Microsatellite Instability in Russian Patients with Colorectal Cancer

The aim of this study was to determine the characteristics of Russian patients with microsatellite instability (MSI) tumors. MSI in the tumor was determined in 514 patients with colon cancer using PCR and subsequent fragment analysis for five markers (NR21, NR24, BAT25, BAT26, and NR27). In the presence of microsatellite instability, the mismatch repair (MMR) system genes were examined using the NGS and MLPA methods to establish the diagnosis of Lynch syndrome. The overall frequency of MSI tumors was 15%: at stage I—19% (9/48), at stage II—21% (44/213), at stage III—16% (26/160), and at stage IV—2% (2/93). Patients with MSI tumors differed in the age of diagnosis, tumor localization, time of cancer recurrence, and stage of the disease. The overall and disease-free survival of patients whose tumors had MSI status was higher than that of patients with microsatellite-stable status, p = 0.04 and p = 0.02, respectively. Analysis of overall and disease-free survival of patients with Lynch syndrome and patients with sporadic colon cancer, but with MSI status, did not reveal significant differences, p = 0.52 and p = 0.24, respectively. The age of patients with Lynch syndrome was significantly younger than that of patients with sporadic colon cancer whose tumors had MSI status (p < 0.001).     

Periostin Expression and Its Prognostic Value for Colorectal Cancer

Integrin is important for cell growth, invasion and metastasis, which are frequently observed in malignant tumors. The periostin (POSTN) gene encodes the ligand for integrin, one of the key focal adhesion proteins contributing to the formation of a structural link between the extracellular matrix and integrins. High expression levels of the POSTN gene are correlated with numerous human malignancies. We examined POSTN protein in colorectal cancer specimens from 115 patients by strictly following up using immunohistochemistry. Cytoplasm immunohistochemical staining showed POSTN protein expression in colorectal cancers. The positive expression rate of POSTN protein (59.13%, 68/115) in colorectal cancers was significantly higher than that in adjacent normal colon mucosa (0.47%, 11/109). POSTN over-expression in colorectal cancers was positively correlated with tumor size, differentiation, lymph node metastasis, serosal invasion, clinical stage and five-year survival rates. Further analysis showed that patients with advanced stage colorectal cancer and high POSTN expression levels had lower survival rates than those with early stage colorectal cancer and low POSTN expression levels. Overall, our results showed that POSTN played an important role in the progression of colorectal cancers.     

Upregulation of TLRs and IL-6 as a Marker in Human Colorectal Cancer

Toll-like receptors (TLRs) not only form an important part of the innate immune system but also serve to activate the adaptive immune system in response to cancer. Real-time PCR; immunohistochemical stain and Western blotting analyses were performed to clarify molecular alterations in colorectal cancer (CRC) patients. We identified Toll-like receptor 1 (TLR1), TLR2, TLR4 and TLR8 gene expression levels and downstream gene, i.e., interleukin-6 (IL-6), IL-8, interferon-α (IFN-α) and myeloid differentiation primary-response protein-88 (MyD88), expression levels in CRC patients and in cancer cell lines. CRC tissues have higher TLR1, TLR2, TLR4, TLR8, IL-6 and IL-8 gene expression levels than do the normal colon mucosa (p < 0.05). TLR2 expression varied in different cell types (mucosa and lymphocytes). There was no difference in the MyD88 and IFN-α gene expression levels between cancerous and normal colon mucosa. CRC patients had higher levels of IL-6 (p = 0.002) and IL-8 (p = 0.038) expression than healthy volunteers did; and higher IL-6 and IL-8 expression was also found to signify a higher risk of recurrence. CL075 (3M002) treatments can reduce the production of IL-8 in different cancer cell lines. The signaling pathway of TLRs in cancer tissue is different from that in normal cells; and is MyD88-independent. Higher expression levels of TLR1, TLR2, TLR 4 and TLR 8 mRNA were related to upregulation inflammatory cytokines IL-6 and IL-8 gene expression in tissue and to the upregulation of IL-6 in blood. The concentration of IL-6 in serum can be used as an indicator of the possibility of CRC recurrence. Treatment with 3M002 can reduce IL-6 production in vitro and may prevent CRC recurrence. Our findings provide evidence that TLR1, TLR2, TLR4 and TLR8 gene expression induce downstream IL-6 and IL-8 gene expression; detection of these expression levels can serve as a CRC marker.     

