 patients, met the inclusion criteria. The analysis revealed that both OS (OR = 1.981; 95% CI = [1.613-2.432]) and RFS (OR = 1.49; 95% CI [1.01-2.21]) were impaired following liver surgery for CRLM in BRAF-mutated patients. Risks of both hepatic (OR = 0.42; 95% CI [0.18-0.98]) and extrahepatic recurrences (OR = 0.53; 95% CI [0.33-0.83] were significantly higher in BRAF-mutated patients. These patients tended to have higher rates of right-sided colon primary tumors, primary positive lymph nodes, and multiple CRLM.

CONCLUSIONS

This meta-analysis confirms that BRAF mutations impair both OS and RFS following liver surgery. Therefore, BRAF mutational status should probably be included in further prognostic scores for the assessment of the expected clinical outcomes following surgery for CRLM.

Tumor Evolution and Therapeutic Choice Seen through a Prism of Circulating Tumor Cell Genomic Instability

Circulating tumor cells (CTCs) provide an accessible tool for investigating tumor heterogeneity and cell populations with metastatic potential. Although an in-depth molecular investigation is limited by the extremely low CTC count in circulation, significant progress has been made recently in single-cell analytical processes. Indeed, CTC monitoring through molecular and functional characterization may provide an understanding of genomic instability (GI) molecular mechanisms, which contribute to tumor evolution and emergence of resistant clones. In this review, we discuss the sources and consequences of GI seen through single-cell analysis of CTCs in different types of tumors. We present a detailed overview of chromosomal instability (CIN) in CTCs assessed by fluorescence in situ hybridization (FISH), and we reveal utility of CTC single-cell sequencing in identifying copy number alterations (CNA) oncogenic drivers. We highlight the role of CIN in CTC-driven metastatic progression and acquired resistance, and we comment on the technical obstacles and challenges encountered during single CTC analysis. We focus on the DNA damage response and depict DNA-repair-related dynamic biomarkers reported to date in CTCs and their role in predicting response to genotoxic treatment. In summary, the suggested relationship between genomic aberrations in CTCs and prognosis strongly supports the potential utility of GI monitoring in CTCs in clinical risk assessment and therapeutic choice.

[Peritoneal recurrence prediction for colon cancer based on immunoexpression]

INTRODUCTION AND OBJECTIVES

Peritoneal relapse as an isolated form of recurrence in colon cancer occurs in 25% of cases during the first two years subsequent to a curative colectomy. Currently, the diagnostic limitations of imaging studies and the absence of predictive scales for peritoneal recurrence warrant "second look" surgery in high-risk patients. The aim of this study is to assess features of some epithelial-mesenchymal transition biomarkers (c-Met, IGF-1R and plexin β1) in order to predict post-surgical peritoneal colonization and develop a mathematical model to predict carcinomatous relapse.

METHODS

A retrospective study of the histopathological samples of 87 patients diagnosed with colon cancer who underwent radical resection was carried out, using immunohistochemical techniques for c-Met, IGF-1R and plexin β1. The patients were divided into two groups; those who had presented peritoneal recurrence and those who only had risk factors for this kind of relapse. Every stained sample was assessed by the rate of stained cells and immunostaining intensity. A possible association between immunohistochemical findings and peritoneal relapse was evaluated. Statistical analysis of the biomarkers with higher prognostic value allowed a risk mathematical formula to be developed based on coefficients, providing a specific value to each biomarker and patient.

RESULTS

c-Met expression in the primary tumour showed a high statistical trend (p: .074) while IGF-1 (p: .022) and plexin β1 (p: .021) revealed a significative association with peritoneal relapse. However, the multivariate analysis selected c-Met y plexin β1 as useful factors for a predictive mathematical model on peritoneal recurrence with a 75.8% sensitivity and 80.5% specificity in patients with a staining more than 50% for both biomarkers.

CONCLUSION

c-Met and plexin B1 overexpression is related to an increased risk of peritoneal relapse in cases of colon cancer where a radical resection is feasible. The encouraging outcomes of the proposed mathematical model may prove useful clinically in the identification of candidates for carcinoprophylaxis.