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases MUTYH and hOGG1 in Colorectal Cancer Patients

Oxidative stress, oxidative DNA damage and resulting mutations play a role in colorectal carcinogenesis. Impaired equilibrium between DNA damage formation, antioxidant status, and DNA repair capacity is responsible for the accumulation of genetic mutations and genomic instability. The lesion-specific DNA glycosylases, e.g., hOGG1 and MUTYH, initiate the repair of oxidative DNA damage. Hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome) with germline mutations causing a loss-of-function in base excision repair glycosylases, serve as straight forward evidence on the role of oxidative DNA damage and its repair. Altered or inhibited function of above glycosylases result in an accumulation of oxidative DNA damage and contribute to the adenoma-adenocarcinoma transition. Oxidative DNA damage, unless repaired, often gives rise G:C > T:A mutations in tumor suppressor genes and proto-oncogenes with subsequent occurrence of chromosomal copy-neutral loss of heterozygosity. For instance, G>T transversions in position c.34 of a KRAS gene serves as a pre-screening tool for MUTYH-associated polyposis diagnosis. Since sporadic colorectal cancer represents more complex and heterogenous disease, the situation is more complicated. In the present study we focused on the roles of base excision repair glycosylases (hOGG1, MUTYH) in colorectal cancer patients by investigating tumor and adjacent mucosa tissues. Although we found downregulation of both glycosylases and significantly lower expression of hOGG1 in tumor tissues, accompanied with G>T mutations in KRAS gene, oxidative DNA damage and its repair cannot solely explain the onset of sporadic colorectal cancer. In this respect, other factors (especially microenvironment) per se or in combination with oxidative DNA damage warrant further attention. Base excision repair characteristics determined in colorectal cancer tissues and their association with disease prognosis have been discussed as well.     

Inflammation-Related Biomarkers for the Prediction of Prognosis in Colorectal Cancer Patients

Colorectal cancer (CRC) is the leading cause of cancer deaths around the world. It is necessary to identify patients with poor prognosis or with high risk for recurrence so that we can selectively perform intensive treatments such as preoperative and/or postoperative chemotherapy and extended surgery. The clinical usefulness of inflammation-related prognostic biomarkers available from routine blood examination has been reported in many types of cancer, e.g., neutrophil–lymphocyte ratio (NLR), lymphocyte–C-reactive protein ratio (LCR), platelet–lymphocyte ratio (PLR), lymphocyte–monocyte ratio (LMR), and so on. Moreover, some scoring systems based on circulating blood cell counts and albumin concentration have been also reported to predict cancer patients’ prognosis, such as the Glasgow prognostic score (GPS), systemic inflammation score (SIS), and prognostic nutritional index (PNI). The optimal biomarker and optimal cutoff value of the markers can be different depending on the cancer type. In this review, we summarize the prognostic impact of each inflammation-related marker in CRC.     

HOXB9 Overexpression Promotes Colorectal Cancer Progression and Is Associated with Worse Survival in Liver Resection Patients for Colorectal Liver Metastases

As is known, HOXB9 is an important factor affecting disease progression and overall survival (OS) in cancer. However, its role in colorectal cancer (CRC) remains unclear. We aimed to explore the role of HOXB9 in CRC progression and its association with OS in colorectal liver metastases (CRLM). We analysed differential HOXB9 expression in CRC using the Tissue Cancer Genome Atlas database (TCGA). We modulated HOXB9 expression in vitro to assess its impact on cell proliferation and epithelial-mesenchymal transition (EMT). Lastly, we explored the association of HOXB9 protein expression with OS, using an institutional patient cohort (n = 110) who underwent liver resection for CRLM. Furthermore, HOXB9 was upregulated in TCGA-CRC (n = 644) vs. normal tissue (n = 51) and its expression levels were elevated in KRAS mutations (p < 0.0001). In vitro, HOXB9 overexpression increased cell proliferation (p < 0.001) and upregulated the mRNA expression of EMT markers (VIM, CDH2, ZEB1, ZEB2, SNAI1 and SNAI2) while downregulated CDH1, (p < 0.05 for all comparisons). Conversely, HOXB9 silencing disrupted cell growth (p < 0.0001). High HOXB9 expression (HR = 3.82, 95% CI: 1.59–9.2, p = 0.003) was independently associated with worse OS in CRLM-HOXB9-expressing patients after liver resection. In conclusion, HOXB9 may be associated with worse OS in CRLM and may promote CRC progression, whereas HOXB9 silencing may inhibit CRC growth.     

Galanin Receptors (GalR1, GalR2, and GalR3) Expression in Colorectal Cancer Tissue and Correlations to the Overall Survival and Poor Prognosis of CRC Patients

Colorectal cancer (CRC) is the second most common cause of cancer in women and the third in men. The postoperative pathomorphological evaluation of patients with CRC is extremely important for future therapeutic decisions. Although our previous studies demonstrated high galanin (GAL) presence within tumor tissue and an elevated concentration of GAL in the serum of CRC patients, to date, there is a lack of data regarding GAL receptor (GalR) protein expression in CRC cells. Therefore, the aim of this study was to evaluate the presence of all three types of GalRs (GalR1, GalR2 and GalR3) within epithelial cells of the human colon and CRC tissue with the use of the immunohistochemical method and to correlate the results with the clinical-pathological data. We found stronger immunoreactivity of GalR1 and GalR3 in CRC cells compared to epithelial cells of the unchanged mucosa of the large intestine. No differences in the GalR2 protein immunoreactivity between the studied tissues were noted. We also found that the increased immunoexpression of the GalR3 in CRC tissue correlated with the better prognosis and longer survival (p < 0.0079) of CRC patients (n = 55). The obtained results suggest that GalR3 may play the role of a prognostic factor for CRC patients. Based on data from the TCGA-COAD project deposited in the GDC Data Portal, we also found that GalR mRNA in cancer samples and the adjacent normal tissue did not correlate with immunoexpression of the GalR proteins in CRC cells and epithelial cells of the unchanged mucosa.     

HER-2 Expression in Brain Metastases from Colorectal Cancer and Corresponding Primary Tumors: A Case Cohort Series

Brain metastases (BM) from colorectal cancer (CRC) are a rare but increasing event. Surgical resection of oligometastatic disease, including BM, may produce a survival benefit in selected patients. Previous studies described the HER-2 expression patterns in CRC patients, but its prognostic role still remains controversial. Information on the HER-2 expression in BM from CRC is currently lacking. Among the over 500 patients treated at our Department of Neurosurgery in the last 13 years (1999–2012), we identified a cohort of 50 consecutive CRC patients resected for BM. Clinical data were retrospectively reviewed using electronic hospital charts and surgical notes. Formalin-fixed, paraffin-embedded tissue samples were retrieved and histologically reviewed. HER-2 status was assessed on 4-μm sections by HerceptTest™, and scored by two pathologists according to gastric cancer HER-2 status guidelines. In score 2+ cases HER-2 gene copy number was analyzed by FISH, performed using the PathVysion HER-2 DNA Probe Kit. Median age at time of BM resection was 65 years (35–82); most patients were males (60%) with a good performance status. The majority of the BM were single (74%) and sited in the supratentorial area (64%); 2–4 lesions were diagnosed in 9 patients (18%), and >4 in 3 patients (6%). The rate of HER-2 positivity (defined as IHC score 3+ or IHC score 2+ and FISH gene amplification) was 8.1% for the primary CRC tumors and 12% for their corresponding BM. The concordance rate between primary tumors and matched BM was 89%. Median overall survival after neurosurgery was 6.5 months for HER-2 IHC score 0 vs. 4.6 months for HER-2 IHC score 1+/2+/3+; the difference was statistically significant (p = 0.01, Log-rank test). HER-2 positivity of our case cohort was low but comparable to literature. Concordance rate of HER-2 expression between BM and corresponding primary tumors is high and similar to those reported for breast and gastric cancers. Our data suggest a potential negative prognostic value of HER-2 expression in brain lesions from CRC.     

Lessons to Learn for Adequate Targeted Therapy Development in Metastatic Colorectal Cancer Patients

Insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase that regulates cell growth and proliferation. Upregulation of the IGF1R pathway constitutes a common paradigm shared with other receptor tyrosine kinases such as EGFR, HER2, and MET in different cancer types, including colon cancer. The main IGF1R signaling pathways are PI3K-AKT and MAPK-MEK. However, different processes, such as post-translational modification (SUMOylation), epithelial-to-mesenchymal transition (EMT), and microenvironment complexity, can also contribute to intrinsic and acquired resistance. Here, we discuss new strategies for adequate drug development in metastatic colorectal cancer patients.     

Brain Metastases from Colorectal Cancer: Microenvironment and Molecular Mechanisms

Colorectal cancer is one of the most common digestive tract malignancies in the world. Owing to the newer and more effective systemic therapies, the life of colorectal cancer patients can be remarkably prolonged, and the incidence of brain metastases is increasing. However, little is known about the underlying mechanisms of brain metastasis from colorectal cancer. Here we review the tumor microenvironment and metastasis associated molecules in brain metastases from colorectal cancer. A further understanding of these mechanisms will help us to propose better strategies for colorectal cancer patients with brain metastasis and improve their life quality.     