An Immune-Magnetophoretic Device for the Selective and Precise Enrichment of Circulating Tumor Cells from Whole Blood

Here, we validated the clinical utility of our previously developed microfluidic device, GenoCTC, which is based on bottom magnetophoresis, for the isolation of circulating tumor cells (CTCs) from patient whole blood. GenoCTC allowed 90% purity, 77% separation rate, and 80% recovery of circulating tumor cells at a 90 μL/min flow rate when tested on blood spiked with epithelial cell adhesion molecule (EpCAM)-positive Michigan Cancer Foundation-7 (MCF7) cells. Clinical studies were performed using blood samples from non-small cell lung cancer (NSCLC) patients. Varying numbers (2 to 114) of CTCs were found in each NSCLC patient, and serial assessment of CTCs showed that the CTC count correlated with the clinical progression of the disease. The applicability of GenoCTC to different cell surface biomarkers was also validated in a cholangiocarcinoma patient using anti-EPCAM, anti-vimentin, or anti-tyrosine protein kinase MET (c-MET) antibodies. After EPCAM-, vimentin-, or c-MET-positive cells were isolated, CTCs were identified and enumerated by immunocytochemistry using anti-cytokeratin 18 (CK18) and anti-CD45 antibodies. Furthermore, we checked the protein expression of PDL1 and c-MET in CTCs. A study in a cholangiocarcinoma patient showed that the number of CTCs varied depending on the biomarker used, indicating the importance of using multiple biomarkers for CTC isolation and enumeration.

The Integrated Analyses of Driver Genes Identify Key Biomarkers in Thyroid Cancer

AIM

Thyroid cancer is the most common endocrine cancer, the incidence rate has continuously increased worldwide. However, there are still lack of effective molecular biomarkers for the diagnosis and treatment of the disease. The study was conducted to identify driver genes that may serve as potential biomarkers for the disease.

METHODS

The computational tools oncodriveCLUST, oncodriveFM, icages and drgap were used to detect driver genes in thyroid cancer using somatic mutations from The Cancer Genome Atlas database. Integrated analyses were performed on the driver genes using multiomics data from the TCGA database.

RESULTS

A set of 291 driver genes were identified in thyroid cancer. BRAF, NRAS, HRAS, OTUD4, EIF1AX were the top 5 frequently mutated genes in thyroid cancer. The weighted gene co-expression network analysis identified 4 coexpression modules. The modules 1-3 were significantly associated with patients' tumor size, residual tumor, cancer stage, distant metastasis and multifocality. SEC24B, MET and ITGAL were the hub genes in the modules 1-3 respectively. Hierarchical clustering analysis of the 20 driver genes with the most frequent copy number changes revealed 3 clusters of PRAD patients. Cluster 1 tumors exhibited significantly older age, tumor size, cancer stages, and poorer prognosis than cluster 2 and 3 tumors. 16 genes were significantly associated with number of lymph nodes, tumor size and pathologic stage, such as IL7 R, IRS1, PTK2B, MAP3K3 and FGFR2.

CONCLUSIONS

The set of cancer genes and subgroups of patients shed insight on the tumorigenesis of thyroid cancer and open up avenues for developing prognostic biomarkers and driver gene-targeted therapies in thyroid cancer.

An overview on clinical, pathological and molecular features of lung metastases from colorectal cancer

Introduction: Lung metastases occur in 10-20% of patients with colorectal cancer (CRC). Most of them are treated with palliative intent and have a poor prognosis. Pulmonary metastasectomy may be a curative option for carefully selected patients with 5-year survival rates ranging from 25% to 60%. However, up to 70% of patients develop recurrence after pulmonary metastasectomy. Therefore, the identification of prognostic factors is essential in CRC patients with resectable lung metastases. Areas covered: This review aims at summarizing the actual body of knowledge available on lung metastases from CRC focusing on their clinical, pathological and molecular profile. Moreover, we provide an update on experts' attitudes towards lung metastasectomy, adjuvant or perioperative chemotherapy. Expert opinion: Traditional clinical prognosticators such as the total number of pulmonary metastases, carcinoembryonic antigen (CEA) serum levels before surgery, and presence of lymph node metastases cannot provide reliable criteria to predict survival after lung metastasectomy. Indeed, research efforts have been directed in recent years toward studying the biological characteristics of lung lesions to better define prognosis and response to treatment, and ultimately shed new light on their proper local and systemic management.

The potential therapeutic and prognostic impacts of the c-MET/HGF signaling pathway in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and a common cause of cancer-related mortality globally. In spite of the improvements in the early diagnosis of CRC, approximately one-third of patients develop metastasis and then have a very poor survival rate. The mesenchymal-epithelial transition factor (c-MET) is a tyrosine kinase cell surface receptor activated by hepatocyte growth factor (HGF). Activation of c-MET/HGF signaling pathway regulates a variety of biological processes including cell motility, cell proliferation, angiogenesis, the epithelial-to-mesenchymal transition, and the development and progression of cancer cells. Recent studies have suggested that the c-MET/HGF signaling pathway is involved in the carcinogenesis of CRC. In this review, we summarize the main findings of recent studies investigating the role of c-MET/HGF signaling pathway in CRC and the potential of the c-MET/HGF signaling pathways in the diagnosis and treatment of CRC. © 2019 IUBMB Life, 2019.

Long Noncoding RNA GAPLINC Promotes Cells Migration and Invasion in Colorectal Cancer Cell by Regulating miR-34a/c-MET Signal Pathway

BACKGROUND

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) has been detected in colorectal cancer (CRC) cells and reportedly performs many functions related to tumor proliferation and metastasis. Aim The present study aimed to comprehensively explore the biological functions of GAPLINC and their underlying mechanism in CRC cell.

METHODS

The human cancer LncRNA PCR array was used to detect the differentially expressed long noncoding RNAs in human CRC samples. Real-time PCR, dual-luciferase assay, RNA pull-down assay, Transwell assay, and western blot analysis were performed to explore the molecular mechanism underlying GAPLINC functions related to migration and invasion of a human CRC cell line (HCT116).

RESULTS

Compared to the non-cancerous tissues, GAPLINC expression was obviously increased in CRC tissues. In HCT116, silencing of GAPLINC weakened cell migration and invasion, while overexpression of GAPLINC significantly promoted cell migration and invasion. Through dual-luciferase, RNA pull-down, and Transwell assays, we verified that miR-34a was the downstream molecule of GAPLINC and that miR-34a negatively regulated the migration and invasion of HCT116 cell. Furthermore, we found that GAPLINC positively regulated the miR-34a target gene c-MET in CRC tissues.

CONCLUSIONS

Our findings revealed that GAPLINC was up-regulated in CRC tissues and was involved in the migration and invasion of CRC cells by regulating miR-34a/c-MET signaling pathway.

Upregulation of c-mesenchymal epithelial transition expression and RAS mutations are associated with late lung metastasis and poor prognosis in colorectal carcinoma

The present study aimed to investigate whether c-mesenchymal epithelial transition factor (C-MET) overexpression combined with RAS (including KRAS, NRAS and HRAS) or BRAF mutations were associated with late distant metastases and the prognosis of patients with colorectal cancer (CRC). A total of 374 patients with stage III CRC were classified into 4 groups based on RAS/BRAF and C-MET status for comprehensive analysis. Mutations in RAS/BRAF were determined using Sanger sequencing and C-MET expression was examined using immunohistochemistry. The associations between RAS/BRAF mutations in combination with C-MET overexpression and clinicopathological variables including survival were evaluated. In addition, their predictive value for late distant metastases were statistically analyzed via logistic regression and receiver operating characteristic analysis. Among 374 patients, mutations in KRAS, NRAS, HRAS, BRAF and C-MET overexpression were observed in 43.9, 2.4, 0.3, 5.9 and 71.9% of cases, respectively. Considering RAS/BRAF mutations and C-MET overexpression, vascular invasion (P=0.001), high carcino-embryonic antigen level (P=0.031) and late distant metastases (P<0.001) were more likely to occur in patients of group 4. Furthermore, survival analyses revealed RAS/BRAF mutations may have a more powerful impact on survival than C-MET overexpression, although they were both predictive factors for adverse prognosis. Further logistic regression suggested that RAS/BRAF mutations and C-MET overexpression may predict late distant metastases. In conclusion, RAS/BRAF mutations and C-MET overexpression may serve as predictive indicators for metastatic behavior and poor prognosis of CRC.