Novel Diagnostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is still a leading cause of cancer death worldwide. Less than half of cases are diagnosed when the cancer is locally advanced. CRC is a heterogenous disease associated with a number of genetic or somatic mutations. Diagnostic markers are used for risk stratification and early detection, which might prolong overall survival. Nowadays, the widespread use of semi-invasive endoscopic methods and feacal blood tests characterised by suboptimal accuracy of diagnostic results has led to the detection of cases at later stages. New molecular noninvasive tests based on the detection of CRC alterations seem to be more sensitive and specific then the current methods. Therefore, research aiming at identifying molecular markers, such as DNA, RNA and proteins, would improve survival rates and contribute to the development of personalized medicine. The identification of “ideal” diagnostic biomarkers, having high sensitivity and specificity, being safe, cheap and easy to measure, remains a challenge. The purpose of this review is to discuss recent advances in novel diagnostic biomarkers for tumor tissue, blood and stool samples in CRC patients.     

The Effectiveness of Glutathione Redox Status as a Possible Tumor Marker in Colorectal Cancer

The role of oxidative stress (OS) in cancer is a matter of great interest due to the implication of reactive oxygen species (ROS) and their oxidation products in the initiation of tumorigenesis, its progression, and metastatic dissemination. Great efforts have been made to identify the mechanisms of ROS-induced carcinogenesis; however, the validation of OS byproducts as potential tumor markers (TMs) remains to be established. This interventional study included a total of 80 colorectal cancer (CRC) patients and 60 controls. By measuring reduced glutathione (GSH), its oxidized form (GSSG), and the glutathione redox state in terms of the GSSG/GSH ratio in the serum of CRC patients, we identified significant changes as compared to healthy subjects. These findings are compatible with the effectiveness of glutathione as a TM. The thiol redox state showed a significant increase towards oxidation in the CRC group and correlated significantly with both the tumor state and the clinical evolution. The sensitivity and specificity of serum glutathione levels are far above those of the classical TMs CEA and CA19.9. We conclude that the GSSG/GSH ratio is a simple assay which could be validated as a novel clinical TM for the diagnosis and monitoring of CRC.     

Leptin Signaling in Obesity and Colorectal Cancer

Obesity and colorectal cancer (CRC) are among the leading diseases causing deaths in the world, showing a complex multifactorial pathology. Obesity is considered a risk factor in CRC development through inflammation, metabolic, and signaling processes. Leptin is one of the most important adipokines related to obesity and an important proinflammatory marker, mainly expressed in adipose tissue, with many genetic variation profiles, many related influencing factors, and various functions that have been ascribed but not yet fully understood and elucidated, the most important ones being related to energy metabolism, as well as endocrine and immune systems. Aberrant signaling and genetic variations of leptin are correlated with obesity and CRC, with the genetic causality showing both inherited and acquired events, in addition to lifestyle and environmental risk factors; these might also be related to specific pathogenic pathways at different time points. Moreover, mutation gain is a crucial factor enabling the genetic process of CRC. Currently, the inconsistent and insufficient data related to leptin’s relationship with obesity and CRC indicate the necessity of further related studies. This review summarizes the current knowledge on leptin genetics and its potential relationship with the main pathogenic pathways of obesity and CRC, in an attempt to understand the molecular mechanisms of these associations, in the context of inconsistent and contradictory data. The understanding of these mechanisms linking obesity and CRC could help to develop novel therapeutic targets and prevention strategies, resulting in a better prognosis and management of these diseases.     

The Role of microRNAs in Development of Colitis-Associated Colorectal Cancer

Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18–25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes’ expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment.     

The Immunotherapy for Colorectal Cancer,Lung Cancer and Pancreatic Cancer

Immunotherapy is a novel anti-cancer method which employs a different mechanism to conventional treatment. It has become a significant strategy because it provides a better or an alternative option for cancer patients. Recently, immunotherapy has been increasingly approved for the treatment of cancer; however, it has various limitations; for instance, it is only suitable for specific patients, the response rate is still low in most cases, etc. Colorectal cancer, lung cancer and pancreatic cancer are known as three major death-causing cancers in most countries. In this review, we discuss immunotherapeutic treatment for these three cancers, and consider the option, prospects and limitations of immunotherapy. The development of immunotherapy should focus on the discovery of biomarkers to screen suitable patients, new targets on tumors, neoadjuvant immunotherapy and the combination of immunotherapy with conventional therapeutic methods. We can expect that immunotherapy potentially will develop as one of the best therapies for patients with advanced cancer or poor responses to traditional methods.     