MicroRNA-181b-5p, ETS1, and the c-Met pathway exacerbate the prognosis of pancreatic ductal adenocarcinoma after radiation therapy

Preoperative chemoradiation therapy (CRT) for pancreatic ductal adenocarcinoma (PDAC) has emerged as a reasonable strategy that shows good prognostic impact. However, after preoperative CRT, resected specimens show remnant tumor cells, which indicate that some tumor cells had acquired or were selected for resistance to CRT. Recently, two oncological mechanisms, the EMT and the presence of CSCs, were reported to be associated with resistance in various cancers. Previous reports showed that HGF could induce EMT in PDAC cells; moreover, the HGF receptor, c‐Met, was identified as a dominant pancreatic CSC marker. However, the clinical significance of c‐Met expression remains unclear. So, we hypothesized that remnant PDAC tissue after CRT might harbor cells with high c‐Met expression, and these cells may exacerbate patients’ prognosis. In the immunohistochemical analysis, we showed that preoperative CRT was significantly associated with high c‐Met expression; moreover, high c‐Met expression was a significant marker of a dismal prognosis. Next, we investigated mechanisms of c‐Met upregulation in PDAC cells. We established GEM‐resistant and radioresistant PDAC cells to analyze the transcriptome involved in c‐Met expression. The microarray data for the established radiation‐resistant PDAC cells indicated miR‐181b‐5p downregulation, which targets ETS1, one of the transcription factors for c‐Met, and it was shown that radiation exposure induced c‐Met expression through ETS1 increase by the suppression of miR‐181b‐5p. These results suggested that targeting these mechanisms may promote the development of a novel multidisciplinary treatment strategy for improving preoperative CRT efficiency.

From bench to bedside: Clinical implications of KRAS status in patients with colorectal liver metastasis

INTRODUCTION

While the role of KRAS in the molecular genetics of colorectal cancer has been studied extensively, its prognostic impact in colorectal liver metastases (CRLM) has only recently been examined. This review aimed to summarize currently reported findings on the clinical implications of KRAS mutant (mut-KRAS) status for patients with CRLM.

MATERIALS AND METHODS

The Pubmed database was searched for relevant articles published from 01/01/2010 to 02/01/2016. Overall survival (OS) and recurrence free survival (RFS) as well as patterns of recurrence were the primary endpoints, but consideration was given to secondary outcomes when the respective findings were of clinical interest.

RESULTS

Out of the 266 studies screened, 15 were included in our review. Fourteen studies were retrospective cohorts while one was a systematic review/meta-analysis. Among the 14 retrospective studies, 12 reported OS with 9 detecting a negative association with mut-KRAS status. Similarly, 11 out of 14 retrospective cohorts reported RFS with 6 detecting a negative association with mut-KRAS status. Five studies examined patterns of recurrence, with 4 detecting increased extrahepatic recurrence in the mut-KRAS group. One study examined the different effects of codon-specific KRAS mutations on prognosis.

CONCLUSION

mut-KRAS status predisposes to worse RFS and OS in patients with CRLM, possibly as a result of aggressive tumor biology. Early unresectable extrahepatic recurrence is more frequent in this patient group and may underlie the unfavorable prognosis. Future research should focus on characterizing the distinct effects of codon-specific KRAS mutations as well their interplay with other less common genetic mutations.

Understanding and Targeting MET Signaling in Solid Tumors - Are We There Yet?

The MET signaling pathway plays an important role in normal physiology and its deregulation has proved critical for development of numerous solid tumors. Different technologies have been used to investigate the genomic and proteomic status of MET in cancer patients and its association with disease prognosis. Moreover, with the development of targeted therapeutic drugs, there is an urgent need to identify potential biomarkers for selection of patients who are more likely to derive benefit from these agents. Unfortunately, the variety of technical platforms and analysis criteria for diagnosis has brought confusion to the field and a lack of agreement in the evaluation of MET status as a prognostic or predictive marker for targeted therapy agents. We review the molecular mechanisms involved in the deregulation of the MET signaling pathway in solid tumors, the different technologies used for diagnosis, and the main factors that affect the outcome, emphasizing the urge for completing analytical and clinical validation of these tests. We also review the current clinical studies with MET targeted agents, which mostly focus on lung cancer.

c-MET expression in colorectal adenomas and primary carcinomas with its corresponding metastases

BACKGROUND

c-MET plays an important role in tumor proliferation, invasion and metastasis. In this study we examined the expression of c-MET in colorectal adenomas, primary adenocarcinomas and their corresponding lymph node, peritoneal and liver metastases. We correlated our findings with clinicopathological features.

METHODS

Twenty three cases of colorectal adenoma and 102 cases of primary colorectal carcinoma and their corresponding metastases (44 lymph nodes, 21 peritoneal deposits and 16 liver metastases) were studied to evaluate c-MET expression by immunohistochemistry. For comparison, 12 sections of adjacent healthy colorectal mucosa were examined.

RESULTS

Statistically significant differences were present among normal tissues, colorectal adenomas and primary colorectal carcinomas (P=0.011). Normal tissues showed a negative or weak reaction in 66.67% and 33.33% of cases respectively. Expression of c-MET was positive in 47.8% of adenomas. A significant positive association was identified between c-MET high expression and degree of dysplasia (P=0.024). c-MET was highly expressed in 66.7% of primary colorectal carcinoma. Significant positive correlations were detected between c-MET expression and TNM stage (P=0.036), lymph node metastasis (LNM), peritoneal deposits and liver metastasis (P=0.038, P=0.094 and P=0.045, respectively). c-MET expression in metastatic tissues was significantly higher than that of the primary tumor.

CONCLUSIONS

c-MET expression is gradually up-regulated in the development and progression of colorectal cancer (CRC) from normal epithelium to adenoma to colorectal carcinoma to metastases.

Clinical impact of c-MET expression and mutational status in patients with colorectal cancer lung metastases

OBJECTIVES

The c-MET tyrosine kinase is known to play a key role in tumour promotion in a variety of cancers. The prognostic significance of c-MET pathway alterations has previously been described in primary colorectal cancer (CRC). However, data on the expression and genetic mutational status of c-MET in CRC pulmonary metastases (PM) are lacking. We aimed to assess the clinical implications of alterations in the c-MET pathway in patients undergoing pulmonary metastasectomy.

METHODS

From April 2009 to November 2013, all patients with complete CRC lung metastasectomy were included in this study and prospectively followed up. Tissue samples of 51 PM and 33 paired primary CRCs were stained immunohistochemically for c-MET and phosphorylated signal transducer and activator of transcription 3 (pSTAT3). Genetic alterations of MET were detected using an exome panel on a next generation sequencing (NGS) platform. Serum hepatocyte growth factor (HGF) levels were measured in a patient subset (n = 10) before and after metastasectomy.

RESULTS

c-MET expression was significantly higher at the invasive front of metastases compared with central tumour areas (P = 0.020) and was associated with nuclear pSTAT3 expression (P = 0.042). pSTAT3 but not c-MET overexpression in PM was associated with time to tumour recurrence after metastasectomy (P = 0.036). Expression levels of neither c-MET nor pSTAT3 had an impact on time to lung-specific recurrence. However, patients with c-MET or pSTAT3 overexpression in PM had a significantly worse overall survival after metastasectomy (P = 0.023 and 0.008, respectively). Mutations in the MET gene were identified in 20 patients of our cohort by NGS, which failed to be of prognostic relevance. Serum HGF did not significantly differ between patients with PM and healthy controls.