Cell Surface Markers in Colorectal Cancer Prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.     

Fatty Acid Unsaturation Degree of Plasma Exosomes in Colorectal Cancer Patients: A Promising Biomarker

Even though colorectal cancer (CRC) is one of the most preventable cancers, it is currently one of the deadliest. Worryingly, incidence in people <50 years has increased unexpectedly, and for unknown causes, despite the successful implementation of screening programs in the population aged >50 years. Thus, there is a need to improve early diagnosis detection strategies by identifying more precise biomarkers. In this scenario, the analysis of exosomes is given considerable attention. Previously, we demonstrated the exosome lipidome was able to classify CRC cell lines according to their malignancy. Herein, we investigated the use of the lipidome of plasma extracellular vesicles as a potential source of non-invasive biomarkers for CRC. A plasma exosome-enriched fraction was analyzed from patients undergoing colonoscopic procedure. Patients were divided into a healthy group and four pathological groups (patients with hyperplastic polyps; adenomatous polyps; invasive neoplasia (CRC patients); or hereditary non-polyposis CRC. The results showed a shift from 34:1- to 38:4-containing species in the pathological groups. We demonstrate that the ratio Σ34:1-containing species/Σ38:4-containing species has the potential to discriminate between healthy and pathological patients. Altogether, the results reinforce the utility of plasma exosome lipid fingerprint to provide new non-invasive biomarkers in a clinical context.     

Defective Generation and Maturation of Dendritic Cells from Monocytes in Colorectal Cancer Patients during the Course of Disease

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths in Western countries. Today, the role of the host’s immune system in controlling the progression and spread of solid tumors is broadly established. Tumor immunosurveillance escape mechanisms, such as those involving dendritic cells (DCs), the most important antigen-presenting cells, are likewise recognized processes involved in cancer. The present study evaluates the ability of CRC patients to generate DCs in vitro from circulating monocytes at both pre- and post-operative timepoints; the results are correlated with the stage of disease to shed light on the systemic immune statuses of CRC patients. Our data showed that patients’ DCs had lower co-stimulatory molecule expression and were less able to present antigens to allogeneic T cells compared to healthy controls’ (HC) DCs. Furthermore altered cytokine secretion, such as increased IL-10 and reduced IL-12 and TNF-α, was observed. At the post-operative timepoints we observed a recovery of the patients’ ability to generate immature DCs, compared to HCs, but the maturational capacity remained affected. Our study conclusively highlights the persistently impaired in vitro generation of fully mature and functional DCs, which appears to be more altered during advanced stages. This work sheds light on a dendritic cell-based tumor immune escape mechanism that could be useful for the development of more effective immunotherapeutic strategies.     

Personalised Medicine for Colorectal Cancer Using Mechanism-Based Machine Learning Models

Gaining insight into the mechanisms of signal transduction networks (STNs) by using critical features from patient-specific mathematical models can improve patient stratification and help to identify potential drug targets. To achieve this, these models should focus on the critical STNs for each cancer, include prognostic genes and proteins, and correctly predict patient-specific differences in STN activity. Focussing on colorectal cancer and the WNT STN, we used mechanism-based machine learning models to identify genes and proteins with significant associations to event-free patient survival and predictive power for explaining patient-specific differences of STN activity. First, we identified the WNT pathway as the most significant pathway associated with event-free survival. Second, we built linear-regression models that incorporated both genes and proteins from established mechanistic models in the literature and novel genes with significant associations to event-free patient survival. Data from The Cancer Genome Atlas and Clinical Proteomic Tumour Analysis Consortium were used, and patient-specific STN activity scores were computed using PROGENy. Three linear regression models were built, based on; (1) the gene-set of a state-of-the-art mechanistic model in the literature, (2) novel genes identified, and (3) novel proteins identified. The novel genes and proteins were genes and proteins of the extant WNT pathway whose expression was significantly associated with event-free survival. The results show that the predictive power of a model that incorporated novel event-free associated genes is better compared to a model focussing on the genes of a current state-of-the-art mechanistic model. Several significant genes that should be integrated into future mechanistic models of the WNT pathway are DVL3, FZD5, RAC1, ROCK2, GSK3B, CTB2, CBT1, and PRKCA. Thus, the study demonstrates that using mechanistic information in combination with machine learning can identify novel features (genes and proteins) that are important for explaining the STN heterogeneity between patients and their association to clinical outcomes.