CONCLUSIONS

To the best of our knowledge, this is the first structured evaluation of the c-MET axis in the context of pulmonary metastasectomy for CRC. Our results suggest that overexpression of c-MET/pSTAT3 is associated with an impaired prognosis following complete resection. Moreover, this work suggests that the value of c-MET tyrosine kinase inhibitors in the treatment of patients with CRC lung metastases should be assessed in clinical trials.

Meta-analysis of KRAS mutations and survival after resection of colorectal liver metastases

BACKGROUND

In patients with advanced colorectal cancer, KRAS mutation status predicts response to treatment with monoclonal antibody targeting the epithelial growth factor receptor (EGFR). Recent reports have provided evidence that KRAS mutation status has prognostic value in patients with resectable colorectal liver metastases (CLM) irrespective of treatment with chemotherapy or anti-EGFR therapy. A meta-analysis was undertaken to clarify the impact of KRAS mutation on outcomes in patients with resectable CLM.

METHODS

PubMed, Embase and Cochrane Library databases were searched systematically to identify full-text articles reporting KRAS-stratified overall (OS) or recurrence-free (RFS) survival after resection of CLM. Hazard ratios (HRs) and 95 per cent c.i. from multivariable analyses were pooled in meta-analyses, and a random-effects model was used to calculate weight and overall results.

RESULTS

The search returned 355 articles, of which 14, including 1809 patients, met the inclusion criteria. Eight studies reported OS after resection of CLM in 1181 patients. The mutation rate was 27.6 per cent, and KRAS mutation was negatively associated with OS (HR 2.24, 95 per cent c.i. 1.76 to 2.85). Seven studies reported RFS after resection of CLM in 906 patients. The mutation rate was 28.0 per cent, and KRAS mutation was negatively associated with RFS (HR 1.89, 1.54 to 2.32).

CONCLUSION

KRAS mutation status is a prognostic factor in patients undergoing resection of colorectal liver metastases and should be considered in the evaluation of patients having liver resection.

Colorectal Cancer Classification and Cell Heterogeneity: A Systems Oncology Approach

Colorectal cancer is a heterogeneous disease that manifests through diverse clinical scenarios. During many years, our knowledge about the variability of colorectal tumors was limited to the histopathological analysis from which generic classifications associated with different clinical expectations are derived. However, currently we are beginning to understand that under the intense pathological and clinical variability of these tumors there underlies strong genetic and biological heterogeneity. Thus, with the increasing available information of inter-tumor and intra-tumor heterogeneity, the classical pathological approach is being displaced in favor of novel molecular classifications. In the present article, we summarize the most relevant proposals of molecular classifications obtained from the analysis of colorectal tumors using powerful high throughput techniques and devices. We also discuss the role that cancer systems biology may play in the integration and interpretation of the high amount of data generated and the challenges to be addressed in the future development of precision oncology. In addition, we review the current state of implementation of these novel tools in the pathological laboratory and in clinical practice.

Prognostic value of c-Met in colorectal cancer: A meta-analysis

AIM: To assess the prognostic value of c-Met status in colorectal cancer.

METHODS: We conducted a search in PubMed, Web of Science, and the Cochrane Library covering all published papers up to July 2014. Only studies assessing survival in colorectal cancer by c-Met status were included. This meta-analysis was performed by using STATA11.0.

RESULTS: Ultimately, 11 studies were included in this analysis. Meta-analysis of the hazard ratios (HR) indicated that patients with high c-Met expression have a significantly poorer overall survival (OR) (HR = 1.33, 95%CI: 1.06-1.59) and progression-free survival (PFS) (HR = 1.47, 95%CI: 1.03-1.91). Subgroup analysis showed a significant association between high c-Met expression and poorer overall survival in the hazard ratio reported (HR = 1.41, 95%CI: 1.08-1.74).

CONCLUSION: The present meta-analysis indicated that high c-Met expression was associated with poor prognosis in patients with colorectal cancer.